WorldWideScience

Sample records for ring hera measurements

  1. Electron ring design for HERA, including spin-matching

    International Nuclear Information System (INIS)

    Skuja, A.; Hand, L.; Steffen, K.; Barber, D.

    1984-01-01

    A. Skuja has been working in collaboration with Professor Lou Hand in obtaining an optics for the electron ring at HERA that satisfies the usual constraints of an electron storage ring, but in addition allows longitudinal polarization in the interaction region without depolarizing the electron beam completely. This collaboration effort grew out of their work on a possible electron ring at Fermilab. When this project was degraded in priority at Fermilab, they turned their attention to the HERA project at DESY. The HERA project will have an electron ring of about 30 GeV e - (or e + ) incident on 800 GeV protons. Recently it has been decided that the collisions should be head on (0 0 crossing), although all previous designs had a crossing angle of the 2 beams of 20 mrad. Professors Hand and Skuja implemented a complete program in the last year and a half that could fit the usual Turis parameters as well as the so called 12 spin-matching conditions of Chao and Yukoya for all possible machine elements including solenoids. The program has the possibility of fully coupling vertical and horizontal motion using the usual eigenvalue method

  2. Cryogenic system for the HERA magnet measurement facility

    International Nuclear Information System (INIS)

    Barton, H.R. Jr.; Clausen, M.; Kebler, G.

    1986-01-01

    This paper describes the design for a helium, cryogenic distribution system that allows independent operation and testing of superconducting magnets of the HERA project before they are installed in the 6-km ring tunnel. The 820-GeV proton storage ring of HERA will contain approximately 650 magnets having superconducting coils which are clamped by aluminum/stainless-steel collars and surrounded by a yoke of magnetic iron at liquid helium temperature. When the magnets arive at DESY from the manufacture, each magnet will be individually tested at helium operating conditions in the magnet measurement facility to insure the quality of the magnetic characteristics and the cryogenic performance. The capabilities of the cryogenic system and the schedule for magnet testing are discussed

  3. Test of internal halo targets in the HERA proton ring

    International Nuclear Information System (INIS)

    Hast, C.; Hofmann, W.; Khan, S.; Knoepfle, K.T.; Reber, M.; Rieling, J.; Spahn, M.; Spengler, J.; Lohse, T.; Pugatch, V.

    1994-07-01

    Internal wire targets in the halo of stored proton beams provide a line source of proton-nucleus interactions for highest-rate fixed target experiments. We have studied such internal halo targets at the 820 GeV proton ring of the HERA ep collider. The tests showed that most of the protons in the beam halo - which would otherwise hit the collimators - can be brought to interaction in a relatively thin target wire at distances of 7 to 8 beam widths from the center of the beam. At less than 10% of the HERA total design current, and less than 20% of the current per bunch, interaction rates up to 8 MHz were observed, corresponding to more than 2 interactions per bunch crossing. The halo targets were used in parallel to the HERA luminosity operation; no significant disturbances of the HERA ep experiments, of the machine stability or beam quality were observed. We present data on the steady-state and transient behaviour of interaction rates and discuss the interpretation in terms of a simple beam dynamics model. Issues of short-, medium- and long-term rate fluctuations and of rate stabilization by feedback are addressed. (orig.)

  4. Test of internal halo targets in the HERA proton ring

    International Nuclear Information System (INIS)

    Hast, C.; Hofmann, W.; Khan, S.; Knoepfle, K.T.; Reber, M.; Rieling, J.; Spahn, M.; Spengler, J.; Lohse, T.; Pugatch, V.

    1995-01-01

    Internal wire targets in the halo of stored proton beams provide a line source of proton-nucleus interactions for highest-rate fixed target experiments. We have studied such internal halo targets at the 820 GeV proton ring of the HERA ep collider. The tests showed that most of the protons in the beam halo - which would otherwise hit the collimators - can be brought to interaction in a relatively thin target wire at distances of 7 to 8 beam widths from the center of the beam. At less than 10% of the HERA total design current, and less than 20% of the current per bunch, interaction rates up to 8 MHz were observed, corresponding to more than 2 interactions per bunch crossing. The halo targets were used in parallel to the HERA luminosity operation; no significant disturbances of the HERA ep experiments, of the machine stability or beam quality were observed. We present data on the steady-state and transient behaviour of interaction rates and discuss the interpretation in terms of a simple beam dynamics model. Issues of short-, medium- and long-term rate fluctuations and of rate stabilization by feedback are addressed. ((orig.))

  5. HERA the new frontier

    International Nuclear Information System (INIS)

    Feltesse, J.

    1992-01-01

    The large storage ring Hardon-Electron-Ring Accelerator (HERA) has been completed at DESY. The first collisions for physics studies are scheduled for spring 1992. HERA is the first electron-proton storage ring ever built. Electrons and protons of nominal energies, E e = 30 GeV and E p = 820 GeV will collide at center of mass energy 314 GeV. The beam energies can be varied, while maintaining luminosity, over the range E e = 10-35 GeV and E p = 300-1000 GeV. The theoretical motivations and questions raised by quantum chromodynamics in this new demain are approached at a phenomenological level. The measurement of x the momentum fraction carried by the struck quark inside the proton, and Q 2 , are reviewed over the accessible domain at HERA energies from the scattered electron and hadron flow laboratory variables. The various experimental methods to extract the gluon distribution are described. Other physics opportunities to test the standard model are briefly given. Finally, a few examples of processes not expected by the standard model, but within the reach of HERA energetics, are outlined

  6. Preservation of beam loss induced quenches, beam lifetime and beam loss measurements with the HERA-p beam-loss-monitor system

    International Nuclear Information System (INIS)

    Wittenburg, K.

    1994-01-01

    The beam-loss-monitors (BLMs) in the HERA-Proton-ring (HERAp) must fulfil the following requirements: They have to measure losses sensitive and fast enough to prevent the superconducting magnets from beam loss induced quenching; the dynamic range of the monitors must exceed several decades in order to measure losses during beam lifetimes of hundreds of hours as well as the much stronger losses that may quench superconducting magnets; they have to be insensitive to the synchrotron radiation of the adjacent electron-ring (HERAe); and their radiation hardness must allow a monitor-lifetime of a few years of HERA operation. These requirements are well satisfied by the HERAp-BLM-System. (orig.)

  7. New storage ring at DESY's. HERA's realm in the shades. Pt. 2

    International Nuclear Information System (INIS)

    Habermann, A.

    1987-01-01

    The venture into the smallest dimensions of the microcosm requires gigantic machines. The HERA storage ring, due for completion in 1989, shall help the scientists at DESY in their venture into new realms of high-energy physics. (orig.) [de

  8. An iterative method for the analysis of Cherenkov rings in the HERA-B RICH

    International Nuclear Information System (INIS)

    Staric, M.; Krizan, P.

    1999-01-01

    A new method is presented for the analysis of data recorded with a Ring Imaging Cherenkov (RICH) counter. The method, an iterative sorting of hits on the photon detector, is particularly useful for events where rings overlap considerably. The algorithm was tested on simulated data for the HERA-B experiment

  9. S.C. correction coils and magnets for the HERA proton ring

    International Nuclear Information System (INIS)

    Daum, C.; Geerinck, J.; Schmueser, P.

    1986-05-01

    The quadrupole and sextupole correction coils of the HERA proton ring are mounted on the cold beam pipe inside the main dipole magnets. Superferric dipole magnets for orbit correction are located adjacent to the main quadrupole magnets in a common cryostat which also contains the beam monitor. The design, manufacture and performance of both types of correction elements are described. (orig.)

  10. Development of the HERA-Β-target-control system and study of target operation at the HERA storage ring

    International Nuclear Information System (INIS)

    Issever, S.

    2001-03-01

    The HERA-B experiment investigates the physics of heavy quarks, which are produced in pN reactions of the 920 GeV protons of HERA with the HERA-B internal fixed target. It consists out of eight wires, which surround the proton beam from four sides and is a high luminosity particle source. As being the closest mechanical device to the proton beam, it has to be operated very carefully and thus needs a secure and automatic control system, which additionally must be efficient and reliable to guarantee an efficient HERA-B data taking. The implementation of the target control system and its performance as well as dedicated studies of target-beam physics are presented. These include the measurement of the aperture limitation, usual target operational position, target efficiency, target independent proton loss in HERA and the scrape velocity of the target. The source of rate fluctuations is investigated in detail; among many dependencies environmental noise has a major impact on the rate fluctuations. Further studies include the analysis of beam position fluctuations and its correlation to the rate fluctuations; the rate changes about a factor of 2, if the beam is changing its position by 10 μm. This rate sensitivity is also verified directly by means of step function measurements. Furthermore the step function measurements can be used to study target-beam dynamics on time scales as short as a second. Experiments to reduce the rate sensitivity - the so called beam tail shaping measurements - are presented as well. During target operation a current, which is proportional to the interaction rate, is measured and used to determine the rate of each single wire. It is shown, that the source of this current is delta electron production. Finally the multiwire performance of the target control system is presented. (orig.)

  11. Structure functions and low Q2 physics at HERA

    International Nuclear Information System (INIS)

    Roeck, A. de; Klein, M.

    1991-12-01

    Important new insights into the hadron structure are expected from the data which will be collected at the electron-proton storage ring HERA at DESY, Hamburg. In this paper the physics opportunities for cross section related measurements at HERA are reviewed. Emphasis is put on the derivation of the proton structure functions, on the QCD effects expected in the newly accessible low χ region and on almost real photoproduction physics. (orig.)

  12. The HERMES polarized hydrogen and deuterium gas target in the HERA electron storage ring

    International Nuclear Information System (INIS)

    Airapetian, A.; Akopov, N.; Akopov, Z.

    2005-01-01

    The HERMES hydrogen and deuterium nuclear-polarized gas targets have been in use since 1996 with the polarized electron beam of HERA at DESY to study the spin structure of the nucleon. Polarized atoms from a Stern-Gerlach Atomic Beam Source are injected into a storage cell internal to the HERA electron ring. Atoms diffusing from the center of the storage cell into a side tube are analyzed to determine the atomic fraction and the atomic polarizations. The atoms have a nuclear polarization, the axis of which is defined by an external magnetic holding field. The holding field was longitudinal during 1996-2000, and was changed to transverse in 2001. The design of the target is described, the method for analyzing the target polarization is outlined, and the performance of the target in the various running periods is presented

  13. The HERMES polarized hydrogen and deuterium gas target in the HERA electron storage ring

    International Nuclear Information System (INIS)

    Airapetian, A.; Akopov, N.; Akopov, Z.; Peking University, Beijing

    2004-08-01

    The HERMES hydrogen and deuterium nuclear-polarized gas targets have been in use since 1996 with the polarized electron beam of HERA at DESY to study the spin structure of the nucleon. Polarized atoms from a Stern-Gerlach Atomic Beam Source are injected into a storage cell internal to the HERA electron ring. Atoms diffusing from the center of the storage cell into a side tube are analyzed to determine the atomic fraction and the atomic polarizations. The atoms have a nuclear polarization, the axis of which is defined by an external magnetic holding field. The holding field was longitudinal during 1996-2000, and was changed to transverse in 2001. The design of the target is described, the method for analyzing the target polarization is outlined, and the performance of the target in the various running periods is presented. (orig.)

  14. Superconducting cavities for HERA

    International Nuclear Information System (INIS)

    Dwersteg, B.; Ebeling, W.; Moeller, W.D.; Renken, D.; Proch, D.; Sekutowicz, J.; Susta, J.; Tong, D.

    1988-01-01

    Superconducting 500 MHz cavities are developed to demonstrate the feasibility of upgrading the e-beam energy of the HERA storage ring. A prototype module with 2 x 4 cell resonators and appropriate fundamental and higher mode couplers has been designed at DESY and is being built by industrial firms. The design and results of RF and cryogenic measurements are reported in detail. 17 references, 10 figures, 2 tables

  15. DESY: All superconducting magnets in place for HERA

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    On 19 September the last of the 646 superconducting magnets for the proton ring of the HERA electron-proton collider was placed in position in the 6.4 kilometre tunnel at the German DESY Laboratory in Hamburg. The different sections of the cryogenic ring are being cooled down, and all magnet connections should be complete by 8 November for the official ceremony marking the end of HERA construction and installation

  16. Measurements of Jets and αs at HERA

    International Nuclear Information System (INIS)

    Bunyatyan, Armen

    2009-01-01

    Jet production in electron-proton scattering at HERA provides an important testing ground for Quantum Chromodynamics and allows improved determinations of the strong coupling, α s . A review of recent measurements of jet cross sections in photoproduction and neutral current DIS (NC DIS) at HERA is presented, and the latest determinations of α s are shown.

  17. DESY: HERA commissioning

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The commissioning of the world's first electron-proton collider - the 6.3 kilometre HERA ring at the DESY Laboratory in Hamburg - last year was the result of more than a decade of careful planning, design and construction

  18. HERA physics

    International Nuclear Information System (INIS)

    Wolf, G.

    1994-02-01

    The HERA project (HERA 1981, Wiik 1982, 1992, Voss 1988) was approved in 1984. Operation of HERA for physics started in 1992 with the two large general purpose detectors H1 (1986) and ZEUS (1986) taking data. A third experiment, HERMES (1990), which has been approved recently for the measurement of the nucleon spin structure by colliding the polarized electron beam with a gas jet of polarized nucleons, is under construction. A fourth experiment, HERA-B (HERA-B 1992), which aims at measuring CP violation in the b anti b system by scattering beam protons on a fixed target, is under discussion. These lectures are intended for the newcomer to the field and focus on results obtained by H1 and ZEUS. (orig.)

  19. High spin polarisation at the HERA electron storage ring

    International Nuclear Information System (INIS)

    Barber, D.P.; Boege, M.; Bremer, H.D.; Brinkmann, R.; Gianfelice-Wendt, E.; Kaiser, R.; Klanner, R.; Lewin, H.C.; Meyners, N.; Ripken, G.; Zapfe, K.; Boettcher, H.; Dueren, M.; Steffens, E.; Lomperski, M.; Rith, K.; Westphal, D.; Zetsche, F.

    1993-04-01

    This paper describes the progress made in 1992 towards increasing the vertical electron beam polarization at HERA. Utilizing harmonic spin-orbit corrections and beam tuning, the vertical polarization has been increased from 15% to nearly 60% at a beam energy of 26.7 GeV. The long-term reproducibility of the polarization is excellent. Measurements of the build-up time and the energy dependence of the polarization are also described. (orig.)

  20. An analysis of the long-term stability of the particle dynamics in hadron storage rings

    International Nuclear Information System (INIS)

    Bruening, O.S.

    1994-05-01

    This thesis extends the stability analysis of the particle motion in a storage ring and estimates the diffusion rates well inside the dynamic aperture. The calculation of the drift and diffusion coefficients focuses on an application to the proton storage ring in HERA, where the proton beam lifetime drops considerably after the proton and electron beams are brought to collision. The analysis shows that the combined effect of slow and fast modulation frequencies leads to an increased emittance growth in the storage ring. HERA the slow frequency components are caused by ground motion in the HERA tunnel and the fast frequency components by ripples in the power supplies. The thesis provides upper limits for the modultion depths of a fast tune modulation which result in tolerable growth rates for the proton emittance. The analytically calculated drift coefficients agree numerical simulations for the particle dynamics. A comparison of the calculated drift coefficients with those measured in the HERA proton storage ring shows that the analyzed mechanism can lead to growth rates of the same order of magnitude as the ones measured during the luminosity operation in the HERA storage ring. Analytical estimates for the proton growth rates predict a high sensitivity to the particle diffusion on the frequency components of the fast fast tune modulation. This prediction was confirmed by a subsequent modulation experiment in the proton storage ring of HERA, where an external tune modulation with fast frequency components led to a drastic increase in the growth rates

  1. Physics at HERA

    International Nuclear Information System (INIS)

    Wolf, G.

    1985-06-01

    The author reviews the physics, which can be studied by the HERA storage ring. Especially he considers deep inelastic electron scattering from protons, the production of new particles like heavy quarks, additional vector bosons, Higgs bosons, excited quarks and leptons, leptoquarks, and supersymmetric particles, as well as the detection of new processes. (HSI)

  2. Optimization of the transverse electron polarization of HERA at 26.7 GeV

    International Nuclear Information System (INIS)

    Grosshauser, C.

    1994-08-01

    The methods applied for the optimization of the transverse electron polarization were presented in the following and the measurements performed by this extensively described. By these measurements could be shown that in pure electron-beam operation a degree of polarization of P similar 67% can be reached. A adjustment of the electron storage ring determined by this allows also under luminosity conditions without further optimization an only fewly deminuished transverse electron polarization. The measured polarization values where thereby over several hours stable and could also after months be reproduced. An interference of the polarization by electron-proton collisions could not be stated in the framework of the measurements. In an optimization of the electron polarization performed during the luminosity operation polarization values of P similar 67% could be reached. Thereby could be stated that an optimization of the electron polarization can be perforemd parallel to the data taking of the experiments H1 and ZEUS without fearing of extensive interferences for the measurement conditions of the experiments. By means of the resonance depolarization, which was at HERA for the first time successfully applied, the electron energy was determined with a maximal error of similar 3 MeV and an energy calibration of the HERA electron storage ring performed. At this energy calibration a mean deviation of the nominal energy from the energy values, which were determined by means of the depolarization measurements, of similar 35 MeV resulted. By the different studies on the transverse electron polarization and by the production of the worldwide first longitudinally polarized electron beam in a storage ring, in which a degree of polarization of P long ≥55% was observed, could be shown that a data taking of the experiment HERMES can be pursued parallel to the experiments H1 and ZEUS in the electron storage ring HERA

  3. DESY: HERA looks back, and forward

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    The HERA electron-proton collider at the DESY Laboratory in Hamburg has completed a successful second year of operation, with achievements and progress so far promising well for 1994. The collider was commissioned in October 1991 and during the winter 1991-92 shutdown the two major experiments (H1 and ZEUS) were installed in the ring. HERA commissioning resumed in April 1992 and by the end of June the experiments had their first meals of electron-proton collisions. 1992 peak luminosity with nine colliding bunches in each ring was roughly 2x10 29 cm -2 s -1 . By the end of that year a total integrated luminosity of 58 nb -1 had been delivered to each of the experiments, with 25 nb -1 recorded

  4. DESY: HERA moves on

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    First encouraging physics results from the new HERA electron-proton collider at DESY, Hamburg, reported last year (October, page 6), came from the machine operating at less than 1% of its design luminosity (a measure of the proton-electron collision rate). In the short time available to the machine specialists, several substantial improvements have been made, and the HERA operating crew is confident of substantially improved performance when operations get underway again in April. The 820 GeV superconducting proton storage ring is behaving as expected. The number of stored bunches has been increased from 10 to 160 (the maximum is 210). Without any optimization the current reached 13 mA, nearly 10% of the design level, and the beam lifetime is generally longer than 50 hours. The protons can thus be kept in the machine over several successive electron fills. The long proton beam lifetime attests to the excellent vacuum in the beam pipe (much of it at liquid helium temperature) and to minimal beam losses. In the electron ring, 100 bunches were stored in the most recent tests (initially only ten bunches could be handled) and the multibunch feedback system brought into action. The 23 mA current represented about 40% of the design figure. The energy is usually kept around 27 GeV, but could be increased to 30 GeV if required

  5. Calibration of the mirror system in the HERA-B RICH

    International Nuclear Information System (INIS)

    Staric, Marko; Krizan, Peter

    2008-01-01

    The mirror system of the HERA-B ring imaging Cherenkov (RICH) counter consists of two spherical and two planar mirrors, composed of altogether 116 mirror segments. Analysis of displacements of the Cherenkov ring center relative to the charged particle track, for given spherical-planar segment pairs, leads to accurate information regarding the orientation of individual mirror segments. The method for mirror calibration is described and the effect of applying the required corrections on the Cherenkov angle resolution of the HERA-B RICH is discussed

  6. Measurement of the proton structure function at HERA using the ZEUS detector

    International Nuclear Information System (INIS)

    Bentvelsen, S.C.M.

    1994-01-01

    In May 1992, the HERA collider produced its first collisions between electrons and protons, at a center-of-mass energy of 295 GeV. The ZEUS experiment, one of the two main detectors at HERA, recorded 24.7 nb -1 of data in the fall of 1992. The analysis of this data, leading to an initial determination of the proton structure function F 2 in the kinematic domain accessible at HERA, is the main subject of this thesis. In the first chapter, a short review of inclusive deep-inelastic-scattering (DIS) is given. We also briefly present the status of pre-HERA fixed target DIS experiments. The second chapter offers a description of the HERA accelerator complex, the luminosity measurement and the ZEUS detector. Chapter three treats the reconstruction of x ans Q 2 from measured quantities. Chapter four describes the selection of the DIS data sample. Chapter five investigates various distributions of the DIS sample in comparison with the Monte Carlo predictions. The Monte Carlo distributions are given for extreme choices of the proton structure function parametrizations. In chapter six, we determine from the x and Q 2 distributions the proton structure function F 2 . A correction is made for the effect of the longitudinal structure function F L . The measured F 2 as a function of x is rising rapidly towards low values of x. (orig.)

  7. Dynamic aperture and transverse proton diffusion in HERA

    International Nuclear Information System (INIS)

    Zimmermann, F.

    1994-04-01

    The dynamic aperture caused by persistent-current nonlinear field errors is an important concern in the design of superconducting hadron storage rings. The HERA proton ring is the second superconducting accelerator in operation. In this lecture note, its measured dynamic aperture is compared with that inferred from comprehensive trackig studies. To understand the difference between prediction and measurement, a semi-analytical method is developed for evaluating transverse diffusion rates due to various processes, such as modulational diffusion or sweeping diffusion this analysis makes use of parameters for high-order resonances in the transverse phase space, which are obtained by normal-form algorithms using differential-algebra software. This semi-analytical results are consistent wit the measurements, and suggest that the actual dynamic aperture is caused by an interplay of tune modulation and nonlinear magnetic fields

  8. Measurement of elastic ω photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1996-08-01

    The reaction γp→ωp (ω→π + π - π 0 and π 0 →γγ) has been studied in ep interactions using the ZEUS detector at photon-proton centre-of-mass energies between 70 and 90 GeV and vertical stroke t vertical stroke 2 , where t is the squared four momentum transferred at the proton vertex. The elastic ω photoproduction cross section has been measured to be σ γp→ωp =1.21±0.12±0.23 μb. The differential cross section dσ γp→ωp /d vertical stroke t vertical stroke has an exponential shape e -b vertical stroke t vertical stroke with a slope b=10.0±1.2±1.3 GeV -2 . The angular distributions of the decay pions are consistent with s-channel helicity conservation. When compared to low energy data, the features of ω photoproduction as measured at HERA energies are in agreement with those of a soft diffractive process. Previous measurements of the ρ 0 and φ photoproduction cross sections at HERA show a similar behaviour. (orig.)

  9. Spin structure function measurements with polarized protons and electrons at HERA

    International Nuclear Information System (INIS)

    Ball, R.D.; Deshpande, A.; Forte, S.; Hughes, V.W.; Lichtenstadt, J.; Ridolfi, G.

    1995-01-01

    Useful insights into the spin structure functions of the nucleon can be achieved by measurements of spin-dependent asymmetries in inclusive scattering of high energy polarized electrons by high energy polarized protons at HERA. Such an experiment would be a natural extension of the polarized lepton-nucleon scattering experiments presently carried out at CERN and SLAC. We present here estimates of possible data in the extended kinematic range of HERA and associated statistical errors. (orig.)

  10. Measurement of $ D^{*\\pm}$ production in deep inelastic scattering at HERA

    CERN Document Server

    Abramowicz, H.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Arslan, O.; Aushev, V.; Bachynska, O.; Bamberger, A.; Barakbaev, A.N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Boos, E.G.; Borras, K.; Boscherini, D.; Bot, D.; Brock, I.; Brownson, E.; Brugnera, R.; Brummer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P.J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C.D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A.M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; del Peso, J.; Dementiev, R.K.; De Pasquale, S.; Derrick, M.; Devenish, R.C.E.; Dobur, D.; Dolinska, G.; Doyle, A.T.; Drugakov, V.; Durkin, L.S.; Dusini, S.; Eisenberg, Y.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M.I.; Figiel, J.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gizhko, A.; Gladilin, L.K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu. A.; Gottlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J.C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Huttmann, A.; Ibrahim, Z.A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Iudin, A.; Jakob, H.P.; Januschek, F.; Jones, T.W.; Jungst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I.I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L.A.; Kim, J.Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I.A.; Kotanski, A.; Kotz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B.B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T.Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Lohr, B.; Lohrmann, E.; Long, K.R.; Longhin, A.; Lontkovskyi, D.; Lukina, O.Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J.F.; Mastroberardino, A.; Mattingly, M.C.K.; Melzer-Pellmann, I.A.; Mergelmeyer, S.; Miglioranzi, S.; Idris, F.Mohamad; Monaco, V.; Montanari, A.; Morris, J.D.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, R.J.; Nuncio-Quiroz, A.E.; Oh, B.Y.; Okazaki, N.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J.M.; Pawlik, B.; Pelfer, P.G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N.S.; Polini, A.; Proskuryakov, A.S.; Przybycien, M.; Raval, A.; Reeder, D.D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y.D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Samson, U.; Sartorelli, G.; Savin, A.A.; Saxon, D.H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W.B.; Schneekloth, U.; Schonberg, V.; Schorner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L.M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I.O.; Slominski, W.; Smith, W.H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T.P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A.D.; Tassi, E.; Terron, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Trusov, V.; Tsurugai, T.; Turcato, M.; Tymieniecka, T.; Vazquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N.N.; Walczak, R.; Wan Abdullah, W.A.T.; Whitmore, J.J.; Wichmann, K.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagues-Molina, A.G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zakharchuk, N.; Zarnecki, A.F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B.O.; Zhmak, N.; Zichichi, A.; Zolkapli, Z.; Zotkin, D.S.

    2013-01-01

    The production of $D^{*\\pm}$ mesons in deep inelastic $ep$ scattering has been measured for exchanged photon virtualities $ 5HERA. Differential cross sections have been measured and compared to next-to-leading-order QCD calculations. The cross-sections are used to extract the charm contribution to the proton structure functions, expressed in terms of the reduced charm cross section, $\\sigma_{\\rm red}^{c\\bar{c}}$. Theoretical calculations based on fits to inclusive HERA data are compared to the results.

  11. Second law analysis of the helium refrigerators for the HERA proton magnet ring

    International Nuclear Information System (INIS)

    Ziegler, B.O.

    1986-01-01

    Each of the three refrigerators for the HERA proton magnet ring must provide 6.775 kW of refrigeration at 4.3 0 K plus 20.5 g/s of helium at 2.5 bar and 4.5 0 K for leads cooling and 20 kW of refrigeration at 40-80 0 K for shield cooling. The capital cost of large refrigerators is small compared with operating costs. Therefore the refrigeration process was analysed on the basis of exergy. This means the irreversibility of each component is expressed as power input into the plant. The process realised consists of the turbine cycle, divided into two streams with 5 gas bearing turbines all together, and the Joule Thomson cycle. Special attention was paid to the cold end of the plant. The optimization resulted in a new configuration with two turboexpanders running in parallel on different temperature levels

  12. HERA's welcome

    International Nuclear Information System (INIS)

    Anon.

    1984-01-01

    The final approval of the big HERA electron-proton collider project was officially announced by Federal German Minister of Research and Technology Heinz Riesenhuber in a ceremony at the German DESY Laboratory on 6 April. In a memorable speech in the crowded experimental hall of the DORIS storage ring. Minister Riesenhuber pointed out the importance of basic research for our future and the absolute priority of freedom for science

  13. Measurement of D{sup *{+-}} production in deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science] [and others; Collaboration: ZEUS Collaboration

    2013-03-15

    The production of D{sup *{+-}} mesons in deep inelastic ep scattering has been measured for exchanged photon virtualities 5HERA. Differential cross sections have been measured and compared to next-to-leading-order QCD calculations. The cross-sections are used to extract the charm contribution to the proton structure functions, expressed in terms of the reduced charm cross section, {sigma}{sub red}{sup c} {sup anti} {sup c}. Theoretical calculations based on fits to inclusive HERA data are compared to the results.

  14. An experiment to study CP violation in the B system using an internal target at the HERA proton ring

    International Nuclear Information System (INIS)

    Hofmann, W.

    1993-03-01

    A group of physicists centered around the ARGUS collaboration got interested in hadron accelerators as a prolific source of B hadrons. The group is presently studying the option of a major-B-physics experiment to be performed at the HERA proton storage ring in fixed target mode using an internal target. Basic goal of the experiment is the detection of CP violation in the 'gold plated' B 0 → J/Ψ K s decay mode, using a dedicated detector triggered on lepton pairs from J/Ψ decay. (orig./HSI)

  15. Alignment of the HERA-B RICH optical system with data

    International Nuclear Information System (INIS)

    Gorisek, A.; Krizan, P.; Korpar, S.; Staric, M.

    1999-01-01

    We present a method for alignment of the mirror segments in the Ring Image Cherenkov Counter of the HERA-B spectrometer. The method will use recorded data, and was tested by using simulated events. The study shows that the mirrors can be aligned accurately enough to make the corresponding error in Cherenkov angle measurement negligible compared to other contributions. The mirrors are aligned relative to one mirror segment which can be chosen arbitrarily

  16. Measurement of beauty production at HERA using events with muons and jets

    International Nuclear Information System (INIS)

    Behnke, Olaf

    2005-01-01

    Several new measurements of beauty production at HERA have been presented at this conference. In this talk we report about the H1 measurement using events with a muon associated to a jet. This is the first beauty analysis at HERA, where both the long lifetime and the large mass of b-flavoured hadrons are exploited to identify the beauty events, leading to an improved signal separation. Differential cross sections are measured both in photoproduction and in deep inelastic scattering. The measured data are found to be somewhat higher then perturbative QCD calculations to next-to-leading order. A significant excess is observed in certain corners of the kinematic phase space. At the end of this report new and recent beauty measurements are summarised

  17. Calibration of the mirror system in the HERA-B RICH

    OpenAIRE

    Starič, Marko; Križan, Peter

    2007-01-01

    The mirror system of the HERA-B RICH consists of two spherical and two planar mirrors, composed of altogether 116 mirror segments. Analysis of displacements of the \\v{C}erenkov ring center relative to the charged particle track, for given spherical-planar segment pairs, leads to accurate information regarding the orientation of individual mirror segments. The method is described and the effect of applying the required corrections on the \\v{C}erenkov angle resolution of the HERA-B RICH is disc...

  18. Measurement of the deep-inelastic spin-dependent structure functions of the proton and neutron at HERA

    International Nuclear Information System (INIS)

    Beck, D.H.; Filippone, B.W.; Jourdan, J.

    1988-01-01

    It is possible to measure the deep-inelastic spin-dependent structure functions g 1 /sup p/(x) and g 1 /sup n/(x) for the proton and neutron using internal polarized hydrogen, deuterium, and 3 He targets of polarization 50% and thickness 10 14 to 10 15 cm -2 and the 60 mA longitudinally polarized 30 GeV electron beam in the HERA electron storage ring. The measurement of the deep-inelastic spin-structure of both isospin states of the nucleon at the same kinematics and using the same apparatus allows the Bjorken sum rule to be experimentally checked. In addition, it uniquely constrains the spin distribution of the u and d quarks as a function of x in any model of the nucleon. Possible target and detector configurations are described and an estimate of the accuracy of such a measurement is presented

  19. Physics at HERA

    International Nuclear Information System (INIS)

    Dainton, J.B.

    1990-06-01

    The possibilities for new and exciting physics at the electron-proton (ep) collider HERA are discussed. Emphasis is placed on topics where the high energy ep physics possible will provide both new measurements of Standard Model parameters and unique searches for new phenomena, and attention is drawn to the contrasting features of the detectors in the two major HERA experiments, Hl and Zeus. (author)

  20. Heavy Flavour Production at HERA

    International Nuclear Information System (INIS)

    Bailey, D.

    2001-01-01

    ZEUS and H1 results on heavy quark production using the HERA data from 1995 to 2000 are summarised with emphasis on unresolved problems. The HERA upgrade and its impact on future heavy flavour measurements is briefly discussed

  1. Measurement of Deeply Virtual Compton Scattering at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Arkadov, V.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bate, P.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, Christoph; Berndt, T.; Bizot, J.C.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cao, Jun; Caron, S.; Clarke, D.; Clerbaux, B.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Fleming, Y.H.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kastli, H.K.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kermiche, S.; Kiesling, Christian M.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Koutouev, R.; Koutov, A.; Krehbiel, H.; Kroseberg, J.; Kruger, K.; Kupper, A.; Kuhr, T.; Kurca, T.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebailly, E.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loginov, A.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Meyer, P.O.; Mikocki, S.; Milstead, D.; Mkrtchyan, T.; Mohr, R.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Nellen, G.; Newman, Paul R.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rabbertz, K.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Solovev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Straumann, U.; Swart, M.; Tasevsky, M.; Chernyshov, V.; Chetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassilev, S.; Vazdik, Y.; Vichnevski, A.; Wacker, K.; Wallny, R.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Werner, C.; Werner, M.; Werner, N.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.; zur Nedden, M.

    2001-01-01

    A measurement is presented of elastic Deeply Virtual Compton Scattering e^+ + p -> e^+ + photon + p at HERA using data taken with the H1 detector. The cross section is measured as a function of the photon virtuality, Q^2, and the invariant mass, W, of the gamma p system, in the kinematic range 2 < Q^2 < 20 GeV^2, 30 < W < 120 GeV and |t| < 1 GeV^2, where t is the squared momentum transfer to the proton. The measurement is compared to QCD based calculations.

  2. Measurement of hot spots inside the proton at HERA and LEP/LHC

    International Nuclear Information System (INIS)

    Bartels, J.

    1991-12-01

    In this paper we discuss the measurement of regions in the proton where the density of small-χ partons is large, called 'hot spots', by means of an associated jet analysis. An analytical estimate of the cross section is presented and the jet kinematics is discussed in the HERA and LEP-LHC frame. A Monte Carlo estimate shows that the number of jets produced in deep inelastic scattering events at HERA, suitable for this analysis, amounts to a few 1000 jets for a data sample with an integrated luminosity of about 10 pb -1 . (orig.)

  3. Measurement of the longitudinal proton structure function at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-03-01

    The reduced cross sections for ep deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. From the cross sections, measured double differentially in Bjorken x and the virtuality, Q 2 , the proton structure functions F L and F 2 have been extracted in the region 5 x 10 -4 2 2 . (orig.)

  4. What HERA May Provide?

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hannes; /DESY; De Roeck, Albert; /CERN; Bartels, Jochen; /Hamburg U., Inst. Theor. Phys. II; Behnke, Olaf; Blumlein, Johannes; /DESY; Brodsky, Stanley; /SLAC /Durham U., IPPP; Cooper-Sarkar, Amanda; /Oxford U.; Deak, Michal; /DESY; Devenish, Robin; /Oxford U.; Diehl, Markus; /DESY; Gehrmann, Thomas; /Zurich U.; Grindhammer, Guenter; /Munich, Max Planck Inst.; Gustafson, Gosta; /CERN /Lund U., Dept. Theor. Phys.; Khoze, Valery; /Durham U., IPPP; Knutsson, Albert; /DESY; Klein, Max; /Liverpool U.; Krauss, Frank; /Durham U., IPPP; Kutak, Krzysztof; /DESY; Laenen, Eric; /NIKHEF, Amsterdam; Lonnblad, Leif; /Lund U., Dept. Theor. Phys.; Motyka, Leszek; /Hamburg U., Inst. Theor. Phys. II /Birmingham U. /Southern Methodist U. /DESY /Piemonte Orientale U., Novara /CERN /Paris, LPTHE /Hamburg U. /Penn State U.

    2011-11-10

    More than 100 people participated in a discussion session at the DIS08 workshop on the topic What HERA may provide. A summary of the discussion with a structured outlook and list of desirable measurements and theory calculations is given. The HERA accelerator and the HERA experiments H1, HERMES and ZEUS stopped running in the end of June 2007. This was after 15 years of very successful operation since the first collisions in 1992. A total luminosity of {approx} 500 pb{sup -1} has been accumulated by each of the collider experiments H1 and ZEUS. During the years the increasingly better understood and upgraded detectors and HERA accelerator have contributed significantly to this success. The physics program remains in full swing and plenty of new results were presented at DIS08 which are approaching the anticipated final precision, fulfilling and exceeding the physics plans and the previsions of the upgrade program. Most of the analyses presented at DIS08 were still based on the so called HERA I data sample, i.e. data taken until 2000, before the shutdown for the luminosity upgrade. This sample has an integrated luminosity of {approx} 100 pb{sup -1}, and the four times larger statistics sample from HERA II is still in the process of being analyzed.

  5. Measurement of heavy-quark jet photoproduction at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2011-04-01

    Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb -1 . The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, p jet T , and pseudorapidity, η jet , were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions. (orig.)

  6. Measurement of heavy-quark jet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max-Planck-Institute for Physics, Munich (Germany); Abt, I. [Max-Planck-Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2011-04-15

    Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb{sup -1}. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, p{sup jet}{sub T}, and pseudorapidity, {eta}{sup jet}, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions. (orig.)

  7. Investigation of the J/ψproduction via the decay J/ψ→μ+μ- at the ep storage ring HERA

    International Nuclear Information System (INIS)

    Sell, R.

    1995-01-01

    The data taken with the H1-detector at the storage ring HERA in the year 1993 are analysed for events of the type ep →eJ/ψX; J/ψ→μ + μ - . In total 42±8 J/ψ→μ + μ - events are found. Only a few of these events (3±2) are produced via large momentum transfer (Q 2 >4 GeV 2 ). The main part is produced in the area of photoproduction with Q 2 2 (Q 2 ∼0). Half of the events (21±5) show no further activity inside the detector (acceptance region: 8 el (ep→eJ/ψX)=(9.5±2.5±2.5)nb is derived for this type of quasielastic J/ψ production in the region 30 GeV γp 2 2 this corresponds to a γp-cross-section of σ el (γp→J/ψX)=(60±15±15)nb at an average γp-CMS-energy of γP >∼90 GeV. The cross-section for the inelastic J/ψ-production is measured in the region 30 GeV γp ψ /E γ in the proton rest frame). In the region 0.5 in (ep→eJ/ψ/X)=(4.8±1.7±1.2)nb and σ in (γp→J/ψX)=(30± 11±7)nb respectively. The possibility to reconstruct the kinematics of inelastic events without detecting the scattered electron is demonstrated. Further results, e.g. the measurement of the gluon density distribution of the proton, can not be obtained due to the limited statistics. It is however shown, that with higher statistics very interesting results can be expected analysing the J/ψ production at HERA. (orig.)

  8. Measurement of charm fragmentation fractions in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max-Planck-Institute for Physics, Munich (Germany); Abt, I. [Max-Planck-Institute for Physics, Muinch (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science] [and others; Collaboration: ZEUS Collaboration

    2013-06-15

    The production of D{sup 0}, D{sup *+}, D{sup +}, D{sub s}{sup +} and {Lambda}{sub c}{sup +} charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb{sup -1}. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to charged D-meson production rates, the fraction of charged D mesons produced in a vector state, and the strangeness-suppression factor have been determined. The measurements have been performed in the photoproduction regime. The charm hadrons were reconstructed in the range of transverse momentum p{sub T} > 3.8GeV and pseudorapidity vertical stroke {eta} vertical stroke <1.6. The charm fragmentation fractions are compared to previous results from HERA and from e{sup +}e{sup -} experiments. The data support the hypothesis that fragmentation is independent of the production process.

  9. Measurement of the longitudinal proton structure function at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2009-03-15

    The reduced cross sections for ep deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. From the cross sections, measured double differentially in Bjorken x and the virtuality, Q{sup 2}, the proton structure functions F{sub L} and F{sub 2} have been extracted in the region 5 x 10{sup -4}

  10. Superconducting magnets for HERA

    International Nuclear Information System (INIS)

    Wolff, S.

    1987-01-01

    The Hadron-Electron-Ring Accelerator (HERA) presently under construction at DESY, Hamburg, consists of an electron storage ring of 30 GeV and a proton storage ring of 820 GeV. Superconducting magnets are used for the proton ring. There are 416 superconducting bending magnets of 4.698 T central field and 8.824 m magnetic length, 224 superconducting quadrupoles of 91.2 T/m central gradient and many superconducting correction dipoles, quadrupoles and sextupoles. The main dipoles and quadrupoles consist of two-layer coils of 75 mm inner diameter clammed with aluminium (for the dipoles) or stainless steel laminations (for the quadrupoles). The collared coils are surrounded by a laminated cold iron yoke and supported inside a low loss cryostat. The protection system uses cold diodes to bypass the current around a quenching magnet. The magnets are cooled with one phase helium supplied by a 3 block central refrigeration system of 20 kW refrigeration power at 4.3 K. Two helium is returned through the magnets in good thermal contact with the one phase helium in the dipoles for temperature control. This paper describes the magnet system and gives the results obtained for prototype magnets

  11. POLARIZED BEAMS: 1 - Longitudinal electron spin polarization at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1994-09-15

    Wednesday 4 May marked a turning point in the art of the manipulation of spins in electron storage rings: longitudinal electron spin polarization (with the spins oriented along the electrons' direction of motion) was established in the electron ring of HERA, the electronproton collider at DESY in Hamburg. A polarization level of about 55% was obtained and polarizations of over 60% were reproducibly obtained in the following days. The beam energy was 27.52 GeV, corresponding to half integer spin tune of 62.5.

  12. Experimentation at HERA

    International Nuclear Information System (INIS)

    1983-10-01

    These proceedings contain three articles concerning the physics which can be studied by HERA, which were presented at the named workshop, together with convenor reports on working groups which concern technologies, the intersecting regions, photoproduction at HERA, currents and structure functions, exotic phenomena at HERA, and the use of existing detectors. Finally the experimental halls at HERA are described. Separated abstracts were prepared for the articles in these proceedings. (HSI)

  13. Measurement of inelastic charmonium production at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Steder, Michael

    2008-09-15

    This thesis presents measurements of inelastic photoproduction and electroproduction of J/{psi} mesons in ep scattering at HERA. The data was collected by the H1 detector during the HERA II running and corresponds to an integrated luminosity of L {approx} 166 pb{sup -1} in the photoproduction analysis and L {approx} 315 pb{sup -1} in the electroproduction analysis. In both analyses the elasticity of the J/{psi} meson is restricted to a medium range of 0.3 {<=} z {<=} 0.9. The kinematic range of the photoproduction analysis is defined by Q{sup 2} {approx} 0 GeV{sup 2}, 60 {<=}W{sub {gamma}}{sub p}{<=} 240 GeV and P{sub {tau}}{sub ,{psi}}{>=} 1 GeV{sup 2}, whereas the electroproduction analysis is restricted to 3.6 {<=} Q{sup 2} {<=} 100 GeV{sup 2}, 50 {<=}W{sub {gamma}}{sub p}{<=} 225 GeV, and P{sup *}{sub {tau}}{sub ,} {sub {psi}} {>=} 1 GeV. Here P{sup *}{sub {tau}}{sub ,} {sub {psi}} denotes the transverse momentum of the J/{psi} in the {gamma}p center of mass frame. In both kinematic ranges, single differential and double differential cross sections are measured with increased precision with respect to previous analyses. The polarisation of the J/{psi} mesons is studied in fits to the decay angular distributions cos({theta}{sup *}) and {phi}{sup *}. The measured cross sections are compared to different theoretical predictions. The most successful calculation in describing the data accounts for higher order corrections by using a k{sub {tau}} factorisation ansatz in the color singlet model (CSM). In addition, this thesis reviews the description of the data by calculations at leading and next to leading order in the CSM. The polarisation variables are compared to calculations in the factorisation ansatz in NRQCD, in addition to the leading order CSM predictions. (orig.)

  14. Measurement of charm in charged current at HERA

    International Nuclear Information System (INIS)

    Zimmermann, Tobias

    2008-12-01

    A measurement of charm production in charged current (CC) polarized electron-proton deep inelastic scattering processes with data from the H1 detector at the HERA collider is presented. This process in principle allows access to the strange quark density in the proton. In total 5460 CC candidate events in e + p and 6253 in e - p data are selected in the kinematic range Q 2 >223 GeV 2 and 0.03 CC =(28.9± 1.4)+P e .(28.6±4.7) pb for e + p and σ CC =(49.2±2.3)-P e .(42.5 ±6.8) pb for e - p, where P e is the lepton beam polarization. While the measured cross section for e + p data is in agreement with the theoretical prediction, the cross section for e - p data shows a weaker dependence on P e than predicted. The charm fractions in the selected CC candidate event samples are extracted using the muon charge asymmetry. Muons originating from charmed hadron decays in CC events at HERA always have the same charge as the beam lepton. The extracted charm fractions in the selected CC candidate event samples are F c =9.5±8.9±3.0 % for e + p and F c =4.4±6.9±2.6 % for e - p. Due to the large statistical errors of the measured charm fractions, the strange quark density in the proton has not been extracted. (orig.)

  15. Measurement of charm in charged current at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Tobias

    2008-12-15

    A measurement of charm production in charged current (CC) polarized electron-proton deep inelastic scattering processes with data from the H1 detector at the HERA collider is presented. This process in principle allows access to the strange quark density in the proton. In total 5460 CC candidate events in e{sup +}p and 6253 in e{sup -}p data are selected in the kinematic range Q{sup 2}>223 GeV{sup 2} and 0.03measured CC cross sections are {sigma}{sub CC}=(28.9{+-} 1.4)+P{sub e}.(28.6{+-}4.7) pb for e{sup +}p and {sigma}{sub CC}=(49.2{+-}2.3)-P{sub e}.(42.5 {+-}6.8) pb for e{sup -}p, where P{sub e} is the lepton beam polarization. While the measured cross section for e{sup +}p data is in agreement with the theoretical prediction, the cross section for e{sup -}p data shows a weaker dependence on P{sub e} than predicted. The charm fractions in the selected CC candidate event samples are extracted using the muon charge asymmetry. Muons originating from charmed hadron decays in CC events at HERA always have the same charge as the beam lepton. The extracted charm fractions in the selected CC candidate event samples are F{sub c}=9.5{+-}8.9{+-}3.0 % for e{sup +}p and F{sub c}=4.4{+-}6.9{+-}2.6 % for e{sup -}p. Due to the large statistical errors of the measured charm fractions, the strange quark density in the proton has not been extracted. (orig.)

  16. First Measurement of Charged Current Cross Sections at HERA with Longitudinally Polarised Positrons

    CERN Document Server

    Aktas, A.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A.J.; Raicevic, N.; Reisert, B.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sedlak, K.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Steder, M.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-01-01

    Data taken with positrons of different longitudinal polarisation states in collision with unpolarised protons at HERA are used to measure the total cross sections of the charged current process, e^+ p \\to \\bar{\

  17. Measurement of J/ψ helicity distributions in inelastic photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-06-01

    The J/ψ decay angular distributions have been measured in inelastic photoproduction in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb -1 . The range in photon-proton centre-of-mass energy, W, was 50 + were measured in the J/ψ rest frame and compared to theoretical predictions at leading and next-to-leading order in QCD. (orig.)

  18. Status of the HERA-B experiment

    CERN Document Server

    Schmidt, B

    2001-01-01

    HERA-B is a fixed target experiment using the halo of the 920 GeV proton beam of HERA on an internal wire target. The aim of the experiment is to trigger on rare B to J/ psi decays, using a highly selective trigger system and to measure the CP violating parameter sin (2 beta ). The specific problems of the experiment arise from the extreme background conditions which put unprecedented requirements on the detector components and the triggering and read out system. After 6 years of intense R&D, HERA-B has been finally completed and is now in its commissioning phase.

  19. Search for Drell Yan in √(s)=41.6 GeV p-N collisions at HERA-b

    International Nuclear Information System (INIS)

    Kessler, J.

    2007-01-01

    In this thesis, the data taken with the HERA-b detector in the running period 2002/2003 is used to measure the cross section of the Drell Yan process q anti q → l + l - , where quark and antiquark annihilate and produce a lepton pair. HERA-b, a fixed target spectrometer, is one of the four experiments at the storage ring HERA at DESY. It uses the proton beam to produce collisions with wire targets of different materials. The main challenge of the thesis is to extract a Drell Yan signal from the dataset without loosing too many events and to find a suitable background simulation which can be subtracted from the kinematical distributions. For this purpose, a Single Track Monte Carlo is generated to calculate event weights, which are applied to the like-sign dataset. This procedure is necessary since the detector acceptance of HERA-b is dependant on the charges of the leptons. After background subtraction and acceptance and luminosity corrections, differential cross sections of the Drell Yan process are plotted, for the first time in the negative x F regime. These are compared to results from E772 and NA50. Also, the dependance of the Drell Yan cross section on the mass number of the target material is calculated. (orig.)

  20. Measurement of the proton structure function F2 at low χand low Q2 at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-10-01

    We report on a measurement of the proton structure function F 2 in the range 3.5x10 -5 ≤x≤4x10 -3 and 1.5 GeV 2 ≤Q 2 ≤15 GeV 2 at the ep collider HERA operating at a centre-of-mass energy of √s=300 GeV. The rise of F 2 with decreasing x observed in the previous HERA measurements persists in this lower x and Q 2 range. The Q 2 evolution of F 2 , even at the lowest Q 2 and x measured, is consistent with perturbative QCD. (orig.)

  1. Measurement of elastic φ photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1996-01-01

    The production of φ mesons in the reaction e + p→e + φp(φ→K + K - ) at a median Q 2 of 10 -4 GeV 2 has been studied with the ZEUS detector at HERA. The differential φ photoproduction cross section dσ/dt has an exponential shape and has been determined in the kinematic range 0.1 2 and 60 γp→φp 0.96±0.19 -0.18 +0.21 μb has been obtained by extrapolating to t=0. When compared to lower energy data, the results show a weak energy dependence of both σ γp→φp and the slope of the t distribution. The φ decay angular distributions are consistent with s-channel helicity conservation. From lower energies to HERA energies, the features of φ photoproduction are compatible with those of a soft diffractive process. (orig.)

  2. Measurement of the Proton Structure Function $F_{2}$ at low $Q^{2}$ in QED Compton Scattering at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brisson, V.; Broker, H.-B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Koblitz, B.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kroseberg, J.; Kuckens, J.; Kuhr, T.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morozov, I.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Ossoskov, G.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Raicevic, N.; Ratiani, Z.; Reimer, P.; Reisert, B.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.-P.; Schleper, P.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Winter, G.-G.; Wissing, Ch.; Woehrling, E.-E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2004-01-01

    The proton structure function F_2(x,Q^2) is measured in inelastic QED Compton scattering using data collected with the H1 detector at HERA. QED Compton events are used to access the kinematic range of very low virtualities of the exchanged photon, Q^2, down to 0.5 GeV^2, and Bjorken x up to \\sim 0.06, a region which has not been covered previously by inclusive measurements at HERA. The results are in agreement with the measurements from fixed target lepton-nucleon scattering experiments.

  3. The spectrometer system for measuring ZEUS luminosity at HERA

    International Nuclear Information System (INIS)

    Helbich, M.; Ning, Y.; Paganis, S.; Ren, Z.; Schmidke, W.B.; Sciulli, F.; Schneekloth, U.; Buettner, C.; Caldwell, A.; Sutiak, J.

    2006-01-01

    The upgrade of the HERA accelerator has provided much increased collider luminosity. In turn, the improvements have necessitated a new design for the ZEUS luminosity measurements. The intense synchrotron radiation field, as well as the high probability of a bremsstrahlung photon in each bunch crossing, posed new experimental constraints. In this report, we describe how these challenges were met with the ZEUS luminosity spectrometer system. The design, testing and commissioning of the device are described, and the results from the initial operational experience are reported

  4. Measurement of Deeply Virtual Compton Scattering at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kapichine, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leiner, B.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxeld, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2005-01-01

    A measurement is presented of elastic deeply virtual Compton scattering \\gamma* p \\to \\gamma p made using e^+ p collision data corresponding to a luminosity of 46.5 pb^{-1}, taken with the H1 detector at HERA. The cross section is measured as a function of the photon virtuality, Q^2, the invariant mass of the \\gamma* p system, W, and for the first time, differentially in the squared momentum transfer at the proton vertex, t, in the kinematic range 2 < Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2. QCD based calculations at next-to-leading order using generalized parton distributions can describe the data, as can colour dipole model predictions.

  5. Hera presentation generator (Poster)

    NARCIS (Netherlands)

    Frasincar, F.; Houben, G.J.P.M.; Barna, P.; Ellis, A.; Hagino, T.

    2005-01-01

    Semantic Web Information Systems (SWIS) are Web Information Systems that use Semantic Web technologies. Hera is a model-driven design methodology for SWIS. In Hera, models are represented in RDFS and model instances in RDF. The Hera Presentation Generator (HPG) is an integrated development

  6. Combined inclusive diffractive cross sections measured with forward proton spectrometers at HERA

    International Nuclear Information System (INIS)

    Ruspa, Marta

    2013-01-01

    A combination is presented of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA. The analysis uses samples of diffractive deep inelastic scattering data where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account by the combination method, resulting in improved precision.

  7. Combined inclusive diffractive cross sections measured with forward proton spectrometers at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Ruspa, Marta [Univ. Piemonte Orientale, via Solaroli 17, 28100 Novara (Italy); Collaboration: H1 Collaboration; ZEUS Collaboration

    2013-04-15

    A combination is presented of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA. The analysis uses samples of diffractive deep inelastic scattering data where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account by the combination method, resulting in improved precision.

  8. Search for Drell Yan in {radical}(s)=41.6 GeV p-N collisions at HERA-b

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, J.

    2007-10-31

    In this thesis, the data taken with the HERA-b detector in the running period 2002/2003 is used to measure the cross section of the Drell Yan process q anti q {yields} l{sup +}l{sup -}, where quark and antiquark annihilate and produce a lepton pair. HERA-b, a fixed target spectrometer, is one of the four experiments at the storage ring HERA at DESY. It uses the proton beam to produce collisions with wire targets of different materials. The main challenge of the thesis is to extract a Drell Yan signal from the dataset without loosing too many events and to find a suitable background simulation which can be subtracted from the kinematical distributions. For this purpose, a Single Track Monte Carlo is generated to calculate event weights, which are applied to the like-sign dataset. This procedure is necessary since the detector acceptance of HERA-b is dependant on the charges of the leptons. After background subtraction and acceptance and luminosity corrections, differential cross sections of the Drell Yan process are plotted, for the first time in the negative x{sub F} regime. These are compared to results from E772 and NA50. Also, the dependance of the Drell Yan cross section on the mass number of the target material is calculated. (orig.)

  9. Measurement of beauty production from dimuon events at HERA

    International Nuclear Information System (INIS)

    2009-01-01

    Beauty production in events containing two muons in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb -1 . A low transverse-momentum threshold for muon identification, in combination with the large rapidity coverage of the ZEUS muon system, gives access to almost the full phase space for beauty production. The total cross section for beauty production in ep collisions at (s) 1/2 = 318 GeV has been measured to be σ tot (ep → b b-bar X) = 13.9 ± 1.5(stat.) +4.0 -4.3 (syst.) nb. Differential cross sections and a measurement of b b-bar correlations are also obtained, and compared to other beauty cross-section measurements, Monte Carlo models and next-to-leading-order QCD predictions.

  10. HERA: Illuminating Our Early Universe

    Science.gov (United States)

    DeBoer, David

    2014-06-01

    The Hydrogen Epoch of Reionization Arrays (HERA) roadmap is a staged plan for using the unique properties of the 21cm line from neutral hydrogen to probe our cosmic dawn, from the birth of the first stars and black holes, through the full reionization of the primordial intergalactic medium (IGM). HERA is a collaboration between the Precision Array Probing the Epoch of Reionization (PAPER), US-Murchison Widefield Array (MWA), and MIT Epoch of Reionization (MITEOR) teams.The first phase of the HERA roadmap entailed the operation of the PAPER and MWA telescopes to explore techniques and designs required to detect the primordial HI signal in the presence of radio continuum foreground emission some four orders of magnitude brighter. Studies with PAPER and the MWA have led to a new understanding of the interplay of foreground and instrumental systematics in the context of a three-dimensional cosmological intensity-mapping experiment. We are now able to remove foregrounds to the limits of our sensitivity with these instruments, culminating in the first physically meaningful upper limits on the power spectrum of 2 cm emission from reionization.Building on this understanding, the next stage of HERA entails a new 14m diameter antenna element that is optimized both for sensitivity and for minimizing foreground systematics. Arranging these elements in a compact hexagonal grid yields an array that facilitates calibration, leverages proven foreground removal techniques, and is scalable to large collecting areas. The HERA phase II will be located in the radio quiet environment of the SKA site in Karoo, South Africa, and have a sensitivity close to two orders of magnitude better than PAPER and the MWA, with broader frequency coverage, HERA can paint an uninterrupted picture through reionization, back to the end of the Dark Ages.This paper will present a summary of the current understanding of the signal characteristics and measurements and describe this planned HERA telescope to

  11. HERA results on QCD and EW physics

    International Nuclear Information System (INIS)

    Zarnecki, A.F.

    1997-01-01

    Selected HERA results on QCD and EW interactions are presented. They include the measurement of the proton structure function and its analysis in terms of the QCD evolution, as well as results concerning deep inelastic scattering at very low and very high Q 2 . Selected HERA limits on new physics and parameters which extend the standard model are also presented. (author)

  12. Analysis of spin depolarizing effects in electron storage rings

    International Nuclear Information System (INIS)

    Boege, M.

    1994-05-01

    In this thesis spin depolarizing effects in electron storage rings are analyzed and the depolarizing effects in the HERA electron storage ring are studied in detail. At high beam energies the equilibrium polarization is limited by nonlinear effects. This will be particularly true in the case of HERA, when the socalled ''spin rotators'' are inserted which are designed to provide longitudinal electron polarization for the HERMES experiment in 1994 and later for the H1 and ZEUS experiment. It is very important to quantify the influence of these effects theoretically by a proper modelling of HERA, so that ways can be found to get a high degree of polarization in the real machine. In this thesis HERA is modelled by the Monte-Carlo tracking program SITROS which was originally written by J. Kewisch in 1982 to study the polarization in PETRA. The first part of the thesis is devoted to a detailed description of the fundamental theoretical concepts on which the program is based. Then the approximations which are needed to overcome computing time limitations are explained and their influence on the simulation result is discussed. The systematic and statistical errors are studied in detail. Extensions of the program which allow a comparison of SITROS with the results given by ''linear'' theory are explained. (orig.)

  13. Comparison of HuRAM+ and HERA for Development of Data Worksheet for Simulator based HERA Databank

    International Nuclear Information System (INIS)

    Choi, Sunyoung; Jung, Wondea

    2013-01-01

    We also compared the existing HERA methods and HERA database to select essential data fields. We performed a preliminary study to see the possibility to induce the operator's emergency operating procedure (EOP) noncompliance behaviors under a simulated emergency. The purpose of this paper is to compare the HuRAM + and HERA to obtain an insight into the construction of a data worksheet for a qualitative HERA. In this paper, we performed a case study for applying simulator training data to HuRAM + and HERA. With this insight, as well as the results of the researches mentioned above, we have a plan to develop a systematic and qualitative HERA and a data worksheet for the work. In this paper, we compared HuRAM + and HERA to obtain an insight into the construction of a data worksheet for a qualitative HERA and performed a case study. HERA requires a burden to analyze and input an event data due to too many data fields even though it is well designed to estimate Heaps. It is somewhat more convenient to input data into the HuRAM + ; however, it is difficult to analyze the organization and safety culture factors. We are now trying to develop the framework of a data worksheet for a qualitative HERA based on simulator training data. The purpose of our data worksheet is to provide key information for HEP estimation and to enhance the understanding of an operators' behavior under an off-normal plant status. We aim less encumbered means of obtaining the needed data for HERA by changing the existing data worksheet framework of HuRAM + and HERA and by reducing data fields that require reading the between the lines

  14. Measurement of J/{psi} helicity distributions in inelastic photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-06-15

    The J/{psi} decay angular distributions have been measured in inelastic photoproduction in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb{sup -1}. The range in photon-proton centre-of-mass energy, W, was 50measured in the J/{psi} rest frame and compared to theoretical predictions at leading and next-to-leading order in QCD. (orig.)

  15. Measurement of charm and beauty photoproduction at HERA using Dμ correlations

    Science.gov (United States)

    H1 Collaboration; Aktas, A.; Andreev, V.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bähr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D. P.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; Delcourt, B.; Demirchyan, R.; de Roeck, A.; Desch, K.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y. H.; Flucke, G.; Fomenko, A.; Foresti, I.; Formánek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, H.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kückens, J.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laycock, P.; Lebedev, A.; Leißner, B.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schröder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlák, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L. N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, M.; Usik, A.; Utkin, D.; Valkár, S.; Valkárová, A.; Vallée, C.; van Mechelen, P.; van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Winter, G.-G.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; Zomer, F.

    2005-08-01

    A measurement of charm and beauty photoproduction at the electron proton collider HERA is presented based on the simultaneous detection of a D meson and a muon. The correlation between the D meson and the muon serves to separate the charm and beauty contributions and the analysis provides comparable sensitivity to both. The total and differential experimental cross sections are compared to LO and NLO QCD calculations. The measured charm cross section is in good agreement with QCD predictions including higher order effects while the beauty cross section is higher.

  16. Measurement of beauty production from dimuon events at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (United States)] (and others)

    2008-09-15

    Beauty production in events containing two muons in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb{sup -1}. A low transverse-momentum threshold for muon identification, in combination with the large rapidity coverage of the ZEUS muon system, gives access to almost the full phase space for beauty production. The total cross section for beauty production in ep collisions at {radical}(s) = 318 GeV has been measured to be {sigma}{sub tot}(ep {yields} b anti bX) = 13.9 {+-} 1.5(stat.){sub -4.3}{sup +4.0}(syst.) nb. Differential cross sections and a measurement of b anti b correlations are also obtained, and compared to other beauty cross-section measurements, Monte Carlo models and next-to-leading-order QCD predictions. (orig.)

  17. DESY: HERA polarization

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization

  18. DESY: HERA polarization

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-03-15

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization.

  19. Hydrogen Epoch of Reionization Array (HERA)

    Science.gov (United States)

    DeBoer, David R.; HERA

    2015-01-01

    end of the Dark Ages.This paper will present a summary of the current understanding of the signal characteristics and measurements and describe the funded and planned HERA telescope to be built to detect and characterize the EoR power spectrum.

  20. DESY: focuses on HERA

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-12-15

    On 1 October, a special 'FestKolloquium' at DESY marked the official start of the research programme at the new HERA electron-proton collider, which began operations earlier this year. The timing could not have been better, as HERA performance had improved by a factor of ten during the two weeks beforehand. More than 600 guests assembled in one of the big halls previously used for assembly of major components for HERA experiments.

  1. DESY: focuses on HERA

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    On 1 October, a special 'FestKolloquium' at DESY marked the official start of the research programme at the new HERA electron-proton collider, which began operations earlier this year. The timing could not have been better, as HERA performance had improved by a factor of ten during the two weeks beforehand. More than 600 guests assembled in one of the big halls previously used for assembly of major components for HERA experiments

  2. What HERA may provide?

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hannes [DESY, Hamburg (Germany); De Roeck, Albert [CERN, Genf (Switzerland); Bartles, Jochen [Univ. Hamburg (DE). Institut fuer Theoretische Physik II] (and others)

    2008-09-15

    More than 100 people participated in a discussion session at the DIS08 workshop on the topic What HERA may provide. A summary of the discussion with a structured outlook and list of desirable measurements and theory calculations is given. (orig.)

  3. What HERA may provide?

    International Nuclear Information System (INIS)

    Jung, Hannes; De Roeck, Albert; Bartles, Jochen

    2008-09-01

    More than 100 people participated in a discussion session at the DIS08 workshop on the topic What HERA may provide. A summary of the discussion with a structured outlook and list of desirable measurements and theory calculations is given. (orig.)

  4. The preparation of particle beams for experiments of hadron physics: Slow extraction at ELFE rate at DESY and ELSA, as well as beam cooling at HERA

    International Nuclear Information System (INIS)

    Gentner, M.

    1999-02-01

    Various complementary experimental approaches are possible to study hadron physics, all of which require dedicated accelerator facilities. One approach, known as the ELFE rate at DESY project, makes use of a continuous electron beam with an energy of 15 to 25 GeV, a current of at least 30 μA and very small emittance, for fixed target experiments. The formation of such a beam by stretching a pulsed LINAC beam with the help of the HERA electron ring has been studied. At lower beam energies and currents this concept is already being used at the ELSA facility of Bonn University. Here the extraction process has been studied intensively and has been compared with measurements. Another approach to study hadron physics is the use of an electron - ion collider. To achieve high integrated luminosities cooling of the ion beam is necessary, especially in the case of heavy ions. For HERA high energy beam cooling with the help of an electron storage ring has been studied. (orig.)

  5. Measurement of the t dependence in exclusive photoproduction of Upsilon(1S) mesons at HERA

    CERN Document Server

    Abramowicz, H.

    2012-02-14

    The exclusive photoproduction reaction gamma p -> Upsilon(1S) p has been studied with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 468 pb^-1. The measurement covers the kinematic range 60 Upsilon(1S) p cross section.

  6. Monte-Carlo studies for the search of top quarks at HERA

    International Nuclear Information System (INIS)

    Fuerstenau, H.

    1989-06-01

    In this thesis the simulation of processes to be observed in the HERA storage ring is described in order to identify events with a top particle. For this particle kinematics is used together with the jet model. As results transverse momentum distributions, mass spectra, and inclusive electron angular distributions are calculated for top particles and also for charm and bottom particles in order to separate top events from the background. (HSI)

  7. The proton collimation system of HERA

    International Nuclear Information System (INIS)

    Seidel, M.

    1994-06-01

    This thesis is concerned with the two stage collimation system in HERA-p which is supposed to suppress this kind of background. The HERA-p collimation system consists of 12 movable tungsten jaws at three locations in the ring. A manual operation of the system is therefore rather time consuming, but also dangerous in the case of an operational mistake. The development of partially automised controls for the system is therefore an important topic of this thesis as well. In order to control the precise positioning of the jaws at the beam edge the induced hadronic showers are monitored immediately downstream the collimators. Small PIN-diode based shower detectors are used for this purpose. A detailed analysis of these shower rates turned out to be a sensitive source of information on the beam. A large section of the thesis is therefore concerned with the diagnostic possibilities of collimators in a proton machine. A passive method for the determination of the machine acceptance is presented. A second topic is the determination of diffusion rates in the beam halo. A stepwise movement of a beam limiting collimator jaw induces relaxation processes in the beam halo. From an analysis of the transient time evolution of the loss rates after the movement one can determine the diffusion coefficient in the beam halo. A completely new method is the frequency analysis of the halo induced shower rates. If the beam oscillates it scrapes periodically at the collimator which results in a modulation of the measured loss rates. The method allows measurements of slow orbit oscillations in the range of some μm. In the last section of the thesis the diffusion of halo protons as a result of beam-beam interaction is investigated. A little collection of diffusion measurements as a function of particle amplitude is presented. With the help of tracking simulations it is demonstrated that diffusion rates of the observed size can be generated by a certain modulation of the betatron frequency

  8. Measurement of Charm and Beauty Photoproduction at HERA using D* mu Correlations

    CERN Document Server

    Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Winter, G.-G.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; Zomer, F.

    2005-01-01

    A measurement of charm and beauty photoproduction at the electron proton collider HERA is presented based on the simultaneous detection of a D*^{\\pm} meson and a muon. The correlation between the D* meson and the muon serves to separate the charm and beauty contributions and the analysis provides comparable sensitivity to both. The total and differential experimental cross sections are compared to LO and NLO QCD calculations. The measured charm cross section is in good agreement with QCD predictions including higher order effects while the beauty cross section is higher.

  9. Measurement of antideuteron photoproduction and a search for heavy stable charged particles at HERA

    CERN Document Server

    Aktas, A; Anthonis, T; Asmone, A; Babaev, A; Backovic, S; Bähr, J; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, Christoph; Berndt, T; Bizot, J C; Boenig, M O; Böhme, J; Boudry, V; Bracinik, J; Brisson, V; Broker, H B; Brown, D P; Bruncko, Dusan; Bunyatyan, A; Buschhorn, G; Büsser, F W; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Chekelian, V; Collard, Caroline; Contreras, J G; Coppens, Y R; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; de Roeck, A; De Wolf, E A; Delcourt, B; Demirchyan, R; Desch, Klaus; Diaconu, C; Dingfelder, J; Dodonov, V; Dubak, A; Duprel, C; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Ellerbrock, M; Elsen, E; Erdmann, M; Erdmann, W; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Flügge, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Gabathuler, E; Gabathuler, K; Garutti, E; Garvey, J; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Görlich, L; Gogitidze, N; Gorbounov, S; Grab, C; Grassler, J; Greenshaw, T; Gregori, M; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Haller, J; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Henshaw, O; Heremans, R; Herrera-Corral, G; Herynek, I; Heuer, R D; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R P; Hoting, P; Hovhannisyan, A; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Johnson, D P; Jönsson, L B; Jung, H; Kant, D; Kapichine, M; Karlsson, M; Katzy, J; Keller, N; Kennedy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Koblitz, B; Korbel, V; Kostka, P; Koutouev, R; Kropivnitskaya, A; Kroseberg, J; Kuckens, J; Kuhr, T; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebedev, A; Leissner, B; Lemrani, R; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; List, B; Lobodzinska, E; Loktionova, N; López-Fernandez, R; Lubimov, V; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovski, E; Mangano, S; Marage, P; Marks, J; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Michine, S; Mikocki, S; Milcewicz, I; Milstead, D; Mohamed, A; Moreau, F; Morozov, A; Morozov, I; Morris, J V; Mozer, M U; Müller, K; Murín, P; Nagovizin, V; Naroska, Beate; Naumann, J; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nikitin, D; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Ossoskov, G; Ozerov, D; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Portheault, B; Pöschl, R; Povh, B; Raicevic, N; Ratiani, Z; Reimer, P; Reisert, B; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rurikova, Z; Rusakov, S; Rybicki, K; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schleper, P; Schmidt, S; Schmitt, S; Schneider, M; Schoeffel, L; Schöning, A; Schröder, V; Schultz Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, T; Smirnov, P; Soloviev, Yu V; South, D; Spaskov, V; Specka, A; Spitzer, H; Stamen, R; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Trevino, A V; Truöl, P; Tsipolitis, G; Tsuri, I; Turnau, J; Tzamariudaki, E; Uraev, A; Urban, M; Usik, A; Utkin, D; Valkár, S; Valkárová, A; Vallée, C; Van Mechelen, P; Van Remortel, N; Vazdik, Ya A; Veelken, C; Vest, A; Vinokurova, S; Volchinski, V; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wessling, B; Winter, G G; Wissing, C; Woerling, E E; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zácek, J; Zaleisak, J; Zhang, Z; Zhokin, A; Zohrabyan, H; Zomer, F; 10.1140/epjc/s2004-01978-x

    2004-01-01

    The cross section for antideuteron photoproduction is measured at HERA at a mean centre-of-mass energy of W/sub gamma p/=200 GeV in the range 0.2

    HERA laboratory frame, respectively. The numbers of antideuterons per event are found to be similar in photoproduction to those in central proton-proton collisions at the CERN ISR but much lower than those in central Au-Au collisions at RHIC. The coalescence parameter B/sub 2/, which characterizes the likelihood of antideuteron production, is measured in photoproduction to be 0.010+or-0.002+or-0.001, which is much higher than in Au-Au collisions at a similar nucleon-nucleon centre-of-mass energy. No significant production of particles heavier than deuterons is observed and upper limits are set on the photoproduction cross sections for such particles.

  10. Bounds on the maximum attainable equilibrium spin polarization of protons at high energy in HERA

    International Nuclear Information System (INIS)

    Vogt, M.

    2000-12-01

    For some years HERA has been supplying longitudinally spin polarised electron and positron (e ± ) beams to the HERMES experiment and in the future longitudinal polarisation will be supplied to the II1 and ZEUS experiments. As a result there has been a development of interest in complementing the polarised e ± beams with polarised protons. In contrast to the case of e ± where spin flip due to synchrotron radiation in the main bending dipoles leads to self polarisation owing to an up-down asymmetry in the spin flip rates (Sokolov-Ternov effect), there is no convincing self polarisation mechanism for protons at high energy. Therefore protons must be polarised almost at rest in a source and then accelerated to the working energy. At HERA, if no special measures are adopted, this means that the spins must cross several thousand ''spin-orbit resonances''. Resonance crossing can lead to loss of polarisation and at high energy such effects are potentially strong since spin precession is very pronounced in the very large magnetic fields needed to contain the proton beam in HERA-p. Moreover simple models which have been successfully used to describe spin motion at low and medium energies are no longer adequate. Instead, careful numerical spin-orbit tracking simulations are needed and a new, mathematically rigorous look at the theoretical concepts is required. This thesis describes the underlying theoretical concepts, the computational tools (SPRINT) and the results of such a study. In particular strong emphasis is put on the concept of the invariant spin field and its non-perturbative construction. The invariant spin field is then used to define the amplitude dependent spin tune and to obtain numerical non-perturbative estimates of the latter. By means of these two key concepts the nature of higher order resonances in the presence of snakes is clarified and their impact on the beam polarisation is analysed. We then go on to discuss the special aspects of the HERA-p ring

  11. Measurement of Dijet Cross Sections in Photoproduction at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Arkadov, V.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Becker, J.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Clarke, D.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haller, J.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, C.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kermiche, S.; Kiesling, Christian M.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Koutouev, R.; Koutov, A.; Krehbiel, H.; Kroseberg, J.; Kruger, K.; Kuhr, T.; Kurca, T.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebailly, E.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loginov, A.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Mangano, S.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Meyer, P.O.; Mikocki, S.; Milstead, D.; Mkrtchyan, T.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Nellen, G.; Newman, Paul R.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Petrukhin, A.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Straumann, U.; Swart, M.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vichnevski, A.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

    2002-01-01

    Dijet cross sections as functions of several jet observables are measured in photoproduction using the H1 detector at HERA. The data sample comprises e^+p data with an integrated luminosity of 34.9 pb^(-1). Jets are selected using the inclusive k_T algorithm with a minimum transverse energy of 25 GeV for the leading jet. The phase space covers longitudinal proton momentum fraction x_p and photon longitudinal momentum fraction x_gamma in the ranges 0.05

  12. Latest on polarization in electron storage rings

    International Nuclear Information System (INIS)

    Chao, A.W.

    1983-01-01

    The field of beam polarization in electron storage rings is making rapid progress in recent several years. This report is an attempt to summarize some of these developments concerning how to produce and maintain a high level of beam polarization. Emphasized will be the ideas and current thoughts people have on what should and could be done on electron rings being designed at present such as HERA, LEP and TRISTAN. 23 references

  13. Measurement of D mesons production in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Chakanov, S.; Derrick, M.; Magill, S.

    2007-04-01

    Charm production in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 82 pb -1 . Charm has been tagged by reconstructing D *+ , D 0 , D + and D + s (+c.c.) charm mesons. The charm hadrons were measured in the kinematic range p T (D *+ ,D 0 ,D + )>3 GeV, p T (D + s )>2 GeV and vertical stroke η(D) vertical stroke 2 2 and 0.02 T (D) and η(D) in order to determine the open-charm contribution, F c anti c 2 (x,Q 2 ), to the proton structure function F 2 . (orig.)

  14. New experimental results at HERA

    International Nuclear Information System (INIS)

    Kuhlen, M.

    1994-10-01

    Recent measurements by the ZEUS and H1 collaborations of the hadronic final state in deep inelastic scattering at HERA are reviewed. QCD is studied by means of charged particle spectra, jet rates and inclusive energy flows. (orig.)

  15. Measurement of dijet cross sections in deep inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Theedt, Thorben

    2009-11-15

    Dijet cross sections have been measured in deep inelastic neutral current electron-proton scattering at HERA. Cross sections have been measured differentially as functions of the photon virtuality, Q{sup 2}, the scaling variable, Bjorken x, the mean transverse jet energy, E{sub T}, the invariant dijet mass, M{sub jj}, the difference in jet pseudorapidity, {eta}'= vertical stroke {eta}{sup jet{sub 1}}-{eta}{sup jet{sub 2}} vertical stroke and the momentum fraction, {xi}. Cross sections as function of {xi} have also been measured in different regions of the photon virtuality. The analysed data were recorded at a centre-of-mass energy of 318 GeV with the ZEUS detector in the years 1998, 1999, and 2000 and correspond to an integrated luminosity of 81.74 pb{sup -1}. The phase space of the analysis is defined by 125HERA II Monte Carlo predictions. The results triggered the so called single pion study, in which single pion events were used to investigate the response of the simulated detector. (orig.)

  16. Report from the ZEUS Collaboration at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Weizmann Institute of Science, Rehovot (Israel)

    1994-12-01

    This is a short overview of the results obtained by the ZEUS Collaboration with data collected during HERA`s first year and corresponding to an integrated luminosity of 25 nb{sup {minus}1}. Included are the measurement of the total, partial, and {rho} photoproduction cross sections, a study of high mass diffractive photoproduction, new results from hard photoproduction where a clear signal of a direct photon contribution has been established, the measurement of the photon structure function F{sub 2}, and first results on diffractive dissociation of the virtual photon in the deep inelastic electron photon scattering. Limits on leptoquarks and excited electrons are also presented.

  17. Results from the H1 experiment at HERA

    International Nuclear Information System (INIS)

    Krasny, M.W.

    1993-01-01

    Results obtained by the H1 collaboration at HERA from the analysis of the data collected in 1992 - the first year of HERA operation are presented. Measurements of the total photoproduction cross-section and the inclusive jet cross-section in γp scattering, the structure function F 2 (x,Q 2 ) and the jet rates in deep inelastic ep scattering, and results of direct searches for leptoquarks are discussed. (author) 37 refs., 6 figs

  18. Measurement of (anti)deuteron and (anti)proton production in DIS at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-05-01

    The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300-318 GeV using an integrated luminosity of 120 pb -1 . The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3 T /M<0.7. The particle rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements. (orig.)

  19. Measurement of the luminosity in the ZEUS experiment at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Adamczyk, L.; Bold, T. [AGH Univ. of Science and Technology, Cracow (Poland); Andruszkow, J. [Polish Academy of Sciences, Cracow (Poland). Inst. of Nuclear Physics] [and others

    2013-06-15

    The luminosity in the ZEUS detector was measured using photons from electron bremsstrahlung. In 2001 the HERA collider was upgraded for operation at higher luminosity. At the same time the luminosity-measuring system of the ZEUS experiment was modified to tackle the expected higher photon rate and synchrotron radiation. The existing lead-scintillator calorimeter was equipped with radiation hard scintillator tiles and shielded against synchrotron radiation. In addition, a magnetic spectrometer was installed to measure the luminosity independently using photons converted in the beam-pipe exit window. The redundancy provided a reliable and robust luminosity determination with a systematic uncertainty of 1.7%. The experimental setup, the techniques used for luminosity determination and the estimate of the systematic uncertainty are reported.

  20. The HERA polarimeter and the first observation of electron spin polarization at HERA

    International Nuclear Information System (INIS)

    Barber, D.P.; Bremer, H.D.; Boege, M.; Brinkmann, R.; Gianfelice-Wendt, E.; Kaiser, H.; Klanner, R.; Lewin, H.C.; Meyners, N.; Vogel, W.; Brueckner, W.; Buescher, C.; Dueren, M.; Gaul, H.G.; Muecklich, A.; Neunreither, F.; Rith, K.; Scholz, C.; Steffens, E.; Veltri, M.; Wander, W.; Zapfe, K.; Zetsche, F.; Chapman, M.; Milner, R.; Coulter, K.; Delheij, P.P.J.; Haeusser, O.; Henderson, R.; Levy, P.; Vetterli, M.; Gressmann, H.; Janke, T.; Micheel, B.; Westphal, D.; Kaiser, R.; Losev, L.; Nowak, W.D.

    1992-10-01

    Electron spin polarizations of about 8% were observed at HERA in November 1991. In runs during 1992 utilizing special orbit corrections, polarization values close to 60% have been achieved. In this paper the polarimeter, the machine conditions, the data analysis, the first results and plans for future measurements are described. (orig.)

  1. First measurement of charged current cross sections at HERA with longitudinally polarised positrons

    Science.gov (United States)

    H1 Collaboration; Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bähr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; de Roeck, A.; Desch, K.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kückens, J.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A. J.; Raicevic, N.; Reimer, P.; Reisert, B.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sedlák, K.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, M.; Usik, A.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-03-01

    Data taken with positrons of different longitudinal polarisation states in collision with unpolarised protons at HERA are used to measure the total cross sections of the charged current process, ep→ν¯X, for negative four-momentum transfer squared Q>400 GeV and inelasticity y<0.9. Together with the corresponding cross section obtained from the previously published unpolarised data, the polarisation dependence of the charged current cross section is measured for the first time at high Q and found to be in agreement with the Standard Model prediction.

  2. Proposal to measure spin-structure functions and semi-exclusive asymmetries for the proton and neutron at HERA

    International Nuclear Information System (INIS)

    Jackson, H.E.; Hansen, J.O.; Jones, C.E.

    1995-01-01

    Nucleon spin physics will be studied in the HERMES experiment, that will use polarized internal targets of essentially pure atomic H, D, and 3 He in the HERA electron storage ring at DESY. A series of measurements of spin-dependent properties of the nucleon and few-body nuclei will be made; the spin structure function g 1 (x) of the proton and neutron will be measured to test the Bjorken sum rule and study the fraction of the nucleon spin carried by quarks; the spin structure function g 2 W, sensitive to quark-gluon correlations, and the structure functions b 1 (x), and Δ(x), sensitive to nuclear binding effects, will be measured; and, using the particle identification capability of the HERMES detector, pions will be detected in coincidence with the scattered electrons. The coincident hadron measurements represent the most important extension that can be made at this time to the existing measurements on the nucleon spin structure functions because they provide information about the flavor-dependence of the quark spin distribution in the nucleon. Argonne is providing the Cerenkov counter to be used for particle identification and developing the drifilm coating technique for the ultrathin target cell required for this experiment. The HERMES collaboration intends to use polarized targets with the highest available figures of merit, and the Argonne laser-driven source offers the most promise for a significant advance in present-day targets

  3. Measurement of open beauty production at HERA in the D*μ final state

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2006-09-01

    The production of beauty quarks with a D *± and a muon in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb -1 . Low transverse-momentum thresholds for the muon and D * meson allow a measurement of beauty production closer to the production threshold than previous measurements. The beauty signal was extracted using the charge correlations and angular distributions of the muon with respect to the D * meson. Cross sections for photoproduction and deep inelastic scattering are somewhat higher than, but compatible with, next-to-leading-order QCD predictions, and compatible with other measurements. (orig.)

  4. Measurement of D± and D0 production in deep inelastic scattering using a lifetime tag at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-12-01

    The production of D ± and D 0 mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb -1 . The measurements cover the kinematic range 5 2 2 , 0.02 D T D vertical stroke c anti c 2 , to the proton structure function, F 2 . (orig.)

  5. Deep inelastic cross-section measurements at large y with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2014-04-01

    The reduced cross sections for e + p deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. The cross sections, measured double differentially in Bjorken x and the virtuality, Q 2 , were obtained in the region 0.13≤y≤0.75, where y denotes the inelasticity and 5≤Q 2 ≤110 GeV 2 . The proton structure functions F 2 and F L were extracted from the measured cross sections.

  6. Measurement of the total and differential b cross sections at HERA and CMS tracker alignment at LHC

    CERN Document Server

    Stefaniuk, Nazar; Gallo, Elisabetta

    2017-01-01

    This thesis is logically divided into two main parts. The first part present a ZEUS analysis which was performed on the data obtained from electron-proton collisions measured by the ZEUS detector for the 2003-2007 running period. The full HERA-II integrated luminosity of 376 $pb^{−1}$ is used. The ZEUS detector is sensitive to the full phase space of beauty production, since it has cylindrical geometry, covers a wide rapidity range and was able to measure low transverse momentum muons. In this part a measurement of beauty production was studied via the process $ep \\rightarrow {e}'b \\bar{b} \\rightarrow {e}'\\mu \\mu X$. Making full use of the HERA-II detector upgrade, $bX$ secondary vertex information was used to constrain the beauty and charm contribution to this process. The result of this analysis is the measurement of the total, visible and differential cross sections for beauty production. The cross sections are compared to next-to-leading order QCD calculations. Similar to the beauty events, instanton ...

  7. Measurement of diffractive scattering of photons with large momentum transfer at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Andreev, V.

    2008-09-01

    The first measurement of diffractive scattering of quasi-real photons with large momentum transfer γp → γY, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q 2 2 . Cross sections are measured as a function of W, the incident photonproton centre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175 2 . The W dependence is well described by a model based on perturbative QCD using a leading logarithmic approximation of the BFKL evolution. The measured vertical stroke t vertical stroke dependence is harder than that predicted by the model and those observed in exclusive vector meson production. (orig.)

  8. Measurement of K0S, Λ and anti Λ production at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2006-12-01

    The production of the neutral strange hadrons K 0 S , Λ and anti Λ has been measured in ep collisions at HERA using the ZEUS detector. Cross sections, baryon-to-meson ratios, relative yields of strange and charged light hadrons, Λ (anti Λ) asymmetry and polarization have been measured in three kinematic regions: Q 2 >25 GeV 2 ; 5 2 2 ; and in photoproduction (Q 2 ≅0), in which the presence of two hadronic jets, each with at least 5 GeV transverse energy, was required. The measurements agree in general with Monte Carlo models and are consistent with measurements made at e + e - colliders, except for an enhancement of baryon relative to meson production in photoproduction. (orig.)

  9. Measurement of Charm and Beauty Jets in Deep Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, A.W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Kogler, R.; Kostka, P.; Kraemer, M.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Makankine, A.; Malinovski, E.; Marage, P.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, M.U.; Mudrinic, M.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Osman, S.; Ozerov, D.; Pahl, P.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Tabasco, J.E.Ruiz; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, I.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Thompson, G.; Thompson, P.D.; Toll, T.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Trevino, A.Vargas; Vazdik, Y.; von den Driesch, M.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2011-01-01

    Measurements of cross sections for events with charm and beauty jets in deep inelastic scattering at HERA are presented. Events with jets of transverse energy E_T^jet > 6 GeV and pseudorapidity -1.0 6 GeV^2 and inelasticity variable 0.07 6 GeV. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb^-1. The numbers of charm and beauty jets are determined using variables reconstructed using the H1 vertex detector with which the impact parameters of the tracks to the primary vertex and the position of secondary vertices are measured. The measurements are compared with QCD predictions and with previous measurements where heavy flavours are identified using muons.

  10. Measurement of (anti)deuteron and (anti)proton production in DIS at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2007-05-15

    The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300-318 GeV using an integrated luminosity of 120 pb{sup -1}. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3measurements. (orig.)

  11. Measurement of Charged Particle Spectra in Deep-Inelastic ep Scattering at HERA

    CERN Document Server

    Alexa, C.; Baghdasaryan, A.; Baghdasaryan, S.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Boudry, V.; Bozovic-Jelisavcic, I.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Buniatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Cvach, J.; Dainton, J.B.; Daum, K.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Eckerlin, G.; Egli, S.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R.C.W.; Hennekemper, E.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hladky, J.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Laycock, P.; Lebedev, A.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lopez-Fernandez, R.; Lubimov, V.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Morozov, A.; Morris, J.V.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Pandurovic, M.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shushkevich, S.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

    2013-04-20

    Charged particle production in deep-inelastic ep scattering is measured with the H1 detector at HERA. The kinematic range of the analysis covers low photon virtualities, 5 < Q^2 < 100 GeV^2, and small values of Bjorken-x, 10^{-4} < x < 10^{-2}. The analysis is performed in the hadronic centre-of-mass system. The charged particle densities are measured as a function of pseudorapidity (eta^*) and transverse momentum (p_T^*) in the range 0< \\eta^* < 5 and 0< p_T^* < 10$ GeV differentially in x and Q^2. The data are compared to predictions from different Monte Carlo generators implementing various options for hadronisation and parton evolutions.

  12. Experimental techniques and physics in a polarized storage ring

    International Nuclear Information System (INIS)

    Dueren, M.

    1994-12-01

    In May 1994 spin rotators were brought into operation at HERA and for the first time longitudinal electron polarization was produced in a high energy storage ring. A Compton polarimeter is used for optimization of the polarization to values of up to 70%. HERMES is a new experiment designed to study the spin structure of the nucleon by deep inelastic scattering from the proton and neutron using the longitudinally polarized electron beam at HERA and internal polarized gas targets. The density of the gas targets is increased by a storage cell by two orders of magnitude compared to a free gas jet. Data taking begins in 1995 with measurements on polarized spin structure functions and also on semi-inclusive polarized hadron production. The inclusive physics program is in competition with experiments at CERN and SLAC. The semi-inclusive physics program promises to solve basic questions of the spin structure of matter by decomposing the spin contributions of the different quark flavors. (orig.)

  13. Measurement of the longitudinal polarization of the HERA electron beam using crystals and the ZEUS luminosity monitor

    International Nuclear Information System (INIS)

    Piotrzkowski, K.

    1995-12-01

    A measurement of the longitudinal polarization of the electron beam at HERA utilizing coherent interactions of high energy photons in crystals is described. Modification of existing facilities would allow an independent polarization measurement and a verification of birefringence phenomena in crystals for 20-30 GeV photons. Relevant experimental issues and systematic uncertainties are also presented. (orig.)

  14. Inclusive Measurement of Diffractive Deep-Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.

    2012-07-18

    The diffractive process ep \\rightarrow eXY, where Y denotes a proton or its low mass excitation with MY < 1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3 \\leq Q2 \\leq 1600 GeV2, the square of the four-momentum transfer at the proton vertex |t| < 1.0 GeV2 and the longitudinal momentum fraction of the incident proton carried by the colourless exchange xIP < 0.05. Triple differential cross sections are measured as a function of xIP, Q2 and beta = x/xIP where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y . High statistics measurements covering the data taking periods 1999-2000 and 2004-2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The comb...

  15. Large scale use of brazing and high temperature brazing for the fabrication of the 6.4 km long vacuum system of the HERA electron storage ring

    International Nuclear Information System (INIS)

    Ballion, R.; Boster, J.; Giesske, W.; Hartwig, H.; Jagnow, D.; Kouptsidis, J.; Pape, R.; Prohl, W.; Schumann, G.; Schwartz, M.; Iversen, K.; Mucklenbeck, J.

    1989-01-01

    The 6.4 km long vacuum system for electrons in the large storage ring HERA at Hamburg consists of about 1,400 components having lengths between .14 and 12 m. The vacuum components are mainly made from variously shaped tubes of the copper alloy CuSn2. This alloy combines sufficient mechanical strength with the high thermal conductivity needed to remove the 6 MW dissipated power of the synchrotron-light. The vacuum components consist additionally of parts made from stainless steel such as flanges, chambers for pumps, beam monitors, etc. All of these parts are connected in a vacuum tight manner and on a large scale by using brazing and high temperature brazing both in a vacuum or in a reducing gas atmosphere. (orig.)

  16. Measurement of deeply virtual Compton scattering using the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Grabowska-Bold, I.

    2004-08-01

    The cross sections for deeply virtual compton scattering in the reaction ep → e'γp' has been measured with the ZEUS detector at HERA using integrated luminosities of 95 pb -1 of e + p and 17 pb -1 of e - p collisions. Cross sections are presented as a function of the exchanged photon virtuality, Q 2 , and the centre-of-mass energy, W, of the γ * p system in the region 5 2 2 and 40 < W < 140 GeV. The obtained results are compared to QCD-based calculations. (orig.)

  17. Tau Lepton Production in ep Collisions at HERA

    OpenAIRE

    Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.

    2006-01-01

    The production of tau leptons in ep collisions is investigated using data recorded by the H1 detector at HERA in the period 1994-2000. Tau leptons are identified by detecting their decay products, using leptonic and hadronic decay modes. The cross section for the production of tau lepton pairs is measured for the first time at HERA. Furthermore, a search for events with an energetic isolated tau lepton and with large missing transverse momentum is performed. The results are found to be in agr...

  18. Charm production and QCD analysis at HERA and LHC

    International Nuclear Information System (INIS)

    Zenaiev, O.

    2017-02-01

    This review is devoted to the study of charm production in ep and pp collisions. The total set of measurements obtained by the two collaborations H1 and ZEUS from HERA and their combination is outlined, as well as complementary data obtained by the LHCb collaboration at the LHC. After fitting the parton distribution functions the charm production cross sections are predicted within perturbative QCD at next-to-leading order using the fixed-flavour-number scheme. Agreement with the data is found. The combined HERA charm data are sensitive to the c-quark mass and enabled its accurate determination. The predictions crucially depend upon the knowledge of the gluon distribution function. It is shown that the shape of the gluon distribution based on the HERA data is considerably improved by adding the measurements from LHCb and applicable down to values x of about 10"-"6, where x is the proton momentum fraction carried by a parton.

  19. Charm production and QCD analysis at HERA and LHC

    Energy Technology Data Exchange (ETDEWEB)

    Zenaiev, O.

    2017-02-15

    This review is devoted to the study of charm production in ep and pp collisions. The total set of measurements obtained by the two collaborations H1 and ZEUS from HERA and their combination is outlined, as well as complementary data obtained by the LHCb collaboration at the LHC. After fitting the parton distribution functions the charm production cross sections are predicted within perturbative QCD at next-to-leading order using the fixed-flavour-number scheme. Agreement with the data is found. The combined HERA charm data are sensitive to the c-quark mass and enabled its accurate determination. The predictions crucially depend upon the knowledge of the gluon distribution function. It is shown that the shape of the gluon distribution based on the HERA data is considerably improved by adding the measurements from LHCb and applicable down to values x of about 10{sup -6}, where x is the proton momentum fraction carried by a parton.

  20. Charm production and QCD analysis at HERA and LHC

    Energy Technology Data Exchange (ETDEWEB)

    Zenaiev, O. [DESY, Hamburg (Germany)

    2017-03-15

    This review is devoted to the study of charm production in ep and pp collisions. The total set of measurements obtained by the two collaborations H1 and ZEUS from HERA and their combination is outlined, as well as complementary data obtained by the LHCb Collaboration at the LHC. After fitting the parton distribution functions the charm-production cross sections are predicted within perturbative QCD at next-to-leading order using the fixed-flavour-number scheme. Agreement with the data is found. The combined HERA charm data are sensitive to the c-quark mass and enabled its accurate determination. The predictions crucially depend upon the knowledge of the gluon distribution function. It is shown that the shape of the gluon distribution based on the HERA data is considerably improved by adding the measurements from LHCb and applicable down to values x of about 10{sup -6}, where x is the proton momentum fraction carried by a parton. (orig.)

  1. Leading Hadron Production at HERA

    Directory of Open Access Journals (Sweden)

    Buniatyan Armen

    2013-06-01

    Full Text Available Data from the recent measurements of very forward baryon and photon production with the H1 and ZEUS detectors at electron-proton collider HERA are presented and compared to the theoretical calculations and Monte Carlo models. Results are presented of the production of leading protons, neutrons and photons in deep inelastic scattering (ep → e' pX, ep → e'nX, ep → e'γX as well as the leading neutron production in the photoproduction of dijets (ep → ejjXn. The forward baryon and photon results from the H1 and ZEUS Experiments are compared also with the models of the hadronic interactions of high energy Cosmic Rays. The sensitivity of the HERA data to the differences between the models is demonstrated.

  2. Measurements of the neutral current e{sup {+-}}p cross sections using longitudinally polarised lepton beams at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Nikiforov, A.

    2007-01-18

    This thesis presents inclusive e{sup {+-}}p single and double differential cross sections for neutral current deep inelastic scattering measured as functions of the four-momentum transfer squared Q{sup 2} and the Bjorken variable x in interactions of longitudinally polarised leptons with unpolarised protons using the H1 detector at HERA II. An overview of the phenomenology of deep inelastic scattering is given and the experimental apparatus as well as the measurement and analysis procedures are described. The analysis is based on e{sup +}p data taken in 2003-04 and e{sup -}p data taken in 2005 at a centre-of-mass energy of {radical}(s)=318 GeV, with integrated luminosities of 47.6 pb{sup -1} and 98.4 pb{sup -1} for the e{sup +}p and e{sup -}p samples, respectively. The cross sections are measured in the range of 200measurements are used to study polarisation e ects in neutral current interactions and to determine the structure function xF{sub 3}. The new HERA II data are combined together with previously published data from HERA I to determine the structure function xF{sub 3} with improved precision. Furthermore, this measurement is combined with the corresponding ZEUS measurement to provide the most accurate measurement of the interference structure function xF{sup {gamma}}{sup Z}{sub 3}, which is sensitive to the valence quark distributions down to low values of x. The data on polarised cross section asymmetries A{sup {+-}} are also combined with the ZEUS data. This leads to the first observation of parity violation in neutral current e{sup {+-}}p scattering at distances down to 10{sup -18} m. The data are well described by the Standard Model predictions. (orig.)

  3. Measurement of isolated photon production in deep-inelastic scattering at HERA

    Science.gov (United States)

    Aaron, F. D.; Aktas, A.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cantun Avila, K. B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J. G.; Coughlan, J. A.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, L.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, T.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A. J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Tran, T. H.; Traynor, D.; Trinh, T. N.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, C.; Wolf, R.; Wünsch, E.; Xella, S.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2008-04-01

    The production of isolated photons in deep-inelastic scattering ep→eγX is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 450 GeV. The analysis is based on a total integrated luminosity of 227 pb-1. The production cross section of isolated photons with a transverse energy in the range 3measured as a function of ET γ, ηγ and Q2. Isolated photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections.

  4. Measurement of Isolated Photon Production in Deep-Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, A.W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, L.; Martisikova, M.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, M.U.; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, T.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, C.; Wolf, R.; Wunsch, E.; Xella, S.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2008-01-01

    The production of isolated photons in deep-inelastic scattering $ep\\to e \\gamma X$ is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared $450$ GeV. The analysis is based on a total integrated luminosity of 227~pb$^{-1}$. The production cross section of isolatedphotons with a transverse energy in the range $3 < E_T^\\gamma < 10$ GeV and pseudorapidity range $-1.2 < \\eta^\\gamma < 1.8$ is measured as a function of $E_T^\\gamma$, $\\eta^\\gamma$ and $Q^2$. Isolated photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections.

  5. Measurement of inclusive jet cross sections in photoproduction at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Beglarian, A.; Behnke, O.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Chekelian, V.; Clarke, D.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Haidt, D.; Hajduk, L.; Haller, J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, C.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Katzy, J.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Koutouev, R.; Koutov, A.; Kroseberg, J.; Kruger, K.; Kuhr, T.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebailly, E.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loginov, A.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milstead, D.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Newman, Paul R.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Petrukhin, A.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schoerner-Sadenius, Thomas; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vassiliev, S.; Vazdik, Y.; Veelken, C.; Vest, A.; Vichnevski, A.; Volchinski, V.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wiesand, S.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

    2003-01-01

    Inclusive jet cross sections are measured in photoproduction at HERA using the H1 detector. The data sample of e+ p -> e+ + jet + X events in the kinematic range of photon virtualities Q^2 < 1 GeV^2 and photon-proton centre-of-mass energies 95 < W_gammap < 285 GeV represents an integrated luminosity of 24.1 pb^-1. Jets are defined using the inclusive k_T algorithm. Single- and multi-differential cross sections are measured as functions of jet transverse energy E_T^jet and pseudorapidity \\eta^jet in the domain 5 < E_T^jet < 75 GeV and -1 < \\eta^jet < 2.5. The cross sections are found to be in good agreement with next-to-leading order perturbative QCD calculations corrected for fragmentation and underlying event effects. The cross section differential in E_T^jet, which varies by six orders of magnitude over the measured range, is compared with similar distributions from p pbar colliders at equal and higher energies.

  6. Measurement of beauty quark mass at HERA and impact on Higgs production in association with beauty quarks at LHC

    International Nuclear Information System (INIS)

    Gizhko, Andrii

    2016-06-01

    Three different, but related topics are the subject of this thesis, performed in the context of the ZEUS and CMS groups at DESY. The first measurement of the MS beauty-quark mass m b (m b ) at an electron-proton collider is presented. The measurement is based on a QCD analysis of beauty production cross sections in deep inelastic (DIS) ep scattering measured by ZEUS at HERA, together with inclusive DIS HERA data, using Next-to-Leading-Order QCD predictions. The measured value of the running beauty-quark mass in the MS scheme was found to be m b (m b )=4.07±0.14 (fit) +0.01 -0.07 (mod.) +0.05 -0.00 (param.) +0.08 -0.05 ( theo.) GeV, which is in good agreement with the world average Particle Data Group value and previous measurements at electron-positron colliders. It is also found to be consistent with the expected running of m b (μ). A first measurement of the charm-quark mass m c (μ) running in the MS scheme is presented. The measurement is based on a QCD analysis of the published H1 and ZEUS combination of charm cross section measurements in DIS ep scattering at HERA, together with inclusive DIS HERA data, using Next-to-Leading-Order QCD predictions. The running charm-quark mass m c (μ) was measured at different scales μ and is presented in a charm-quark mass running plot with a comparison to the world average Particle Data Group m c (m c ) evolved to higher scales. The running is found to be consistent with the expectations from QCD. The uncertainties of the theoretical predictions for Higgs production in association with beauty-quarks originating from the beauty-quark mass were studied and reduced for massive and massless QCD calculations. The beauty-quark mass measurement m b (m b ) was used to decrease the variation of the beauty-quark mass to 0.17 GeV. It was shown that the uncertainty from the beauty-quark mass m b (m b ) in the case of massive calculations for Hb anti b production at LHC can be reduced to 2%. This makes it negligible compared to other

  7. Measurement of beauty quark mass at HERA and impact on Higgs production in association with beauty quarks at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Gizhko, Andrii

    2016-06-15

    Three different, but related topics are the subject of this thesis, performed in the context of the ZEUS and CMS groups at DESY. The first measurement of the MS beauty-quark mass m{sub b}(m{sub b}) at an electron-proton collider is presented. The measurement is based on a QCD analysis of beauty production cross sections in deep inelastic (DIS) ep scattering measured by ZEUS at HERA, together with inclusive DIS HERA data, using Next-to-Leading-Order QCD predictions. The measured value of the running beauty-quark mass in the MS scheme was found to be m{sub b}(m{sub b})=4.07±0.14 (fit){sup +0.01}{sub -0.07}(mod.){sup +0.05}{sub -0.00}(param.){sup +0.08}{sub -0.05}( theo.) GeV, which is in good agreement with the world average Particle Data Group value and previous measurements at electron-positron colliders. It is also found to be consistent with the expected running of m{sub b}(μ). A first measurement of the charm-quark mass m{sub c}(μ) running in the MS scheme is presented. The measurement is based on a QCD analysis of the published H1 and ZEUS combination of charm cross section measurements in DIS ep scattering at HERA, together with inclusive DIS HERA data, using Next-to-Leading-Order QCD predictions. The running charm-quark mass m{sub c}(μ) was measured at different scales μ and is presented in a charm-quark mass running plot with a comparison to the world average Particle Data Group m{sub c}(m{sub c}) evolved to higher scales. The running is found to be consistent with the expectations from QCD. The uncertainties of the theoretical predictions for Higgs production in association with beauty-quarks originating from the beauty-quark mass were studied and reduced for massive and massless QCD calculations. The beauty-quark mass measurement m{sub b}(m{sub b}) was used to decrease the variation of the beauty-quark mass to 0.17 GeV. It was shown that the uncertainty from the beauty-quark mass m{sub b}(m{sub b}) in the case of massive calculations for Hb anti b

  8. Measurement of diffractive scattering of photons with large momentum transfer at HERA

    Science.gov (United States)

    H1 Collaboration; Aaron, F. D.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Bacchetta, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cantun Avila, K. B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J. G.; Coughlan, J. A.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Daum, K.; Deák, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kutak, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Mudrinic, M.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G. D.; Pejchal, O.; Peng, H.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; Radescu, V.; Rahmat, A. J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J. E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Shushkevich, S.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Tran, T. H.; Traynor, D.; Trinh, T. N.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wegener, D.; Wessels, M.; Wissing, Ch.; Wünsch, E.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2009-02-01

    The first measurement of diffractive scattering of quasi-real photons with large momentum transfer γp→γY, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q<0.01 GeV. Single differential cross sections are measured as a function of W, the incident photon-proton centre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175measured |t| dependence is harder than that predicted by the model and those observed in exclusive vector meson production.

  9. Tau Lepton Production in ep Collisions at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Flucke, G.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Marti, L.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A.J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Toll, T.; Tomasz, F.; Traynor, D.; Truol, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, Marcel; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-01-01

    The production of tau leptons in ep collisions is investigated using data recorded by the H1 detector at HERA in the period 1994-2000. Tau leptons are identified by detecting their decay products, using leptonic and hadronic decay modes. The cross section for the production of tau lepton pairs is measured for the first time at HERA. Furthermore, a search for events with an energetic isolated tau lepton and with large missing transverse momentum is performed. The results are found to be in agreement with the Standard Model predictions.

  10. Tau lepton production in ep collisions at HERA

    Science.gov (United States)

    Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Flucke, G.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Marti, L.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A. J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, M.; Usik, A.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wissing, C.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-12-01

    The production of tau leptons in ep collisions is investigated using data recorded by the H1 detector at HERA in the period 1994 2000. Tau leptons are identified by detecting their decay products, using leptonic and hadronic decay modes. The cross section for the production of tau lepton pairs is measured for the first time at HERA. Furthermore, a search for events with an energetic isolated tau lepton and with large missing transverse momentum is performed. The results are found to be in agreement with the Standard Model predictions.

  11. Prospects for measuring ΔG from jets at HERA with polarized protons and electrons

    International Nuclear Information System (INIS)

    Roeck, A. de; Feltesse, J.; Kunne, F.; Maul, M.; Schaefer, A.; Wu, C.Y.; Mirkes, E.; Raedel, G.

    1996-09-01

    The measurement of the polarized gluon distribution function ΔG(x) from photon-gluon fusion processes in electron-proton deep inelastic scattering producing two jets has been investigated. The study is based on the MEPJET and PEPSI simulation programs. The size of the expected spin asymmetry and corresponding statistical uncertainties for a possible measurement with polarized beams of electrons and protons at HERA have been estimated. The results show that the asymmetry can reach a few percent, and is not washed out by hadronization and higher order processes. (orig.)

  12. Prospects for Measuring $\\Delta$G from Jets at HERA with Polarized Protons and Electrons

    CERN Document Server

    De Roeck, A.; Kunne, F.; Maul, M.; Schafer, A.; Wu, C.Y.; Mirkes, E.; Radel, G.

    1996-01-01

    The measurement of the polarized gluon distribution function Delta G(x) from photon-gluon fusion processes in electron-proton deep inelastic scattering producing two jets has been investigated. The study is based on the MEPJET and PEPSI simulation programs. The size of the expected spin asymmetry and corresponding statistical uncertainties for a possible measurement with polarized beams of electrons and protons at HERA have been estimated. The results show that the asymmetry can reach a few percent, and is not washed out by hadronization and higher order processes.

  13. Measurement of isolated photon production in deep-inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.

    2007-10-01

    The production of isolated photons in deep-inelastic scattering ep → eγX is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 4 2 2 and a mass of the hadronic system W X >50 GeV. The analysis is based on a total integrated luminosity of 227 pb -1 . The production cross section of isolated photons with a transverse energy in the range 3 γ T γ γ T , η γ and Q 2 . Isolated photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections. (orig.)

  14. Inclusive charm production at HERA and charm content of the proton

    Energy Technology Data Exchange (ETDEWEB)

    Drees, M [Wisconsin Univ., Madison, WI (United States). Dept. of Physics; Godbole, R M [Istituto Nazionale di Fisica Nucleare, Frascati (Italy)

    1995-05-01

    The authors calculate the contribution to inclusive high transverse momentum (p{sub T}) charm production at HERA (hadron electron ring at large) from the excitation of charm in the photon. At large values of p{sub T} the results of such a calculation, in the structure function language, will be more reliable as it sums the large logs log(p{sub T}{sup 2}/m{sub C}{sup 2}), as opposed to calculating the contribution of the 2{yields}3 subprocesses in fixed order of perturbation theory. They find that this contribution is large and comparable to the contribution from {gamma}g fusion production of charm. Suitable cuts on the rapidity of the `away-side` large p{sub T} jet allow a very neat separation between the contributions from the excitation process and from pair-production. Including this excitation contribution the authors can reproduce the measured inclusive D{sup *} and {mu} cross-section measured by the ZEUS and H1 collaborations respectively, in a LO calculation.

  15. Measurement of open beauty production at HERA in the D{sup *}{mu} final state

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, IL (US)] (and others)

    2006-09-15

    The production of beauty quarks with a D{sup *{+-}} and a muon in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb{sup -1}. Low transverse-momentum thresholds for the muon and D{sup *} meson allow a measurement of beauty production closer to the production threshold than previous measurements. The beauty signal was extracted using the charge correlations and angular distributions of the muon with respect to the D{sup *} meson. Cross sections for photoproduction and deep inelastic scattering are somewhat higher than, but compatible with, next-to-leading-order QCD predictions, and compatible with other measurements. (orig.)

  16. Measurement of beauty and charm production in deep inelastic scattering at HERA and measurement of the beauty-quark mass

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2014-05-01

    The production of beauty and charm quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared 5 2 2 using an integrated luminosity of 354 pb -1 . The beauty and charm content in events with at least one jet have been extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of Q 2 , Bjorken x, jet transverse energy and pseudorapidity were measured and compared with next-to-leading-order QCD calculations. The beauty and charm contributions to the proton structure functions were extracted from the double-differential cross section as a function of x and Q 2 . The running beauty-quark mass, m b at the scale m b , was determined from a QCD fit at next-to-leading order to HERA data for the first time and found to be m b (m b )=4.07±0.14(fit) +0.01 -0.07 (mod.) +0.05 -0.00 (param.) +0.08 -0.05 (theo) GeV.

  17. Measurement of the proton structure function F2 in ep scattering at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1993-08-01

    This paper presents our first measurement of the F 2 structure function in neutral-current, deep inelastic scattering using the ZEUS detector at HERA, the ep colliding beam facility at DESY. The data correspond to an integrated luminosity of 24.7 nb -1 . Results are presented for data in a range of Q 2 from 10 GeV 2 to 4700 GeV 2 and Bjorken x down to 3.0x10 -4 . The F 2 structure function increases rapidly as x decreases. (orig.)

  18. Measurement of Dijet Production in Diffractive Deep-Inelastic ep Scattering at HERA

    CERN Document Server

    Andreev, V.; Begzsuren, K.; Belousov, A.; Boudry, V.; Brandt, G.; Brisson, V.; Britzger, D.; Buniatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Cvach, J.; Dainton, J.B.; Daum, K.; Diaconu, C.; Dobre, M.; Dodonov, V.; Eckerlin, G.; Egli, S.; Elsen, E.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Haidt, D.; Henderson, R.C.W.; Herbst, M.; Hladky, J.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jung, H.; Kapichine, M.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Laycock, P.; Lebedev, A.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Morozov, A.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nowak, G.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shushkevich, S.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Straumann, U.; Sykora, T.; Thompson, P.D.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zhang, Z.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

    2015-03-18

    A measurement is presented of single- and double-differential dijet cross sections in diffractive deep-inelastic $ep$ scattering at HERA using data collected by the H1 experiment corresponding to an integrated luminosity of 290 pb^{-1}. The investigated phase space is spanned by the photon virtuality in the range of 4

  19. Measurement of the charm fragmentation function in D* photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-12-01

    The charm fragmentation function has been measured in D * photoproduction with the ZEUS detector at HERA using an integrated luminosity of 120 pb -1 . The fragmentation function is measured versus z=(E+p parallel ) D * /2E jet , where E is the energy of the D * meson and p parallel is the longitudinal momentum of the D * meson relative to the axis of the associated jet of energy E jet . Jets were reconstructed using the k T clustering algorithm and required to have transverse energy larger than 9 GeV. The D * meson associated with the jet was required to have a transverse momentum larger than 2 GeV. The measured function is compared to different fragmentation models incorporated in leading-logarithm Monte Carlo simulations and in a next-to-leading-order QCD calculation. The free parameters in each fragmentation model are fitted to the data. The extracted parameters and the function itself are compared to measurements from e + e - experiments. (orig.)

  20. Measurement of Diffractive Scattering of Photons with Large Momentum Transfer at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Bacchetta, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Mudrinic, M.; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Peng, H.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Smirnov, P.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wegener, D.; Wessels, M.; Wissing, Ch.; Wunsch, E.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2009-01-01

    The first measurement of diffractive scattering of quasi-real photons with large momentum transfer gamma p -> gamma Y, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q^2 < 0.01 GeV^2. Cross sections are measured as a function of W, the incident photon-proton entre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175 < W < 247 GeV and 4<|t|<36 GeV^2. The W dependence is well described by a model based on perturbative QCD using a leading logarithmic approximation of the BFKL evolution. The measured |t| dependence is harder than that predicted by the model and those observed in exclusive vector meson production.

  1. Hard diffraction at HERA and Tevatron

    International Nuclear Information System (INIS)

    Kaidalov, A.B.

    2001-01-01

    A relation between hard diffraction at HERA and Tevatron is discussed. A model, which takes into account unitarity effects is developed for interaction of high-energy virtual photons with nucleons. It is shown that this model gives a good description of HERA data on both total γ* p total cross section and diffractive dissociation of virtual photons in a broad region of Q 2 . It is shown how to describe the CDF data on diffractive jet production at Tevatron using an information on distribution of partons in the Pomeron from HERA experiments

  2. Measurement of charged particle spectra in deep-inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (Russian Federation); Baghdasaryan, A. [Yerevan Physics Institute (Armenia)] [and others; Collaboration: H1 Collaboration

    2013-01-15

    Charged particle production in deep-inelastic ep scattering is measured with the H1 detector at HERA. The kinematic range of the analysis covers low photon virtualities, 5measured as a function of pseudorapidity ({eta}{sup *}) and transverse momentum (p{sub T}{sup *}) in the range 0<{eta}{sup *}<5 and 0

  3. Measurement of charged particle spectra in deep-inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Alexa, C.; Dobre, M.; Rotaru, M.; Stoicea, G. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Vazdik, Y. [Lebedev Physical Institute, Moscow (Russian Federation); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Institute, Yerevan (Armenia); Bartel, W.; Belov, P.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Begzsuren, K.; Ravdandorj, T. [Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Boudry, V.; Specka, A. [Ecole Polytechnique, CNRS/IN2P3, LLR, Palaiseau (France); Bozovic-Jelisavcic, I.; Pandurovic, M. [University of Belgrade, Vinca Institute of Nuclear Sciences, Belgrade (Serbia); Brandt, G. [Oxford University, Department of Physics, Oxford (United Kingdom); Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F. [Universite Paris-Sud, CNRS/IN2P3, LAL, Orsay (France); Buniatyan, A.; Huber, F.; Pirumov, H.; Sauter, M.; Schoening, A. [Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Lubimov, V.; Rostovtsev, A.; Tseepeldorj, B. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E. [CINVESTAV, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Ceccopieri, F.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Roosen, R.; Staykova, Z.; Mechelen, P.Van [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerpen (Belgium); Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R. [Charles University, Faculty of Mathematics and Physics, Praha (Czech Republic); Chekelian, V.; Grindhammer, G.; Kiesling, C. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Cvach, J.; Hladky and grave, J.; Reimer, P.; Zalesak, J. [Academy of Sciences of the Czech Republic, Institute of Physics, Praha (Czech Republic); Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D. [University of Liverpool, Department of Physics, Liverpool (United Kingdom); Daum, K.; Meyer, H. [Universitaet Wuppertal, Fachbereich C, Wuppertal (Germany); Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C. [Aix-Marseille Univ, CNRS/IN2P3, CPPM, Marseille (France); Dodonov, V. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Dossanov, A. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Max-Planck-Institut fuer Physik, Muenchen (Germany); Egli, S.; Hildebrandt, M.; Horisberger, R. [Paul Scherrer Institut, Villigen (Switzerland); Feltesse, J.; Perez, E.; Schoeffel, L. [CE-Saclay, CEA, DSM/Irfu, Gif-sur-Yvette (France); Ferencei, J. [Slovak Academy of Sciences, Institute of Experimental Physics, Kosice (Slovakia); Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J. [Institute for Nuclear Physics, Cracow (Poland); Grab, C. [ETH, Institut fuer Teilchenphysik, Zuerich (Switzerland); Henderson, R.C.W. [University of Lancaster, Department of Physics, Lancaster (United Kingdom); Hennekemper, E.; Herbst, M.; Schultz-Coulon, H.C. [Universitaet Heidelberg, Kirchhoff-Institut fuer Physik, Heidelberg (Germany); Herrera, G.; Lopez-Fernandez, R. [CINVESTAV IPN, Departamento de Fisica, Mexico City (Mexico); Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T. [DESY, Zeuthen (Germany); Joensson, L. [University of Lund, Physics Department, Lund (Sweden); Jung, H. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerpen (Belgium); DESY, Hamburg (Germany); Kapichine, M.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kogler, R.; Nowak, K. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Landon, M.P.J.; Rizvi, E.; Traynor, D. [Queen Mary, University of London, School of Physics and Astronomy, London (United Kingdom); Martyn, H.U. [I. Physikalisches Institut der RWTH, Aachen (Germany); Morris, J.V.; Sankey, D.P.C. [STFC, Rutherford Appleton Laboratory, Didcot, Oxfordshire (United Kingdom); Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P. [Physik-Institut der Universitaet Zuerich, Zuerich (Switzerland); Newman, P.R.; Thompson, P.D. [University of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Picuric, I.; Raicevic, N. [University of Montenegro, Faculty of Science, Podgorica (Montenegro); Soloviev, Y. [DESY, Hamburg (Germany); Lebedev Physical Institute, Moscow (Russian Federation); Stella, B. [Dipartimento di Fisica Universita di Roma Tre (Italy); INFN Roma 3, Roma (Italy); Sykora, T. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerpen (Belgium); Charles University, Faculty of Mathematics and Physics, Praha (Czech Republic); Tsakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (Bulgaria); Wegener, D. [TU Dortmund, Institut fuer Physik, Dortmund (Germany); Collaboration: The H1 Collaboration

    2013-04-15

    Charged particle production in deep-inelastic ep scattering is measured with the H1 detector at HERA. The kinematic range of the analysis covers low photon virtualities, 5 < Q{sup 2} < 100 GeV{sup 2}, and small values of Bjorken-x, 10{sup -4} < x < 10{sup -2}. The analysis is performed in the hadronic centre-of-mass system. The charged particle densities are measured as a function of pseudorapidity ({eta}{sup *}) and transverse momentum (p{sub T}{sup *}) in the range 0<{eta}{sup *} < 5 and 0

  4. On the measurability of the structure function g1(x,Q2) in ep collisions at HERA

    International Nuclear Information System (INIS)

    Bluemlein, J.

    1995-08-01

    The possibility is investigated to measure the polarized structure function g 1 (x, Q 2 ) in the collider mode of HERA operating with a polarized lepton and proton beam. The x dependence of g 1 can be measured at a statistical precision of ∝15% to 70% in the range 0.0005 2 > 2 at beam polarizations λ p ∝λ e =0.8 and L int =60 pb -1 . (orig.)

  5. High PT leptons and single W boson production at HERA

    International Nuclear Information System (INIS)

    Korcsak-Gorzo, Katherine

    2010-12-01

    A search for isolated electrons and muons with high transverse momentum in events with large missing transverse momentum has been conducted. The results have been found to be compatible with the Standard Model expectations. The cross section for single W production has been measured and the total cross section in electron-proton collisions at HERA has been found to be σ(ep → eWX) = 0.93 -0.23 +0.26 (stat.)±0.08(syst.) pb. The measurements are based on the complete available ZEUS data sets from the HERA I and II running periods taken between 1994-2007. (orig.)

  6. Measurement of elastic ρ0 photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-01-01

    Elastic ρ 0 photoproduction has been measured using the ZEUS detector at HERA. Untagged photoproduction events from ep interactions were used to measure the reaction γp→ρ 0 p (ρ 0 →π + π - )at photon-proton centre-of-mass energies between 60 and 80 GeV and vertical stroke t vertical stroke 2 , where t is the square of the four-momentum transferred at the proton vertex. The differential cross section dσ/dM ππ , where M ππ is the invariant mass of the two pions, and the integrated cross section, σ γp →ρ 0 p , are presented; the latter was measured to be 14.7 ±0.4(stat.)±2.4(syst.) μb. The differential cross section dσ/dt has an approximately exponential shape; a fit of the type A' t exp(-b' t vertical stroke t vertical stroke +c' t t 2 ) yields a t-slope b' t =9.9±1.2(stat.)±1.4(syst.) GeV -2 . The results, when compared to low energy data, show a weak energy dependence of both σ γp→ρ 0 p and of the t-slope. The ρ 0 is produced predominantly with transverse polarisation, demostrating that s-channel helicity conservation holds at these energies. (orig.)

  7. Measurement of elastic ρ0 photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-07-01

    Elastic ρ 0 photoproduction has been measured using the ZEUS detector at HERA. Untagged photoproduction events from ep interactions were used to measure the reaction γp→ρ 0 p (ρ 0 →π + π - ) at photon-proton centre-of-mass energies between 60 and 80 GeV and vertical stroke tvertical stroke 2 , where t is the square of the four-momentum transferred at the proton vertex. The differential cross section dσ/dM ππ , where M ππ is the invariant mass of the two pions, and the integrated cross section, σsub(γp→ρ 0 p), are presented; the latter was measured to be 14.7±0.4(stat.)±2.4(syst.) μb. The differential cross section dσ/dt has an approximately exponential shape; a fit of the type A' t exp(-b' t vertical stroke tvertical stroke +c' t t 2 ) yields a t-slope b' t =9.9±1.2(stat.)±1.4(syst.) μb. The results, when compared to low energy data, show a weak energy dependence of both σsub(γp→ρ 0 p) and of the t-slope. The ρ 0 is produced predominantly with transverse polarisation, demonstrating that s-channel helicity conservation holds at these energies. (orig.)

  8. Structure of the hexameric HerA ATPase reveals a mechanism of translocation-coupled DNA-end processing in archaea.

    Science.gov (United States)

    Rzechorzek, Neil J; Blackwood, John K; Bray, Sian M; Maman, Joseph D; Pellegrini, Luca; Robinson, Nicholas P

    2014-11-25

    The HerA ATPase cooperates with the NurA nuclease and the Mre11-Rad50 complex for the repair of double-strand DNA breaks in thermophilic archaea. Here we extend our structural knowledge of this minimal end-resection apparatus by presenting the first crystal structure of hexameric HerA. The full-length structure visualizes at atomic resolution the N-terminal HerA-ATP synthase domain and a conserved C-terminal extension, which acts as a physical brace between adjacent protomers. The brace also interacts in trans with nucleotide-binding residues of the neighbouring subunit. Our observations support a model in which the coaxial interaction of the HerA ring with the toroidal NurA dimer generates a continuous channel traversing the complex. HerA-driven translocation would propel the DNA towards the narrow annulus of NurA, leading to duplex melting and nucleolytic digestion. This system differs substantially from the bacterial end-resection paradigms. Our findings suggest a novel mode of DNA-end processing by this integrated archaeal helicase-nuclease machine.

  9. Measurement of the longitudinal proton structure function with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Grebenyuk, Julia

    2010-01-01

    The reduced neutral current cross sections for ep deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. The reduced cross sections were measured double differentially in Bjorken x and the virtuality Q 2 . From these the proton structure functions F L and F 2 have been extracted in the region 5 x 10 -4 measured reduced cross sections were combined with results from the H1 collaboration, in the region 2.4 x 10 -4 measurement was performed.

  10. Measurement of diffractive scattering of photons with large momentum transfer at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania)]|[Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2008-09-15

    The first measurement of diffractive scattering of quasi-real photons with large momentum transfer {gamma}p {yields} {gamma}Y, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q{sup 2} < 0.01 GeV{sup 2}. Cross sections are measured as a function of W, the incident photonproton centre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175 < W < 247 GeV and 4 < vertical stroke t vertical stroke < 36 GeV{sup 2}. The W dependence is well described by a model based on perturbative QCD using a leading logarithmic approximation of the BFKL evolution. The measured vertical stroke t vertical stroke dependence is harder than that predicted by the model and those observed in exclusive vector meson production. (orig.)

  11. Transverse momentum of gluons in ep-scattering at HERA

    International Nuclear Information System (INIS)

    Cholewa, A.

    2005-11-01

    A Monte Carlo analysis of the phase space of hard interacting gluons in ep-scattering is presented. The event generator CASCADE is used in combination with the program HZTOOL to identify the accessible regions of phase space of present HERA measurements. A map of the k t -x g -plane is presented to show that in the region -3≤log g ≤-1 transverse gluon momenta of up to k t >or sim 20 GeV are accessible to HERA measurements. Furthermore the observables x γ and the transverse jet energy E T are found to be highly sensitive to the transverse momentum and the longitudinal momentum fraction of gluons. (orig.) (orig.)

  12. Measurement of high-Q2 deep inelastic scattering cross sections with a longitudinally polarised positron beam at HERA

    NARCIS (Netherlands)

    Chekanov, S.; Kooijman, P.

    2006-01-01

    The cross sections for charged and neutral current deep inelastic scattering in e+p collisions with a longitudinally polarised positron beam have been measured using the ZEUS detector at HERA. The results, based on data corresponding to an integrated luminosity of 23.8 pb−1 at , are given for both

  13. Measurement of D+ and Λc+ production in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2010-06-01

    Charm production in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 120 pb -1 . The hadronic decay channels D + → K S 0 π + , Λ c + → pK S 0 and Λ c + →Λπ + , and their charge conjugates, were reconstructed. The presence of a neutral strange hadron in the final state reduces the combinatorial background and extends the measured sensitivity into the low transverse momentum region. The kinematic range is 0 T (D + , Λ c + ) + , Λ c + ) vertical stroke 2 2 and 0.02 + mesons are compared to next-to-leading-order QCD predictions. The fraction of c quarks hadronizing into Λ c + baryons is extracted. (orig.)

  14. Measurement of beauty photoproduction using decays into muons in dijet events at HERA

    International Nuclear Information System (INIS)

    2009-01-01

    Beauty photoproduction in dijet events has been measured at HERA with the ZEUS detector using an integrated luminosity of 126 pb -1 . Beauty was identified in events with a muon in the final state by using the transverse momentum of the muon relative to the closest jet. Lifetime information from the silicon vertex detector was also used; the impact parameter of the muon with respect to the primary vertex was exploited to discriminate between signal and background. Cross sections for beauty production as a function of the muon and the jet variables as well as dijet correlations are compared to QCD predictions and to previous measurements. The data are well described by predictions from next-to-leading-order QCD.

  15. New aspects of the structure of the proton revealed by the collider Hera; Nouveaux aspects de la structure du proton avec le collisionneur HERA

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z

    2000-12-01

    Since its commissioning in 1991, the ep collider HERA has been running successfully for almost a decade without stopping improving its performance. In this report, the inclusive cross section and structure function measurements for the deep inelastic scattering of neutral and charged current processes in the full HERA kinematic domain are reviewed. The results are compared with the Standard Model expectations for the deep inelastic scattering processes. The new insights into the proton structure and on the underlying strong and electroweak interactions are discussed. (author)

  16. Probing Positron Gravitation at HERA

    International Nuclear Information System (INIS)

    Gharibyan, Vahagn

    2015-07-01

    An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Here I develop a method based on high energy Compton scattering to measure the gravitational interaction of accelerated charged particles. Within that formalism the Compton spectra measured at HERA rule out the positron's anti-gravity and hint for a positron's 1.3(0.2)% weaker coupling to the gravitational field relative to an electron.

  17. Probing Positron Gravitation at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Gharibyan, Vahagn

    2015-07-15

    An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Here I develop a method based on high energy Compton scattering to measure the gravitational interaction of accelerated charged particles. Within that formalism the Compton spectra measured at HERA rule out the positron's anti-gravity and hint for a positron's 1.3(0.2)% weaker coupling to the gravitational field relative to an electron.

  18. Measurement of beauty quark mass at HERA and impact on Higgs production in association with beauty quarks at LHC

    CERN Document Server

    Gizhko, Andrii; Foster, Brian

    2016-01-01

    Three different, but related topics are the subject of this thesis, performed in the contextof the ZEUS and CMS groups at DESY. The first measurement of the MS beauty-quarkmass mb (mb ) at an electron-proton collider is presented. The measurement is based ona QCD analysis of beauty production cross sections in deep inelastic (DIS) ep scatteringmeasured by ZEUS at HERA, together with inclusive DIS HERA data, using Next-toLeading-Order QCD predictions. The measured value of the running beauty-quark massin the MS scheme was found to bemb (mb ) = 4.07 ± 0.14 (fit)+0.01 (mod.)+0.05 (param.) +0.08 (theo.) GeV, which is in good−0.07−0.00−0.05agreement with the world average Particle Data Group value and previous measurementsat electron-positron colliders. It is also found to be consistent with the expected runningof mb (µ).A first measurement of the charm-quark mass mc (µ) running in the MS scheme ispresented. The measurement is based on a QCD analysis of the published H1 and ZEUScombination of charm cr...

  19. A Precision Measurement of the Inclusive ep Scattering Cross Section at HERA

    CERN Document Server

    Aaron, F.D.; Alimujiang, K.; Andreev, V.; Antunovic, B.; Asmone, A.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.-J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Glushkov, I.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Mudrinic, M.; Muller, K.; Murin, P.; Naroska, B.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Preda, T.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; von den Driesch, M.; Wegener, D.; Wallny, R.; Wissing, Ch.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.; Zus, R.

    2009-01-01

    A measurement of the inclusive deep-inelastic neutral current e+p scattering cross section is reported in the region of four-momentum transfer squared, 12<=Q^2<=150 GeV^2, and Bjorken x, 2x10^-4<=x<=0.1. The results are based on data collected by the H1 Collaboration at the ep collider HERA at positron and proton beam energies of E_e=27.6 GeV and E_p=920 GeV, respectively. The data are combined with previously published data, taken at E_p=820 GeV. The accuracy of the combined measurement is typically in the range of 1.3-2%. A QCD analysis at next-to-leading order is performed to determine the parton distributions in the proton based on H1 data.

  20. Measurement of Beauty Production at HERA Using Events with Muons and Jets

    CERN Document Server

    Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kroseberg, J.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxeld, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Winter, G.-G.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; Zomer, F.

    2005-01-01

    A measurement of the beauty production cross section in ep collisions at a centre-of-mass energy of 319 GeV is presented. The data were collected with the H1 detector at the HERA collider in the years 1999-2000. Events are selected by requiring the presence of jets and muons in the final state. Both the long lifetime and the large mass of b-flavoured hadrons are exploited to identify events containing beauty quarks. Differential cross sections are measured in photoproduction, with photon virtualities Q^2 < 1 GeV^2, and in deep inelastic scattering, where 2 < Q^2 < 100 GeV^2. The results are compared with perturbative QCD calculations to leading and next-to-leading order. The predictions are found to be somewhat lower than the data.

  1. Heavy Quark Production at HERA in KT Factorization Supplemented With CCFM Evolution

    International Nuclear Information System (INIS)

    Jung, H.

    2001-01-01

    The application of k t - factorization, supplemented with the CCFM small-x evolution equation, to heavy quark production is discussed. Differential cross sections of bb production and also inelastic J/ψ production as measured at HERA are compared to the hadron level CCFM Monte Carlo generator Cascade, using the unintegrated gluon density obtained within the CCFM evolution approach from a fit to HERA F 2 data. (author)

  2. The HERA Approach To Morally Competent Robots

    DEFF Research Database (Denmark)

    Lindner, Felix; Bentzen, Martin Mose; Nebel, Bernhard

    2017-01-01

    for implementation in robots. The novelty is that HERA implements multiple ethical principles like utilitarianism, the principle of double effect, and a Pareto-inspired principle. These principles can be used to automatically assess moral situations represented in a format we call causal agency models. We discuss......To address the requirement for autonomous moral decision making, we introduce a software library for modeling hybrid ethical reasoning agents (short: HERA). The goal of the HERA project is to provide theoretically well-founded and practically usable logic-based machine ethics tools...... how to model moral situations using our approach, and how it can cope with uncertainty about moral values. Finally, we briefly outline the architecture of our robot IMMANUEL, which implements HERA and is able to explain ethical decisions to humans....

  3. Measurement of Beauty Photoproduction near Threshold using Di-electron Events with the H1 Detector at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, A.W.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lopez-Fernandez, R.; Lubimov, V.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Pandurovic, M.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

    2012-10-03

    The cross section for ep -> e b\\bar{b} X in photoproduction is measured with the H1 detector at the ep-collider HERA. The decay channel b\\bar{b} -> ee X' is selected by identifying the semi-electronic decays of the b-quarks. The total production cross section is measured in the kinematic range given by the photon virtuality Q^2 down to the threshold. The results are compared to next-to-leading-order QCD predictions.

  4. Charm, Beauty and Top at HERA

    International Nuclear Information System (INIS)

    Behnke, O.; Geiser, A.; Lisovyi, M.

    2015-06-01

    Results on open charm and beauty production and on the search for top production in high-energy electron-proton collisions at HERA are reviewed. This includes a discussion of relevant theoretical aspects, a summary of the available measurements and measurement techniques, and their impact on improved understanding of QCD and its parameters, such as parton density functions and charm- and beauty-quark masses. The impact of these results on measurements at the LHC and elsewhere is also addressed.

  5. Measurement of charm and beauty production in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Roloff, Philipp

    2011-12-01

    In this thesis two measurements of heavy quark production in deep inelastic scattering at HERA are presented. Cross sections for the production of heavy quarks can be calculated in quantum chromodynamics (QCD). The heavy quark masses represent hard scales, which allow to apply perturbative methods. Charm production has been measured with the ZEUS detector using an integrated luminosity of 120 pb -1 . The hadronic decay channels D + → K 0 S π + , Λ + c → pK 0 S and Λ + c → Λπ + were reconstructed. The presence of a neutral strange hadron in the final state reduces the combinatorial background and extends the measured sensitivity into the region p T (D + , Λ + c ) T 2 (D + ), η(D + ), Q 2 and x for the production of D + mesons are in reasonable agreement with predictions from perturbative QCD. The fraction of c quarks hadronising into Λ + c baryons was extracted from a combination of both investigated Λ + c decay channels. The result is consistent with a previous measurement in the photoproduction regime and with the average e + e - value. The production of charm and beauty quarks has been measured with the ZEUS detector using the data collected between 2004 and 2007. This data sample corresponds to an integrated luminosity of 354 pb -1 . The charm and beauty contents in events with a jet were determined using the decay-length significance and invariant mass of the reconstructed secondary decay vertices. Differential cross sections in E jet T , η jet , Q 2 and x are in reasonable agreement with predictions for perturbative QCD. The open charm and beauty contributions to the inclusive proton structure function F 2 were extracted from double differential cross sections in x and Q 2 . The obtained F c anti c 2 and F b anti b 2 values are in good agreement with previous measurements and theoretical predictions. This measurement represents the most precise determination of F b anti b 2 at the HERA collider in a large part of the accessible phase space

  6. Measurement of beauty photoproduction using decays into muons in dijet events at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2008-12-15

    Beauty photoproduction in dijet events has been measured at HERA with the ZEUS detector using an integrated luminosity of 126 pb{sup -1}. Beauty was identified in events with a muon in the final state by using the transverse momentum of the muon relative to the closest jet. Lifetime information from the silicon vertex detector was also used; the impact parameter of the muon with respect to the primary vertex was exploited to discriminate between signal and background. Cross sections for beauty production as a function of the muon and the jet variables as well as dijet correlations are compared to QCD predictions and to previous measurements. The data are well described by predictions from next-to-leading-order QCD. (orig.)

  7. Measurement of D* photoproduction at three different centre-of-mass energies at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2014-05-01

    The cross sections for the photoproduction of D *± mesons have been measured with the ZEUS detector at HERA at three different ep centre-of-mass energies, √(s), of 318, 251 and 225 GeV. For each data set, D *± mesons were required to have transverse momentum, p D* T , and pseudorapidity, η D * , in the ranges 1.9 D* T D* vertical stroke 2 , of less than 1 GeV 2 . The dependence on √(s) was studied by normalising to the high-statistics measurement at √(s)=318 GeV. This led to the cancellation of a number of systematic effects both in data and theory. Predictions from next-to-leading-order QCD describe the √(s) dependence of the data well.

  8. Measurement of beauty photoproduction using decays into muons in dijet events at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-12-01

    Beauty photoproduction in dijet events has been measured at HERA with the ZEUS detector using an integrated luminosity of 126 pb -1 . Beauty was identified in events with a muon in the final state by using the transverse momentum of the muon relative to the closest jet. Lifetime information from the silicon vertex detector was also used; the impact parameter of the muon with respect to the primary vertex was exploited to discriminate between signal and background. Cross sections for beauty production as a function of the muon and the jet variables as well as dijet correlations are compared to QCD predictions and to previous measurements. The data are well described by predictions from next-to-leading-order QCD. (orig.)

  9. The New Web-Based Hera Data Processing System at the HEASARC

    Science.gov (United States)

    Pence, W.; Chai, P.

    2012-09-01

    The HEASARC at NASA/GSFC has hosted an on-line astronomical data processing system called Hera for several years. Hera provides a complete data processing environment, including installed software packages, local data storage, and the CPU resources needed to support astronomical research by external users. The original design of Hera was based on a ‘client/server’ model which required that the user a) download and install a small helper program on their own computer before using Hera, and b) ensure that several non-standard computer ports/sockets be open for communication through any local firewalls on the user's machine. Hera has now been redesigned to eliminate these restrictions by operating within a purely Web-based environment which is accessed via a standard Web browser. Web-Hera is available at http://heasarc.gsfc.nasa.gov/webHera.

  10. A precision measurement of the inclusive ep scattering cross section at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Alimujiang, K. [DESY Hamburg (DE)] (and others)

    2009-03-15

    A measurement of the inclusive deep-inelastic neutral current e{sup +}p scattering cross section is reported in the region of four-momentum transfer squared, 12 GeV{sup 2} {<=} Q{sup 2} {<=} 150 GeV{sup 2}, and Bjorken x, 2. 10{sup -4} {<=} x {<=}0.1. The results are based on data collected by the H1 Collaboration at the ep collider HERA at positron and proton beam energies of E{sub e}=27.6 GeV and E{sub p}=920 GeV, respectively. The data are combined with previously published data, taken at E{sub p} = 820 GeV. The accuracy of the combined measurement is typically in the range of 1.3-2%. A QCD analysis at next-to-leading order is performed to determine the parton distributions in the proton based on H1 data. (orig.)

  11. A precision measurement of the inclusive ep scattering cross section at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Preda, T.; Rotaru, M.; Stoicea, G.; Zus, R.; Alimujiang, K.; Antunovic, B.; Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Boer, Y. de; Roeck, A. de; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Glazov, A.; Gouzevitch, M.; Grell, B.R.; Haidt, D.; Helebrant, C.; Janssen, M.E.; Jung, H.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Korbel, V.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; List, J.; Marti, Ll.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Niebuhr, C.; Nikiforov, A.; Nozicka, M.; Olsson, J.E.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Radescu, V.; Rurikova, Z.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Vargas Trevino, A.; Vinokurova, S.; Driesch, M. von den; Wissing, C.; Wuensch, E.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Sheviakov, I.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Asmone, A.; Stella, B.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Ghazaryan, S.; Volchinski, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Faulkner, P.J.W.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Brinkmann, M.; Habib, S.; Jemanov, V.; Lipka, K.; List, B.; Naroska, B.; Pokorny, B.; Toll, T.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Olivier, B.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cassol-Brunner, F.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Cerny, K.; Pejchal, O.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Schoeffel, L.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Degan, M. del; Grab, C.; Leibenguth, G.; Sauter, M.; Zimmermann, T.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Dodonov, V.; Lytkin, L.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Piec, S.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Joensson, L.; Osman, S.; Kapichine, M.; Makankine, A.; Morozov, A.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Schmitz, C.; Straumann, U.; Truoel, P.; Wallny, R.; Schoening, A.; South, D.; Wegener, D.; Tsakov, I.

    2009-01-01

    A measurement of the inclusive deep inelastic neutral current e + p scattering cross section is reported in the region of four-momentum transfer squared, 12 GeV 2 ≤Q 2 ≤150 GeV 2 , and Bjorken x, 2 x 10 -4 ≤x≤0.1. The results are based on data collected by the H1 Collaboration at the ep collider HERA at positron and proton beam energies of E e =27.6 GeV and E p =920 GeV, respectively. The data are combined with previously published data, taken at E p =820 GeV. The accuracy of the combined measurement is typically in the range of 1.3-2%. A QCD analysis at next-to-leading order is performed to determine the parton distributions in the proton based on H1 data. (orig.)

  12. Measurement of beauty photoproduction at threshold using di-electron events with the H1 detector at HERA

    International Nuclear Information System (INIS)

    Sauter, Michel David

    2009-12-01

    The cross section of b anti b photoproduction in ep collisions has been measured with the H1 detector at HERA. Events containing b-quarks were identified through detection of two low momentum electrons in the nal state. Semileptonic decays b anti b→eeX were exploited in the kinematic range of the photon virtuality Q 2 2 , the inelasticity 0.2 T -electron identification. (orig.)

  13. Polarized gas targets for storage rings

    International Nuclear Information System (INIS)

    Holt, R.J.

    1990-01-01

    It is widely recognized that polarized gas targets in electron storage rings represent a new opportunity for precision nuclear physics studies. New developments in polarized target technology specific to internal applications will be discussed. In particular, polarized gas targets have been used in the VEPP-3 electron ring in Novosibirsk. A simple storage cell was used to increase the total target thickness by a factor of 15 over the simple gas jet target from an atomic beam source. Results from the initial phase of this project will be reported. In addition, the plans for increasing the luminosity by an additional order or magnitude will be presented. The application of this work to polarized hydrogen and deuterium targets for the HERA ring will be noted. The influence of beam-induced depolarization, a phenomena encountered in short-pulse electron storage rings, will be discussed. Finally, the performance tests of laser-driven sources will be presented. 8 refs., 12 figs., 1 tab

  14. Measurement of K{sup 0}{sub S}, {lambda} and anti {lambda} production at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2006-12-15

    The production of the neutral strange hadrons K{sup 0}{sub S}, {lambda} and anti {lambda} has been measured in ep collisions at HERA using the ZEUS detector. Cross sections, baryon-to-meson ratios, relative yields of strange and charged light hadrons, {lambda} (anti {lambda}) asymmetry and polarization have been measured in three kinematic regions: Q{sup 2}>25 GeV{sup 2}; 5measurements agree in general with Monte Carlo models and are consistent with measurements made at e{sup +}e{sup -} colliders, except for an enhancement of baryon relative to meson production in photoproduction. (orig.)

  15. Measurement of inelastic J/{psi} and {psi}' photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science] [and others; Collaboration: ZEUS Collaboration

    2012-11-15

    The cross sections for inelastic photoproduction of J/{psi} and {psi}' mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb{sup -1} collected in the period 1996-2007. The {psi}' to J/{psi} cross section ratio was measured in the range 0.55measured for 0.11 GeV. Theoretical predictions within the non-relativistic QCD framework including NLO colour-singlet and colour-octet contributions were compared to the data, as were predictions based on the k{sub T}-factorisation approach.

  16. Measurement of beauty-production in deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Michels, Volker

    2008-09-15

    A measurement of the beauty production cross section in ep collisions at a centre-of-mass energy of 319 GeV is presented. The data was collected with the H1 detector at the HERA collider in the years 2005-2007 and corresponds to an integrated luminosity of 285 pb{sup -1}. Events are selected by requiring the presence of at least one jet together with a muon in the final state. The large mass of b-flavoured hadrons is exploited to identify events containing beauty quarks on a statistical basis. Single and double differential cross sections are measured in deep inelastic scattering, with photon virtualities 3.5measurement. The deficiencies of the prediction are found in the forward direction of the muon, which is defined by the direction of the proton beam, and at low transverse momenta of the muon and jet. The leading-order predictions, which are augmented by parton showers, describe the shape of the measurements very well, but not the normalization. The predictions are about a factor two too low, which is compatible with the next-to-leading order prediction. (orig.)

  17. Measurement of beauty-production in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Michels, Volker

    2008-09-01

    A measurement of the beauty production cross section in ep collisions at a centre-of-mass energy of 319 GeV is presented. The data was collected with the H1 detector at the HERA collider in the years 2005-2007 and corresponds to an integrated luminosity of 285 pb -1 . Events are selected by requiring the presence of at least one jet together with a muon in the final state. The large mass of b-flavoured hadrons is exploited to identify events containing beauty quarks on a statistical basis. Single and double differential cross sections are measured in deep inelastic scattering, with photon virtualities 3.5 2 2 . The results are compared to perturbative QCD calculations. The next-to-leading order prediction is 1.8σ below the measurement. The deficiencies of the prediction are found in the forward direction of the muon, which is defined by the direction of the proton beam, and at low transverse momenta of the muon and jet. The leading-order predictions, which are augmented by parton showers, describe the shape of the measurements very well, but not the normalization. The predictions are about a factor two too low, which is compatible with the next-to-leading order prediction. (orig.)

  18. Leading Baryon Production at HERA

    International Nuclear Information System (INIS)

    Dodonov, V.; Schmitt, S.

    2009-01-01

    The production of highly energetic forward neutrons has been studied in deep-inelastic scattering. The data were taken with the H1 detector at HERA in the years 2006-2007 and correspond to an integrated luminosity of 117 pb -1 . Semi-inclusive cross sections have been measured in the kinematic region 4 2 2 , 0.7*10 -4 -1 and the fractional momentum of the neutron 0.3 L T and compared to the predictions of models of leading neutron production. Differential cross sections for dijet photoproduction and in association with a leading neutron have been measured in the reaction e + p → e + jet jet X n with the ZEUS detector at HERA using an integrated luminosity of 40pb -1 . The data are consistent with a simple pion exchange model. The ratio of the neutron-tagged and dijet cross sections show violations of factorization of the lepton and photon vertices which can be explained by kinematic effects constraining the phase space for neutron production. Normalised double-differential leading-neutron cross sections have been measured in dijet photoproduction for the first time. The distributions can be fully characterised by only two energy dependent parameters extracted from fits to the data. Absorption effects were studied by comparing the dijet photoproduction measurements and similar results in deep inelastic scattering. No clear effect, not related to kinematics, was observed. In a resolved-enriched dijet photoproduction sample, significantly fewer neutrons were seen than for direct. This depletion can also be accounted for by kinematic constraints. The semi-inclusive reaction e + p → e + X p was studied with the ZEUS detector at HERA using an integrated luminosity of 12.8 pb -1 . The final state proton, which was detected with the ZEUS leading proton spectrometer, carried a large fraction of the incoming proton energy, x L > 0.32, and its transverse momentum squared satisfied p T 2 2 ; the exchanged photon virtuality, Q 2 , was greater than 3 GeV 2 and the range of

  19. Measurement of Deeply Virtual Compton Scattering and its t-dependence at HERA

    CERN Document Server

    Aaron, F.D.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, M.U.; Mudrinic, M.; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smiljanic, Ivan; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2008-01-01

    A measurement of elastic deeply virtual Compton scattering gamma* p -> gamma p using e-p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 145 pb^-1. The cross section is measured as a function of the virtuality Q^2 of the exchanged photon and the centre-of-mass energy W of the gamma*p system in the kinematic domain 6.5 < Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q^2 and W values and exponential t-slope parameters are derived. The measurements are compared to a NLO QCD calculation based on generalised parton distributions. In the context of the dipole approach, the geometric scaling property of the DVCS cross section is studied for different values of t.

  20. Measurement of deeply virtual Compton scattering and its t-dependence at HERA

    Science.gov (United States)

    H1 Collaboration; Aaron, F. D.; Aktas, A.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cantun Avila, K. B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J. G.; Coughlan, J. A.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kutak, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Mudrinic, M.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A. J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Tran, T. H.; Traynor, D.; Trinh, T. N.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2008-01-01

    A measurement of elastic deeply virtual Compton scattering γp→γp using ep collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 145 pb. The cross section is measured as a function of the virtuality Q of the exchanged photon and the centre-of-mass energy W of the γp system in the kinematic domain 6.5measurements are compared to a NLO QCD calculation based on generalised parton distributions. In the context of the dipole approach, the geometric scaling property of the DVCS cross section is studied for different values of t.

  1. Measurement of charm and beauty jets in deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Zohrabyan, H. [Yerevan Physics Inst., Yerevan (Armenia); Barrelet, E. [Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris 7, CNRS/IN2P3, LPNHE, Paris (France); Bartel, W.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Cholewa, A.; Deak, M.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Grell, B.R.; Habib, S.; Haidt, D.; Helebrant, C.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nikiforov, A.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Piec, S.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Toll, T.; Vargas Trevino, A.; Driesch, M. von den; Wuensch, E. [DESY, Hamburg (Germany); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [Univ. Paris-Sud, CNRS/IN2P3, LAL, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [Ecole Polytechnique, CNRS/IN2P3, LLR, Palaiseau (France); Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I. [Vinca Inst. of Nuclear Sciences, Belgrade (RS); Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D. [Univ. of Birmingham, Birmingham (United Kingdom)] [and others

    2011-01-15

    Measurements of cross sections for events with charm and beauty jets in deep inelastic scattering at HERA are presented. Events with jets of transverse energy E{sub T}{sup jet}>6 GeV and pseudorapidity -1.0<{eta}{sup jet}<1.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q {sup 2}>6 GeV{sup 2} and inelasticity variable 0.07Measurements are also made requiring a jet in the Breit frame with E{sub T}{sup *jet}>6 GeV. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb{sup -1}. The numbers of charm and beauty jets are determined using variables reconstructed using the H1 vertex detector with which the impact parameters of the tracks to the primary vertex and the position of secondary vertices are measured. The measurements are compared with QCD predictions and with previous measurements where heavy flavours are identified using muons. (orig.)

  2. Inclusive measurement of diffractive deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2012-03-15

    The diffractive process ep {yields} eXY, where Y denotes a proton or its low mass excitation with M{sub Y}<1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3{<=} Q{sup 2} {<=}1600 GeV{sup 2}, the square of the four-momentum transfer at the proton vertex vertical stroke t vertical stroke <1.0 GeV{sup 2} and the longitudinal momentum fraction of the incident proton carried by the colourless exchange x{sub P}<0.05. Triple differential cross sections are measured as a function of x{sub P}, Q{sup 2} and {beta}=x/x{sub P} where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y. High statistics measurements covering the data taking periods 1999-2000 and 2004-2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The combined data represent a factor between three and thirty increase in statistics with respect to the previously published results. The measurements are compared with predictions from NLO QCD calculations based on diffractive parton densities and from a dipole model. The proton vertex factorisation hypothesis is tested. (orig.)

  3. Inclusive measurement of diffractive deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H.; Barrelet, E.; Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Pandurovic, M.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D.; Bruncko, D.; Cerny, V.; Ferencei, J.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Lubimov, V.; Ozerov, D.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Ceccopieri, F.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Roosen, R.; Staykova, Z.; Mechelen, P. van; Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cvach, J.; Hladky, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C.; Dobre, M.; Kogler, R.; Dodonov, V.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Feltesse, J.; Perez, E.; Schoeffel, L.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Grab, C.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Herrera, G.; Lopez-Fernandez, R.; Huber, F.; Pirumov, H.; Sauter, M.; Schoening, A.; Joensson, L.; Jung, H.; Kapichine, M.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Landon, M.P.J.; Rizvi, E.; Traynor, D.; Martyn, H.U.; Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P.; Stella, B.; Sykora, T.; Tsakov, I.; Wegener, D.; Collaboration: H1 Collaboration

    2012-07-15

    The diffractive process ep{yields}eXY, where Y denotes a proton or its low mass excitation with M{sub Y}<1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3{<=}Q{sup 2}{<=} 1600 GeV {sup 2}, the square of the four-momentum transfer at the proton vertex vertical stroke t vertical stroke < 1.0 GeV {sup 2} and the longitudinal momentum fraction of the incident proton carried by the colourless exchange x{sub P}<0.05. Triple differential cross sections are measured as a function of x{sub P}, Q {sup 2} and {beta}=x/x{sub P} where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y. High statistics measurements covering the data taking periods 1999-2000 and 2004-2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The combined data represent a factor between three and thirty increase in statistics with respect to the previously published results. The measurements are compared with predictions from NLO QCD calculations based on diffractive parton densities and from a dipole model. The proton vertex factorisation hypothesis is tested. (orig.)

  4. The New Web-Based Hera Data Processing System at the HEASARC

    Science.gov (United States)

    Pence, W.

    2011-01-01

    The HEASARC at NASA/GSFC has provide an on-line astronomical data processing system called Hera for several years. Hera provides a complete data processing environment, including installed software packages, local data storage, and the CPU resources needed to process the user's data. The original design of Hera, however, has 2 requirements that has limited it's usefulness for some users, namely, that 1) the user must download and install a small helper program on their own computer before using Hera, and 2) Hera requires that several computer ports/sockets be allowed to communicate through any local firewalls on the users machine. Both of these restrictions can be problematic for some users, therefore we are now migrating Hera into a purely Web based environment which only requires a standard Web browser. The first release of Web Hera is now publicly available at http://heasarc.gsfc.nasa.gov/webheara/. It currently provides a standard graphical interface for running hundreds of different data processing programs that are available in the HEASARC's ftools software package. Over the next year we to add more features to Web Hera, including an interactive command line interface, and more display and line capabilities.

  5. High P{sub T} leptons and single W boson production at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Korcsak-Gorzo, Katherine

    2010-12-15

    A search for isolated electrons and muons with high transverse momentum in events with large missing transverse momentum has been conducted. The results have been found to be compatible with the Standard Model expectations. The cross section for single W production has been measured and the total cross section in electron-proton collisions at HERA has been found to be {sigma}(ep {yields} eWX) = 0.93{sub -0.23}{sup +0.26}(stat.){+-}0.08(syst.) pb. The measurements are based on the complete available ZEUS data sets from the HERA I and II running periods taken between 1994-2007. (orig.)

  6. Measurement of azimuthal asymmetries in neutral current deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2006-08-15

    The distribution of the azimuthal angle of charged and neutral hadrons relative to the lepton plane has been studied for neutral current deep inelastic ep scattering using an integrated luminosity of 45 pb{sup -1} taken with the ZEUS detector at HERA. The measurements were made in the hadronic centre-of-mass system. The analysis exploits the energy-flow method, which allows the measurement to be made over a larger range of pseudorapidity compared to previous results. The dependence of the moments of the azimuthal distributions on the pseudorapidity and minimum transverse energy of the final-state hadrons are presented. Although the predictions from next-to-leading-order QCD describe the data better than do the Monte Carlo models incorporating leading-logarithm parton showers, they still fail to describe the magnitude of the asymmetries. This suggests that higher-order calculations may be necessary to describe these data. (Orig.)

  7. Measurement of azimuthal asymmetries in neutral current deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2006-08-01

    The distribution of the azimuthal angle of charged and neutral hadrons relative to the lepton plane has been studied for neutral current deep inelastic ep scattering using an integrated luminosity of 45 pb -1 taken with the ZEUS detector at HERA. The measurements were made in the hadronic centre-of-mass system. The analysis exploits the energy-flow method, which allows the measurement to be made over a larger range of pseudorapidity compared to previous results. The dependence of the moments of the azimuthal distributions on the pseudorapidity and minimum transverse energy of the final-state hadrons are presented. Although the predictions from next-to-leading-order QCD describe the data better than do the Monte Carlo models incorporating leading-logarithm parton showers, they still fail to describe the magnitude of the asymmetries. This suggests that higher-order calculations may be necessary to describe these data. (Orig.)

  8. Measurement of Dijet Cross Sections in ep Interactions with a Leading Neutron at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxeld, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Winter, G.-G.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; Zomer, F.

    2005-01-01

    Measurements are reported of the production of dijet events with a leading neutron in ep interactions at HERA. Differential cross sections for photoproduction and deep inelastic scattering are presented as a function of several kinematic variables. Leading order QCD simulation programs are compared with the measurements. Models in which the real or virtual photon interacts with a parton of an exchanged pion are able to describe the data. Next-to-leading order perturbative QCD calculations based on pion exchange are found to be in good agreement with the measured cross sections. The fraction of leading neutron dijet events with respect to all dijet events is also determined. The dijet events with a leading neutron have a lower fraction of resolved photon processes than do the inclusive dijet data.

  9. Measurement of the charm fragmentation function in D{sup *} photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., IL (US)] (and others)

    2008-12-15

    The charm fragmentation function has been measured in D{sup *} photoproduction with the ZEUS detector at HERA using an integrated luminosity of 120 pb{sup -1}. The fragmentation function is measured versus z=(E+p {sub parallel}){sup D{sup *}}/2E{sup jet}, where E is the energy of the D{sup *} meson and p {sub parallel} is the longitudinal momentum of the D{sup *} meson relative to the axis of the associated jet of energy E{sup jet}. Jets were reconstructed using the k{sub T} clustering algorithm and required to have transverse energy larger than 9 GeV. The D{sup *} meson associated with the jet was required to have a transverse momentum larger than 2 GeV. The measured function is compared to different fragmentation models incorporated in leading-logarithm Monte Carlo simulations and in a next-to-leading-order QCD calculation. The free parameters in each fragmentation model are fitted to the data. The extracted parameters and the function itself are compared to measurements from e{sup +}e{sup -} experiments. (orig.)

  10. Results From PAPER/HERA

    Science.gov (United States)

    Pober, Jonathan C.

    2018-05-01

    The Precision Array for Probing the Epoch of Reionization (PAPER) was a first-generation 21 cm cosmology experiment with the specific goal of detecting the power spectrum of the 21 cm emission from the Epoch of Reionization. Analysis of PAPER data is still ongoing, but lessons learned from PAPER to date have played a critical role in designing the next-generation Hydrogen Epoch of Reionization Array (HERA) experiment. This article reviews five key design choices made by PAPER: use of a non-imaging configuration, redundancy, short baselines, small antenna elements, and a large instantaneous bandwidth. We describe the impact of these choices and the role they played in designing HERA.

  11. Summary of workshop on future physics with HERA data

    International Nuclear Information System (INIS)

    Bacchetta, A.; Bluemlein, J.; Behnke, O.

    2015-12-01

    Recent highlights from the HERA experiments, Hermes, H1 and ZEUS, are reviewed and ideas for future analyses to fully exploit this unique data set are proposed. This document is a summary of a workshop on future physics with HERA data held at DESY, Hamburg at the end of 2014. All areas of HERA physics are covered and contributions from both experimentalists and theorists are included. The document outlines areas where HERA physics can still make a significant contribution, principally in a deeper understanding of QCD, and its relevance to other facilities. Within the framework of the Data Preservation in High Energy Physics, the HERA data have been preserved for analyses to take place over a timescale of 10 years and more. Therefore, although an extensive list of possibilities is presented here, safe storage of the data ensures that it can also be used in the far future should new ideas and analyses be proposed.

  12. Combination and QCD analysis of charm production cross section measurements in deep-inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science] [and others; Collaboration: H1 and ZEUS Collaboration

    2012-10-15

    Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections {sigma}{sup c} {sup anti} {sup c}{sub red} for charm production are obtained in the kinematic range of photon virtuality 2.5 {<=} Q{sup 2} {<=} 2000 GeV{sup 2} and Bjorken scaling variable 3.10{sup -5}{<=}x{<=}5.10{sup -2}. The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deepinelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W{sup {+-}} and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined.

  13. Measurement of the Polarized Structure Function $g_1^p$ at HERA

    CERN Document Server

    Ball, R.D.; Forte, S.; Hughes, V.W.; Lichtenstadt, J.; Ridolfi, G.; Ball, Richard D.; Deshpande, Abhay; Forte, Stefano; Hughes, Vernon W.; Lichtenstadt, Jechiel; Ridolfi, Giovanni

    1996-01-01

    We present estimates of possible data on spin-dependent asymmetries in inclusive scattering of high energy polarized electrons by high energy polarized protons at HERA, including statistical errors, and discuss systematic uncertainties. We show that these data would shed light on the small x behaviour of the polarized structure function g_1, and would reduce substantially the uncertainty on the determination of the polarized gluon distribution.

  14. Measurement of J/{psi} photoproduction at large momentum transfer at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-09-15

    The proton-dissociative diffractive photoproduction of J/{psi} mesons has been studied in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 112 pb{sup -1}. The cross section is presented as a function of the photon- proton centre-of-mass energy and of the squared four-momentum transfer at the proton vertex. The results are compared to perturbative QCD calculations. (orig.)

  15. Measurement of J/ψ photoproduction at large momentum transfer at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-09-01

    The proton-dissociative diffractive photoproduction of J/ψ mesons has been studied in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 112 pb -1 . The cross section is presented as a function of the photon- proton centre-of-mass energy and of the squared four-momentum transfer at the proton vertex. The results are compared to perturbative QCD calculations. (orig.)

  16. Neutral strangeness production with the ZEUS detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Liu Chuanlei

    2007-12-15

    The inclusive production of the neutral strange particles, {lambda}, anti {lambda} and K{sup 0}{sub S} has been studied with the ZEUS detector at HERA. The measurement provides a way to understand the fragmentation process in ep collisions and to check the universality of this process. The strangeness cross sections have been measured and compared with Monte Carlo (MC) predictions. Over the kinematic regions of interest, no {lambda} to anti {lambda} asymmetry was observed. The relative yield of {lambda} and K{sup 0}{sub S} was determined and the result was compared with MC calculations and results from other experiments. A good agreement was found except for the enhancement in the photoproduction process. Clear rapidity correlation was observed for particle pairs where either quark flavor or baryon number compensation occurs. The K{sup 0}{sub S}K{sup 0}{sub S} Bose-Einstein correlation measurement gives a result consistent with those from LEP measurements. The {lambda} polarizations were measured to be consistent with zero for HERA I data. (orig.)

  17. Measurement of beauty-production in deep inelastic scattering at HERA II

    International Nuclear Information System (INIS)

    Kahle, B.

    2006-04-01

    This thesis presents a measurement of beauty quark production in deep inelastic scattering at the ep-collider HERA at √(s)=318 GeV. The measurement is based on data collected at the ZEUS detector in the years 2003/2004, using an integrated luminosity of 39 pb -1 . In the analysis presented in this thesis, events were selected that contain a scattered electron, a jet and a muon inside the jet. The fraction of events from beauty quark production was extracted using the characteristic distribution of the transverse momenta of muons relative to the associated jets. The total visible cross section was measured to be: σ b anti b (ep→eb anti b X→e jetμX')=57.9±5.8(stat.) +3.5 -8.1 (syst.) pb in the kinematic region defined by: Q 2 >4 GeV 2 , y>0.05 und y jet t,lab >5 GeV und -2 jet μ t >1.5 GeV and η μ >-1.6. Differential cross sections were measured in p μ t and η μ , in p jet t and η jet and in Q 2 .Furthermore double differential cross sections d 2 σ/dQ 2 dx were measured. (Orig.)

  18. Measurement of D0, D+, Ds+ and D*+ production in fixed target 920 GeV proton-nucleus collisions

    International Nuclear Information System (INIS)

    Abt, I.; Kisel, I.; Adams, M.; Cruse, C.; Ehret, K.; Funcke, M.; Schwenninger, B.; Wegener, D.; Agari, M.; Bauer, C.; Braeuer, M.; Hofmann, W.; Jagla, T.; Knoepfle, K.T.; Pleier, M.A.; Reeves, K.; Sanchez, F.; Schmelling, M.; Schwingenheuer, B.; Sciacca, F.; Albrecht, H.; Aplin, S.J.; Egorytchev, V.; Emeliyanov, D.; Flammer, J.; Hohlmann, M.; Kapitza, H.; Lewendel, B.; Masciocchi, S.; Medinnis, M.; Mevius, M.; Michetti, A.; Noerenberg, M.; Nunez Pardo de Vera, M.T.; Padilla, C.; Ressing, D.; Riu, I.; Rybnikov, V.; Schmidt, B.; Schwarz, A.S.; Soezueer, L.; Somov, A.; Spengler, J.; Wurth, R.; Aleksandrov, A.; Bohm, G.; Gellrich, A.; Hernandez, J.M.; Mankel, R.; Nowak, S.; Schreiner, A.; Schwanke, U.; Walter, M.; Amaral, V.; Amorim, A.; Bastos, J.; Batista, J.; Carvalho, J.; Silva, L.; Wolters, H.; Aushev, V.; Prystupa, S.; Pugatch, V.; Vassiliev, Y.; Bagaturia, Y.; Balagura, V.; Bobchenko, B.; Bogatyrev, A.; Danilov, M.; Essenov, S.; Fominykh, B.; Golutvin, A.; Gouchtchine, O.; Igonkina, O.; Khasanov, F.; Kvaratskheliia, T.; Matchikhilian, I.; Mizuk, R.; Popov, V.; Rostovtseva, I.; Tikhomirov, I.; Titov, M.; Zaitsev, Y.; Zhelezov, A.; Bargiotti, M.; Bertin, A.; Bruschi, M.; De Castro, S.; Fabbri, L.; Faccioli, P.; Giacobbe, B.; Grimaldi, F.; Massa, I.; Piccinini, M.; Semprini-Cesari, N.; Spighi, R.; Villa, M.; Zoccoli, A.; Barsukova, O.; Belkov, A.; Belkov, A.; Belotelov, I.; Golutvin, I.; Karpenko, N.; Kiryushin, Y.; Lanyov, A.; Solunin, S.; Bauer, T.S.; Hulsbergen, W.; Sbrizzi, A.; Boecker, M.; Buchholz, P.; Husemann, U.; Keller, S.; Walenta, A.H.; Werthenbach, U.; Bruinsma, M.; Ouchrif, M.; Buran, T.; Danielsen, K.M.; Ould-Saada, F.; Pylypchenko, Y.; Conde, P.; Dam, M.; Groth-Jensen, J.; Hansen, J.D.; Klinkby, E.; Muresan, R.; Petersen, B.A.A.; Xella-Hansen, S.; Deppe, H.; Dreis, H.B.; Eisele, F.; Feuerstack-Raible, M.; Gradl, S.; Gradl, W.; Hott, T.; Kessler, J.; Krauss, C.; Rick, H.; Uwer, U.; Dong, X.; Jiang, C.; Zheng, Z.; Garrido, L.; Peralta, D.; Glaess, J.; Maenner, R.; Wurz, A.; Goloubkov, D.; Somov, S.; Golubkov, Y.; Gorbounov, I.; Zeuner, T.; Gorisek, A.; Kupper, S.; Pestotnik, R.; Skrk, D.; Staric, M.; Zivko, T.; Goulart, D.C.; Schwartz, A.J.; Guilitsky, Y.; Mikhailov, Y.; Ispiryan, M.; Lau, K.; Pyrlik, J.; Subramania, H.S.; Karabekyan, S.; Pernack, R.; Schroeder, H.; Zimmermann, R.; Kolanoski, H.; Kruecker, D.; Lohse, T.; Medin, G.; zur Nedden, M.; Stegmann, C.; Korpar, S.; Kreuzer, P.; Krizan, P.; Stanovnik, A.; Lomonosov, B.; Negodaev, M.; Poli, M.; Pose, D.; Robmann, P.; Shuvalov, S.; Spiridonov, A.; Symalla, M.; van Eldik, C.; Tsakov, I.; Vitale, A.; Vukotic, I.; Wahlberg, H.; Wang, J.J.; Zavertyaev, M.

    2007-01-01

    The inclusive production cross sections of the charmed mesons D 0 , D + , D s + and D *+ have been measured in interactions of 920 GeV protons on C, Ti, and W targets with the HERA-B detector at the HERA storage ring. Differential cross sections as a function of transverse momentum and Feynman's x variable are given for the central rapidity region and for transverse momenta up to p T =3.5 GeV/c. The atomic mass number dependence and the leading to non-leading particle production asymmetries are presented as well. (orig.)

  19. Measurement of the t dependence in exclusive photoproduction of Υ(1S) mesons at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2011-10-01

    The exclusive photoproduction reaction γp→Υ(1S)p has been studied with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 468 pb -1 . The measurement covers the kinematic range 60 2 2 , where W is the photon-proton centre-of-mass energy and Q 2 is the photon virtuality. The exponential slope, b, of the t dependence of the cross section, where t is the squared four-momentum transfer at the proton vertex, has been measured, yielding b=4.3 +2.0 -1.3 (stat.) +0.5 -0.6 (syst.) GeV -2 . This constitutes the first measurement of the t dependence of the γp→Υ(1S)p cross section. (orig.)

  20. Measurement of Inclusive and Dijet D* Meson Cross Sections in Photoproduction at HERA

    CERN Document Server

    Aaron, F.D.

    2012-05-04

    The inclusive photoproduction of D\\ast mesons and of D\\ast-tagged dijets is investigated with the H1 detector at the ep collider HERA. The kinematic region covers small photon virtualities Q2 1.8 GeV. The heavy quark production process is further investigated in events with at least two jets with transverse momentum pT (jet) > 3.5 GeV each, one containing the D\\ast meson. Differential cross sections for D\\ast-tagged dijet production and for correlations between the jets are measured in the range |eta(D\\ast)| 2.1 GeV. The results are compared with predictions from Monte Carlo simulations and next-to-leading order perturbative QCD calculations.

  1. Measurement of D* production in diffractive deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Soloviev, Y.; Vazdik, Y. [Lebedev Physical Institute, Moscow (Russian Federation); Baghdasaryan, A.; Zohrabyan, H. [Yerevan Physics Institute, Yerevan (Armenia); Begzsuren, K.; Ravdandorj, T. [Academy of Sciences, Institute of Physics and Technology of the Mongolian, Ulaanbaatar (Mongolia); Bolz, A.; Huber, F.; Sauter, M.; Schoening, A. [Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Boudry, V.; Specka, A. [LLR, Ecole Polytechnique, CNRS/IN2P3, Palaiseau (France); Brandt, G. [Universitaet Goettingen, II. Physikalisches Institut, Goettingen (Germany); Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F. [LAL, Universite Paris-Sud, CNRS/IN2P3, Orsay (France); Britzger, D.; Campbell, A.J.; Dodonov, V.; Eckerlin, G.; Elsen, E.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Haidt, D.; Jung, A.; Jung, H.; Katzy, J.; Kleinwort, C.; Kruecker, D.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Buniatyan, A.; Newman, P.R.; Thompson, P.D. [University of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Bylinkin, A. [Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region (Russian Federation); Bystritskaya, L.; Fedotov, A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Avila, K.B.C.; Contreras, J.G. [CINVESTAV, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Cerny, K.; Jansova, M.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Chekelian, V.; Grindhammer, G.; Kiesling, C.; Lobodzinski, B. [Max-Planck-Institut fuer Physik, Munich (Germany); Cvach, J.; Hladky, J.; Reimer, P. [Academy of Sciences of the Czech Republic, Institute of Physics, Prague (Czech Republic); Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kostka, P.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D. [University of Liverpool, Department of Physics, Liverpool (United Kingdom); Daum, K.; Meyer, H. [Fachbereich C, Universitaet Wuppertal, Wuppertal (Germany); Diaconu, C.; Hoffmann, D.; Vallee, C. [Aix Marseille Universite, CNRS/IN2P3, CPPM UMR 7346, Marseille (France); Dobre, M.; Rotaru, M. [Horia Hulubei National Institute for R and D in Physics and Nuclear Engineering (IFIN-HH), Bucharest (Romania); Egli, S.; Horisberger, R.; Ozerov, D. [Paul Scherrer Institute, Villigen (Switzerland); Favart, L.; Grebenyuk, A.; Hreus, T.; Janssen, X.; Roosen, R.; Mechelen, P. van [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); Feltesse, J.; Schoeffel, L. [Irfu/SPP, CE Saclay, Gif-sur-Yvette (France); Ferencei, J. [Nuclear Physics Institute of the CAS, Rez (Czech Republic); Goerlich, L.; Mikocki, S.; Nowak, G.; Sopicki, P. [Institute of Nuclear Physics, Polish Academy of Sciences, Krakow (Poland); Gouzevitch, M.; Petrukhin, A. [IPNL, Universite Claude Bernard Lyon 1, CNRS/IN2P3, Villeurbanne (France); Grab, C. [Institut fuer Teilchenphysik, ETH, Zurich (Switzerland); Henderson, R.C.W. [University of Lancaster, Department of Physics, Liverpool (United Kingdom); Kapichine, M.; Morozov, A.; Spaskov, V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kogler, R. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Landon, M.P.J.; Rizvi, E.; Traynor, D. [University of London, School of Physics and Astronomy, London (United Kingdom); Lange, W.; Naumann, T. [DESY, Zeuthen (Germany); Martyn, H.U. [I. Physikalisches Institut der RWTH, Aachen (Germany); Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P. [Physik-Institut der Universitaet Zuerich, Zurich (Switzerland); Perez, E. [CERN, Geneva (Switzerland); Picuric, I.; Raicevic, N. [University of Montenegro, Faculty of Science, Podgorica (Montenegro); Polifka, R. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); University of Toronto, Department of Physics, Toronto, ON (Canada); Radescu, V. [Oxford University, Department of Physics, Oxford (United Kingdom); Rostovtsev, A. [Institute for Information Transmission Problems RAS, Moscow (Russian Federation); Sankey, D.P.C. [STFC, Rutherford Appleton Laboratory, Didcot, Oxfordshire (United Kingdom); Sauvan, E. [Aix Marseille Universite, CNRS/IN2P3, CPPM UMR 7346, Marseille (France); Universite de Savoie, CNRS/IN2P3, LAPP, Annecy-le-Vieux (France); Shushkevich, S. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Stella, B. [Dipartimento di Fisica Universita di Roma Tre (Italy); INFN Roma 3, Rome (Italy); Sykora, T. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Tsakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (Bulgaria); Tseepeldorj, B. [Academy of Sciences, Institute of Physics and Technology of the Mongolian, Ulaanbaatar (Mongolia); Ulaanbaatar University, Ulaanbaatar (Mongolia); Wegener, D. [Institut fuer Physik, TU Dortmund, Dortmund (Germany)

    2017-05-15

    Measurements of D*(2010) meson production in diffractive deep inelastic scattering (5 < Q{sup 2} < 100 GeV{sup 2}) are presented which are based on HERA data recorded at a centre-of-mass energy √(s) = 319 GeV with an integrated luminosity of 287 pb{sup -1}. The reaction ep → eXY is studied, where the system X, containing at least one D*(2010) meson, is separated from a leading low-mass proton dissociative system Y by a large rapidity gap. The kinematics of D* candidates are reconstructed in the D* → Kππ decay channel. The measured cross sections compare favourably with next-to-leading order QCD predictions, where charm quarks are produced via boson-gluon fusion. The charm quarks are then independently fragmented to the D* mesons. The calculations rely on the collinear factorisation theorem and are based on diffractive parton densities previously obtained by H1 from fits to inclusive diffractive cross sections. The data are further used to determine the diffractive to inclusive D* production ratio in deep inelastic scattering. (orig.)

  2. Energy Flow and Leading Neutron Production at HERA

    International Nuclear Information System (INIS)

    Yan Wenbiao

    2006-01-01

    The azimuthal asymmetry of hadrons in the semi-inclusive process e+p → e+h+X is studied in deep inelastic scattering at HERA. A measurement of the dijet cross section with a leading neutron is also reported, the P T 2 distribution of the leading neutron is investigated

  3. High transverse momentum dijet cross section measurements in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Dossanov, Aziz

    2013-06-15

    The measurement of high transverse momentum differential dijet cross sections in photoproduction at HERA in the {gamma}p center-of-mass energy 101HERA collider in e{sup +}p mode during the year 2006, collecting an integrated luminosity of 92.4 pb{sup -1}. The results correspond to a kinematic range of photon virtualities Q{sup 2}<4.0 GeV{sup 2} and inelasticities 0.115.0 GeV and pseudorapidities in the range of -0.5<{eta}{sub 1st,2nd}<2.5 are required. In order to suppress background and be able to compare the cross sections with reliable and safe pQCD NLO predictions an invariant mass of the two leading jets M{sub 12}>40.0 GeV is required. Single differential dijet cross sections are measured, including cross sections in the direct and resolved photon enhanced regions. In order to study the contribution of partons interacting in the hard process, which are sensitive to the jet pseudorapidities, three different topologies of jets pseudorapidities are investigated. Single differential cross sections as a function of proton momentum fraction, taken by the interacting parton, x{sub P}, the fraction of photon momentum, x{sub {gamma}}, the angle between the incoming and outgoing partons in the hard scatter, vertical stroke cos {theta}{sup *} vertical stroke are presented. Additionally, the cross sections as a function of the invariant mass of dijets, M{sub 12}, anti {eta}=({eta}{sub 1st}+{eta}{sub 2nd})/2, anti P{sub T}=(P{sub T,1st}+P{sub T,2nd})/2 and P{sub T,1st} are also presented. The data are compared to predictions from the Pythia event generator, based on the LO matrix elements and parton showers, and to the NLO QCD calculations corrected for hadronization effects.

  4. Measurement of D0, D+, D+s and D*+ production in fixed target 920 GeV proton-nucleus collisions

    International Nuclear Information System (INIS)

    Abt, I.

    2007-08-01

    The inclusive production cross sections of the charmed mesons D 0 , D + , D + s and D *+ have been measured in interactions of 920 GeV protons on C, Ti, and W targets with the HERA-B detector at the HERA storage ring. Differential cross sections as a function of transverse momentum and Feynman's x variable are given for the central rapidity region and for transverse momenta up to p T =3.5 GeV/c. The atomic mass number dependence and the leading to non-leading particle production asymmetries are presented as well. (orig.)

  5. Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA

    International Nuclear Information System (INIS)

    Breitweg, J.; Chekanov, S.; Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Pellegrino, A.; Repond, J.; Stanek, R.; Yoshida, R.; Mattingly, M.C.K.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cara Romeo, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; De Pasquale, S.; Giusti, P.; Iacobucci, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Pesci, A.; Sartorelli, G.; Zichichi, A.; Amelung, C.; Bornheim, A.; Brock, I.; Coboeken, K.; Crittenden, J.; Deffner, R.; Hartmann, H.; Heinloth, K.; Hilger, E.; Irrgang, P.; Jakob, H.-P.; Kappes, A.; Katz, U.F.; Kerger, R.; Paul, E.; Rautenberg, J.; Schnurbusch, H.; Stifutkin, A.; Tandler, J.; Voss, K.C.; Weber, A.; Wieber, H.; Bailey, D.S.; Barret, O.; Brook, N.H.; Foster, B.; Heath, G.P.; Heath, H.F.; Rodrigues, E.; Scott, J.; Tapper, R.J.; Capua, M.; Schioppa, M.; Susinno, G.; Jeoung, H.Y.; Kim, J.Y.; Lee, J.H.; Lim, I.T.; Ma, K.J.; Pac, M.Y.; Caldwell, A.; Liu, W.; Liu, X.; Mellado, B.; Paganis, S.; Sampson, S.; Schmidke, W.B.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Klimek, K.; Olkiewicz, K.; Piotrzkowski, K.; Przybycien, M.B.; Stopa, P.; Zawiejski, L.; Bednarek, B.; Jelen, K.; Kisielewska, D.; Kowal, A.M.; Kowalski, T.; Przybycien, M.; Rulikowska-Zarebska, E.; Suszycki, L.; Szuba, D.; Kotanski, A.; Bauerdick, L.A.T.; Behrens, U.; Bienlein, J.K.; Borras, K.; Chiochia, V.; Dannheim, D.; Desler, K.; Drews, G.; Fox-Murphy, A.; Fricke, U.; Goebel, F.; Goers, S.; Goettlicher, P.; Graciani, R.; Haas, T.; Hain, W.; Hartner, G.F.; Hebbel, K.; Hillert, S.; Koch, W.; Koetz, U.; Kowalski, H.; Labes, H.; Loehr, B.; Mankel, R.; Martens, J.; Martinez, M.; Milite, M.; Moritz, M.; Notz, D.; Petrucci, M.C.; Polini, A.; Rohde, M.; Savin, A.A.; Schneekloth, U.; Selonke, F.; Sievers, M.; Stonjek, S.; Wolf, G.; Wollmer, U.; Youngman, C.; Zeuner, W.; Coldewey, C.; Lopez-Duran Viani, A.; Meyer, A.; Schlenstedt, S.; Straub, P.B.; Barbagli, G.; Gallo, E.; Parenti, A.; Pelfer, P.G.; Bamberger, A.; Benen, A.; Coppola, N.; Eisenhardt, S.; Markun, P.; Raach, H.; Woelfle, S.; Bussey, P.J.; Bell, M.; Doyle, A.T.; Glasman, C.; Lee, S.W.; Lupi, A.; Macdonald, N.; McCance, G.J.; Saxon, D.H.; Sinclair, L.E.; Skillicorn, I.O.; Waugh, R.; Bohnet, I.; Gendner, N.; Holm, U.; Meyer-Larsen, A.; Salehi, H.; Wick, K.; Carli, T.; Garfagnini, A.; Gialas, I.; Gladilin, L.K.; Kcira, D.; Klanner, R.; Lohrmann, E.; Goncalo, R.; Long, K.R.; Miller, D.B.; Tapper, A.D.; Walker, R.; Cloth, P.; Filges, D.; Ishii, T.; Kuze, M.; Nagano, K.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Ahn, S.H.; Lee, S.B.; Park, S.K.; Lim, H.; Son, D.; Barreiro, F.; Garcia, G.; Gonzalez, O.; Labarga, L.; del Peso, J.; Redondo, I.; Terron, J.; Vazquez, M.; Barbi, M.; Corriveau, F.; Hanna, D.S.; Ochs, A.; Padhi, S.; Stairs, D.G.; Wing, M.; Tsurugai, T.; Antonov, A.; Bashkirov, V.; Danilov, M.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Suchkov, S.; Dementiev, R.K.; Ermolov, P.F.; Golubkov, Yu.A.; Katkov, I.I.; Khein, L.A.; Korotkova, N.A.; Korzhavina, I.A.; Kuzmin, V.A.; Lukina, O.Yu.; Proskuryakov, A.S.; Shcheglova, L.M.; Solomin, A.N.; Vlasov, N.N.; Zotkin, S.A.; Bokel, C.; Botje, M.; Bruemmer, N.; Engelen, J.; Grijpink, S.; Koffeman, E.; Kooijman, P.; Schagen, S.; van Sighem, A.; Tassi, E.; Tiecke, H.; Tuning, N.; Velthuis, J.J.; Vossebeld, J.; Wiggers, L.; de Wolf, E.; Bylsma, B.; Durkin, L.S.; Gilmore, J.; Ginsburg, C.M.; Kim, C.L.; Ling, T.Y.; Boogert, S.; Cooper-Sarkar, A.M.; Devenish, R.C.E.; Grosse-Knetter, J.; Matsushita, T.; Ruske, O.; Sutton, M.R.; Walczak, R.; Bertolin, A.; Brugnera, R.; Carlin, R.; Dal Corso, F.; Dusini, S.; Limentani, S.; Longhin, A.; Posocco, M.; Stanco, L.; Turcato, M.; Adamczyk, L.; Iannotti, L.; Oh, B.Y.; Okrasinski, J.R.; Saull, P.R.B.; Toothacker, W.S.; Whitmore, J.J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cormack, C.; Hart, J.C.; McCubbin, N.A.; Shah, T.P.; Epperson, D.; Heusch, C.; Sadrozinski, H.F.-W.; Seiden, A.; Wichmann, R.; Williams, D.C.; Park, I.H.; Pavel, N.; Abramowicz , H.; Dagan, S.; Kananov, S.; Kreisel, A.; Levy, A.; Abe, T.; Fusayasu, T.; Kohno, T.; Umemori, K.; Yamashita, T.; Hamatsu, R.; Hirose, T.; Inuzuka, M.; Kitamura, S.; Matsuzawa, K.; Nishimura, T.; Arneodo, M.; Cartiglia, N.; Cirio, R.; Costa, M.; Ferrero, M.I.; Maselli, S.; Monaco, V.; Peroni, C.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Bailey, D.C.; Fagerstroem, C.-P.; Galea, R.; Koop, T.; Levman, G.M.; Martin, J.F.; Mirea, A.; Sabetfakhri, A.; Butterworth, J.M.; Hayes, M.E.; Heaphy, E.A.; Jones, T.W.; Lane, J.B.; West, B.J.; Ciborowski, J.; Ciesielski, R.; Grzelak, G.; Nowak, R.J.; Pawlak, J.M.; Pawlak, R.; Smalska, B.; Tymieniecka, T.; Wroblewski, A.K.; Zakrzewski, J.A.; Zarnecki, A.F.; Adamus, M.; Gadaj, T.; Deppe, O.; Eisenberg, Y.; Hochman, D.; Karshon, U.; Badgett, W.F.; Chapin, D.; Cross, R.; Foudas, C.; Mattingly, S.; Reeder, D.D.; Smith, W.H.; Vaiciulis, A.; Wildschek, T.; Wodarczyk, M.; Deshpande, A.; Dhawan, S.; Hughes, V.W.; Bhadra, S.; Catterall, C.; Cole, J.E.; Frisken, W.R.; Hall-Wilton, R.; Khakzad, M.; Menary, S.

    2001-01-01

    Differential cross sections for dijet photoproduction in association with a leading neutron using the reaction e + +p→e + +n+jet+jet+X r have been measured with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb -1 . The fraction of dijet events with a leading neutron in the final state was studied as a function of the jet kinematic variables. The cross sections were measured for jet transverse energies E T jet >6 GeV, neutron energy E n >400 GeV, and neutron production angle θ n <0.8 mrad. The data are broadly consistent with factorization of the lepton and hadron vertices and with a simple one-pion-exchange model

  6. Events with Isolated Leptons and Missing Transverse Momentum and Measurement of W Production at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Behnke, O.; Belousov, A.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.-J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Mudrinic, M.; Muller, K.; Murin, P.; Naroska, B.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wegener, D.; Wissing, Ch.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2009-01-01

    Events with high energy isolated electrons, muons or tau leptons and missing transverse momentum are studied using the full e^\\pm p data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb^{-1}. Within the Standard Model, events with isolated leptons and missing transverse momentum mainly originate from the production of single W bosons. The total single W boson production cross section is measured as 1.14 \\pm 0.25 (stat.) \\pm 0.14 (sys.) pb, in agreement with the Standard Model expectation. The data are also used to establish limits on the WW\\gamma gauge couplings and for a measurement of the W boson polarisation.

  7. Events with isolated leptons and missing transverse momentum and measurement of W production at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Preda, T.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Sheviakov, I.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Antunovic, B.; Aplin, S.; Bartel, W.; Brandt, G.; Brinkmann, M.; Campbell, A.J.; Cholewa, A.; Deak, M.; Boer, Y. de; Roeck, A. de; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Glazov, A.; Grell, B.R.; Haidt, D.; Helebrant, C.; Janssen, M.E.; Jung, H.; Katzy, J.; Kleinwort, C.; Klimkovich, T.; Knutsson, A.; Korbel, V.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; List, J.; Marti, Ll.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Niebuhr, C.; Nikiforov, A.; Nozicka, M.; Olsson, J.E.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Radescu, V.; Rurikova, Z.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Toll, T.; Vargas Trevino, A.; Vinokurova, S.; Wissing, C.; Wuensch, E.; Asmone, A.; Stella, B.; Astvatsatourov, A.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Ghazaryan, S.; Volchinski, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Behnke, O.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Gouzevitch, M.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Faulkner, P.J.W.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Olivier, B.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Essenov, S.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cassol-Brunner, F.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Cerny, K.; Pejchal, O.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Schoeffel, L.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Del Degan, M.; Grab, C.; Leibenguth, G.; Sauter, M.; Zimmermann, T.; Dodonov, V.; Lytkin, L.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Piec, S.; Goettlich, M.; Habib, S.; Jemanov, V.; Lipka, K.; List, B.; Naroska, B.; Hansson, M.; Joensson, L.; Osman, S.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Jung, A.W.; Krueger, K.; Lendermann, V.; Meier, K.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Kapichine, M.; Makankine, A.; Morozov, A.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Schmitz, C.; Straumann, U.; Truoel, P.; Schoening, A.; South, D.; Wegener, D.; Tsakov, I.

    2009-01-01

    Events with high energy isolated electrons, muons or tau leptons and missing transverse momentum are studied using the full e ± p data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb -1 . Within the Standard Model, events with isolated leptons and missing transverse momentum mainly originate from the production of single W bosons. The total single W boson production cross section is measured as 1.14±0.25(stat.)±0.14(sys.) pb, in agreement with the Standard Model expectation. The data are also used to establish limits on the WWγ gauge couplings and for a measurement of the W boson polarisation. (orig.)

  8. Measurement of deeply virtual Compton scattering and its t-dependence at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Insitute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania)]|[Bucharest Univ. (Romania). Faculty of Physics; Aktas, A. [DESY Hamburg (Germany); Alexa, C. [National Insitute for Physics and Nuclear Engineering (NIPNE), Bucharest (RO)] (and others)

    2007-09-15

    A measurement of elastic deeply virtual Compton scattering {gamma}{sup *}p {yields} {gamma}p using e{sup -}p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 145 pb{sup -1}. The cross section is measured as a function of the virtuality Q{sup 2} of the exchanged photon and the centre-of-mass energy W of the {gamma}{sup *}p system in the kinematic domain 6.5measurements are compared to a NLO QCD calculation based on generalised parton distributions. In the context of the dipole approach, the geometric scaling property of the DVCS cross section is studied for different values of t. (orig.)

  9. Measurement of charm and beauty dijet cross sections in photoproduction at HERA using the H1 vertex detector

    International Nuclear Information System (INIS)

    Aktas, A.; Andreev, V.; Anthonis, T.

    2006-04-01

    A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. Events are selected with two or more jets of transverse momentum p jet 1(2)t >11(8) GeV in the central range of pseudo-rapidity -0.9 jet 1(2) obs γ . Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, while the predicted cross sections for beauty production are somewhat lower than the measurement. (Orig.)

  10. Measurement of leading neutron production in deep-inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Antunovic, B.; Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grell, B.R.; Haidt, D.; Helebrant, C.; Jung, H.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Marti, L.; Meyer, A.B.; Meyer, H.; Meyer, J.; Niebuhr, C.; Nikiforov, A.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Sunar, D.; Vargas Trevino, A.; Vinokurova, S.; Driesch, M. von den; Wissing, C.; Wuensch, E.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Volchinski, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Brinkmann, M.; Habib, S.; List, B.; Toll, T.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cerny, K.; Pejchal, O.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Schoeffel, L.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sykora, T.; Mechelen, P. van; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Dodonov, V.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Piec, S.; Grab, C.; Zimmermann, T.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Joensson, L.; Osman, S.; Kapichine, M.; Lytkin, L.; Makankine, A.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Straumann, U.; Truoel, P.; Radescu, V.; Sauter, M.; Schoening, A.; South, D.; Wegener, D.; Stella, B.; Tsakov, I.

    2010-01-01

    The production of leading neutrons, where the neutron carries a large fraction x L of the incoming proton's longitudinal momentum, is studied in deep-inelastic positron-proton scattering at HERA. The data were taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 122 pb -1 . The semi-inclusive cross section is measured in the phase space defined by the photon virtuality 6 2 2 , Bjorken scaling variable 1.5 .10 -4 -2 , longitudinal momentum fraction 0.32 L T 2 LN(3) (Q 2 ,x,x L ), and the fraction of deep-inelastic scattering events containing a leading neutron are studied as a function of Q 2 , x and x L . Assuming that the pion exchange mechanism dominates leading neutron production, the data provide constraints on the shape of the pion structure function. (orig.)

  11. Polarisation at HERA. Reanalysis of the HERA II polarimeter data

    Energy Technology Data Exchange (ETDEWEB)

    Sobloher, B.; Behnke, T.; Olsson, J.; Pitzl, D.; Schmitt, S.; Tomaszewska, J.; Fabbri, R.

    2012-01-15

    In this technical note we briefly present the analysis of the HERA polarimeters (transversal and longitudinal) as of summer 2011. We present the final reanalysis of the TPOL data, and discuss the systematic uncertainties. A procedure to combine and average LPOL and TPOL data is presented. (orig.)

  12. Polarisation at HERA. Reanalysis of the HERA II polarimeter data

    International Nuclear Information System (INIS)

    Sobloher, B.; Behnke, T.; Olsson, J.; Pitzl, D.; Schmitt, S.; Tomaszewska, J.; Fabbri, R.

    2012-01-01

    In this technical note we briefly present the analysis of the HERA polarimeters (transversal and longitudinal) as of summer 2011. We present the final reanalysis of the TPOL data, and discuss the systematic uncertainties. A procedure to combine and average LPOL and TPOL data is presented. (orig.)

  13. Performance of 1m long/100 mm bore superconducting dipole prototypes for HERA

    International Nuclear Information System (INIS)

    Horlitz, G; Wolff, S.

    1983-01-01

    Three 1 m long superconducting dipole prototypes with 100 mm inner coil diameter for the proposed HERA electron-proton storage ring have been built and tested. Main design principles are a two layer coil clamped with stainless steel collars inside a cryostat with warm beam tube and surrounded by a warm iron yoke. All prototypes have been tested without yoke and one of them with yoke. The design induction of 4.73 Tesla at 4.6 K has been easily surpassed up to short sample fields with negligible training. The quench behaviour has been investigated between temperatures of 3.8 K and 5.0 K. The field quality has been found well within the specified limits given by the requirements of the storage ring optics. The reproducibility found in this sample of magnets gives great confidence for the production of dipole prototypes of full length

  14. An experimental study on the long-term stability of particle motion in hadron storage rings

    International Nuclear Information System (INIS)

    Fischer, W.

    1995-12-01

    Nonlinear magnetic fields in conjunction with tune modulation may lead to chaotic particle motion and thereby limit the dynamic aperture in hadron storage rings. This is on particular interest for high energy storage rings with superconducting magnets at injection energy where magnetic field errors and the beam size have their maximum values. At the CERN SPS a dynamic aperture experiment was performed with the aim of finding the relevant effects for the stability of single particle motion in hadron storage rings. Experimental results are compared to long-term particle tracking to test to which extent computer programs can predict the dynamic aperture under well known conditions. In addition, detailed investigations of the loss mechanisms were pursued to improve the phenomenological understanding of the intricate details of particle motion in phase space. In a complementary experiment at the HERA proton ring at injection energy the dynamic aperture was measured under normal operating conditions. The computer simulations for these measurements included a very detailed model of the nonlinear fields which were measured for each individual magnet. Simulation results for the LHC are shown that estimate the effect of tune ripple of different strength on the dynamic aperture for different sets of random nonlinear field errors. (orig.)

  15. The soft pomeron and HERA

    International Nuclear Information System (INIS)

    Donnachie, A.; Landshoff, P.V.

    1996-01-01

    The standard phenomenology of the soft pomeron in hadron-hadron interactions is recalled briefly. The model is confronted with the HERA data for the total photoproduction cross section, deep inelastic scattering, diffractive vector meson photoproduction and diffractive electroproduction of vector mesons. Although much of the data can be explained by the model, there are some aspects of the HERA data which require a more rapid variation with energy than can be incorporated. It is argued that the perturbative (BFKL) pomeron cannot give a sufficiently large contribution to explain these observations. Possible non-perturbative solutions to this problem are indicated. (author)

  16. The soft pomeron and HERA

    International Nuclear Information System (INIS)

    Donnachie, A.; Landshoff, P.V.

    1996-01-01

    The standard phenomenology of the soft pomeron in hadron-hadron interactions is recalled briefly. The model is confronted with the HERA data for the total photoproduction cross section, deep inelastic scattering, diffractive vector meson photoproduction and diffractive electroproduction of vector mesons. Although much of the data can be explained by the model, there are some aspects of the HERA data which require a more rapid variation with energy than can be incorporated. It is argued that the perturbative (BFKL) pomeron cannot give a sufficiently large contribution to explain these observations. Possible nonperturbative solutions to this problem are indicated. (author)

  17. Measurement of charm and beauty dijet cross sections in photoproduction at HERA using the H1 vertex detector

    International Nuclear Information System (INIS)

    Finke, L.

    2007-01-01

    A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. The lifetime signature of c- and b-flavoured hadrons is exploited to determine the fractions of events in the sample containing charm or beauty. Differential dijet cross sections for charm and beauty, and their relative contributions to the flavour inclusive dijet photoproduction cross section, are measured. Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, the predicted cross sections for beauty production being somewhat lower than the measurement. (author)

  18. A measurement of the Q2, W and t dependences of deeply virtual Compton scattering at HERA

    International Nuclear Information System (INIS)

    2009-01-01

    Deeply virtual Compton scattering, γ*p → γp, has been measured in e + p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb -1 . Cross sections are presented as a function of the photon virtuality, Q 2 , and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q 2 > 1.5 GeV 2 and 40 -1 , is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex.

  19. A measurement of the Q2, W and t dependences of deeply virtual Compton scattering at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-12-01

    Deeply virtual Compton scattering, γ * p→γp, has been measured in e + p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb -1 . Cross sections are presented as a function of the photon virtuality, Q 2 , and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q 2 >1.5 GeV 2 and 40 -1 , is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex. (orig.)

  20. B-physics at HERA

    International Nuclear Information System (INIS)

    Gladilin, L.K.

    2000-01-01

    The beauty photoproduction cross-section measurements in ep collisions at HERA are reviewed. Data samples of events having a lepton (μ or e) and two jets in the final state, have been collected with the H1 and ZEUS detectors. The beauty signals have been extracted by fitting the p T rel distribution of the data with beauty, charm and light flavor components, where p T rel is the transverse momentum of the lepton relative to the axis of the associated jet. The obtained beauty cross sections are larger than leading order Monte Carlo and next-to-leading order perturbative QCD predictions

  1. Lifetime measurement of ATF damping ring

    International Nuclear Information System (INIS)

    Okugi, T.; Hayano, H.; Kubo, K.; Naito, T.; Terunuma, N.; Urakawa, J.; Zimmermann, F.

    1998-06-01

    The purpose of the ATF damping ring is the development of technologies for producing a low emittance beam required in future linear colliders such as JLC. The lifetime of the damping ring is very short (typically a few minutes). It is limited by elastic beam-gas scattering along with a small dynamic aperture, and by single intra-beam scattering (Touschek effect). The Touschek lifetime strongly depends upon the charge density of the beam, especially, the size of the vertical emittance. In this paper, the authors report the results of beam lifetime measurements in the ATF damping ring and the estimation of the vertical emittance from these measurements

  2. Measurement of charm and beauty production in deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Roloff, Philipp

    2011-12-15

    In this thesis two measurements of heavy quark production in deep inelastic scattering at HERA are presented. Cross sections for the production of heavy quarks can be calculated in quantum chromodynamics (QCD). The heavy quark masses represent hard scales, which allow to apply perturbative methods. Charm production has been measured with the ZEUS detector using an integrated luminosity of 120 pb{sup -1}. The hadronic decay channels D{sup +} {yields} K{sup 0}{sub S}{pi}{sup +}, {lambda}{sup +}{sub c} {yields} pK{sup 0}{sub S} and {lambda}{sup +}{sub c} {yields} {lambda}{pi}{sup +} were reconstructed. The presence of a neutral strange hadron in the final state reduces the combinatorial background and extends the measured sensitivity into the region p{sub T}(D{sup +}, {lambda}{sup +}{sub c}) < 1.5 GeV. The inclusive cross section and differential cross sections in p{sub T}{sup 2} (D{sup +}), {eta}(D{sup +}), Q{sup 2} and x for the production of D{sup +} mesons are in reasonable agreement with predictions from perturbative QCD. The fraction of c quarks hadronising into {lambda}{sup +}{sub c} baryons was extracted from a combination of both investigated {lambda}{sup +}{sub c} decay channels. The result is consistent with a previous measurement in the photoproduction regime and with the average e{sup +}e{sup -} value. The production of charm and beauty quarks has been measured with the ZEUS detector using the data collected between 2004 and 2007. This data sample corresponds to an integrated luminosity of 354 pb{sup -1}. The charm and beauty contents in events with a jet were determined using the decay-length significance and invariant mass of the reconstructed secondary decay vertices. Differential cross sections in E{sup jet}{sub T}, {eta}{sup jet}, Q{sup 2} and x are in reasonable agreement with predictions for perturbative QCD. The open charm and beauty contributions to the inclusive proton structure function F{sub 2} were extracted from double differential cross

  3. HERA and the LHC: A Workshop on the implications of HERA for LHC physics: Proceedings Part A

    CERN Document Server

    De Roeck, A.; Startup Meeting; Working Group Meeting; Mid-term Review Meeting; Working Group Meeting; Working Group Meeting; Final Meeting

    2005-01-01

    The HERA electron--proton collider has collected 100 pb$^{-1}$ of data since its start-up in 1992, and recently moved into a high-luminosity operation mode, with upgraded detectors, aiming to increase the total integrated luminosity per experiment to more than 500 pb$^{-1}$. HERA has been a machine of excellence for the study of QCD and the structure of the proton. The Large Hadron Collider (LHC), which will collide protons with a centre-of-mass energy of 14 TeV, will be completed at CERN in 2007. The main mission of the LHC is to discover and study the mechanisms of electroweak symmetry breaking, possibly via the discovery of the Higgs particle, and search for new physics in the TeV energy scale, such as supersymmetry or extra dimensions. Besides these goals, the LHC will also make a substantial number of precision measurements and will offer a new regime to study the strong force via perturbative QCD processes and diffraction. For the full LHC physics programme a good understanding of QCD phenomena and the ...

  4. Overview of the Human Exploration Research Analog (HERA)

    Science.gov (United States)

    Neigut, J.

    2015-01-01

    In 2013, the Human Research Program at NASA began developing a new confinement analog specifically for conducting research to investigate the effects of confinement on the human system. The HERA (Human Exploration Research Analog) habitat has been used for both 7 and 14 day missions to date to examine and mitigate exploration risks to enable safe, reliable and productive human space exploration. This presentation will describe how the Flight Analogs Project developed the HERA facility and the infrastructure to suit investigator requirements for confinement research and in the process developed a new approach to analog utilization and a new state of the art analog facility. Details regarding HERA operations will be discussed including specifics on the mission simulation utilized for the current 14-day campaign, the specifics of the facility (total volume, overall size, hardware), and the capabilities available to researchers. The overall operational philosophy, mission fidelity including timeline, schedule pressures and cadence, and development and implementation of mission stressors will be presented. Research conducted to date in the HERA has addressed risks associated with behavioral health and performance, human physiology, as well as human factors. This presentation will conclude with a discussion of future research plans for the HERA, including infrastructure improvements and additional research capabilities planned for the upcoming 30-day missions in 2016.

  5. Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Breitweg, J.; Chekanov, S.; Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Pellegrino, A.; Repond, J.; Stanek, R.; Yoshida, R.; Mattingly, M.C.K.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cara Romeo, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; De Pasquale, S.; Giusti, P.; Iacobucci, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Pesci, A.; Sartorelli, G.; Zichichi, A.; Amelung, C.; Bornheim, A.; Brock, I.; Coboeken, K.; Crittenden, J.; Deffner, R.; Hartmann, H.; Heinloth, K.; Hilger, E.; Irrgang, P.; Jakob, H.-P.; Kappes, A.; Katz, U.F.; Kerger, R.; Paul, E.; Rautenberg, J.; Schnurbusch, H.; Stifutkin, A.; Tandler, J.; Voss, K.C.; Weber, A.; Wieber, H.; Bailey, D.S.; Barret, O.; Brook, N.H.; Foster, B. E-mail: b.foster@bristol.ac.uk; Heath, G.P.; Heath, H.F.; Rodrigues, E.; Scott, J.; Tapper, R.J.; Capua, M.; Schioppa, M.; Susinno, G.; Jeoung, H.Y.; Kim, J.Y.; Lee, J.H.; Lim, I.T.; Ma, K.J.; Pac, M.Y.; Caldwell, A.; Liu, W.; Liu, X.; Mellado, B.; Paganis, S.; Sampson, S.; Schmidke, W.B.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Klimek, K.; Olkiewicz, K.; Piotrzkowski, K.; Przybycien, M.B.; Stopa, P.; Zawiejski, L.; Bednarek, B.; Jelen, K.; Kisielewska, D.; Kowal, A.M.; Kowalski, T.; Przybycien, M.; Rulikowska-Zarebska, E.; Suszycki, L.; Szuba, D.; Kotanski, A.; Bauerdick, L.A.T.; Behrens, U.; Bienlein, J.K.; Borras, K.; Chiochia, V.; Dannheim, D.; Desler, K.; Drews, G.; Fox-Murphy, A.; Fricke, U.; Goebel, F.; Goers, S.; Goettlicher, P.; Graciani, R.; Haas, T.; Hain, W.; Hartner, G.F.; Hebbel, K.; Hillert, S.; Koch, W.; Koetz, U.; Kowalski, H.; Labes, H.; Loehr, B.; Mankel, R.; Martens, J.; Martinez, M.; Milite, M.; Moritz, M.; Notz, D.; Petrucci, M.C.; Polini, A.; Rohde, M.; Savin, A.A.; Schneekloth, U.; Selonke, F.; Sievers, M.; Stonjek, S.; Wolf, G.; Wollmer, U.; Youngman, C.; Zeuner, W.; Coldewey, C.; Lopez-Duran Viani, A.; Meyer, A.; Schlenstedt, S.[and others

    2001-02-26

    Differential cross sections for dijet photoproduction in association with a leading neutron using the reaction e{sup +}+p{yields}e{sup +}+n+jet+jet+X{sub r} have been measured with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb{sup -1}. The fraction of dijet events with a leading neutron in the final state was studied as a function of the jet kinematic variables. The cross sections were measured for jet transverse energies E{sub T}{sup jet}>6 GeV, neutron energy E{sub n}>400 GeV, and neutron production angle {theta}{sub n}<0.8 mrad. The data are broadly consistent with factorization of the lepton and hadron vertices and with a simple one-pion-exchange model.

  6. The Future is Hera! Analyzing Astronomical Over the Internet

    Science.gov (United States)

    Valencic, L. A.; Chai, P.; Pence, W.; Shafer, R.; Snowden, S.

    2008-01-01

    Hera is the data processing facility provided by the High Energy Astrophysics Science Archive Research Center (HEASARC) at the NASA Goddard Space Flight Center for analyzing astronomical data. Hera provides all the pre-installed software packages, local disk space, and computing resources need to do general processing of FITS format data files residing on the users local computer, and to do research using the publicly available data from the High ENergy Astrophysics Division. Qualified students, educators and researchers may freely use the Hera services over the internet of research and educational purposes.

  7. Possible future HERA analyses

    International Nuclear Information System (INIS)

    Geiser, Achim

    2015-12-01

    A variety of possible future analyses of HERA data in the context of the HERA data preservation programme is collected, motivated, and commented. The focus is placed on possible future analyses of the existing ep collider data and their physics scope. Comparisons to the original scope of the HERA pro- gramme are made, and cross references to topics also covered by other participants of the workshop are given. This includes topics on QCD, proton structure, diffraction, jets, hadronic final states, heavy flavours, electroweak physics, and the application of related theory and phenomenology topics like NNLO QCD calculations, low-x related models, nonperturbative QCD aspects, and electroweak radiative corrections. Synergies with other collider programmes are also addressed. In summary, the range of physics topics which can still be uniquely covered using the existing data is very broad and of considerable physics interest, often matching the interest of results from colliders currently in operation. Due to well-established data and MC sets, calibrations, and analysis procedures the manpower and expertise needed for a particular analysis is often very much smaller than that needed for an ongoing experiment. Since centrally funded manpower to carry out such analyses is not available any longer, this contribution not only targets experienced self-funded experimentalists, but also theorists and master-level students who might wish to carry out such an analysis.

  8. Signals for supersymmetry at HERA

    International Nuclear Information System (INIS)

    Dreiner, H.; Morawitz, P.

    1994-07-01

    We consider the baryon parity signals at HERA for the case of the MSSM production mechanisms and the decays via the lepton number violating couplings L i Q anti D. We can probe very small Yukawa couplings λ'> or ∼3.10 -6 , limited only by the decay length of the LSP. We assume the LSP to be the lightest neutralino and study its decays in detail. We present the matrix element squared for the tree-level decay amplitude of a generally mixed neutralino explicitly. We find that the branching fraction to charged leptons strongly depends on the SUSY parameters and can differ significantly from the naively expected 50%. The SUSY mass reaches of the studied processes in the ZEUS detector at HERA were found to be: (m(e, anti ν)+m( anti q)) ≤ 170 GeV, 195 GeV and 205 GeV for the L t Q anti D, L μ Q anti D and L e Q anti D couplings respectively. These are well above existing limits on R-parity violating (R p ) SUSY from previous experiments. We conclude that HERA offers a very promising discovery potential for R p SUSY. (orig.)

  9. Measurement of beauty production in deep inelastic scattering at HERA using decays into electrons

    Energy Technology Data Exchange (ETDEWEB)

    Shehzadi, Ramoona

    2011-01-15

    The production of beauty quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared Q{sup 2}>10 GeV{sup 2}, using an integrated luminosity of 363 pb{sup -1}. The beauty events were identified using electrons from semileptonic b decays with a transverse momentum 0.9measured and compared with next-to-leading-order QCD calculations. The beauty contribution to the proton structure function F{sub 2} was extracted from the double-differential cross section as a function of Bjorken-x and Q{sup 2}. (orig.)

  10. Combined Measurement and QCD Analysis of the Inclusive ep Scattering Cross Sections at HERA

    CERN Document Server

    Aaron, F.D.; Abt, I.; Adamczyk, L.; Adamus, M.; Aldaya Martin, M.; Alexa, C.; Andreev, V.; Antonelli, S.; Antonioli, P.; Antonov, A.; Antunovic, B.; Arneodo, M.; Aushev, V.; Bachynska, O.; Backovic, S.; Baghdasaryan, A.; Bamberger, A.; Barakbaev, A.N.; Barbagli, G.; Bari, G.; Barreiro, F.; Barrelet, E.; Bartel, W.; Bartsch, D.; Basile, M.; Begzsuren, K.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Belousov, A.; Bertolin, A.; Bhadra, S.; Bindi, M.; Bizot, J.C.; Blohm, C.; Bold, T.; Boos, E.G.; Borodin, M.; Borras, K.; Boscherini, D.; Bot, D.; Boudry, V.; Boutle, S.K.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Brock, I.; Brownson, E.; Brugnera, R.; Brummer, N.; Bruncko, D.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bunyatyan, A.; Buschhorn, G.; Bussey, P.J.; Butterworth, J.M.; Bylsma, B.; Bystritskaya, L.; Caldwell, A.; Campbell, A.J.; Cantun Avila, K.B.; Capua, M.; Carlin, R.; Catterall, C.D.; Cerny, K.; Cerny, V.; Chekanov, S.; Chekelian, V.; Cholewa, A.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Contreras, J.G.; Cooper-Sarkar, A.M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; D'Agostini, G.; Dainton, J.B.; Dal Corso, F.; Daum, K.; Deak, M.; de Favereau, J.; Delcourt, B.; del Peso, J.; Delvax, J.; Dementiev, R.K.; De Pasquale, S.; Derrick, M.; Devenish, R.C.E.; De Wolf, E.A.; Diaconu, C.; Dobur, D.; Dodonov, V.; Dolgoshein, B.A.; Dossanov, A.; Doyle, A.T.; Drugakov, V.; Dubak, A.; Durkin, L.S.; Dusini, S.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eisenberg, Y.; Eliseev, A.; Elsen, E.; Ermolov, P.F.; Eskreys, A.; Falkiewicz, A.; Fang, S.; Favart, L.; Fazio, S.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrando, J.; Ferrero, M.I.; Figiel, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Forrest, M.; Foster, B.; Fourletov, S.; Gabathuler, E.; Galas, A.; Gallo, E.; Garfagnini, A.; Gayler, J.; Geiser, A.; Ghazaryan, S.; Gialas, I.; Gladilin, L.K.; Gladkov, D.; Glasman, C.; Glazov, A.; Glushkov, I.; Goerlich, L.; Gogitidze, N.; Golubkov, Yu.A.; Gottlicher, P.; Gouzevitch, M.; Grab, C.; Grabowska-Bold, I.; Grebenyuk, J.; Greenshaw, T.; Gregor, I.; Grell, B.R.; Grigorescu, G.; Grindhammer, G.; Grzelak, G.; Gwenlan, C.; Haas, T.; Habib, S.; Haidt, D.; Hain, W.; Hamatsu, R.; Hart, J.C.; Hartmann, H.; Hartner, G.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hilger, E.; Hiller, K.H.; Hochman, D.; Hoffmann, D.; Holm, U.; Hori, R.; Horisberger, R.; Horton, K.; Hreus, T.; Huttmann, A.; Iacobucci, G.; Ibrahim, Z.A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jacquet, M.; Jakob, H.P.; Janssen, X.; Januschek, F.; Jimenez, M.; Jones, T.W.; Jonsson, L.; Jung, A.W.; Jung, H.; Jungst, M.; Kadenko, I.; Kahle, B.; Kamaluddin, B.; Kananov, S.; Kanno, T.; Kapichine, M.; Karshon, U.; Karstens, F.; Katkov, I.I.; Katzy, J.; Kaur, M.; Kaur, P.; Kenyon, I.R.; Keramidas, A.; Khein, L.A.; Kiesling, C.; Kim, J.Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, M.; Klein, U.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Koffeman, E.; Kogler, R.; Kollar, D.; Kooijman, P.; Korol, Ie.; Korzhavina, I.A.; Kostka, P.; Kotanski, A.; Kotz, U.; Kowalski, H.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kulinski, P.; Kuprash, O.; Kutak, K.; Kuze, M.; Kuzmin, V.A.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lee, A.; Lendermann, V.; Levchenko, B.B.; Levonian, S.; Levy, A.; Li, G.; Libov, V.; Limentani, S.; Ling, T.Y.; Lipka, K.; Liptaj, A.; Lisovyi, M.; List, B.; List, J.; Lobodzinska, E.; Lohmann, W.; Lohr, B.; Lohrmann, E.; Loizides, J.H.; Loktionova, N.; Long, K.R.; Longhin, A.; Lontkovskyi, D.; Lopez-Fernandez, R.; Lubimov, V.; Lukasik, J.; Lukina, O.Yu.; Luzniak, P.; Maeda, J.; Magill, S.; Makankine, A.; Makarenko, I.; Malinovski, E.; Malka, J.; Mankel, R.; Marage, P.; Margotti, A.; Marini, G.; Marti, Ll.; Martin, J.F.; Martyn, H.U.; Mastroberardino, A.; Matsumoto, T.; Mattingly, M.C.K.; Maxfield, S.J.; Mehta, A.; Melzer-Pellmann, I.A.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Miglioranzi, S.; Mikocki, S.; Milcewicz-Mika, I.; Mohamad Idris, F.; Monaco, V.; Montanari, A.; Moreau, F.; Morozov, A.; Morris, J.D.; Morris, J.V.; Mozer, M.U.; Mudrinic, M.; Muller, K.; Murin, P.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Naumann, Th.; Newman, P.R.; Nicholass, D.; Niebuhr, C.; Nigro, A.; Nikiforov, A.; Nikitin, D.; Ning, Y.; Noor, U.; Notz, D.; Nowak, G.; Nowak, K.; Nowak, R.J.; Nuncio-Quiroz, A.E.; Oh, B.Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Olsson, J.E.; Onishchuk, Yu.; Osman, S.; Ota, O.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Papageorgiu, K.; Parenti, A.; Pascaud, C.; Patel, G.D.; Paul, E.; Pawlak, J.M.; Pawlik, B.; Pejchal, O.; Pelfer, P.G.; Pellegrino, A.; Perez, E.; Perlanski, W.; Perrey, H.; Petrukhin, A.; Picuric, I.; Piec, S.; Piotrzkowski, K.; Pitzl, D.; Placakyte, R.; Plucinski, P.; Pokorny, B.; Pokrovskiy, N.S.; Polifka, R.; Polini, A.; Povh, B.; Proskuryakov, A.S.; Przybycien, M.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Raval, A.; Ravdandorj, T.; Reeder, D.D.; Reimer, P.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y.D.; Rizvi, E.; Robertson, A.; Robmann, P.; Roland, B.; Roloff, P.; Ron, E.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rubinsky, I.; Ruiz Tabasco, J.E.; Rusakov, S.; Ruspa, M.; Sacchi, R.; Salek, D.; Salii, A.; Samson, U.; Sankey, D.P.C.; Sartorelli, G.; Sauter, M.; Sauvan, E.; Savin, A.A.; Saxon, D.H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W.B.; Schmitt, S.; Schneekloth, U.; Schoeffel, L.; Schonberg, V.; Schoning, A.; Schorner-Sadenius, T.; Schultz-Coulon, H.C.; Schwartz, J.; Sciulli, F.; Sefkow, F.; Shaw-West, R.N.; Shcheglova, L.M.; Shehzadi, R.; Shimizu, S.; Shtarkov, L.N.; Shushkevich, S.; Singh, I.; Skillicorn, I.O.; Sloan, T.; Slominski, W.; Smiljanic, I.; Smith, W.H.; Sola, V.; Solano, A.; Soloviev, Y.; Son, D.; Sopicki, P.; Sorokin, Iu.; Sosnovtsev, V.; South, D.; Spaskov, V.; Specka, A.; Spiridonov, A.; Stadie, H.; Stanco, L.; Staykova, Z.; Steder, M.; Stella, B.; Stern, A.; Stewart, T.P.; Stifutkin, A.; Stoicea, G.; Stopa, P.; Straumann, U.; Suchkov, S.; Sunar, D.; Susinno, G.; Suszycki, L.; Sykora, T.; Sztuk, J.; Szuba, D.; Szuba, J.; Tapper, A.D.; Tassi, E.; Tchoulakov, V.; Terron, J.; Theedt, T.; Thompson, G.; Thompson, P.D.; Tiecke, H.; Tokushuku, K.; Toll, T.; Tomasz, F.; Tomaszewska, J.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsurugai, T.; Turcato, M.; Turnau, J.; Tymieniecka, T.; Urban, K.; Uribe-Estrada, C.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vazquez, M.; Verbytskyi, A.; Viazlo, V.; Vinokurova, S.; Vlasov, N.N.; Volchinski, V.; Volynets, O.; von den Driesch, M.; Walczak, R.; Wan Abdullah, W.A.T.; Wegener, D.; Whitmore, J.J.; Whyte, J.; Wiggers, L.; Wing, M.; Wissing, Ch.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Wunsch, E.; Yagues-Molina, A.G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zacek, J.; Zalesak, J.; Zarnecki, A.F.; Zawiejski, L.; Zeniaev, O.; Zeuner, W.; Zhang, Z.; Zhautykov, B.O.; Zhokin, A.; Zhou, C.; Zichichi, A.; Zimmermann, T.; Zohrabyan, H.; Zolko, M.; Zomer, F.; Zotkin, D.S.

    2010-01-01

    A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised ep scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q^2, and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions HERAPDF1.0 with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.

  11. Measurement of D mesons production in deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chakanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2007-04-15

    Charm production in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 82 pb{sup -1}. Charm has been tagged by reconstructing D{sup *+}, D{sup 0}, D{sup +} and D{sup +}{sub s} (+c.c.) charm mesons. The charm hadrons were measured in the kinematic range p{sub T}(D{sup *+},D{sup 0},D{sup +})>3 GeV, p{sub T}(D{sup +}{sub s})>2 GeV and vertical stroke {eta}(D) vertical stroke <1.6 for 1.5

  12. Measurement of charm and beauty production in deep inelastic ep scattering from decays into muons at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S

    2009-04-01

    The production of charm and beauty quarks in ep interactions has been measured with the ZEUS detector at HERA for squared four-momentum exchange Q 2 > 20GeV 2 , using an integrated luminosity of 126 pb -1 . Charm and beauty quarks were identified through their decays into muons. Differential cross sections were measured for muon transverse momenta p T μ >1.5 GeV and pseudorapidities -1.6 μ T μ , η μ , Q 2 and Bjorken x. The charm and beauty contributions to the proton structure function F 2 were also extracted. The results agree with previous measurements based on independent techniques and are well described by QCD predictions. (orig.)

  13. Measurement of the charm and beauty structure functions using the H1 vertex detector at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Preda, T.; Rotaru, M.; Stoicea, G.; Zus, R.; Aldaya Martin, M.; Alimujiang, K.; Antunovic, B.; Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Boer, Y. de; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Glazov, A.; Gouzevitch, M.; Grell, B.R.; Haidt, D.; Helebrant, C.; Janssen, M.E.; Jung, H.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Marti, L.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Niebuhr, C.; Nikiforov, A.; Nozicka, M.; Olsson, J.E.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Radescu, V.; Rurikova, Z.; Schmitt, S.; Schoeffel, L.; Sefkow, F.; Staykova, Z.; Steder, M.; Vargas Trevino, A.; Vinokurova, S.; Driesch, M. von den; Wissing, C.; Wuensch, E.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Asmone, A.; Stella, B.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Ghazaryan, S.; Volchinski, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Brinkmann, M.; Habib, S.; List, B.; Pokorny, B.; Toll, T.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Olivier, B.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cassol-Brunner, F.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Cerny, K.; Pejchal, O.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Del Degan, M.; Grab, C.; Leibenguth, G.; Sauter, M.; Zimmermann, T.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Dodonov, V.; Lytkin, L.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Piec, S.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Joensson, L.; Osman, S.; Kapichine, M.; Makankine, A.; Morozov, A.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Straumann, U.; Truoel, P.; Schoening, A.; South, D.; Wegener, D.; Tsakov, I.

    2010-01-01

    Inclusive charm and beauty cross sections are measured in e - p and e + p neutral current collisions at HERA in the kinematic region of photon virtuality 5≤Q 2 ≤2000 GeV 2 and Bjorken scaling variable 0.0002≤x≤0.05. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb -1 . The numbers of charm and beauty events are determined using variables reconstructed by the H1 vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions. (orig.)

  14. Measurement of the Charm and Beauty Structure Functions using the H1 Vertex Detector at HERA

    CERN Document Server

    Aaron, FD; Alexa, C; Alimujiang, K; Andreev, V; Antunovic, B; Asmone, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D -J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, Samvel; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jonsson, L; Jung, Andreas Werner; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H -U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, Matthias Ulrich; Mudrinic, M; Muller, K; Murin, P; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schoeffel, L; Schoning, A; Schultz-Coulon, H -C; Sefkow, F; Shaw-West, R N; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, Ivan; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, Arnd E; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F; Zus, R

    2010-01-01

    Inclusive charm and beauty cross sections are measured in e-p and e+p neutral current collisions at HERA in the kinematic region of photon virtuality 5measurements are combined with previous data and compared to QCD predictions.

  15. Measurement of the t dependence in exclusive photoproduction of {upsilon}(1S) mesons at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2011-10-15

    The exclusive photoproduction reaction {gamma}p{yields}{upsilon}(1S)p has been studied with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 468 pb{sup -1}. The measurement covers the kinematic range 60measured, yielding b=4.3{sup +2.0}{sub -1.3}(stat.){sup +0.5}{sub -0.6}(syst.) GeV{sup -2}. This constitutes the first measurement of the t dependence of the {gamma}p{yields}{upsilon}(1S)p cross section. (orig.)

  16. HERA Broadband Feed Design for Low-Frequency Radio Astronomy

    Science.gov (United States)

    Garza, Sierra; Trung, Vincent; Ewall-Wice, Aaron Michael; Li, Jianshu; Hewitt, Jacqueline; Riley, Daniel; Bradley, Richard F.; Makhija, Krishna

    2018-01-01

    As part of the Hydrogen Epoch of Reionization Array (HERA) project, we are designing a broadband low-frequency radio feed to extend the bandwidth from 100-200 MHz to 50-220 MHz. By extending the lower-limit to 50 MHz, we hope to detect the signatures of the first black holes heating the hydrogen gas in the intergalactic medium.The isolation of a very faint signal from vastly brighter foregrounds sets strict requirements on antenna spectral smoothness, polarization purity, forward gain, and internal reflections. We are currently working to meet these requirements with a broad-band sinuous antenna feed suspended over the 14-m parabolic HERA dish, using a combination of measurements and simulations to verify the performance of our design.A sinuous feed has been designed and simulated with Computer Simulation Technology (CST) software. We will present the construction of a prototype sinuous antenna and measurements of its reflection coefficient, S11, including laboratory characterization of baluns. Our measurements agree well with the CST simulations of the antenna’s performance, giving us confidence in our ability to model the feed and ensure that it meets the requirements of a 21cm cosmology measurement.

  17. Prompt photons in photoproduction at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Zus, R.; Aldaya Martin, M.; Antunovic, B.; Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Boer, Y. de; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Glazov, A.; Gouzevitch, M.; Grell, B.R.; Haidt, D.; Helebrant, C.; Jung, H.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Marti, Ll.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Niebuhr, C.; Nikiforov, A.; Nozicka, M.; Olsson, J.E.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Radescu, V.; Rurikova, Z.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Vargas Trevino, A.; Vinokurova, S.; Driesch, M. von den; Wissing, C.; Wuensch, E.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Ghazaryan, S.; Volchinski, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Brinkmann, M.; Habib, S.; List, B.; Pokorny, B.; Toll, T.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Olivier, B.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cerny, K.; Pejchal, O.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Schoeffel, L.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Del Degan, M.; Grab, C.; Leibenguth, G.; Sauter, M.; Zimmermann, T.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Dodonov, V.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Piec, S.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Joensson, L.; Osman, S.; Kapichine, M.; Makankine, A.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Straumann, U.; Truoel, P.; Schoening, A.; South, D.; Wegener, D.; Stella, B.; Tsakov, I.

    2010-01-01

    The production of prompt photons is measured in the photoproduction regime of electron-proton scattering at HERA. The analysis is based on a data sample corresponding to a total integrated luminosity of 340 pb -1 collected by the H1 experiment. Cross sections are measured for photons with transverse momentum and pseudorapidity in the range 6 T γ γ γ and x p carried by the partons entering the hard scattering process. The correlation between the photon and the jet is also studied. The results are compared with QCD predictions based on the collinear and on the k T factorization approaches. (orig.) 7

  18. Measurement of the structure function F2 of the proton in deep inelastic e-p scattering with the H1 detector at the HERA storage ring

    International Nuclear Information System (INIS)

    Wellisch, J.P.

    1994-02-01

    This thesis presents the measurement of the structure function F 2 of the proton with the H1 detector at 10 GeV 2 2 2 and 10 -4 -2 . The analysis contains the data of the first year of the HERA operation. The applied integrated luminosity amounts to 22.5 nb -1 . Contrarily to earlier experiments of the deep inelastic scattering it is at H1 possible to apply also the hadronic final state for the reconstruction of the event kinematics. In this thesis ten methods for the reconstruction of the event kinematics are indicated and studied in the region Q 2 2 in detailed detector simulation on resolution, systematic effects, measurable kinematical range and sensitivity to radiation of photons from the electron. For H1 as most advantageous methods for the reconstruction of the event kinematics on the one hand the exclusive application of the electron information and on the other hand the combination of the measurement of the momentum transfer from energy and direction of the scattered electron with the measurement of the relative energy transfer y from the scattering of electron and quark have been proved. Thereby a new, for the range of small momentum transfers especially suited method, for the reconstruction of the scattering angle of the quark was indicated. A significant increasement of the structure function F 2 of the proton at small x. At large x the continuation to the results found in earlier measurements is continuous. At fixed x the structure function increases slowly in agreement with the predictions of QCD with increasing momentum transfer

  19. Measurement of the Inclusive ep Scattering Cross Section at Low Q^2 and x at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Eckstein, D.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Jung, A.W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lastovicka, T.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, M.U.; Mudrinic, M.; Muller, K.; Murin, P.; Naroska, B.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, I.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; von den Driesch, M.; Wegener, D.; Wissing, Ch.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2009-01-01

    A measurement of the inclusive ep scattering cross section is presented in the region of low momentum transfers, 0.2 GeV^2 < Q^2 < 12 GeV^2, and low Bjorken x, 5x10^-6 < x < 0.02. The result is based on two data sets collected in dedicated runs by the H1 Collaboration at HERA at beam energies of 27.6 GeV and 920 GeV for positrons and protons, respectively. A combination with data previously published by H1 leads to a cross section measurement of a few percent accuracy. A kinematic reconstruction method exploiting radiative ep events extends the measurement to lower Q^2 and larger x. The data are compared with theoretical models which apply to the transition region from photoproduction to deep inelastic scattering.

  20. Search for events with an isolated lepton and missing transverse momentum and a measurement of W production at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-07-01

    A search for events with an isolated high-energy lepton and large missing transverse momentum has been performed with the ZEUS detector at HERA using a total integrated luminosity of 504 pb -1 . The results agree well with Standard Model predictions. The cross section for production of single W bosons in electron-proton collisions with unpolarised electrons is measured to be 0.89 +0.25 -0.22 (stat.)±0.10(syst.) pb. (orig.)

  1. Kinematic fitting of neutral current events at HERA

    International Nuclear Information System (INIS)

    Chaves, H.; Seifert, R.J.; Zech, G.

    1993-01-01

    The measurement of the scaling variables in deep inelastic scattering at HERA can be improved considerably by constraining the scattered electrons and the produced hadrons to energy-momentum conservation. It is shown how unobserved particles moving down the beam pipe and initial state radiation can be included in the kinematics. The particle momenta are adjusted in a linear least squares fit. (orig.)

  2. Measurement of the cross-section ratio σψ(2S)/σJ/ψ(1S) in deep inelastic exclusive ep scattering at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2016-01-01

    The exclusive deep inelastic electroproduction of ψ(2S) and J/ψ(1S) at an ep centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range 2HERA I and HERA II periods and correspond to an integrated luminosity of 468 pb -1 . The decay modes analysed were μ + μ - and J/ψ(1S) π + π - for the ψ(2S) and μ + μ - for the J/ψ(1S). The cross-section ratio σ ψ(2S) /σ J/ψ(1S) has been measured as a function of Q 2 , W and t. The results are compared to predictions of QCD-inspired models of exclusive vector-meson production.

  3. Preservation of the HERA-B Collaboration heritage

    International Nuclear Information System (INIS)

    Ozerov, Dmitry; Rostovtseva, Irina; Goloubkov, Dmitri

    2011-01-01

    We present the concept of the data preservation developed for the HERA-B experiment which studied proton-nucleus interactions of the 920 GeV/c beam at HERA/DESY. The full analysis chain (starting from raw data) is to be preserved based on the rolling DPHEP model with open access to the data. We have frozen the full working analysis software environment using chroot-jail virtualization and report first experience of porting the software to a newer OS/compiler.

  4. Nuclei at HERA and heavy ion physics

    International Nuclear Information System (INIS)

    Gavin, S.; Strikman, M.

    1995-01-01

    Copies of 16 viewgraph sets from a workshop held at Brookhaven National Laboratory, 17-18 November, 1995. Titles of talks: HERA: The Present; HERA: Potential with Nuclei; Review of Hadron-Lepton Nucleus Data; Fermilab E665: results in muon scattering; Interactions of Quarks and Gluons with Nuclear Matter; Rescattering in Nuclear Targets for Photoproduction and DIS; Structure Functions and Nuclear Effect at PHENIX; Probing Spin-Averaged and Spin-Dependent Parton Distributions Using the Solenoidal Tracker at RHIC (STAR); Jet Quenching in eA, pA, AA; Nuclear Gluon Shadowing via Continuum Lepton Pairs; What can we learn from HERA with a colliding heavy ion beam? The limiting curve of leading particles at infinite A; Coherent Production of Vector Mesons off Light Nuclei in DIS; A Model of High Parton Densities in PQCD; Gluon Production for Weizaecker-Williams Field in Nucleus-Nucleus Collisions; Summary Talk

  5. Measurement of charm fragmentation in DIS at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Rurikova, Z.

    2006-04-15

    The charm fragmentation function has been studied in deep inelastic ep collisions with the H1 detector at HERA. The data were analyzed in the kinematic range given by the photon virtuality 2measured in the D{sup *}-meson visible range de ned by cuts on pseudorapidity vertical stroke {eta}(D{sup *}) vertical stroke <1.5 and transverse momentum 1.53 GeV was required in the latter case. Both distributions were used to extract the parameters of the nonperturbative Peterson and Kartvelishvili fragmentation functions for the Monte Carlo models RAPGAP/PYTHIA and CASCADE/PYTHIA and for the next-to-leading-order massive QCD calculation HVQDIS. (orig.)

  6. Working Group I: Parton distributions: Summary report for the HERA LHC Workshop Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Dittmar, M.; /Zurich, ETH; Forte, S.; /Milan U. /INFN, Milan; Glazov, A.; /DESY; Moch, S.; /DESY, Zeuthen; Alekhin, S.; Altarelli, G.; Andersen, Jeppe R.; Ball, R.D.; Blumlein, J.; Bottcher, H.; Carli, T.; Ciafaloni, M.; Colferai, D.; Cooper-Sarkar, A.; Corcella, G.; Del Debbio, L.; Dissertori, G.; Feltesse, J.; Guffanti, A.; Gwenlan, C.; Huston, J.; /Zurich, ETH /DESY, Zeuthen /Serpukhov, IHEP /CERN /Rome III U. /INFN, Rome3 /Cambridge U. /Edinburgh U. /Florence U. /INFN, Florence /Oxford U. /DSM, DAPNIA, Saclay

    2005-11-01

    We provide an assessment of the impact of parton distributions on the determination of LHC processes, and of the accuracy with which parton distributions (PDFs) can be extracted from data, in particular from current and forthcoming HERA experiments. We give an overview of reference LHC processes and their associated PDF uncertainties, and study in detail W and Z production at the LHC.We discuss the precision which may be obtained from the analysis of existing HERA data, tests of consistency of HERA data from different experiments, and the combination of these data. We determine further improvements on PDFs which may be obtained from future HERA data (including measurements of F{sub L}), and from combining present and future HERA data with present and future hadron collider data. We review the current status of knowledge of higher (NNLO) QCD corrections to perturbative evolution and deep-inelastic scattering, and provide reference results for their impact on parton evolution, and we briefly examine non-perturbative models for parton distributions. We discuss the state-of-the art in global parton fits, we assess the impact on them of various kinds of data and of theoretical corrections, by providing benchmarks of Alekhin and MRST parton distributions and a CTEQ analysis of parton fit stability, and we briefly presents proposals for alternative approaches to parton fitting. We summarize the status of large and small x resummation, by providing estimates of the impact of large x resummation on parton fits, and a comparison of different approaches to small x resummation, for which we also discuss numerical techniques.

  7. Measurement of beauty production in deep inelastic scattering at HERA using decays into electrons

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max-Planck-Institut fuer Physik, Muenchen (Germany); Abt, I. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2011-01-15

    The production of beauty quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared Q{sup 2}>10 GeV{sup 2}, using an integrated luminosity of 363 pb{sup -1}. The beauty events were identified using electrons from semileptonic b decays with a transverse momentum 0.9 measured and compared with next-to-leading-order QCD calculations. The beauty contribution to the proton structure function F{sub 2} was extracted from the double-differential cross section as a function of Bjorken-x and Q{sup 2}. (orig.)

  8. Measurement of internal jet structure in dijet production in deep-inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Adloff, C.; Andreev, V.; Andrieu, B.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Baehr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Bate, P.; Beglarian, A.; Behnke, O.; Behrend, H.-J.; Beier, C.; Belousov, A.; Berger, Ch.; Bernardi, G.; Berndt, T.; Bertrand-Coremans, G.; Biddulph, P.; Bizot, J.C.; Boudry, V.; Braunschweig, W.; Brisson, V.; Brown, D.P.; Brueckner, W.; Bruel, P.; Bruncko, D.; Buerger, J.; Buesser, F.W.; Buniatian, A.; Burke, S.; Buschhorn, G.; Calvet, D.; Campbell, A.J.; Carli, T.; Chabert, E.; Charlet, M.; Clarke, D.; Clerbaux, B.; Cocks, S.; Contreras, J.G.; Cormack, C.; Coughlan, J.A.; Cousinou, M.-C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; David, M.; Davidsson, M.; De Roeck, A.; De Wolf, E.A.; Delcourt, B.; Demirchyan, R.; Diaconu, C.; Dirkmann, M.; Dixon, P.; Dlugosz, W.; Donovan, K.T.; Dowell, J.D.; Droutskoi, A.; Ebert, J.; Eckerlin, G.; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Elsen, E.; Enzenberger, M.; Erdmann, M.; Farh, A.B.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrarotto, F.; Fleischer, M.; Fluegge, G.; Fomenko, A.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Gaede, F.; Garvey, J.; Gassner, J.; Gayler, J.; Gerhards, R.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Gorelov, I.; Grab, C.; Graessler, H.; Greenshaw, T.; Griffiths, R.K.; Grindhammer, G.; Hadig, T.; Haidt, D.; Hajduk, L.; Hampel, M.; Haustein, V.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herynek, I.; Hewitt, K.; Hiller, K.H.; Hilton, C.D.; Hladky, J.; Hoffmann, D.; Holtom, T.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C.; Jacquet, M.; Jaffre, M.; Jansen, D.M.; Joensson, L.; Johnson, D.P.; Jung, H.; Kaestli, H.K.; Kander, M.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnik, O.; Katzy, J.; Kaufmann, O.; Kausch, M.; Keller, N.; Kenyon, I.R.; Kermiche, S.; Keuker, C.; Kiesling, C.; Klein, M.; Kleinwort, C.; Knies, G.; Koehne, J.H.; Kolanoski, H.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Kraemerkaemper, T.; Krasny, M.W.; Krehbiel, H.; Kruecker, D.; Krueger, K.; Kuepper, A.; Kuester, H.; Kuhlen, M.; Kurca, T.; Lachnit, W.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Langenegger, U.; Lebedev, A.; Lehner, F.; Lemaitre, V.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; Lobo, G.; Lobodzinska, E.; Lubimov, V.; Lueders, S.; Lueke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Krueger, H.; Malden, N.; Malinovsky, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.-U.; Martyniak, J.; Maxfield, S.J.; McMahon, S.J.; McMahon, T.R.; Mehta, A.; Meier, K.; Merkel, P.; Metlica, F.; Meyer, A.; Meyer, A.; Meyer, H.; Meyer, J.; Meyer, P.-O.; Mikocki, S.; Milstead, D.; Mohr, R.; Mohrdieck, S.; Mondragon, M.; Moreau, F.; Morozov, A.; Morris, J.V.; Mueller, D.; Mueller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Negri, I.; Newman, P.R.; Nguyen, H.K.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Niedzballa, Ch.; Niggli, H.; Nix, O.; Nowak, G.; Nunnemann, T.; Oberlack, H.; Olsson, J.E.; Ozerov, D.; Palmen, P.; Panassik, V.; Pascaud, C.; Passaggio, S.; Patel, G.D.; Pawletta, H.; Perez, E.; Phillips, J.P.; Pieuchot, A.; Pitzl, D.; Poeschl, R.; Pope, G.; Povh, B.; Rabbertz, K.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Rick, H.; Riess, S.; Rizvi, E.; Robmann, P.; Roosen, R.; Rosenbauer, K.; Rostovtsev, A.; Rouse, F.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Schacht, P.; Scheins, J.; Schilling, F.-P.; Schleif, S.; Schleper, P.; Schmidt, D.; Schmidt, D.; Schoeffel, L.; Schroeder, V.; Schultz-Coulon, H.-C.; Sefkow, F.; Semenov, A.; Shekelyan, V.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sirois, Y.; Sloan, T.; Smirnov, P.; Smith, M.; Solochenko, V.; Soloviev, Y.; Sonnenschein, L.; Spaskov, V.; Specka, A.; Spitzer, H.; Squinabol, F.; Stamen, R.; Steffen, P.; Steinberg, R.; Steinhart, J.; Stella, B.; Ste llberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Sutton, J.P.; Swart, M.; Tapprogge, S.; Tasevsky, M.; Tchernyshov, V.; Tchetchelnitski, S.; Theissen, J.; Thompson, G.; Thompson, P.D.; Tobien, N.; Todenhagen, R.; Traynor, D.; Truoel, P.; Tsipolitis, G.; Turnau, J.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Esch, P.; Van Haecke, A.; Van Mechelen, P.; Vazdik, Y.; Villet, G.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Wegner, A.; Wengler, T.; Werner, M.; West, L.R.; Wiesand, S.; Wilksen, T.; Willard, S.; Winde, M.; Winter, G.-G.; Wissing, Ch.; Wittek, C.; Wittmann, E.; Wobisch, M.; Wollatz, H.; Wuensch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zini, P.; Zomer, F.; Zsembery, J.; zur Nedden, M.

    1999-01-01

    Internal jet structure in dijet production in deep-inelastic scattering is measured with the H1 detector at HERA. Jets with transverse energies E T,Breit > 5 GeV are selected in the Breit frame employing k perpendicular and cone jet algorithms. In the kinematic region of ssquared momentum transfers 10 2 2 and Bjorken-x values 2 -4 Bj -3 , jet shapes and subjet multiplicities are measured as a function of a resolution parameter. Distributions of both observables are corrected for detector effects and presented as functions of the transverse jet energy and jet pseudo-rapidity. Dependences of the jet shape and the average number of subjets on the transverse energy and the pseudo-rapidity of the jet are observed. With increasing transverse jet energies and decreasing pseudo-rapidities, i.e. towards the photon hemisphere, the jets are more collimated. QCD models give a fair description of the data

  9. Three- and four-jet final states in photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-08-01

    Three- and four-jet final states have been measured in photoproduction at HERA using the ZEUS detector with an integrated luminosity of 121 pb -1 . The results are presented for jets with transverse energy E jet T >6 GeV and pseudorapidity vertical stroke η jet vertical stroke 2 2 and the inelasticity 0.2≤y≤0.85 and in two mass regions defined as 25≤M nj nj ≥50 GeV, where M nj is the invariant mass of the n-jet system. The four-jet photoproduction cross section has been measured for the first time and represents the highest-order process studied at HERA. Both the three- and four-jet cross sections have been compared with leading-logarithmic parton-shower Monte Carlo models, with and without multi-parton interactions. The three-jet cross sections have been compared to an O(αα 2 s ) perturbative QCD calculation. (orig.)

  10. Gluon density determination from open charm events at HERA

    International Nuclear Information System (INIS)

    Woudenberg, R. van; Ould-Saada, F.; Eisenberg, Y.; Glasman, C.; Karshon, U.; Montag, A.; Egli, S.

    1992-01-01

    We study some prospects of measuring the gluon density in the proton using charm events at HERA for the ep center of mass energy √s = 314 GeV. We invoke the QCD-improved boson-gluon fusion model and find the following cross-section: σ(ep → ecanti cX) ≅ O(0.6 μb). This cross-section would provide O(10 8 ) events/year, for an integrated luminosity of 100 pb -1 . We have investigated two traditional methods for tagging of charm, namely, D *± reconstruction using the process D *± → D 0 π ± → (K -+ π ± )π ± , and dileptonic decays of charmed hadrons (canti c → l + l - X). The inclusive cross-sections after full detector simulation are 10 3 pb and 10 2 pb, respectively. In both cases the background was strongly reduced. By using these events, the gluon distribution in the proton can be measured in the range 10 -3 ≤ x g ≤ 10 -1 . We conclude that an adequate discrimination among the present theoretical parametrizations can be achieved at HERA. (orig.)

  11. Search for single top production at HERA

    International Nuclear Information System (INIS)

    Brandt, G.

    2008-01-01

    A search for single top production in e p collisions using the complete high-energy data from HERA is presented. This search is based on the analysis of events containing isolated leptons (electronic or muons) and missing transverse momentum P T miss . In the absence of a signal, an upper limit on the top production cross-section σ ep→etX tuγ T miss and the measurements of W boson polarisation fractions.

  12. Measurement of D*± meson production in deep-inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Bachynska, Olena

    2012-12-01

    Measurements of charm production in deep-inelastic scattering at HERA at a centre-of-mass energy of 318 GeV are reported in this thesis. The analysis was performed using the data collected with the ZEUS detector during the years 2004 to 2007, corresponding to an integrated luminosity of 363 pb -1 . The production of charm quarks was studied through the full kinematic reconstruction of D* ± mesons in the decay channel D* ± → D 0 / anti D 0 π ± . The studies have been performed for virtualities of the exchanged photon of 5 2 2 and inelasticities of 0.02 ± kinematic phase space is defined by the transverse momentum range, 1.5 T D* ± D* ± vertical stroke ± mesons. The total visible cross section for D* ± production as well as single-and double-differential cross sections were measured and compared to the corresponding D* ± measurements performed by the H1 collaboration in the same phase-space region. The measurements are well described by NLO QCD predictions. The double-differential cross sections were exploited to extract the charm contribution to the proton structure function, F 2 c anti c , expressed in terms of the reduced charm-production cross sections, σ red c anti c , and compared to the predictions from HERAPDF1.5 and to the recent measurements from the H1 and ZEUS collaborations.

  13. Search for events with an isolated lepton and missing transverse momentum and a measurement of W production at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2008-07-15

    A search for events with an isolated high-energy lepton and large missing transverse momentum has been performed with the ZEUS detector at HERA using a total integrated luminosity of 504 pb{sup -1}. The results agree well with Standard Model predictions. The cross section for production of single W bosons in electron-proton collisions with unpolarised electrons is measured to be 0.89{sup +0.25}{sub -0.22}(stat.){+-}0.10(syst.) pb. (orig.)

  14. Measurement of Leading Neutron Production in Deep-Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.; Alimujiang, K.; Andreev, V.; Antunovic, B.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Falkiewicz, A.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.-J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Glushkov, I.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Kogler, R.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Mudrinic, M.; Muller, K.; Murin, P.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Osman, S.; Ozerov, D.; Pahl, P; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; von den Driesch, M.; Wegener, D.; Wissing, Ch.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2010-01-01

    The production of leading neutrons, where the neutron carries a large fraction x_L of the incoming proton's longitudinal momentum, is studied in deep-inelastic positron-proton scattering at HERA. The data were taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 122 pb^{-1}. The semi-inclusive cross section is measured in the phase space defined by the photon virtuality 6 < Q^2 < 100 GeV^2, Bjorken scaling variable 1.5x10^{-4} < x < 3x10^{-2}, longitudinal momentum fraction 0.32 < x_L < 0.95 and neutron transverse momentum p_T < 0.2 GeV. The leading neutron structure function, F_2^{LN(3)}(Q^2,x,x_L), and the fraction of deep-inelastic scattering events containing a leading neutron are studied as a function of Q^2, x and x_L. Assuming that the pion exchange mechanism dominates leading neutron production, the data provide constraints on the shape of the pion structure function.

  15. Measurement of charm and beauty cross sections in photoproduction using events with muons and dijets at HERA

    International Nuclear Information System (INIS)

    Kraemer, M.

    2009-09-01

    A measurement of open charm and beauty cross sections in photoproduction using dijet events containing a muon at the ep collider HERA is presented. The analysed data are collected with the H1 detector in the years 2006 and 2007, corresponding to an integrated luminosity of 179 pb -1 . Events are selected, which contain at least two jets with transverse momenta of p t jet1(2) >7(6) GeV in the pseudorapidity region -2.5 jet1(2) t μ >2.5 GeV in the pseudorapidity range -1.3 μ γ obs . Double differential cross sections for charm and beauty are measured in the region of direct and resolved processes. (orig.)

  16. Search for leptoquarks at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Huettmann, Antje

    2009-10-15

    A search for first generation leptoquarks was performed in polarized electron-proton collider data recorded with the ZEUS detector at HERA in the years 2003-2007. They were analyzed for final states with an electron and jets or with missing transverse momentum and jets and a search for resonance structures or other deviations from the Standard Model predictions in the spectra of the invariant mass of lepton and jets was performed. No evidence for leptoquark signals was found. The data were combined with the previously taken data at HERA corresponding to an integrated luminosity of 488 pb{sup -1} and limits were set on the Yukawa coupling {lambda} as a function of the leptoquark mass for different leptoquark types within the Buchmueller-Rueckl-Wyler model. (orig.)

  17. Heavy quark production at the TEVATRON and HERA using kt-factorization with CCFM evolution

    International Nuclear Information System (INIS)

    Jung, H.

    2001-10-01

    The application of k t -factorization supplemented with the CCFM small-x evolution equation to heavy quark production at the TEVATRON and at HERA is discussed. The bb production cross sections at the TEVATRON can be consistently described using the k t -factorization formalism together with the unintegrated gluon density obtained within the CCFM evolution approach from a fit to HERA F 2 data. Special attention is drawn to the comparison with measured visible cross sections, which are compared to the hadron level Monte Carlo generator Cascade. (orig.)

  18. Measurement of dijet photoproduction for events with a leading neutron at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, B.

    2009-09-01

    Differential cross sections for dijet photoproduction and this process in association with a leading neutron, e + +p→e + +jet+jet+X(+n), have been measured with the ZEUS detector at HERA using an integrated luminosity of 40 pb -1 . The fraction of dijet events with a leading neutron was studied as a function of different jet and event variables. Single- and double-differential cross sections are presented as a function of the longitudinal fraction of the proton momentum carried by the leading neutron, x L , and of its transverse momentum squared, p T 2 . The dijet data are compared to inclusive DIS and photoproduction results; they are all consistent with a simple pion-exchange model. The neutron yield as a function of x L was found to depend only on the fraction of the proton beam energy going into the forward region, independent of the hard process. No firm conclusion can be drawn on the presence of rescattering effects. (orig)

  19. Recent results from the H1 collaboration at HERA

    International Nuclear Information System (INIS)

    Feltesse, J.

    1994-01-01

    New results from the H1 experiment at the electron-proton collider HERA are reported. Evidence for hard scattering in gamma diffraction in photoproduction events is presented. The hadronic final state in low x deep inelastic scattering (DIS) events has been analyzed. Transverse energy flow and cross section for production of jets at high x j are compared to the expectations of present Monte Carlo programs and to analytical calculations based on the BFKL evolution equation. DIS interactions with no hadronic energy flow in a large interval of rapidity around the incident proton direction are presented. The data are compared to models based on deep inelastic pomeron scattering or on MVD contributions. Measured cross sections for the production of multijet in DIS events at HERA are used to provide a preliminary measurement of the strong coupling constant alpha s , together with the first direct measurement of the gluon density in the proton. The cross section of the charged current process e - p → ν e + hadrons is measured. The effects of the W propagator term is visible for the first time. New limits on leptoquarks, leptogluons, Squarks from R-parity violating supersymmetry and on excited leptons are given. (author). 20 figs., 34 refs

  20. HERA-B framework for online calibration and alignment

    International Nuclear Information System (INIS)

    Hernandez, J.M.; Ressing, D.; Rybnikov, V.; Sanchez, F.; Medinnis, M.; Kreuzer, P.; Schwanke, U.; Amorim, A.

    2004-09-01

    This paper describes the architecture and implementation of the HERA-B framework for online calibration and alignment. At HERA-B the performance of all trigger levels, including the online reconstruction, strongly depends on using the appropriate calibration and alignment constants, which might change during data taking. A system to monitor, recompute and distribute those constants to online processes has been integrated in the data acquisition and trigger systems. (orig.)

  1. Measurement of the inclusive ep scattering cross section at low Q2 and x at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Preda, T.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Sheviakov, I.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Antunovic, B.; Aplin, S.; Bartel, W.; Brandt, G.; Brinkmann, M.; Campbell, A.J.; Cholewa, A.; Deak, M.; Boer, Y. de; Roeck, A. de; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Glazov, A.; Grell, B.R.; Haidt, D.; Helebrant, C.; Janssen, M.E.; Jung, H.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Korbel, V.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; List, J.; Marti, L.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Niebuhr, C.; Nikiforov, A.; Nozicka, M.; Olsson, J.E.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Radescu, V.; Rurikova, Z.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Toll, T.; Vargas Trevino, A.; Vinokurova, S.; Driesch, M. von den; Wissing, C.; Wuensch, E.; Asmone, A.; Stella, B.; Astvatsatourov, A.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Ghazaryan, S.; Volchinski, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Behnke, O.; Behrendt, O.; South, D.; Wegener, D.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Gouzevitch, M.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Faulkner, P.J.W.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Olivier, B.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cassol-Brunner, F.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Cerny, K.; Pejchal, O.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Schoeffel, L.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Del Degan, M.; Grab, C.; Leibenguth, G.; Sauter, M.; Zimmermann, T.; Dodonov, V.; Lytkin, L.; Povh, B.; Eckstein, D.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Lastovicka, T.; Lobodzinska, E.; Naumann, T.; Piec, S.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Habib, S.; Jemanov, V.; Lipka, K.; List, B.; Naroska, B.; Hansson, M.; Joensson, L.; Osman, S.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Meier, K.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Kapichine, M.; Makankine, A.; Morozov, A.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Schmitz, C.; Straumann, U.; Truoel, P.; Schoening, A.; Tsakov, I.

    2009-01-01

    A measurement of the inclusive ep scattering cross section is presented in the region of low momentum transfers, 0.2 GeV 2 ≤Q 2 ≤12 GeV 2 , and low Bjorken x, 5.10 -6 ≤x≤0.02. The result is based on two data sets collected in dedicated runs by the H1 Collaboration at HERA at beam energies of 27.6 GeV and 920 GeV for positrons and protons, respectively. A combination with data previously published by H1 leads to a cross section measurement of a few percent accuracy. A kinematic reconstruction method exploiting radiative ep events extends the measurement to lower Q 2 and larger x. The data are compared with theoretical models which apply to the transition region from photoproduction to deep inelastic scattering. (orig.)

  2. Measurement of Beauty and Charm Photoproduction using Semi-muonic Decays in Dijet Events at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Kogler, R.; Kostka, P.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lopez-Fernandez, R.; Lubimov, V.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

    2012-07-13

    Measurements of cross sections for beauty and charm events with dijets and a muon in the photoproduction regime at HERA are presented. The data were collected with the H1 detector and correspond to an integrated luminosity of 179 pb^{-1}. Events with dijets of transverse momentum P_T^{jet1} > 7 GeV and P_T^{jet2} > 6 GeV in the pseudorapidity range -1.5 2.5 GeV in the pseudorapidity range -1.3 < \\eta^{\\mu} < 1.5. The fractions of beauty and charm events are determined using the impact parameters of the muon tracks with respect to the primary vertex and their transverse momentum relative to the axis of the associated jet. Both variables are reconstructed using the H1 vertex detector. The measurements are in agreement with QCD predictions at leading and next-to-leading order.

  3. An investigation into the radiation damage of the silicon detectors of the H1-PLUG calorimeter within the HERA environment

    International Nuclear Information System (INIS)

    Hildesheim, W.; Seidel, M.

    1995-07-01

    The silicon detectors used in the H1-PLUG calorimeter have shown increasing aging effects during the '94 run period of the electron proton storage ring HERA. These effects were particularly manifest as degradation of the signal to noise level and the calibration stability. The reasons for this behaviour have been found to be correlated with radiation damage to the silicon oxide passivation edges of the detectors in strong and fluctuating increases of the leakage currents and in severe changes of the flat band voltages. Depletion voltages however are found to be stable and therefore bulk damage of the silicon can be excluded. A comparison with measurements made by thermoluminescence dosimeters as well as related laboratory experiments suggest that the aging is due to very low energetic electrons and photons. (orig.)

  4. Physics results from the first electron-proton collider HERA

    Energy Technology Data Exchange (ETDEWEB)

    Roeck, A de

    1995-03-01

    After two years of experimenting at the new ep collider HERA many new results have been obtained. In this report we have presented results on interactions of high energy photons with matter, and showed that similar to hadronic interactions, hard scattering is observed in these collisions. The different photoproduction processes have been isolated, and a first attempt was made to measure the structure of the photon at HERA. A new region has been explored for deep inelastic scattering interactions. The proton structure is probed to very small values of Bjorken-x, showing a large increase of with decreasing x. Events with a large rapidity gap have been observed and are identified as diffractive scattering. The first electroweak results became available by studying the production of charged current events. Searches for new, exotic phenomena were made, but no evidence for the breakdown of the standard model has been found. (orig.)

  5. Measurement of beauty-production in deep inelastic scattering at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Kahle, B.

    2006-04-15

    This thesis presents a measurement of beauty quark production in deep inelastic scattering at the ep-collider HERA at {radical}(s)=318 GeV. The measurement is based on data collected at the ZEUS detector in the years 2003/2004, using an integrated luminosity of 39 pb{sup -1}. In the analysis presented in this thesis, events were selected that contain a scattered electron, a jet and a muon inside the jet. The fraction of events from beauty quark production was extracted using the characteristic distribution of the transverse momenta of muons relative to the associated jets. The total visible cross section was measured to be: {sigma}{sup b} {sup anti} {sup b}(ep{yields}eb anti b X{yields}e jet{mu}X')=57.9{+-}5.8(stat.){sup +3.5}{sub -8.1}(syst.) pb in the kinematic region defined by: Q{sup 2}>4 GeV{sup 2}, y>0.05 und y<0.7, one jet originating from a beauty quark with: E{sup jet}{sub t,lab}>5 GeV und -2<{eta}{sup jet}<2.5 and a muon originating from a beauty quark decay (direct or indirect) included in this jet with: p{sup {mu}}{sub t}>1.5 GeV and {eta}{sup {mu}}>-1.6. Differential cross sections were measured in p{sup {mu}}{sub t} and {eta}{sup {mu}}, in p{sup jet}{sub t} and {eta}{sup jet} and in Q{sup 2}.Furthermore double differential cross sections d{sup 2}{sigma}/dQ{sup 2}dx were measured. (Orig.)

  6. Measurement of the diffractive structure function in deep inelastic scattering hat HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-05-01

    This paper presents an analysis of the inclusive properties of diffractive deep inelastic scattering events produced in ep interactions at HERA. The events are characterised by a rapidity gap between the outgoing proton system and the remaining hadronic system. Inclusive distributions are presented and compared with Monte Carlo models for diffractive processes. The data are consistent with models where the pomeron structure function has a hard and a soft contribution. The diffractive structure function is measured as a function of x IP , the momentum fraction lost by the proton, of β, the momentum fraction of the struck quark with respect to x IP , and of Q 2 . The x IP dependence is consistent with the form (1/x IP ) a where a=1.30-±0.80(stat) -0.14 +0.08 (sys) in all bins of βand Q 2 . In the measured Q 2 range, the diffractive structure function approximately scales with Q 2 at fixed β. In an Ingelman-Schlein type model, where commonly used pomeron flux factor normalisations are assumed, it is found that the quarks within the pomeron do not saturate the momentum sum rule. (orig.)

  7. Exclusive photoproduction of Υ mesons at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-03-01

    The exclusive photoproduction reaction γ p → Υ p has been studied with the ZEUS experiment in ep collisions at HERA using an integrated luminosity of 468 pb -1 . The measurement covers the kinematic range 60 2 2 , where W is the photon-proton centre-of-mass energy and Q 2 is the photon virtuality. These results, which represent the analysis of the full ZEUS data sample for this channel, are compared to predictions based on perturbative QCD. (orig.)

  8. Measurement of inelastic J/ψ production in deep inelastic ep scattering at HERA

    International Nuclear Information System (INIS)

    Antonov, A.

    2007-08-01

    This thesis presents a measurement of the inelastic production of J/ψ mesons in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 109 pb -1 . The J/ψ mesons were identified using the decay channel J/ψ → μ + μ - . The measurements were performed in the kinematic range 2 2 2 , 50 lab 2 is the virtuality of the exchanged photon, W is the photon-proton centre-of-mass energy, z is the fraction of the photon energy carried by the J/ψ meson in the proton rest frame and Y lab is the rapidity of the J/ψ in the laboratory frame. The measured cross sections are compared to theoretical predictions within the non-relativistic QCD framework including colour-singlet and colour-octet contributions, as well as to predictions based on the k T -factorisation approach. Calculations of the colour-singlet process generally agree with the data, whereas inclusion of colour-octet terms spoils this agreement. As a technical part of this thesis, the Straw-Tube Tracker (STT) GEANT simulation and track reconstruction software developed. Studies of the STT performance with MC data and real data presented. (orig.)

  9. Measurement and QCD Analysis of Neutral and Charged Current Cross Sections at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Beglarian, A.; Behnke, O.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cao, Jun; Caron, S.; Cassol-Brunner, F.; Chekelian, V.; Clarke, D.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Haidt, D.; Hajduk, L.; Haller, J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, C.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Katzy, J.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Koutouev, R.; Koutov, A.; Kroseberg, J.; Kruger, K.; Kuhr, T.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebailly, E.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loginov, A.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milstead, D.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Newman, Paul R.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Petrukhin, A.; Phillips, J.P.; Pitzl, D.; Portheault, B.; Poschl, R.; Potachnikova, I.; Povh, B.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schoerner-Sadenius, Thomas; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vassiliev, S.; Vazdik, Y.; Veelken, C.; Vest, A.; Vichnevski, A.; Volchinski, V.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wiesand, S.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

    2003-01-01

    The inclusive e^+ p single and double differential cross sections for neutral and charged current processes are measured with the H1 detector at HERA. The data were taken in 1999 and 2000 at a centre-of-mass energy of \\sqrt{s} = 319 GeV and correspond to an integrated luminosity of 65.2 pb^-1. The cross sections are measured in the range of four-momentum transfer squared Q^2 between 100 and 30000 GeV^2 and Bjorken x between 0.0013 and 0.65. The neutral current analysis for the new e^+ p data and the earlier e^- p data taken in 1998 and 1999 is extended to small energies of the scattered electron and therefore to higher values of inelasticity y, allowing a determination of the longitudinal structure function F_L at high Q^2 (110 - 700 GeV^2). A new measurement of the structure function x F_3 is obtained using the new e^+ p and previously published e^\\pm p neutral current cross section data at high Q^2. These data together with H1 low Q^2 precision data are further used to perform new next-to-leading order QCD ...

  10. First Polarized Power Spectra from HERA-19 Commissioning Data: Comparison with Simulations

    Science.gov (United States)

    Igarashi, Amy; Chichura, Paul; Fox Fortino, Austin; Kohn, Saul; Aguirre, James; HERA Collaboration, CHAMP

    2018-01-01

    The Hydrogen Epoch of Reionization Array (HERA) is a radio telescope whose primary goal is the detection of redshifted 21-cm line radiation produced from the spin-flip transition of HI during the Epoch of Reionization (EoR). HERA is currently under construction in South Africa, and will eventually be an array of 350 14-m antennas. HERA aims for a statistical detection of the power spectrum of this emission, using the so-called delay spectrum technique (Parsons et al 2012). We examine a first season of commissioning data from the first 19 elements (HERA-19) to characterize Galactic and extragalactic foregrounds. We compare the delay spectrum for HERA-19 constructed from data to those constructed from simulations done using a detailed instrument electromagnetic model and using the unpolarized Global Sky Model (GSM2008). We compare the data and simulations to explore the effects of Stokes-I to Q and U leakage, and further examine whether statistical models of polarization match the observed polarized power spectra.

  11. Measurement of Jet Production Cross Sections in Deep-inelastic ep Scattering at HERA

    CERN Document Server

    Andreev, Vladimir; Begzsuren, Khurelbaatar; Belousov, Anatoli; Bolz, Arthur; Boudry, Vincent; Brandt, Gerhard; Brisson, Violette; Britzger, Daniel; Buniatyan, Armen; Bylinkin, Alexander; Bystritskaya, Lena; Campbell, Alan; Cantun Avila, Karla Beatriz; Cerny, Karel; Chekelian, Vladimir; Contreras, Guillermo; Cvach, Jaroslav; Dainton, John; Daum, Karin; Diaconu, Cristinel; Dobre, Monica; Dodonov, Vitaliy; Eckerlin, Guenter; Egli, Stephan; Elsen, Eckhard; Favart, Laurent; Fedotov, Alexandre; Feltesse, Joel; Ferencei, Jozef; Fleischer, Manfred; Fomenko, Alexander; Gabathuler, Erwin; Gayler, Joerg; Ghazaryan, Samvel; Goerlich, Lidia; Gogitidze, Nelly; Gouzevitch, Maxime; Grab, Christoph; Grebenyuk, Anastasia; Greenshaw, Timothy; Grindhammer, Guenter; Haidt, Dieter; Henderson, Rob~CW; Hladky, Jan; Hoffmann, Dirk; Horisberger, Roland; Hreus, Tomas; Huber, Florian; Jacquet, Marie; Janssen, Xavier; Jung, Hannes; Kapichine, Mikhail; Katzy, Judith; Kiesling, Christian; Klein, Max; Kleinwort, Claus; Kogler, Roman; Kostka, Peter; Kretzschmar, Jan; Kruecker, Dirk; Krueger, Katja; Landon, Murrough; Lange, Wolfgang; Laycock, Paul; Lebedev, Andrei; Levonian, Sergey; Lipka, Katerina; List, Benno; List, Jenny; Lobodzinski, Bogdan; Malinovski, Evgenij; Martyn, Hans-Ulrich; Maxfield, Steve~J; Mehta, Andrew; Meyer, Andreas; Meyer, Hinrich; Meyer, Joachim; Mikocki, Stanislav; Morozov, Anatoly; Mueller, Katharina; Naumann, Thomas; Newman, Paul~R; Niebuhr, Carsten; Nowak, Grazyna; Olsson, Jan~Erik; Ozerov, Dmitri; Pascaud, Christian; Patel, Girish; Perez, Emmanuelle; Petrukhin, Alexey; Picuric, Ivana; Pirumov, Hayk; Pitzl, Daniel; Placakyte, Ringaile; Polifka, Richard; Radescu, Voica; Raicevic, Natasa; Ravdandorj, Togoo; Reimer, Petr; Rizvi, Eram; Robmann, Peter; Roosen, Robert; Rostovtsev, Andrei; Rotaru, Marina; Salek, David; Sankey, Dave~PC; Sauter, Michel; Sauvan, Emmanuel; Schmitt, Stefan; Schoeffel, Laurent; Schoening, Andre; Sefkow, Felix; Shushkevich, Stanislav; Soloviev, Yuri; Sopicki, Pawel; South, David; Spaskov, Vladimir; Specka, Arnd; Steder, Michael; Stella, Bruno; Straumann, Ulrich; Sykora, Tomas; Thompson, Paul; Traynor, Daniel; Truoel, Peter; Tsakov, Ivan; Tseepeldorj, Baatar; Valkarova, Alice; Vallee, Claude; VanMechelen, Pierre; Vazdik, Iakov; Wegener, Dietrich; Wuensch, Eberhard; Zacek, Jozef; Zhang, Zhiqing; Zlebcik, Radek; Zohrabyan, Hamlet

    2017-04-04

    A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities $5.5HERA, corresponding to an integrated luminosity of $290\\,{\\rm pb}^{-1}$. Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of $Q^2$. Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective $Q^2$-interval are also determined. Previous results of inclusive jet cross sections in the range $150

  12. Measurement of charm and beauty production in deep inelastic ep scattering from decays into muons at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-04-15

    The production of charm and beauty quarks in ep interactions has been measured with the ZEUS detector at HERA for squared four-momentum exchange Q{sup 2} > 20GeV{sup 2}, using an integrated luminosity of 126 pb{sup -1}. Charm and beauty quarks were identified through their decays into muons. Differential cross sections were measured for muon transverse momenta p{sub T}{sup {mu}}>1.5 GeV and pseudorapidities -1.6<{eta}{sup {mu}}<2.3, as a function of p{sub T}{sup {mu}}, {eta}{sup {mu}}, Q{sup 2} and Bjorken x. The charm and beauty contributions to the proton structure function F{sub 2} were also extracted. The results agree with previous measurements based on independent techniques and are well described by QCD predictions. (orig.)

  13. Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-12-01

    Measurements of the cross sections for charged current deep inelastic scattering in e - p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb -1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections dσ/dQ 2 , dσ/dx and dσ/dy are presented for Q 2 >200 GeV 2 . The double-differential cross-section d 2 σ/dxdQ 2 is presented in the kinematic range 280 2 and 0.015< x<0.65. The measured cross sections are compared with the predictions of the Standard Model. (orig.)

  14. Measurement of beauty photoproduction near threshold using di-electron events with the H1 detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F. D.; Alexa, C.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J. C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A. J.; Cantun Avila, K. B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cvach, J.; Dainton, J. B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E. A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D. -J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R. C. W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jönsson, L.; Jung, A. W.; Jung, H.; Kapichine, M.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Krämer, M.; Kretzschmar, J.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lopez-Fernandez, R.; Lubimov, V.; Malinovski, E.; Martyn, H. -U.; Maxfield, S. J.; Mehta, A.; Meyer, A. B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J. V.; Müller, K.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olivier, B.; Olsson, J. E.; Ozerov, D.; Pahl, P.; Palichik, V.; Pandurovic, M.; Pascaud, C.; Patel, G. D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Plačakytė, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J. E.; Rusakov, S.; Šálek, D.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H. -C.; Sefkow, F.; Shtarkov, L. N.; Shushkevich, S.; Sloan, T.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P. D.; Tran, T. H.; Traynor, D.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkárová, A.; Vallée, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wünsch, E.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhokin, A.; Žlebčík, R.; Zohrabyan, H.; Zomer, F.

    2012-10-01

    The cross section for $ep \\to e b\\bar{b} X$ in photoproduction is measured with the H1 detector at the $ep$-collider HERA. The decay channel $b\\bar{b} \\to ee X^\\prime$ is selected by identifying the semi-electronic decays of the b-quarks. The total production cross section is measured in the kinematic range given by the photon virtuality $Q^2 \\le 1 GeV^2$, the inelasticity $0.05 \\le y \\le 0.65$ and the pseudorapidity of the $b$-quarks $|\\eta(b)|$,$|\\eta(\\bar{b})| \\le 2$. The differential production cross section is measured as a function of the average transverse momentum of the beauty quarks <$P_T$(b)> down to the threshold. The results are compared to next-to-leading-order QCD predictions.

  15. The processor farm for online triggering and full event reconstruction of the HERA-B experiment at HERA

    International Nuclear Information System (INIS)

    Gellrich, A.; Dippel, R.; Gensch, U.; Kowallik, R.; Legrand, I.C.; Leich, H.; Sun, F.; Wegner, P.

    1996-01-01

    The main goal of the HERA-B experiment which start taking data in 1988 is to study CP violation in B decays. This article describes the concept and the planned implementation of a multi-processor system, called processor farm,as the last part of the data acquisition and trigger system of the HERA B experiment. The third level trigger task and a full online event reconstruction will be performed on this processor farm, consisting of more then 100 powerful RISC processors which are based on commercial hardware boards. The controlling will be done by a real-time operating system which provides a software development environment, including FORTRAN and C compilers. (author)

  16. Angular correlations in three-jet events in ep collisions at HERA

    NARCIS (Netherlands)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Bondarenko, K.; Boos, E. G.; Borras, K.; Boscherini, D.; Brock, I.; Brownson, E.; Brugnera, R.; Bruemmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Pellegrino, A.

    2012-01-01

    Three-jet production in deep inelastic ep scattering and photoproduction was investigated with the ZEUS detector at HERA using an integrated luminosity of up to 127 pb(-1). Measurements of differential cross sections are presented as functions of angular correlations between the three jets in the

  17. The rise in F$_{2}^{p}$ at HERA

    CERN Document Server

    Ball, Richard D.; Forte, S

    1994-01-01

    We show that the rise in F_2^p at small x and large Q^2 seen at HERA is indeed the non-Regge double asymptotic scaling behaviour expected from the perturbative emission of strongly ordered hard gluons. An alternative explanation, in which there is no strong ordering, and a new hard Reggeon is generated, is also tried but found wanting: its theoretical short-comings are betrayed by its failure to properly account for the HERA data.

  18. The HERA physics programme

    International Nuclear Information System (INIS)

    Saxon, D.H.

    1991-09-01

    The construction of the HERA accelerator and its detectors H1 and ZEUS opens up new physic regimes to explore at high-Q 2 and low-x. The physics interest and methods of exploration are described, starting from the environment provided by the accelerator and the reaction kinematics. (orig.)

  19. An experiment to study CP violation in the B system using an internal target at the HERA proton ring

    International Nuclear Information System (INIS)

    Hofmann, W.

    1993-01-01

    Using the HERA proton beam striking an internal wire target, sufficient numbers of B mesons are produced to allow the search for CP violation in B decays with a sensitivity Δsin(2β)∼0.05, provided that the detector can accept and separate multiple interactions per bunch crossing. This report summarizes our present views concerning the layout of the target, of the spectrometer, and of the trigger system, which selects events containing J/ψ candidates. (orig.)

  20. Diffractive charm and jet production at HERA

    International Nuclear Information System (INIS)

    Savin, Alexander A.

    2003-01-01

    A new high precision inclusive measurement of the diffractive production of D* ± (2010) mesons in deep inelastic scattering (DIS) in the kinematic region Q 2 >1.5 GeV 2 , 0.02 IP 2 2 , 165 2 , χ IP < 0.03 are presented. Diffractive parton densities extracted using a NLO DGLAP QCD fit are used for comparisons with diffractive DIS and PHP dijet and open charm cross sections at HERA and the Tevatron, thus testing the factorization properties of hard diffraction

  1. Short-range and long-range correlations in DIS at HERA

    International Nuclear Information System (INIS)

    Chekanov, S. V.; Zawiejski, L.

    1999-01-01

    Correlations in deep-inelastic scattering (DIS) at HERA are investigated in order to test perturbative QCD and quark fragmentation universality. Two-particle correlations at small angular separations are measured in the Breit frame and compared to e + e - collisions. Also presented are the correlations between the current and target regions of the Breit frame

  2. Three- and four-jet final states in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2007-08-15

    Three- and four-jet final states have been measured in photoproduction at HERA using the ZEUS detector with an integrated luminosity of 121 pb{sup -1}. The results are presented for jets with transverse energy E{sup jet}{sub T}>6 GeV and pseudorapidity vertical stroke {eta}{sup jet} vertical stroke <2.4, in the kinematic region given by the virtuality of the photon Q{sup 2}<1 GeV{sup 2} and the inelasticity 0.2{<=}y{<=}0.85 and in two mass regions defined as 25{<=}M{sub nj}<50 GeV and M{sub nj}{>=}50 GeV, where M{sub nj} is the invariant mass of the n-jet system. The four-jet photoproduction cross section has been measured for the first time and represents the highest-order process studied at HERA. Both the three- and four-jet cross sections have been compared with leading-logarithmic parton-shower Monte Carlo models, with and without multi-parton interactions. The three-jet cross sections have been compared to an O({alpha}{alpha}{sup 2}{sub s}) perturbative QCD calculation. (orig.)

  3. Measuring the electron-ion ring parameters by bremsstrahlung

    International Nuclear Information System (INIS)

    Inkin, V.D.; Mozelev, A.A.; Sarantsev, V.P.

    1982-01-01

    A system is described for measuring the number of electrons and ions in the electron-ion rings of a collective heavy ion accelerator. The system operation is based on detecting gamma quanta of bremsstrahlung following the ring electron interaction with the nuclei of neutral atoms and ions at different stages of filling the ring with ions. The radiation detector is a scintillation block - a photomultiplier operating for counting with NaI(Tl) crystal sized 30x30 mm and ensuring the detection efficiency close to unity. The system apparatus is made in the CAMAC standard and rems on-line with the TRA/i miniature computer. The block-diagrams of the system and algorithm of data processing are presented. A conclusion is drawn that the results of measuring the ring parameters with the use of the diagnostics system described are in good agreement within the range of measuring errors with those obtained by means of the diagnostics system employing synchrotron radiation and induction sensors

  4. Precision measurement of the cross section of charged-current and neutral current processes at large Q2 at HERA with the polarized-electron beam

    International Nuclear Information System (INIS)

    Tran, Trong Hieu

    2010-03-01

    The inclusive cross sections for both charged and neutral current processes have been measured in interactions of longitudinally polarized electrons (positrons) with unpolarized protons using the full data samples collected by H1 at HERA-II. The data taken at a center-of-mass energy of 319 GeV correspond to an integrated luminosity of 149.1 pb -1 and 180.0 pb -1 for e - p and e + p collisions, representing an increase in statistics of a factor of 10 and 2, respectively, over the data from HERA-I. The measured double differential cross sections d 2 σ/dxdQ 2 cover more than two orders of magnitude in both Q 2 , the negative four-momentum transfer squared, up to 30000 GeV 2 , and Bjorken x, down to 0.003. The cross section data are compared to predictions of the Standard Model which is able to provide a good description of the data. The polarization asymmetry as a function of Q 2 is measured with improved precision, confirming the previous observation of P violation effect in neutral current ep scattering at distances down to 10 -18 m. The total cross sections of the charged current process, for Q 2 > 400 GeV 2 and inelasticity y ± beams and different polarization values. Together with the corresponding cross section obtained from the previously published unpolarized data, the polarization dependence of the charged current cross section is measured and found to be in agreement with the Standard Model prediction with the absence of right-handed charged current. The cross sections are combined with previously published data from H1 to obtain the most precise unpolarized measurements. These are used to extract the structure function xF 3 γZ which is sensitive to the valence quark distributions down to low x values. The new cross sections have also been used in a combined electroweak and QCD fit to significantly improve the light quark couplings to the Z-boson than those obtained based on the HERA-I data alone. (orig.)

  5. Angular correlations in three-jet events in ep collisions at HERA

    NARCIS (Netherlands)

    Abramowicz, H.; et al., [Unknown; Grigorescu, G.; Keramidas, A.; Koffeman, E.; Kooijman, P.; Pellegrino, A.; Tiecke, H.; Vázquez, M.; Wiggers, L.

    2012-01-01

    Three-jet production in deep inelastic ep scattering and photoproduction was investigated with the ZEUS detector at HERA using an integrated luminosity of up to 127  pb−1. Measurements of differential cross sections are presented as functions of angular correlations between the three jets in the

  6. Angular correlations in three-jet events in ep collisions at HERA

    NARCIS (Netherlands)

    Abramowicz, H.; Abt, I.; Kooijman, P.; Zotkin, D.S.

    2012-01-01

    Three-jet production in deep inelastic ep scattering and photoproduction was investigated with the ZEUS detector at HERA using an integrated luminosity of up to 127  pb-1. Measurements of differential cross sections are presented as functions of angular correlations between the three jets in the

  7. H1 at HERA Exhibition

    CERN Multimedia

    2000-01-01

    H1 is one of the two large detectors installed at HERA, the first electron-proton accelerator, located at DESY in Hamburg. The H1 collaboration regroups physicists from 32institutes of 11countries all over the world.

  8. Combined measurement and QCD analysis of the inclusive e{sup {+-}}p scattering cross sections at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Abramowicz, H. [Tel Aviv Univ. (Israel). Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics; Max-Planck-Institute, Muenchen (Germany); Abt, I. [Max-Planck-Institut fuer Physik, Muenchen (DE)] (and others)

    2009-10-15

    A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e{sup {+-}}p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q{sup 2}, and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions HERAPDF1.0 with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result. (orig.)

  9. Measurement of neutral current cross sections at high Bjorken-x with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2006-07-01

    A new method is employed to measure the neutral current cross section up to Bjorken-x values of one with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb -1 for e + p collisions and 16.7 pb -1 for e - p collisions at √(s)=318 GeV and 38.6 pb -1 for e + p collisions at √(s)=300 GeV. Cross sections have been extracted for Q 2 ≥648 GeV 2 and are compared to predictions using different parton density functions. For the highest x bins, the data have a tendency to lie above the expectations using recent parton density function parametrizations. (orig.)

  10. Measurement of beauty and charm photoproduction using inclusive secondary vertexing with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Schoenberg, Verena Ellen

    2010-04-01

    Photoproduction of heavy quarks in events with two jets has been measured with the ZEUS detector at HERA using data recorded in the years 2006-2007 corresponding to an integrated luminosity of 128 pb -1 . The beauty and charm content was extracted using the decay-length significance of the b and c hadrons and the invariant mass of the decay vertices. Differential cross sections as a function of P Jet T and η Jet were compared with the PYTHIA leading order plus parton shower Monte Carlo and QCD predictions calculated at next-to-leading order. In order to study the theoretical description of higher-order effects correlations between the two highest energy jets were also investigated. (orig.)

  11. Measurement of the photon-proton total cross section at a center-of-mass energy of 209 GeV at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Pellegrino, A.; Repond, J.; Yoshida, R.; Mattingly, M.C.K.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cara Romeo, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; De Pasquale, S.; Giusti, P.; Iacobucci, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Pesci, A.; Sartorelli, G.; Zichichi, A.; Aghuzumtsyan, G.; Bartsch, D.; Brock, I.; Crittenden, J.; Goers, S.; Hartmann, H.; Hilger, E.; Irrgang, P.; Jakob, H.-P.; Kappes, A.; Katz, U.F.; Kerger, R.; Kind, O.; Paul, E.; Rautenberg, J.; Renner, R.; Schnurbusch, H.; Stifutkin, A.; Tandler, J.; Voss, K.C.; Weber, A.; Wessoleck, H.; Bailey, D.S.; Brook, N.H.; Cole, J.E.; Foster, B.; Heath, G.P.; Heath, H.F.; Robins, S.; Rodrigues, E.; Scott, J.; Tapper, R.J.; Wing, M.; Capua, M.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Jeoung, H.Y.; Kim, J.Y.; Lee, J.H.; Lim, I.T.; Ma, K.J.; Pac, M.Y.; Caldwell, A.; Helbich, M.; Liu, X.; Mellado, B.; Paganis, S.; Schmidke, W.B.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Olkiewicz, K.; Przybycien, M.B.; Stopa, P.; Zawiejski, L.; Bednarek, B.; Grabowska-Bold, I.; Jelen, K.; Kisielewska, D.; Kowal, A.M.; Kowal, M.; Kowalski, T.; Mindur, B.; Przybycien, M.; Rulikowska-Zarebska, E.; Suszycki, L.; Szuba, D.; Szuba, J.; Kotanski, A.; Slominski, W.; Bauerdick, L.A.T.; Behrens, U.; Borras, K.; Chiochia, V.; Dannheim, D.; Desler, K.; Drews, G.; Fourletova, J.; Fox-Murphy, A.; Fricke, U.; Geiser, A.; Goebel, F.; Goettlicher, P.; Graciani, R.; Haas, T.; Hain, W.; Hartner, G.F.; Hillert, S.; Koetz, U.; Kowalski, H.; Labes, H.; Lelas, D.; Loehr, B.; Mankel, R.; Martens, J.; Martinez, M.; Moritz, M.; Notz, D.; Petrucci, M.C.; Polini, A.; Schneekloth, U.; Selonke, F.; Stonjek, S.; Surrow, B.; Whitmore, J.J.; Wichmann, R.; Wolf, G.; Youngman, C.; Zeuner, W.; Coldewey, C.; Lopez-Duran Viani, A.; Meyer, A.; Schlenstedt, S.; Barbagli, G.; Gallo, E.; Genta, C.; Pelfer, P.G.; Bamberger, A.; Benen, A.; Coppola, N.; Markun, P.; Raach, H.; Woelfle, S.; Bell, M.; Bussey, P.J.; Doyle, A.T.; Glasman, C.; Hanlon, S.; Lee, S.W.; Lupi, A.; McCance, G.J.; Saxon, D.H.; Skillicorn, I.O.; Bodmann, B.; Holm, U.; Salehi, H.; Wick, K.; Ziegler, A.; Ziegler, Ar.; Carli, T.; Gialas, I.; Klimek, K.; Lohrmann, E.; Milite, M.; Collins-Tooth, C.; Foudas, C.; Goncalo, R.; Long, K.R.; Metlica, F.; Miller, D.B.; Tapper, A.D.; Walker, R.; Cloth, P.; Filges, D.; Kuze, M.; Nagano, K.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Barakbaev, A.N.; Boos, E.G.; Pokrovskiy, N.S.; Zhautykov, B.O.; Ahn, S.H.; Lee, S.B.; Park, S.K.; Lim, H.; Son, D.; Barreiro, F.; Garcia, G.; Gonzalez, O.; Labarga, L.; del Peso, J.; Redondo, I.; Terron, J.; Vazquez, M.; Barbi, M.; Bertolin, A.; Corriveau, F.; Ochs, A.; Padhi, S.; Stairs, D.G.; St-Laurent, M.; Tsurugai, T.; Antonov, A.; Bashkirov, V.; Danilov, P.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Suchkov, S.; Dementiev, R.K.; Ermolov, P.F.; Golubkov, Yu.A.; Katkov, I.I.; Khein, L.A.; Korotkova, N.A.; Korzhavina, I.A.; Kuzmin, V.A.; Levchenko, B.B.; Lukina, O.Yu.; Proskuryakov, A.S.; Shcheglova, L.M.; Solomin, A.N.; Vlasov, N.N.; Zotkin, S.A.; Bokel, C.; Engelen, J.; Grijpink, S.; Koffeman, E.; Kooijman, P.; Maddox, E.; Schagen, S.; Tassi, E.; Tiecke, H.; Tuning, N.; Velthuis, J.J.; Wiggers, L.; de Wolf, E.; Bruemmer, N.; Bylsma, B.; Durkin, L.S.; Gilmore, J.; Ginsburg, C.M.; Kim, C.L.; Ling, T.Y.; Boogert, S.; Cooper-Sarkar, A.M.; Devenish, R.C.E.; Ferrando, J.; Matsushita, T.; Rigby, M.; Ruske, O.; Sutton, M.R.; Walczak, R.; Brugnera, R.; Carlin, R.; Dal Corso, F.; Dusini, S.; Garfagnini, A.; Limentani, S.; Longhin, A.; Parenti, A.; Posocco, M.; Stanco, L.; Turcato, M.; Adamczyk, L.; Oh, B.Y.; Saull, P.R.B.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cormack, C.; Hart, J.C.; McCubbin, N.A.; Heusch, C.; Park, I.H.; Pavel, N.; Abramowicz, H.; Dagan, S.; Gabareen, A.; Kananov, S.; Kreisel, A.; Levy, A.; Abe, T.; Fusayasu, T.; Kohno, T.; Umemori, K.; Yamashita, T.; Hamatsu, R.; Hirose, T.; Inuzuka, M.; Kitamura, S.; Matsuzawa, K.; Nishimura, T.; Arneodo, M.; Cartiglia, N.; Cirio, R.; Costa, M.; Ferrero, M.I.; Maselli, S.; Monaco, V.; Peroni, C.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Galea, R.; Koop, T.; Levman, G.M.; Martin, J.F.; Mirea, A.; Sabetfakhri, A.; Butterworth, J.M.; Gwenlan, C.; Hall-Wilton, R.; Hayes, M.E.; Heaphy, E.A.; Jones, T.W.; Lane, J.B.; Lightwood, M.S.; West, B.J.; Ciborowski, J.; Ciesielski, R.; Grzelak, G.; Nowak, R.J.; Pawlak, J.M.; Smalska, B.; Sztuk, J.; Tymieniecka, T.; Ukleja, A.; Ukleja, J.; Zakrzewski, J.A.; Zarnecki, A.F.; Adamus, M.; Plucinski, P.; Eisenberg, Y.; Gladilin, L.K.; Hochman, D.; Karshon, U.; Breitweg, J.; Chapin, D.; Cross, R.; Kcira, D.; Lammers, S.; Reeder, D.D.; Savin, A.A.; Smith, W.H.; Deshpande, A.; Dhawan, S.; Hughes, V.W.; Straub, P.B.; Bhadra, S.; Catterall, C.D.; Fourletov, S.; Menary, S.; Soares, M.; Standage, J.

    2002-01-01

    The photon-proton total cross section has been measured in the process e + p→e + γp→e + X with the ZEUS detector at HERA. Events were collected with photon virtuality Q 2 2 and average γp center-of-mass energy W γp =209 GeV in a dedicated run, designed to control systematic effects, with an integrated luminosity of 49 nb -1 . The measured total cross section is σ tot γp =174±1 (stat.)±13 (syst.) μb. The energy dependence of the cross section is compatible with parameterizations of high-energy pp and pp-bar data

  12. The Hera Saturn Entry Probe Mission: a Proposal in Response to the ESA M5 Call

    Science.gov (United States)

    Mousis, Olivier; Atkinson, David; Amato, Michael; Aslam, Shahid; Atreya, Sushil; Blanc, Michel; Bolton, Scott; Brugger, Bastien; Calcutt, Simon; Cavalié, Thibault; Charnoz, Sébastien; Coustenis, Athena; Deleuil, Magali; Dobrijevic, Michel; Ferri, Francesca; Fletcher, Leigh; Gautier, Daniel; Guillot, Tristan; Hartogh, Paul; Holland, Andrew

    2017-04-01

    The Hera Saturn entry probe mission is proposed as an ESA M-class mission to be piggybacked on a NASA spacecraft sent to or past the Saturn system. Hera consists of an atmospheric probe built by ESA and released into the atmosphere of Saturn by its NASA companion Saturn Carrier-Relay spacecraft. Hera will perform in situ measurements of the chemical and isotopic composition as well as the structure and dynamics of Saturn's atmosphere using a single probe, with the goal of improving our understanding of the origin, formation, and evolution of Saturn, the giant planets and their satellite systems, with extrapolation to extrasolar planets. Hera will probe well into and possibly beneath the cloud-forming region of the troposphere, below the region accessible to remote sensing, to locations where certain cosmogenically abundant species are expected to be well mixed. The Hera probe will be designed from ESA elements with possible contributions from NASA, and the Saturn/Carrier-Relay Spacecraft will be supplied by NASA through its selection via the New Frontier 2016 call or in the form of a flagship mission selected by the NASA "Roadmaps to Ocean Worlds" (ROW) program. The Hera probe will be powered by batteries, and we therefore anticipate only one major subsystems to be possibly supplied by the United States, either by direct procurement by ESA or by contribution from NASA: the thermal protection system of the probe. Following the highly successful example of the Cassini-Huygens mission, Hera will carry European and American instruments, with scientists and engineers from both agencies and many affiliates participating in all aspects of mission development and implementation. A Saturn probe is one of the six identified desired themes by the Planetary Science Decadal Survey committee on the NASA New Frontier's list, providing additional indication that a Saturn probe is of extremely high interest and a very high priority for the international community.

  13. Measurement of leading neutron production in deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Antunovic, B.; Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grell, B.R.; Haidt, D.; Helebrant, C.; Jung, H.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Marti, L.; Meyer, A.B.; Meyer, H.; Meyer, J.; Niebuhr, C.; Nikiforov, A.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Sunar, D.; Vargas Trevino, A.; Vinokurova, S.; Driesch, M. von den; Wissing, C.; Wuensch, E. [DESY, Hamburg (Germany); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Volchinski, V.; Zohrabyan, H. [Yerevan Physics Inst. (Armenia); Barrelet, E. [Universites Paris VI et VII, CNRS/IN2P3, LPNHE, Paris (France); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Mongolian Academy of Sciences, Inst. of Physics and Technology, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [Univ. Paris-Sud, CNRS/IN2P3, LAL, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [Ecole Polytechnique, CNRS/IN2P3, LLR, Palaiseau (France); Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I. [Vinca Inst. of Nuclear Sciences, Belgrade (RS); Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D. [Univ. of Birmingham, School of Physics and Astronomy (United Kingdom)] [and others

    2010-08-15

    The production of leading neutrons, where the neutron carries a large fraction x{sub L} of the incoming proton's longitudinal momentum, is studied in deep-inelastic positron-proton scattering at HERA. The data were taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 122 pb {sup -1}. The semi-inclusive cross section is measured in the phase space defined by the photon virtuality 6

  14. Measurement of the inclusive ep scattering cross section at low Q{sup 2} and x at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev (P.N.) Physical Inst., Moscow (RU)] (and others)

    2009-02-15

    A measurement of the inclusive ep scattering cross section is presented in the region of low momentum transfers, 0.2 GeV{sup 2}{<=}Q{sup 2}{<=}12 GeV{sup 2}, and low Bjorken x, 5.10{sup -6}HERA at beam energies of 27.6 GeV and 920 GeV for positrons and protons, respectively. A combination with data previously published by H1 leads to a cross section measurement of a few percent accuracy. A kinematic reconstruction method exploiting radiative ep events extends the measurement to lower Q{sup 2} and larger x. The data are compared with theoretical models which apply to the transition region from photoproduction to deep inelastic scattering. (orig.)

  15. Measurement of beauty photoproduction near threshold using Di-electron events with the H1 detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2012-05-15

    The cross section for ep {yields} eb anti bX in photoproduction is measured with the H1 detector at the ep-collider HERA. The decay channel b anti b {yields} eeX' is selected by identifying the semi-electronic decays of the b-quarks. The total production cross section is measured in the kinematic range given by the photon virtuality Q{sup 2} {<=}1 GeV{sup 2}, the inelasticity 0.05{<=} y {<=}0.65 and the pseudorapidity of the b-quarks vertical stroke {eta}(b) vertical stroke, vertical stroke {eta}(anti b) vertical stroke {<=}2. The differential production cross section is measured as a function of the average transverse momentum of the beauty quarks left angle P{sub T}(b) right angle down to the threshold. The results are compared to next-to-leading-order QCD predictions.

  16. Measurement of beauty photoproduction near threshold using Di-electron events with the H1 detector at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Andreev, V.

    2012-05-01

    The cross section for ep → eb anti bX in photoproduction is measured with the H1 detector at the ep-collider HERA. The decay channel b anti b → eeX' is selected by identifying the semi-electronic decays of the b-quarks. The total production cross section is measured in the kinematic range given by the photon virtuality Q 2 ≤1 GeV 2 , the inelasticity 0.05≤ y ≤0.65 and the pseudorapidity of the b-quarks vertical stroke η(b) vertical stroke, vertical stroke η(anti b) vertical stroke ≤2. The differential production cross section is measured as a function of the average transverse momentum of the beauty quarks left angle P T (b) right angle down to the threshold. The results are compared to next-to-leading-order QCD predictions.

  17. Hard scattering of (almost) real photons at HERA

    International Nuclear Information System (INIS)

    Jong, S.J. de; Engelen, J.J.

    1988-01-01

    High P T photoproduction will play an important role at HERA, both as interesting physics in its own right and as a background. Photoproduction reactions producing large transverse momenta will be reviewed, as well as the possibility of using them for tests of perturbative QCD. Pointlike coupling of the photon to the proton constituents will be considered in detail in leading log approximation. Although the cross sections of these processes, photon gluon fusion and QCD Compton scattering, get their largest contribution from low Q 2 (almost) real photons, we calculate them over the full Q 2 range. Photoproduction as a background to the standard deep inelastic physics at HERA and to exotic phenomena is discussed. Heavy flavour production through photon gluon fusion may offer good possibilities of studying charm and bottom quarks. An attempt is made to determine a possible strategy to identify the top quark at HERA. 29 refs.; 20 figs.; 7 tabs

  18. Photoproduction of multi-jet events at HERA: A Monte Carlo simulation

    International Nuclear Information System (INIS)

    Butterworth, J.M.; Forshaw, J.R.

    1993-07-01

    We study the regime of high-energy photoproduction, currently under exploration at the DESY ep Collider, HERA. In particular we discuss the possible production of more than one pair of 'back-to-back' jets which may occur at reasonably high-p T as a consequence of the high parton density regime opened up at HERA centre-of-mass energies. We describe the construction of a multi-jet event generator based upon leading order QCD perturbation theory and an eikonal formalism, and show that the effect of multiple parton interactions on event shapes at HERA could indeed be significant. (orig.)

  19. Measurement of dijet photoproduction for events with a leading neutron at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, B. [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-09-15

    Differential cross sections for dijet photoproduction and this process in association with a leading neutron, e{sup +}+p{yields}e{sup +}+jet+jet+X(+n), have been measured with the ZEUS detector at HERA using an integrated luminosity of 40 pb{sup -1}. The fraction of dijet events with a leading neutron was studied as a function of different jet and event variables. Single- and double-differential cross sections are presented as a function of the longitudinal fraction of the proton momentum carried by the leading neutron, x{sub L}, and of its transverse momentum squared, p{sub T}{sup 2}. The dijet data are compared to inclusive DIS and photoproduction results; they are all consistent with a simple pion-exchange model. The neutron yield as a function of x{sub L} was found to depend only on the fraction of the proton beam energy going into the forward region, independent of the hard process. No firm conclusion can be drawn on the presence of rescattering effects. (orig)

  20. Saturation and forward jets at HERA

    International Nuclear Information System (INIS)

    Marquet, C.; Peschanski, R.; Royon, C.

    2004-01-01

    We analyse forward-jet production at HERA in the framework of the Golec-Biernat and Wusthoff saturation models. We obtain a good description of the forward-jet cross-sections measured by the H1 and ZEUS Collaborations in the two-hard-scale region (k T∼ Q >> Λ QCD ) with two different parametrizations with either significant or weak saturation effects. The weak saturation parametrization gives a scale compatible with the one found for the proton structure function F2. We argue that Mueller-Navelet jets at the Tevatron and the LHC could help distinguishing between both options

  1. Measurements of the exclusive production of a real photon with the ZEUS detector at HERA II

    International Nuclear Information System (INIS)

    Santamarta Martinez, R.

    2007-06-01

    The study of exclusive processes is one of the most promising tools to obtain information on the nucleon via generalized parton distributions. The simplest of these reactions is the Deeply Virtual Compton Scattering process in which a real photon is produced via diffractive exchange. Using the interference term between Deeply Virtual Compton Scattering and the Bethe-Heitler processes it is possible to extract the generalized parton distributions. The measurement presented in this thesis is a study of Deeply Virtual Compton Scattering and Bethe-Heitler processes recorder with the ZEUS detector. The data analyzed were taken with HERA II in the years 2003 to 2005, corresponding to an integrated luminosity of 41 pb -1 for e + p and 136 pb -1 for e - p scattering data. The cross section of the elastic Bethe-Heitler process measured in the kinematic region 230 2 2 and vertical stroke t vertical stroke 2 is presented. The feasibility of measurement of the Deeply Virtual Compton Scattering process is also reported. (orig.)

  2. Measurement of elastic electroproduction of $\\phi$ mesons at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Bate, P.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, Christoph; Bernardi, G.; Berndt, T.; Bizot, J.C.; Borras, K.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruel, P.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burkhardt, H.; Burrage, A.; Buschhorn, G.; Campbell, A.J.; Cao, Jun; Carli, T.; Caron, S.; Chabert, E.; Clarke, D.; Clerbaux, B.; Collard, C.; Contreras, J.G.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; David, M.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Duprel, C.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Ghazarian, S.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Hoprich, W.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C.; Jacquet, M.; Jaffre, M.; Janauschek, L.; Jansen, D.M.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kastli, H.K.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Kaufmann, O.; Kausch, M.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kermiche, S.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Krasny, M.W.; Krehbiel, H.; Kroseberg, J.; Krucker, D.; Kruger, K.; Kupper, A.; Kuhr, T.; Kurca, T.; Kutuev, R.; Lachnit, W.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstrom, M.; Lobodzinska, E.; Lobodzinski, B.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Mehta, A.; Meier, K.; Merkel, P.; Metlica, F.; Meyer, H.; Meyer, J.; Meyer, P.O.; Mikocki, S.; Milstead, D.; Mkrtchyan, T.; Mohr, R.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Nellen, G.; Newman, Paul R.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nunnemann, T.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rabbertz, K.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Riess, S.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Sedlak, K.; Sefkow, F.; Chekelian, V.I.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; Solochenko, V.; Solovev, Y.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Steinhart, J.; Stella, B.; Stellberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Swart, M.; Tasevsky, M.; Tchernyshov, V.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; von Dombrowski, S.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Wegner, A.; Wengler, T.; Werner, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Wollatz, H.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.

    2000-01-01

    The elastic electroproduction of phi mesons is studied at HERA with the H1 detector for photon virtualities 1 < Q^2 < 15 GeV^2 and hadronic centre of mass energies 40 < W < 130 GeV. The Q^2 and t dependences of the cross section are extracted (t being the square of the four-momentum transfer to the target proton). When plotted as function of (Q^2 + M_V^2) and scaled by the appropriate SU(5) quark charge factor, the phi meson cross section agrees within errors with the cross sections of the vector mesons V = rho, omega and J/psi. A detailed analysis is performed of the phi meson polarisation state and the ratio of the production cross sections for longitudinally and transversely polarised phi mesons is determined. A small but significant violation of s-channel helicity conservation (SCHC) is observed.

  3. Measurement of Anti-Deuteron Photoproduction and a Search for Heavy Stable Charged Particles at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.O.; Boudry, V.; Bracinik, J.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Heuer, R.D.; Hildebrandt, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Knutsson, A.; Koblitz, B.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kroseberg, J.; Kuckens, J.; Kuhr, T.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martisikova, M.; Martyn, H.U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milcewicz, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morozov, I.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Ossoskov, G.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Raicevic, N.; Ratiani, Z.; Reimer, P.; Reisert, B.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vassiliev, S.; Vazdik, Y.; Veelken, C.; Vest, A.; Vichnevski, A.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Winter, G.G.; Wissing, Ch.; Woehrling, E.E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2004-01-01

    The cross section for anti-deuteron photoproduction is measured at HERA at a mean centre-of-mass energy of W_{\\gamma p} = 200 GeV in the range 0.2 < p_T/M < 0.7 and |y| < 0.4, where M, p_T and y are the mass, transverse momentum and rapidity in the laboratory frame of the anti-deuteron, respectively. The numbers of anti-deuterons per event are found to be similar in photoproduction to those in central proton-proton collisions at the CERN ISR but much lower than those in central Au-Au collisions at RHIC. The coalescence parameter B_2, which characterizes the likelihood of anti-deuteron production, is measured in photoproduction to be 0.010 \\pm 0.002 \\pm 0.001, which is much higher than in Au-Au collisions at a similar nucleon-nucleon centre-of-mass energy. No significant production of particles heavier than deuterons is observed and upper limits are set on the photoproduction cross sections for such particles.

  4. Measurement of inclusive and dijet D{sup *} meson cross sections in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Insitute, Moscow (RU)] (and others)

    2011-12-15

    The inclusive photoproduction of D{sup *} mesons and of D{sup *}-tagged dijets is investigated with the H1 detector at the ep collider HERA. The kinematic region covers small photon virtualities Q{sup 2}<2 GeV{sup 2} and photon-proton centre-of-mass energies of 100measured for central rapidities vertical stroke {eta}(D{sup *}) vertical stroke <1.5 and transverse momenta p{sub T}(D{sup *})>1.8 GeV. The heavy quark production process is further investigated in events with at least two jets with transverse momentum p{sub T}(jet)>3.5 GeV each, one containing the D{sup *} meson. Differential cross sections for D{sup *}-tagged dijet production and for correlations between the jets are measured in the range vertical stroke {eta}(D{sup *}) vertical stroke <1.5 and p{sub T} (D{sup *})>2.1 GeV. The results are compared with predictions from Monte Carlo simulations and next-to-leading order perturbative QCD calculations. (orig.)

  5. Measurement of inclusive and dijet D{sup *} meson cross sections in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Inst. (Armenia); Barrelet, E. [CNRS/IN2P3, LPNHE, Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris 7, Paris (France); Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Helebrant, C.; Kleinwort, C.; Kogler, R.; Kraemer, M.; Levonian, S.; Lipka, K.; List, B.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Piec, S.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [CNRS/IN2P3, LAL, Univ. Paris-Sud, Orsay (France); Boenig, M.O.; Wegener, D. [TU Dortmund, Inst. fuer Physik, Dortmund (Germany); Boudry, V.; Moreau, F.; Specka, A. [CNRS/IN2P3, LLR, Ecole Polytechnique, Palaiseau (France); Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I. [Univ. of Belgrade, Vinca Inst. of Nuclear Sciences, Belgrade (RS); Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D. [Univ. of Birmingham (United Kingdom)] [and others

    2012-05-15

    The inclusive photoproduction of D {sup *} mesons and of D {sup *}-tagged dijets is investigated with the H1 detector at the ep collider HERA. The kinematic region covers small photon virtualities Q {sup 2}<2 GeV{sup 2} and photon-proton centre-of-mass energies of 100measured for central rapidities vertical stroke {eta}(D{sup *}) vertical stroke <1.5 and transverse momenta p{sub T}(D {sup *})>1.8 GeV. The heavy quark production process is further investigated in events with at least two jets with transverse momentum p{sub T} (jet) >3.5 GeV each, one containing the D{sup *} meson. Differential cross sections for D{sup *}-tagged dijet production and for correlations between the jets are measured in the range vertical stroke {eta}(D{sup *}) vertical stroke <1.5 and p{sub T}(D {sup *})>2.1 GeV. The results are compared with predictions from Monte Carlo simulations and next-to-leading order perturbative QCD calculations. (orig.)

  6. Latest results from HERA

    Indian Academy of Sciences (India)

    Standard Model where particles that have quantum numbers of both leptons and quarks are produced. Then a search ..... The limits from HERA can be seen to be very competitive with limits from other colliders especially for low values ... the decay t —bW. A similar decay chain is possible for the production of a single stop in.

  7. Exclusive photoproduction of {upsilon} mesons at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2009-03-15

    The exclusive photoproduction reaction {gamma} p {yields} {upsilon} p has been studied with the ZEUS experiment in ep collisions at HERA using an integrated luminosity of 468 pb{sup -1}. The measurement covers the kinematic range 60

  8. Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, IL (US)] (and others)

    2008-12-15

    Measurements of the cross sections for charged current deep inelastic scattering in e{sup -}p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb{sup -1} collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy are presented for Q{sup 2}>200 GeV{sup 2}. The double-differential cross-section d{sup 2}{sigma}/dxdQ{sup 2} is presented in the kinematic range 280measured cross sections are compared with the predictions of the Standard Model. (orig.)

  9. Measurement of neutral current cross sections at high Bjorken-x with the ZEUS detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2006-07-15

    A new method is employed to measure the neutral current cross section up to Bjorken-x values of one with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb{sup -1} for e{sup +}p collisions and 16.7 pb{sup -1} for e{sup -}p collisions at {radical}(s)=318 GeV and 38.6 pb{sup -1} for e{sup +}p collisions at {radical}(s)=300 GeV. Cross sections have been extracted for Q{sup 2}{>=}648 GeV{sup 2} and are compared to predictions using different parton density functions. For the highest x bins, the data have a tendency to lie above the expectations using recent parton density function parametrizations. (orig.)

  10. Measurement of beauty and charm photoproduction using inclusive secondary vertexing with the ZEUS detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberg, Verena Ellen

    2010-04-15

    Photoproduction of heavy quarks in events with two jets has been measured with the ZEUS detector at HERA using data recorded in the years 2006-2007 corresponding to an integrated luminosity of 128 pb{sup -1}. The beauty and charm content was extracted using the decay-length significance of the b and c hadrons and the invariant mass of the decay vertices. Differential cross sections as a function of P{sup Jet}{sub T} and {eta}{sup Jet} were compared with the PYTHIA leading order plus parton shower Monte Carlo and QCD predictions calculated at next-to-leading order. In order to study the theoretical description of higher-order effects correlations between the two highest energy jets were also investigated. (orig.)

  11. Measurement of the Azimuthal Correlation between the most Forward Jet and the Scattered Positron in Deep-Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Kogler, R.; Kostka, P.; Kraemer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lopez-Fernandez, R.; Lubimov, V.; Makankine, A.; Malinovski, E.; Marage, P.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mudrinic, M.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, I.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2012-03-06

    Deep-inelastic positron-proton scattering events at low photon virtuality Q^2 with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, Delta phi, between the forward jet and the scattered positron. The sensitivity to QCD evolution mechanisms is tested by comparing the data to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations.

  12. Studies of spin relaxation and recombination at the HERMES hydrogen/deuterium gas target

    International Nuclear Information System (INIS)

    Baumgarten, C.

    2000-09-01

    The HERMES (HERA measurement of spin) experiment is located in the eastern straight section of the HERA storage ring at DESY in Hamburg. It is designed to study the spin structure of the nucleons by deep inelastic scattering of polarized positrons resp. electrons provided by the HERA storage ring at 27.5 GeV impingingon the nucleons of internal polarized gas targets. The setup of the HERMES experiment is shown. First results are the measurement of the spin structure functions g 1 n with the polarized 3 He target (1995) and of g 1 p with polarized atomic hydrogen target, which was operated in 1996 and 1997. Beneath the inclusive physics, the possibility to detect and identify hadronic scattering products allows the measurement of semi-inclusive processes with the central item of the HERMES physics program. (orig.)

  13. Ring to measure magnetic permeability at cryogenic temperatures

    CERN Multimedia

    1977-01-01

    While for magn. permeability measurements at room temperature a split-coil permeameter is used (see photo 7708553X), for measurements at cryogenic temperatures the excitation and the flux-measuring coils are wound directly on the ring sample by means of a toroidal winding machine. The ring in the picture was made to select the mild steel for the ISR Prototype Superconducting Quadrupole(see photo 7702690X). The excitation coil was wound with 1 mm diam. copper wire and had about 2730 turns. For measurements at 4.2 K a max. current of 90 A was used. See also photos 7708553X,7708100,7708103.

  14. Experimental techniques and physics in a polarized storage ring

    International Nuclear Information System (INIS)

    Dueren, M.

    1995-01-01

    In May 1994 spin rotators were brought into operation at HERA and for the first time longitudinal electron polarization was produced in a high energy storage ring. A Compton polarimeter is used for empirical optimization of the polarization to values of up to 70%. HERMES makes use of the stored polarized beam with an internal polarized target. The density of a gas target is increased by a storage cell by two orders of magnitude compared to a free gas jet. Data taking begins in 1995 with measurements on polarized spin structure functions and also on semi-inclusive polarized hadron production. The inclusive physics program is in competition with experiments at CERN and SLAC. The semi-inclusive physics program promises to solve basic questions of the spin structure of matter by decomposing the spin contributions of the different quark flavors. (author) 24 figs., 3 tabs., 44 refs

  15. A global analysis of inclusive diffractive cross sections at HERA

    International Nuclear Information System (INIS)

    Royon, C.; Schoeffel, L.; Sapeta, S.; Peschanski, R.; Sauvan, E.

    2006-10-01

    We describe the most recent data on the diffractive structure functions from the H1 and ZEUS Collaborations at HERA using four models. First, a Pomeron Structure Function (PSF) model, in which the Pomeron is considered as an object with parton distribution functions. Then, the Bartels Ellis Kowalski Wuesthoff (BEKW) approach is discussed, assuming the simplest perturbative description of the Pomeron using a two-gluon ladder. A third approach, the Bialas Peschanski (BP) model, based on the dipole formalism is then described. Finally, we discuss the Golec-Biernat-Wuesthoff (GBW) saturation model which takes into account saturation effects. The best description of all available measurements can be achieved with either the PSF based model or the BEKW approach. In particular, the BEKW prediction allows to include the highest β measurements, which are dominated by higher twists effects and provide an efficient and compact parametrisation of the diffractive cross section. The two other models also give a good description of cross section measurements at small x with a small number of parameters. The comparison of all predictions allows us to identify interesting differences in the behaviour of the effective pomeron intercept and in the shape of the longitudinal component of the diffractive structure functions. In this last part, we present some features that can be discriminated by new experimental measurements, completing the HERA program. (authors)

  16. A global analysis of inclusive diffractive cross sections at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Royon, C.; Schoeffel, L. [Service de Physique des Particules, CE-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Sapeta, S. [M. Smoluchowski Institue of Physics Jagellonian University Reymonta 4, 30-059 Krakow (Poland); Peschanski, R. [Service de Physique Theorique, CE-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Sauvan, E. [CPPM, IN2P3-CNRS et Universitie de la Mediterranee, F-13288 Marseille Cedex 09 (France)

    2006-10-15

    We describe the most recent data on the diffractive structure functions from the H1 and ZEUS Collaborations at HERA using four models. First, a Pomeron Structure Function (PSF) model, in which the Pomeron is considered as an object with parton distribution functions. Then, the Bartels Ellis Kowalski Wuesthoff (BEKW) approach is discussed, assuming the simplest perturbative description of the Pomeron using a two-gluon ladder. A third approach, the Bialas Peschanski (BP) model, based on the dipole formalism is then described. Finally, we discuss the Golec-Biernat-Wuesthoff (GBW) saturation model which takes into account saturation effects. The best description of all available measurements can be achieved with either the PSF based model or the BEKW approach. In particular, the BEKW prediction allows to include the highest {beta} measurements, which are dominated by higher twists effects and provide an efficient and compact parametrisation of the diffractive cross section. The two other models also give a good description of cross section measurements at small x with a small number of parameters. The comparison of all predictions allows us to identify interesting differences in the behaviour of the effective pomeron intercept and in the shape of the longitudinal component of the diffractive structure functions. In this last part, we present some features that can be discriminated by new experimental measurements, completing the HERA program. (authors)

  17. A measurement of the Q{sup 2}, W and t dependences of deeply virtual Compton scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2008-12-15

    Deeply virtual Compton scattering, {gamma}{sup *}p{yields}{gamma}p, has been measured in e{sup +}p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb{sup -1}. Cross sections are presented as a function of the photon virtuality, Q{sup 2}, and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q{sup 2}>1.5 GeV{sup 2} and 40measured in the leading proton spectrometer, corresponding to an integrated luminosity of 31.3 pb{sup -1}, is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex. (orig.)

  18. Prompt Photons in Photoproduction at HERA

    CERN Document Server

    Aaron, F.D.; Alexa, C.; Andreev, V.; Antunovic, B.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Falkiewicz, A.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, A.W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Kogler, R.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, M.U.; Mudrinic, M.; Muller, K.; Murin, P.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shaw-West, R.N.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, I.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; von den Driesch, M.; Wegener, D.; Wissing, Ch.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.; Zus, R.

    2010-01-01

    The production of prompt photons is measured in the photoproduction regime of electron-proton scattering at HERA. The analysis is based on a data sample corresponding to a total integrated luminosity of 340 pb^-1 collected by the H1 experiment. Cross sections are measured for photons with transverse momentum and pseudorapidity in the range 6 < Et < 15 GeV and -1.0 < eta < 2.4, respectively. Cross sections for events with an additional jet are measured as a function of the transverse energy and pseudorapidity of the jet, and as a function of the fractional momenta x_gamma and x_p carried by the partons entering the hard scattering process. The correlation between the photon and the jet is also studied. The results are compared with QCD predictions based on the collinear and on the k_T factorisation approaches.

  19. Exclusive vector meson production at HERA

    International Nuclear Information System (INIS)

    Szuba, Dorota

    2013-01-01

    The exclusive photoproduction of Υ has been studied with the ZEUS detector in ep collisions at HERA. The exponential slope, b, of the |t|-dependence of the cross section, where t is the squared four-momentum transfer at the proton vertex, has been measured. This constitutes the first measurement of the |t|-dependence of the γp→Υp cross section. The differential crosssections as a function of t at lower energies of γp centre-of-mass has been studied in exclusive diffractive photoproduction of J/ψ mesons with the H1 detector. The exclusive electroproduction of two pions has been measured by the ZEUS experiment. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, assuming that the studied mass range includes the contributions of the ρ, ρ′ and . ρ'' vector-meson states.

  20. Measurement of beauty production in deep inelastic scattering at HERA using decays into electrons

    International Nuclear Information System (INIS)

    Shehzadi, Ramoona

    2011-01-01

    The production of beauty quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared Q 2 >10 GeV 2 , using an integrated luminosity of 363 pb -1 . The beauty events were identified using electrons from semileptonic b decays with a transverse momentum 0.9 T e e 2 was extracted from the double-differential cross section as a function of Bjorken-x and Q 2 . (orig.)

  1. J/ψ-production mechanisms and determination of the gluon density at HERA

    International Nuclear Information System (INIS)

    Jung, H.; Schuler, G.A.; Terron, J.

    1992-02-01

    We discuss photo- and leptoproduction of J/ψ-mesons at energies ranging from fixed-target experiments up to HERA. Elastic and diffractive production as well as various inelastic processes are studied. We investigate the range in which J/ψ-production is described by photon-gluon fusion in the colour-singlet model. We show how inelastic J/ψ production at HERA can be used to extract the gluon density. We estimate an accessible range of 3 x 10 -4 < x < 0.1 and discuss sources of errors in the reconstruction of the gluon density at HERA. (orig.)

  2. Heavy Quark Production in ep Collisions at HERA

    International Nuclear Information System (INIS)

    Bloch, I.

    2006-01-01

    Collisions of electrons with protons at a centre-of-mass energy of 318 GeV are being recorded by the two experiments H1 and ZEUS at the ep accelerator HERA at DESY, Hamburg (Germany). Measurements involving beauty and charm quarks, performed by these experiments, provide a good environment to test perturbative QCD predictions as the large quark mass supplies a hard scale. Recent measurements of beauty and charm production in ep collisions are presented here. QCD predictions at next-to-leading order are found to generally agree with the measurements. Beauty measurements however are sometimes slightly higher than the predicted cross sections. Beauty and charm contributions to the proton structure were also measured and are well described by QCD predictions

  3. Measurement of high-Q2 charged current cross sections in e+p deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Rautenberg, J.

    2004-06-01

    Cross sections for charged current deep inelastic scattering have been measured in e + p collisions at a center-of-mass energy of 318 GeV. The data collected with the ZEUS detector at HERA in the running periods 1999 and 2000 correspond to an integrated luminosity of 61 pb -1 . Single differential cross sections dσ/dQ 2 , dσ/dx and dσ/dy have been measured for Q 2 >200 GeV 2 , as well as the double differential reduced cross section d 2 σ/dxdQ 2 in the kinematic range 280 GeV 2 2 2 and 0.008 - p charged current deep inelastic scattering cross sections. The helicity structure is investigated in particular. The mass of the space-like W boson propagator has been determined from a fit to dσ/dQ 2 . (orig.)

  4. Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA

    CERN Document Server

    Aaron, F.D.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Alexa, C.; Andreev, V.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Bamberger, A.; Barakbaev, A.N.; Barbagli, G.; Bari, G.; Barreiro, F.; Barrelet, E.; Bartel, W.; Bartosik, N.; Bartsch, D.; Basile, M.; Begzsuren, K.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Belousov, A.; Belov, P.; Bertolin, A.; Bhadra, S.; Bindi, M.; Bizot, J.C.; Blohm, C.; Bokhonov, V.; Bondarenko, K.; Boos, E.G.; Borras, K.; Boscherini, D.; Bot, D.; Boudry, V.; Bozovic-Jelisavcic, I.; Bold, T.; Brummer, N.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Brock, I.; Brownson, E.; Brugnera, R.; Bruncko, D.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bunyatyan, A.; Bussey, P.J.; Bylinkin, A.; Bylsma, B.; Bystritskaya, L.; Caldwell, A.; Campbell, A.J.; Cantun Avila, K.B.; Capua, M.; Carlin, R.; Catterall, C.D.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekanov, S.; Chekelian, V.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Contreras, J.G.; Cooper-Sarkar, A.M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; Coughlan, J.A.; Cvach, J.; D'Agostini, G.; Dainton, J.B.; Dal Corso, F.; Daum, K.; Delcourt, B.; Delvax, J.; Dementiev, R.K.; Derrick, M.; Devenish, R.C.E.; De Pasquale, S.; De Wolf, E.A.; del Peso, J.; Diaconu, C.; Dobre, M.; Dobur, D.; Dodonov, V.; Dolgoshein, B.A.; Dolinska, G.; Dossanov, A.; Doyle, A.T.; Drugakov, V.; Dubak, A.; Durkin, L.S.; Dusini, S.; Eckerlin, G.; Egli, S.; Eisenberg, Y.; Eliseev, A.; Elsen, E.; Ermolov, P.F.; Eskreys, A.; Fang, S.; Favart, L.; Fazio, S.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrando, J.; Ferrero, M.I.; Figiel, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Forrest, M.; Foster, B.; Gabathuler, E.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Gayler, J.; Geiser, A.; Ghazaryan, S.; Gialas, I.; Gizhko, A.; Gladilin, L.K.; Gladkov, D.; Glasman, C.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gogota, O.; Golubkov, Yu.A.; Gottlicher, P.; Gouzevitch, M.; Grab, C.; Grabowska-Bold, I.; Grebenyuk, A.; Grebenyuk, J.; Greenshaw, T.; Gregor, I.; Grigorescu, G.; Grindhammer, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Huttmann, A.; Haas, T.; Habib, S.; Haidt, D.; Hain, W.; Hamatsu, R.; Hart, J.C.; Hartmann, H.; Hartner, G.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hilger, E.; Hiller, K.H.; Hladky, J.; Hochman, D.; Hoffmann, D.; Hori, R.; Horisberger, R.; Hreus, T.; Huber, F.; Ibrahim, Z.A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jacquet, M.; Jakob, H.P.; Janssen, X.; Januschek, F.; Jones, T.W.; Jonsson, L.; Jungst, M.; Jung, H.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Kapichine, M.; Karshon, U.; Karstens, F.; Katkov, I.I.; Kaur, P.; Kaur, M.; Kenyon, I.R.; Keramidas, A.; Khein, L.A.; Kiesling, C.; Kim, J.Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, M.; Klein, U.; Kleinwort, C.; Koffeman, E.; Kogler, R.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I.A.; Kostka, P.; Kotanski, A.; Kotz, U.; Kowalski, H.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Kuprash, O.; Kuze, M.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lee, A.; Lendermann, V.; Levchenko, B.B.; Levonian, S.; Levy, A.; Libov, V.; Limentani, S.; Ling, T.Y.; Lipka, K.; Lisovyi, M.; List, B.; List, J.; Lobodzinska, E.; Lobodzinski, B.; Lohmann, W.; Lohr, B.; Lohrmann, E.; Long, K.R.; Longhin, A.; Lontkovskyi, D.; Lopez-Fernandez, R.; Lubimov, V.; Lukina, O.Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malinovski, E.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J.F.; Martyn, H.U.; Mastroberardino, A.; Mattingly, M.C.K.; Maxfield, S.J.; Mehta, A.; Melzer-Pellmann, I.A.; Mergelmeyer, S.; Meyer, A.B.; Meyer, H.; Meyer, J.; Miglioranzi, S.; Mikocki, S.; Milcewicz-Mika, I.; Idris, F.Mohamad; Monaco, V.; Montanari, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Morris, J.D.; Mujkic, K.; Muller, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nigro, A.; Nikitin, D.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, G.; Nowak, K.; Nowak, R.J.; Nuncio-Quiroz, A.E.; Oh, B.Y.; Okazaki, N.; Olkiewicz, K.; Olsson, J.E.; Onishchuk, Yu.; Ozerov, D.; Pahl, P.; Palichik, V.; Pandurovic, M.; Papageorgiu, K.; Parenti, A.; Pascaud, C.; Patel, G.D.; Paul, E.; Pawlak, J.M.; Pawlik, B.; Pelfer, P.G.; Pellegrino, A.; Perez, E.; Perlanski, W.; Perrey, H.; Petrukhin, A.; Picuric, I.; Piotrzkowski, K.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Plucinski, P.; Pokorny, B.; Pokrovskiy, N.S.; Polifka, R.; Polini, A.; Povh, B.; Proskuryakov, A.S.; Przybycien, M.; Radescu, V.; Raicevic, N.; Raval, A.; Ravdandorj, T.; Reeder, D.D.; Reimer, P.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y.D.; Rizvi, E.; Robertson, A.; Robmann, P.; Roloff, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rubinsky, I.; Ruiz Tabasco, J.E.; Rusakov, S.; Ruspa, M.; Sacchi, R.; Salek, D.; Samson, U.; Sankey, D.P.C.; Sartorelli, G.; Sauter, M.; Sauvan, E.; Savin, A.A.; Saxon, D.H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W.B.; Schmitt, S.; Schneekloth, U.; Schoeffel, L.; Schonberg, V.; Schoning, A.; Schorner-Sadenius, T.; Schultz-Coulon, H.C.; Schwartz, J.; Sciulli, F.; Sefkow, F.; Shcheglova, L.M.; Shehzadi, R.; Shimizu, S.; Shtarkov, L.N.; Shushkevich, S.; Singh, I.; Skillicorn, I.O.; Slominski, W.; Sloan, T.; Smith, W.H.; Sola, V.; Solano, A.; Soloviev, Y.; Son, D.; Sopicki, P.; Sosnovtsev, V.; South, D.; Spaskov, V.; Specka, A.; Spiridonov, A.; Stadie, H.; Stanco, L.; Staykova, Z.; Steder, M.; Stefaniuk, N.; Stella, B.; Stern, A.; Stewart, T.P.; Stifutkin, A.; Stoicea, G.; Stopa, P.; Straumann, U.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sykora, T.; Sztuk-Dambietz, J.; Szuba, J.; Szuba, D.; Tapper, A.D.; Tassi, E.; Terron, J.; Theedt, T.; Thompson, P.D.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Tran, T.H.; Traynor, D.; Truol, P.; Trusov, V.; Tsakov, I.; Tseepeldorj, B.; Tsurugai, T.; Turcato, M.; Turkot, O.; Turnau, J.; Tymieniecka, T.; Vazquez, M.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Verbytskyi, A.; Viazlo, O.; Vlasov, N.N.; Walczak, R.; Wan Abdullah, W.A.T.; Wegener, D.; Whitmore, J.J.; Wichmann, K.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Wunsch, E.; Yagues-Molina, A.G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zabiegalov, O.; Zacek, J.; Zalesak, J.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhang, Z.; Zhautykov, B.O.; Zhmak, N.; Zhokin, A.; Zichichi, A.; Zlebcik, R.; Zohrabyan, H.; Zolkapli, Z.; Zomer, F.; Zotkin, D.S.; Zarnecki, A.F.

    2012-10-10

    A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy sqrt(s) = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6% for the most precise points. The combined data cover the range 2.5 < Q2 < 200 GeV2 in photon virtuality, 0.00035 < xIP < 0.09 in proton fractional momentum loss, 0.09 < |t| < 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < beta < 0.816 in beta = x/xIP, where x is the Bjorken scaling variable.

  5. STUDY OF THE STABILITY OF PARTICLE MOTION IN STORAGE RINGS. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Jack J. Shi

    2012-09-07

    During this period, our research was concentrated on the study of beam-beam effects in large storage-ring colliders and coherent synchrotron radiation (CSR) effect in light sources. Our group was involved in and made significant contribution to several international accelerator projects such as the US-LHC project for the design of the LHC interaction regions, the luminosity upgrade of Tevatron and HERA, the design of eRHIC, and the U.S. LHC Accelerator Research Program (LARP) for the future LHC luminosity upgrade.

  6. Measurement of charm and beauty production in deep inelastic scattering at HERA using semi-leptonic decays into muons

    International Nuclear Information System (INIS)

    Bindi, Marcello

    2008-10-01

    In this thesis the experimental study of the process ep→ec anti cX at HERA is described. The differential cross sections in dependence on the transverse momentum and rapidity of the decay muon are presented. (HSI)

  7. Measurement of charm and beauty production in deep inelastic scattering at HERA using semi-leptonic decays into muons

    Energy Technology Data Exchange (ETDEWEB)

    Bindi, Marcello

    2008-10-15

    In this thesis the experimental study of the process ep{yields}ec anti cX at HERA is described. The differential cross sections in dependence on the transverse momentum and rapidity of the decay muon are presented. (HSI)

  8. Measurement of D*{sup {+-}} meson production in deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Bachynska, Olena

    2012-12-15

    Measurements of charm production in deep-inelastic scattering at HERA at a centre-of-mass energy of 318 GeV are reported in this thesis. The analysis was performed using the data collected with the ZEUS detector during the years 2004 to 2007, corresponding to an integrated luminosity of 363 pb{sup -1}. The production of charm quarks was studied through the full kinematic reconstruction of D*{sup {+-}} mesons in the decay channel D*{sup {+-}} {yields} D{sup 0}/ anti D{sup 0}{pi}{sup {+-}}. The studies have been performed for virtualities of the exchanged photon of 5 < Q{sup 2} < 1000 GeV{sup 2} and inelasticities of 0.02 < y < 0.7. The visible D*{sup {+-}} kinematic phase space is defined by the transverse momentum range, 1.5 < p{sub T}{sup D*{sup {+-}}} < 20 GeV, and by the pseudorapidity region, vertical stroke {eta}{sup D*{sup {+-}}} vertical stroke < 1.5, of the produced D*{sup {+-}} mesons. The total visible cross section for D*{sup {+-}} production as well as single-and double-differential cross sections were measured and compared to the corresponding D*{sup {+-}} measurements performed by the H1 collaboration in the same phase-space region. The measurements are well described by NLO QCD predictions. The double-differential cross sections were exploited to extract the charm contribution to the proton structure function, F{sub 2}{sup c} {sup anti} {sup c}, expressed in terms of the reduced charm-production cross sections, {sigma}{sub red}{sup c} {sup anti} {sup c}, and compared to the predictions from HERAPDF1.5 and to the recent measurements from the H1 and ZEUS collaborations.

  9. Simulations of Polarization Leakage and Ionospheric Attenuation in Visibility Measurements for the HERA and PAPER Experiments

    Science.gov (United States)

    Martinot, Zachary; Kohn, Saul; Aguirre, James; Washington, Immanuel; HERA Collaboration, PAPER Collaboration

    2018-01-01

    The HERA and PAPER experiments that aim to detect the power spectrum of the 21cm brightness temperature during the Epoch of Reionization (EoR) are planned with the expectation that foregrounds will be separated from the cosmological signal by a clearly demarcated boundary in Fourier space. Polarized foregrounds with complex frequency structure present a potential systematic as their mixing into unpolarized signal by the polarized response of an instrument's beam may be confused for the unpolarized EoR signal. There are two factors we believe will mitigate this systematic to the point that it will not impede the detection of the cosmological power spectrum in the foreground avoidance scheme. First, variation in the ionospheric plasma density observed between different days produces attenuation of the effective polarized power on the sky when visibilities are averaged coherently over many days. Second, the absolute level of polarization leakage can be suppressed through careful design of the instrument. We have performed detailed visibility simulations to investigate both effects, and present the results of these simulations for both the HERA and PAPER instruments.

  10. Measurement of inelastic J/{psi} production in deep inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Antonov, A.

    2007-08-15

    This thesis presents a measurement of the inelastic production of J/{psi} mesons in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 109 pb{sup -1}. The J/{psi} mesons were identified using the decay channel J/{psi} {yields} {mu}{sup +}{mu}{sup -}. The measurements were performed in the kinematic range 2measured cross sections are compared to theoretical predictions within the non-relativistic QCD framework including colour-singlet and colour-octet contributions, as well as to predictions based on the k{sub T}-factorisation approach. Calculations of the colour-singlet process generally agree with the data, whereas inclusion of colour-octet terms spoils this agreement. As a technical part of this thesis, the Straw-Tube Tracker (STT) GEANT simulation and track reconstruction software developed. Studies of the STT performance with MC data and real data presented. (orig.)

  11. High-ET dijet photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-06-01

    The cross section for high-E T dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb -1 . The events were required to have a virtuality of the incoming pho- ton, Q 2 , of less than 1 GeV 2 and a photon-proton centre-of-mass energy in the range 142 γp T jet1 >20 GeV and E T jet2 >15 GeV and pseudorapidity requirements of -1 jet1,2 jet <2.5. The measurements show sensitivity to the parton distributions in the photon and proton and effects beyond next-to-leading order in QCD. Hence these data can be used to constrain further the parton densities in the proton and photon. (orig.)

  12. Measurement of beauty production in deep inelastic scattering at HERA using decays into electrons

    International Nuclear Information System (INIS)

    Abramowicz, H.; Gueta, O.; Ingbir, R.; Kananov, S.; Levy, A.; Stern, A.

    2011-01-01

    The production of beauty quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared Q 2 >10 GeV 2 , using an integrated luminosity of 363 pb -1 . The beauty events were identified using electrons from semileptonic b decays with a transverse momentum 0.9 T e e vertical stroke 2 was extracted from the double-differential cross section as a function of Bjorken-x and Q 2 . (orig.)

  13. Study of χc production using HERA-B data

    International Nuclear Information System (INIS)

    Aleksandrov, Aleksandar

    2010-01-01

    In this thesis the production of the charmonium states χ c1 and χ c2 in protonnucleus collisions at a proton-nucleon center-of-mass energy √(s)=41.6 GeV was studied. The data used for the analysis have been taken by the fixed-target experiment HERA-B that uses the HERA proton beam to scatter protons off the nuclei of different wire targets. About 122.10 3 recorded muonic J/ψ decays, J/ψ→μ + μ - , resulted in almost 10000 reconstructed χ c →J/ψγ. The ratio R χ c = sum i=1,2 σ(χ ci )Br(χ ci →J/ψγ)/σ(J/ψ), which is the ratio of J/ψ from χ c decays to all produced J/ψ, was measured in the kinematical range -0.35 F J/ψ χ c =0.190 -0.029 +0.030 . Despite the small separation of the masses of the two χ c states, comparable to the detector resolution, the ratio R 12 =R χ c1 /R χ c2 was measured yielding R 12 =1.30 -0.37 +0.59 which corresponds to a production cross section ratio (σ(χ c1 ))/(σ(χ c2 ))=0.74 -0.22 +0.34 . By using the known J/ψ production cross section, the χ c1 and χ c2 production cross sections are calculated to be σ(χ c1 )=(153±27) nb/nucleon and σ(χ c2 )=(207±39) nb/nucleon, respectively. All results were obtained under the assumption that both the J/ψ and χ c states are produced without polarization. In addition a study of possible deviations of R χ c and R 12 due to the polarization of J/ψ and χ c was performed. By varying the polarization parameter, λ obs , of all produced J/ψ by 2σ around the value measured by HERA-B, and assuming fully polarized χ c states, the maximum variations of R χ c and R 12 were evaluated. These studies show that R χ c could change up to 21% and R 12 from -11% to +16% relative to the values calculated without polarization. (orig.)

  14. Beauty production at HERA using the ZEUS experiment

    International Nuclear Information System (INIS)

    Yaguees, A

    2008-01-01

    Beauty quark production in ep collisions is being studied with the ZEUS detector at HERA. The latest measurements of beauty production in deep inelastic scattering and photoproduction regime are presented. The first measurement exploits the potential of the ZEUS microvertex detector to identify beauty in photoproduction dijet events with a muon in the final state. The second is based on statistical methods to determine the fraction of beauty in photoproduction dijet events with an electron in the final state. Finally, the first measurement by ZEUS of the beauty contribution to the proton structure function, F 2 bb, in deep inelastic scattering is presented. The three measurements are compared with QCD predictions as well as with previous results. All the results presented here are preliminary

  15. Measurement of jet production cross sections in deep-inelastic ep scattering at HERA

    International Nuclear Information System (INIS)

    Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Vazdik, Y.; Baghdasaryan, A.; Zohrabyan, H.; Begzsuren, K.; Ravdandorj, T.; Bolz, A.; Huber, F.; Sauter, M.; Schoening, A.; Boudry, V.; Specka, A.; Brandt, G.; Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F.; Britzger, D.; Campbell, A.J.; Dodonov, V.; Eckerlin, G.; Elsen, E.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Haidt, D.; Katzy, J.; Kleinwort, C.; Kruecker, D.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; South, D.; Steder, M.; Wuensch, E.; Buniatyan, A.; Newman, P.R.; Thompson, P.D.; Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Avila, K.B.C.; Contreras, J.G.; Cerny, K.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R.; Chekelian, V.; Grindhammer, G.; Kiesling, C.; Lobodzinski, B.; Cvach, J.; Hladky, J.; Reimer, P.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kostka, P.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Diaconu, C.; Hoffmann, D.; Vallee, C.; Dobre, M.; Rotaru, M.; Egli, S.; Horisberger, R.; Ozerov, D.; Favart, L.; Grebenyuk, A.; Hreus, T.; Janssen, X.; Roosen, R.; Mechelen, P. van; Feltesse, J.; Schoeffel, L.; Ferencei, J.; Goerlich, L.; Mikocki, S.; Nowak, G.; Sopicki, P.; Gouzevitch, M.; Petrukhin, A.; Grab, C.; Henderson, R.C.W.; Jung, H.; Kapichine, M.; Morozov, A.; Spaskov, V.; Kogler, R.; Landon, M.P.J.; Rizvi, E.; Traynor, D.; Lange, W.; Naumann, T.; Martyn, H.U.; Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P.; Perez, E.; Picuric, I.; Raicevic, N.; Polifka, R.; Radescu, V.; Rostovtsev, A.; Sankey, D.P.C.; Sauvan, E.; Shushkevich, S.; Soloviev, Y.; Stella, B.; Sykora, T.; Tsakov, I.; Tseepeldorj, B.; Wegener, D.

    2017-01-01

    A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities 5.5 < Q"2 < 80 GeV"2 and inelasticities 0.2 < y < 0.6 is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of 290 pb"-"1. Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of Q"2. Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective Q"2-interval are also determined. Previous results of inclusive jet cross sections in the range 150 < Q"2 < 15,000 GeV"2 are extended to low transverse jet momenta 5 < P_T"j"e"t < 7 GeV. The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of Q"2, the strong coupling constant α_s(M_Z) is determined in next-to-leading order. (orig.)

  16. Measurement of jet production cross sections in deep-inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Vazdik, Y. [Lebedev Physical Institute, Moscow (Russian Federation); Baghdasaryan, A.; Zohrabyan, H. [Yerevan Physics Institute, Yerevan (Armenia); Begzsuren, K.; Ravdandorj, T. [Academy of Sciences, Institute of Physics and Technology of the Mongolian, Ulaanbaatar (Mongolia); Bolz, A.; Huber, F.; Sauter, M.; Schoening, A. [Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Boudry, V.; Specka, A. [LLR, Ecole Polytechnique, CNRS/IN2P3, Palaiseau (France); Brandt, G. [Universitaet Goettingen, II. Physikalisches Institut, Goettingen (Germany); Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F. [LAL, Universite Paris-Sud, CNRS/IN2P3, Orsay (France); Britzger, D.; Campbell, A.J.; Dodonov, V.; Eckerlin, G.; Elsen, E.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Haidt, D.; Katzy, J.; Kleinwort, C.; Kruecker, D.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Buniatyan, A.; Newman, P.R.; Thompson, P.D. [University of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Bylinkin, A. [Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region (Russian Federation); Bystritskaya, L.; Fedotov, A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Avila, K.B.C.; Contreras, J.G. [CINVESTAV, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Cerny, K.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R. [Charles University, Faculty of Mathematics and Physics, Praha (Czech Republic); Chekelian, V.; Grindhammer, G.; Kiesling, C.; Lobodzinski, B. [Max-Planck-Institut fuer Physik, Munich (Germany); Cvach, J.; Hladky, J.; Reimer, P. [Academy of Sciences of the Czech Republic, Institute of Physics, Praha (Czech Republic); Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kostka, P.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D. [University of Liverpool, Department of Physics (United Kingdom); Daum, K.; Meyer, H. [Fachbereich C, Universitaet Wuppertal, Wuppertal (Germany); Diaconu, C.; Hoffmann, D.; Vallee, C. [Aix Marseille Universite, CNRS/IN2P3, CPPM UMR 7346, Marseille (France); Dobre, M.; Rotaru, M. [Horia Hulubei National Institute for R and D in Physics and Nuclear Engineering (IFIN-HH), Bucharest (Romania); Egli, S.; Horisberger, R.; Ozerov, D. [Paul Scherrer Institute, Villigen (Switzerland); Favart, L.; Grebenyuk, A.; Hreus, T.; Janssen, X.; Roosen, R.; Mechelen, P. van [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); Feltesse, J.; Schoeffel, L. [Irfu/SPP, CE Saclay, Gif-sur-Yvette (France); Ferencei, J. [Nuclear Physics Institute of the CAS, Rez (Czech Republic); Goerlich, L.; Mikocki, S.; Nowak, G.; Sopicki, P. [Institute of Nuclear Physics, Polish Academy of Sciences, Krakow (Poland); Gouzevitch, M.; Petrukhin, A. [IPNL, Universite Claude Bernard Lyon 1, CNRS/IN2P3, Villeurbanne (France); Grab, C. [Institut fuer Teilchenphysik, ETH, Zurich (Switzerland); Henderson, R.C.W. [University of Lancaster, Department of Physics (United Kingdom); Jung, H. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); DESY, Hamburg (Germany); Kapichine, M.; Morozov, A.; Spaskov, V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kogler, R. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Landon, M.P.J.; Rizvi, E.; Traynor, D. [University of London, School of Physics and Astronomy, Queen Mary, London (United Kingdom); Lange, W.; Naumann, T. [DESY, Zeuthen (Germany); Martyn, H.U. [I. Physikalisches Institut der RWTH, Aachen (Germany); Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P. [Physik-Institut der Universitaet Zuerich, Zurich (Switzerland); Perez, E. [CERN, Geneva (Switzerland); Picuric, I.; Raicevic, N. [University of Montenegro, Faculty of Science, Podgorica (Montenegro); Polifka, R. [Charles University, Faculty of Mathematics and Physics, Praha (Czech Republic); University of Toronto, Department of Physics, Toronto, ON (CA); Radescu, V. [Oxford University, Department of Physics, Oxford (GB); Rostovtsev, A. [Institute for Information Transmission Problems RAS, Moscow (RU); Sankey, D.P.C. [STFC, Rutherford Appleton Laboratory, Didcot, Oxfordshire (GB); Sauvan, E. [Aix Marseille Universite, CNRS/IN2P3, CPPM UMR 7346, Marseille (FR); Universite de Savoie, LAPP, Annecy-le-Vieux (FR); Shushkevich, S. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (RU); Soloviev, Y. [DESY, Hamburg (DE); Lebedev Physical Institute, Moscow (RU); Stella, B. [Dipartimento di Fisica Universita di Roma Tre (IT); INFN Roma 3, Rome (IT); Sykora, T. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (BE); Charles University, Faculty of Mathematics and Physics, Praha (CZ); Tsakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (BG); Tseepeldorj, B. [Academy of Sciences, Institute of Physics and Technology of the Mongolian, Ulaanbaatar (MN); Ulaanbaatar University, Ulaanbaatar (MN); Wegener, D. [Institut fuer Physik, TU Dortmund, Dortmund (DE); Collaboration: H1 Collaboration

    2017-04-15

    A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities 5.5 < Q{sup 2} < 80 GeV{sup 2} and inelasticities 0.2 < y < 0.6 is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of 290 pb{sup -1}. Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of Q{sup 2}. Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective Q{sup 2}-interval are also determined. Previous results of inclusive jet cross sections in the range 150 < Q{sup 2} < 15,000 GeV{sup 2} are extended to low transverse jet momenta 5 < P{sub T}{sup jet} < 7 GeV. The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of Q{sup 2}, the strong coupling constant α{sub s}(M{sub Z}) is determined in next-to-leading order. (orig.)

  17. Photoproduction of J/{psi} mesons at medium and low elasticities at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Salvaire, F.

    2007-09-15

    V{sup 2}. The results are in agreement within the statistical uncertainties at one or two standard deviations with the previous H1 measurements using HERA I data. At this stage of the analysis of the HERA II data, the statistics do not permit an improvement to the previous measurements and thus do not provide an improved comparison with theoretical models. (orig.)

  18. Charm production and QCD analysis at HERA and LHC

    International Nuclear Information System (INIS)

    Zenaiev, Oleksandr

    2015-03-01

    In this thesis the study of charm production in ep and pp collisions is presented. The heavy-quark masses provide a hard scale, allowing the application of perturbative QCD. A measurement of D + -meson production in deep inelastic scattering with the ZEUS detector at HERA is presented. The analysis was performed using a data sample with an integrated luminosity of 354 pb -1 . Differential cross sections were measured as a function of virtuality Q 2 , inelasticity y, transverse momentum and pseudorapidity of the D + mesons. Lifetime information was used to reduce the combinatorial background significantly. Next-to-leading-order QCD predictions in the fixed-flavour-number scheme were compared to the data. This measurement was combined with other H1 and ZEUS measurements of charm production. The combination was performed at inclusive level for the reduced charm cross sections, which were obtained from the measured visible cross sections, extrapolated to the full phase space using the shape of the theoretical predictions in the fixed-flavour-number scheme. The combination method accounts for the correlations of the systematic uncertainties among the different datasets, thus allowing cross calibration of different measurements. The combined charm data were compared to QCD predictions in various heavy-flavour schemes and used together with the inclusive production data at HERA as input for QCD analyses to determine the charm running mass in the MS renormalisation scheme and the optimal values of the charm-quark mass parameters in other heavy-flavour schemes. An additional combination of the H1 and ZEUS D *+ visible cross sections was performed to provide the combined cross sections without theory-related uncertainties from the extrapolation procedure. This combination also provides differential cross sections as a function of the D *+ kinematic variables. Next-to-leading-order QCD predictions in the fixed-flavour-number scheme were compared to the combined D *+ cross

  19. Study of tau-pair production at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (Poland). Faculty of Physics and Applied Computer Science; Adamus, M. [Institute for Nuclear Studies, Warsaw (PL)] (and others)

    2010-12-15

    A study of events containing two tau leptons with high transverse momentum has been performed with the ZEUS detector at HERA, using a data sample corresponding to an integrated luminosity of 0.33 fb{sup -1}. The tau candidates were identified from their decays into electrons, muons or hadronic jets. The number of tau-pair candidates has been compared with the prediction from the Standard Model, where the largest contribution is expected from Bethe-Heitler processes. The total visible cross section was extracted. Standard Model expectations agree well with the measured distributions, also at high invariant mass of the tau pair. (orig.)

  20. Measurement of the azimuthal correlation between the most forward jet and the scattered positron in deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2011-10-15

    Deep-inelastic positron-proton scattering events at low photon virtuality Q{sup 2} with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, {delta}{phi}, between the forward jet and the scattered positron. The sensitivity to QCD evolution mechanisms is tested by comparing the data to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations. (orig.)

  1. Measurement of the azimuthal correlation between the most forward jet and the scattered positron in deep-inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Andreev, V.

    2011-10-01

    Deep-inelastic positron-proton scattering events at low photon virtuality Q 2 with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, Δφ, between the forward jet and the scattered positron. The sensitivity to QCD evolution mechanisms is tested by comparing the data to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations. (orig.)

  2. TREE SELECTING AND TREE RING MEASURING IN DENDROCHRONOLOGICAL INVESTIGATIONS

    Directory of Open Access Journals (Sweden)

    Sefa Akbulut

    2004-04-01

    Full Text Available Dendrochronology is a method of dating which makes use of the annual nature of tree growth. Dendrochronology may be divided into a number of subfields, each of which covers one or more aspects of the use of tree ring data: dendroclimatology, dendrogeomorphology, dendrohydrology, dendroecology, dendroarchaelogy, and dendrogylaciology. Basic of all form the analysis of the tree rings. The wood or tree rings can aid to dating past events about climatology, ecology, geology, hydrology. Dendrochronological studies are conducted either on increment cores or on discs. It may be seen abnormalities on tree rings during the measurement like that false rings, missing rings, reaction wood. Like that situation, increment cores must be extracted from four different sides of each tree and be studied as more as on tree.

  3. Study of the photon remnant in resolved photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-01-01

    Photoproduction at HERA is studied in ep collisions, with the ZEUS detector, for γp centre-of-mass energies ranging from 130-270 GeV. A sample of events with two high-p T jets (p T >6 GeV, η T with respect to the beam axis is measured to be 2.1±0.2 GeV, which demonstrates substantial mean transverse momenta for the photon remnant. (orig.)

  4. Jets and diffraction results from HERA

    International Nuclear Information System (INIS)

    Buniatyan, A.

    2014-01-01

    The latest results on precision measurements of jet and diffractive cross sections obtained by the H1 and ZEUS experiments at HERA are reported. The inclusive jet and multi-jet cross-sections are used in QCD calculations at next-to-leading order (NLO) to determine the strong coupling α s . The cross-section measurements for diffractive inclusive DIS processes with a leading proton in the final state are combined for the H1 and ZEUS experiments in order to improve the precision and extend the kinematic range. The di-jet cross sections are measured in diffractive DIS with a leading proton and compared with QCD predictions based on diffractive parton densities in the proton. The cross sections for exclusive heavy vector meson photoproduction are studied in terms of the momentum transfer at the proton vertex and of the photon-proton centre-of-mass energy. (author)

  5. Exclusive vector meson production at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Szuba, Dorota [Hamburg University, Hamburg (Germany); Collaboration: H1 Collaboration; ZEUS Collaboration

    2013-04-15

    The exclusive photoproduction of {Upsilon} has been studied with the ZEUS detector in ep collisions at HERA. The exponential slope, b, of the |t|-dependence of the cross section, where t is the squared four-momentum transfer at the proton vertex, has been measured. This constitutes the first measurement of the |t|-dependence of the {gamma}p{yields}{Upsilon}p cross section. The differential crosssections as a function of t at lower energies of {gamma}p centre-of-mass has been studied in exclusive diffractive photoproduction of J/{psi} mesons with the H1 detector. The exclusive electroproduction of two pions has been measured by the ZEUS experiment. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, assuming that the studied mass range includes the contributions of the {rho}, {rho} Prime and . {rho}'' vector-meson states.

  6. Hera: High Energy Astronomical Data Analysis via the Internet

    Science.gov (United States)

    Valencic, Lynne A.; Chai, P.; Pence, W.; Snowden, S.

    2011-09-01

    The HEASARC at NASA Goddard Space Flight Center has developed Hera, a data processing facility for analyzing high energy astronomical data over the internet. Hera provides all the software packages, disk space, and computing resources needed to do general processing of and advanced research on publicly available data from High Energy Astrophysics missions. The data and data products are kept on a server at GSFC and can be downloaded to a user's local machine. This service is provided for free to students, educators, and researchers for educational and research purposes.

  7. Combined inclusive diffractive cross sections measured with foreward proton spectrometers in deep inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (DE)] (and others)

    2012-07-15

    A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy {radical}(s)=318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6% for the most precise points. The combined data cover the range 2.5

  8. Leading neutron energy and pT distributions in deep inelastic scattering and photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-02-01

    The production of energetic neutrons in ep collisions has been studied with the ZEUS detector at HERA. The neutron energy and p T 2 distributions were measured with a forward neutron calorimeter and tracker in a 40 pb -1 sample of inclusive deep inelastic scattering (DIS) data and a 6 pb -1 sample of photoproduction data. The neutron yield in photoproduction is suppressed relative to DIS for the lower neutron energies and the neutrons have a steeper p T 2 distribution, consistent with the expectation from absorption models. The distributions are compared to HERA measurements of leading protons. The neutron energy and transverse-momentum distributions in DIS are compared to Monte Carlo simulations and to the predictions of particle exchange models. Models of pion exchange incorporating absorption and additional secondary meson exchanges give a good description of the data. (orig.)

  9. Beauty photoproduction using decays into electrons at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2008-05-15

    Photoproduction of beauty quarks in events with two jets and an electron associated with one of the jets has been studied with the ZEUS detector at HERA using an integrated luminosity of 120 pb{sup -1}. The fractions of events containing b quarks, and also of events containing c quarks, were extracted from a likelihood fit using variables sensitive to electron identification as well as to semileptonic decays. Total and differential cross sections for beauty and charm production were measured and compared with next-to-leading-order QCD calculations and Monte Carlo models. (orig.)

  10. Beauty photoproduction using decays into electrons at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-05-01

    Photoproduction of beauty quarks in events with two jets and an electron associated with one of the jets has been studied with the ZEUS detector at HERA using an integrated luminosity of 120 pb -1 . The fractions of events containing b quarks, and also of events containing c quarks, were extracted from a likelihood fit using variables sensitive to electron identification as well as to semileptonic decays. Total and differential cross sections for beauty and charm production were measured and compared with next-to-leading-order QCD calculations and Monte Carlo models. (orig.)

  11. Analysis of possibilities for a spin flip in high energy electron ring HERA

    International Nuclear Information System (INIS)

    Stres, S.; Pestotnik, R.

    2007-01-01

    In a high energy electron ring the spins of electrons become spontaneously polarized via the emission of spin-flip synchrotron radiation. By employing a radio frequency (RF) radial dipole field kicker, particle spin directions can be rotated slowly over many turns. A model which couples three dimensional spin motion and longitudinal particle motion was constructed to describe non-equilibrium spin dynamics in high energy electron storage rings. The effects of a stochastic synchrotron radiation on the orbital motion in the accelerator synchrotron plane and its influence on the spin motion are studied. The main contributions to the spin motion, the synchrotron oscillations and the stochastic synchrotron radiation, have different influence on the spin polarization reversal in different regions of the parameter space. The results indicate that polarization reversal might be obtained in high energy electron storage rings with a significant noise even with relatively small strengths of a perturbing magnetic field. The only experimental datum avaliable agrees with the model prediction, however further experimental data would be necessary to validate the model

  12. A determination of electroweak parameters at HERA

    Science.gov (United States)

    H1 Collaboration; Aktas, A.; Andreev, V.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bähr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D. P.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; de Boer, Y.; Delcourt, B.; de Roeck, A.; Desch, K.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y. H.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Keller, N.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kückens, J.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sedlák, K.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, M.; Usik, A.; Utkin, D.; Valkár, S.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-01-01

    Using the deep inelastic ep and ep charged and neutral current scattering cross sections previously published, a combined electroweak and QCD analysis is performed to determine electroweak parameters accounting for their correlation with parton distributions. The data used have been collected by the H1 experiment in 1994 2000 and correspond to an integrated luminosity of 117.2 pb. A measurement is obtained of the W propagator mass in charged current ep scattering. The weak mixing angle sinθ is determined in the on-mass-shell renormalisation scheme. A first measurement at HERA is made of the light quark weak couplings to the Z boson and a possible contribution of right-handed isospin components to the weak couplings is investigated.

  13. A Determination of Electroweak Parameters at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxeld, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sedlak, K.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-01-01

    Using the deep inelastic e^+p and e^-p charged and neutral current scattering cross sections previously published, a combined electroweak and QCD analysis is performed to determine electroweak parameters accounting for their correlation with parton distributions. The data used have been collected by the H1 experiment in 1994-2000 and correspond to an integrated luminosity of 117.2 pb^{-1}. A measurement is obtained of the W propagator mass in charged current ep scattering. The weak mixing angle sin^2 theta_W is determined in the on-mass-shell renormalisation scheme. A first measurement at HERA is made of the light quark weak couplings to the Z^0 boson and a possible contribution of right-handed isospin components to the weak couplings is investigated.

  14. Forward-jet production in deep inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., IL (US)] (and others)

    2007-07-15

    Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb{sup -1}. Measurements are presented for inclusive forward jets as well as for forward jets accompanied by a dijet system. The explored phase space, with jet pseudorapidity up to 4.3 is expected to be particularly sensitive to the dynamics of QCD parton evolution at low x. The measurements are compared to fixed-order QCD calculations and to leading-order parton-shower Monte Carlo models. (orig.)

  15. Forward-jet production in deep inelastic ep scattering at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-07-01

    Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb -1 . Measurements are presented for inclusive forward jets as well as for forward jets accompanied by a dijet system. The explored phase space, with jet pseudorapidity up to 4.3 is expected to be particularly sensitive to the dynamics of QCD parton evolution at low x. The measurements are compared to fixed-order QCD calculations and to leading-order parton-shower Monte Carlo models. (orig.)

  16. Measurement of K*±(892) production in deep inelastic ep scattering with the H1 detector at HERA

    International Nuclear Information System (INIS)

    Sunar, Deniz

    2009-07-01

    A first measurement is presented of K * (892) ± vector mesons, observed through the decay chain K * (892) ± → K 0 S π ± → π + π - π ± ; in neutral current deep-inelastic ep scattering. The data were taken at the HERA collider in the years 2005.2007 with centre of mass energy √(s)=319 GeV using the H1 detector and correspond to an integrated luminosity of approximately 302 pb -1 . The measurement of differential cross section was performed in the kinematic range which covers the photon virtuality 5 2 2 and the inelasticity 0:1 *± vector meson is restricted in transverse momentum p T (K *± )>1 GeV and pseudorapidity -1.5 *± )<1.5. The results are compared to predictions of leading order Monte Carlo models matched with the parton showers. Persbericht (orig.)

  17. Determination of the integrated luminosity at HERA using elastic QED Compton events

    International Nuclear Information System (INIS)

    Aaron, F.D.; Andreev, V.

    2012-04-01

    A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep→eγp. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3%. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process.

  18. Determination of the Integrated Luminosity at HERA using Elastic QED Compton Events

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Kogler, R.; Kostka, P.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lopez-Fernandez, R.; Lubimov, V.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

    2012-10-10

    A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep \\rightarrow ep. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3%. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process.

  19. Search for first-generation leptoquarks at HERA

    CERN Document Server

    Abramowicz, H.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A.N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartosik, N.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bokhonov, V.; Bold, T.; Bondarenko, K.; Boos, E.G.; Borras, K.; Boscherini, D.; Bot, D.; Brock, I.; Brownson, E.; Brugnera, R.; Brummer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P.J.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C.D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Cooper-Sarkar, A.M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; D'Agostini, G.; Dal Corso, F.; del Peso, J.; Dementiev, R.K.; De Pasquale, S.; Derrick, M.; Devenish, R.C.E.; Dobur, D.; Dolinska, G.; Doyle, A.T.; Drugakov, V.; Durkin, L.S.; Dusini, S.; Eisenberg, Y.; Fang, S.; Fazio, S.; Ferrando, J.; Ferrero, M.I.; Figiel, J.; Forrest, M.; Foster, B.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gizhko, A.; Gladilin, L.K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu.A.; Gottlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J.C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Horton, K.; Huttmann, A.; Ibrahim, Z.A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H.P.; Januschek, F.; Jones, T.W.; Jungst, M.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Karshon, U.; Karstens, F.; Katkov, I.I.; Kaur, M.; Kaur, P.; Keramidas, A.; Khein, L.A.; Kim, J.Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, U.; Koffeman, E.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I.A.; Kotanski, A.; Kotz, U.; Kowalski, H.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B.B.; Levy, A.; Libov, V.; Limentani, S.; Ling, T.Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Lohr, B.; Lohrmann, E.; Long, K.R.; Longhin, A.; Lontkovskyi, D.; Lukina, O.Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J.F.; Mastroberardino, A.; Mattingly, M.C.K.; Melzer-Pellmann, I.A.; Mergelmeyer, S.; Miglioranzi, S.; Idris, F.Mohamad; Monaco, V.; Montanari, A.; Morris, J.D.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nigro, A.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, R.J.; Nuncio-Quiroz, A.E.; Oh, B.Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Yu.; Papageorgiu, K.; Parenti, A.; Paul, E.; Pawlak, J.M.; Pawlik, B.; Pelfer, P.G.; Pellegrino, A.; Perlanski, W.; Perrey, H.; Piotrzkowski, K.; Plucinski, P.; Pokrovskiy, N.S.; Polini, A.; Proskuryakov, A.S.; Przybycien, M.; Raval, A.; Reeder, D.D.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y.D.; Robertson, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Samson, U.; Sartorelli, G.; Savin, A.A.; Saxon, D.H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W.B.; Schneekloth, U.; Schonberg, V.; Schorner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L.M.; Shehzadi, R.; Shimizu, S.; Singh, I.; Skillicorn, I.O.; Slominski, W.; Smith, W.H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T.P.; Stifutkin, A.; Stopa, P.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tapper, A.D.; Tassi, E.; Terron, J.; Theedt, T.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Vazquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N.N.; Walczak, R.; Wan Abdullah, W.A.T.; Whitmore, J.J.; Wichmann, K.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yagues-Molina, A.G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zabiegalov, O.; Zarnecki, A.F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B.O.; Zhmak, N.; Zhou, C.; Zichichi, A.; Zolkapli, Z.; Zotkin, D.S.

    2012-01-01

    A search for first-generation leptoquarks was performed in electron-proton and positron-proton collisions recorded with the ZEUS detector at HERA in 2003-2007 using an integrated luminosity of 366 pb^-1. Final states with an electron and jets or with missing transverse momentum and jets were analysed, searching for resonances or other deviations from the Standard Model predictions. No evidence for any leptoquark signal was found. The data were combined with data previously taken at HERA, resulting in a total integrated luminosity of 498 pb^-1. Limits on the Yukawa coupling, lambda, of leptoquarks were set as a function of the leptoquark mass for different leptoquark types within the Buchmueller-Rueckl-Wyler model. Leptoquarks with a coupling lambda=0.3 are excluded for masses up to 699 GeV.

  20. Search for first-generation leptoquarks at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2012-05-15

    A search for first-generation leptoquarks was performed in electron-proton and positron-proton collisions recorded with the ZEUS detector at HERA in 2003-2007 using an integrated luminosity of 366 pb{sup -}1. Final states with an electron and jets or with missing transverse momentum and jets were analysed, searching for resonances or other deviations from the Standard Model predictions. No evidence for any leptoquark signal was found. The data were combined with data previously taken at HERA, resulting in a total integrated luminosity of 498 pb{sup -}1. Limits on the Yukawa coupling, {lambda}, of leptoquarks were set as a function of the leptoquark mass for different leptoquark types within the Buchmueller-Rueckl-Wyler model. Leptoquarks with a coupling {lambda}=0.3 are excluded for masses up to 699 GeV.

  1. Study of charm production at HERA using the ZEUS detector

    International Nuclear Information System (INIS)

    Woudenberg, R. van.

    1995-01-01

    The subject of this thesis is charm production at HERA, especially in photoproduction (Q 2 ∼0). In lowest order, the production of heavy quarks proceeds via photo-gluon fusion. Thus a measurement of charm production provides a handle on the gluon structure of the proton. (Leading and next-to-leading order processes together result in a total cross section of σ(ep→ec anti cX)≅O(1.0 μb)). (orig./HSI)

  2. Radiocarbon measurements of tree-ring samples from Japanese woods

    International Nuclear Information System (INIS)

    Ozaki, Hiromasa; Sakamoto, Minoru; Imamura, Mineo; Mitsutani, Takumi

    2008-01-01

    Since radiocarbon age is a model age based on constancy of atmospheric radiocarbon concentration and a provisional value of 5568 years for the 14 C half-life, calibration to calendar age is required for practical dating. The dataset, called IntCal, used for the calibration has been constructed by international consortium. Most parts of the IntCal have been based on the measurement of radiocarbon in dendrochronologically dated tree-ring samples from woods in Europe and North America. Regional offsets, which are designed as differences of local atmospheric radiocarbon from IntCal, have been pointed out based on recent radiocarbon measurements for tree-ring samples from a few regions. We have also measured radiocarbon of tree-ring samples from Japanese woods in order to investigate regional offsets in Japan. In this study, radiocarbon measurements for tree-ring samples from three different Japanese woods at around AD500 were carried out. Consequently, differences from IntCal04 at around AD500 were confirmed, although no systematic offset are found. However, the results obtained in this study agree with the raw data used for construction of IntCal04. This could pose a question to calculation method of IntCal04. (author)

  3. Human errors during the simulations of an SGTR scenario: Application of the HERA system

    International Nuclear Information System (INIS)

    Jung, Won Dea; Whaley, April M.; Hallbert, Bruce P.

    2009-01-01

    Due to the need of data for a Human Reliability Analysis (HRA), a number of data collection efforts have been undertaken in several different organizations. As a part of this effort, a human error analysis that focused on a set of simulator records on a Steam Generator Tube Rupture (SGTR) scenario was performed by using the Human Event Repository and Analysis (HERA) system. This paper summarizes the process and results of the HERA analysis, including discussions about the usability of the HERA system for a human error analysis of simulator data. Five simulated records of an SGTR scenario were analyzed with the HERA analysis process in order to scrutinize the causes and mechanisms of the human related events. From this study, the authors confirmed that the HERA was a serviceable system that can analyze human performance qualitatively from simulator data. It was possible to identify the human related events in the simulator data that affected the system safety not only negatively but also positively. It was also possible to scrutinize the Performance Shaping Factors (PSFs) and the relevant contributory factors with regard to each identified human event

  4. Events with an isolated lepton and missing transverse momentum and measurement of W production at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Abramowicz, H. [Tel Aviv Univ. (Israel). Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics; Max-Planck-Institute, Muenchen (Germany).; Abt, I. [Max-Planck-Institut fuer Physik, Muenchen (DE)] (and others)

    2009-09-15

    A search for events containing an isolated electron or muon and missing transverse momentum produced in e{sup {+-}}p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb{sup -1}. The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e{sup +}p data, at large hadronic transverse momentum P{sub T}{sup X}>25 GeV, a total of 23 events are observed compared to a prediction of 14.0{+-}1.9. The total single W boson production cross section is measured as 1.06{+-}0.16(stat.){+-}0.07(sys.) pb, in agreement with an SM expectation of 1.26{+-}0.19 pb. (orig.)

  5. Differential distributions for heavy flavour production at HERA

    CERN Document Server

    Frixione, Stefano; Ridolfi, G C

    1995-01-01

    We compute pseudorapidity and transverse momentum distributions for charm and bottom production at HERA. We examine the effect of next-to-leading order QCD corrections, the effect of possible intrinsic transverse momenta of the incoming partons, and of fragmentation. We compare our results with full Monte Carlo simulation using HERWIG. The importance of the hadronic component of the photon is also studied. We examine the possibility to distinguish among different parametrizations of the photon parton densities using charm production data, and the possibilty to extract information about the small-x behaviour of the gluon density of the proton. We also give a prediction for the transverse momentum and pseudorapidity distributions for bottom production at HERA.

  6. Differential distributions for heavy flavour production at HERA

    International Nuclear Information System (INIS)

    Frixione, S.; Ridolfi, G.

    1995-01-01

    We compute pseudorapidity and transverse momentum distributions for charm and bottom production at HERA. We examine the effect of next-to-leading order QCD corrections, the effect of possible intrinsic transverse momenta of the incoming partons, and of fragmentation. We compare our results with those of a full Monte Carlo simulation using HERWIG. The importance of the hadronic component of the photon is also studied. We examine the possibility of distinguishing between different parametrizations of the photon parton densities using charm production data, and the possibility of extracting information about the small-x behaviour of the gluon density of the proton. We also give a prediction for the transverse momentum and pseudorapidity distributions for bottom production at HERA. (orig.)

  7. Carbon-14 dating of tree rings for tritium measurement

    International Nuclear Information System (INIS)

    Yamada, Y.; Yasuike, K.; Kiriyama, N.; Komura, K.; Ueno, K.

    1998-01-01

    The carbon-14 concentration in tree-ring cellulose of an 80-year-old pine tree which has been used for tritium measurement was measured during the 1941-1987 period. This was done to determine the formation year of each tree ring in order to study the pathway of tritium uptake into the tree rings. In the 1941 to 1953 period, the δ 14 C value remained slightly lower than 0 per mille. It began to increase from 1954 to a small broad peak of 250 per mille between 1959 and 1961, followed by rapid increase to the highest value of approximately 800 per mille in 1964. Since 1964, it had been diminishing year by year to reach a level of 190 per mille in 1987. The two peak years coincided with those in the known carbon-14 patterns in tree rings. However, there existed a difference in the amplitude of the δ 14 C values during the period of 1963-1967. (author)

  8. Subjet distributions in deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2008-12-15

    Subjet distributions were measured in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 81.7 pb{sup -1}. Jets were identified using the k{sub T} cluster algorithm in the laboratory frame. Sub-jets were defined as jet-like substructures identified by a reapplication of the cluster algorithm at a smaller value of the resolution parameter y{sub cut}. Measurements of subjet distributions for jets with exactly two subjets for y{sub cut}=0.05 are presented as functions of observables sensitive to the pattern of parton radiation and to the colour coherence between the initial and final states. Perturbative QCD predictions give an adequate description of the data. (orig.)

  9. Subjet distributions in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-12-01

    Subjet distributions were measured in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 81.7 pb -1 . Jets were identified using the k T cluster algorithm in the laboratory frame. Sub-jets were defined as jet-like substructures identified by a reapplication of the cluster algorithm at a smaller value of the resolution parameter y cut . Measurements of subjet distributions for jets with exactly two subjets for y cut =0.05 are presented as functions of observables sensitive to the pattern of parton radiation and to the colour coherence between the initial and final states. Perturbative QCD predictions give an adequate description of the data. (orig.)

  10. Measurement of the azimuthal correlation between the most forward jet and the scattered positron in deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Inst., Yerevan (Armenia); Barrelet, E. [Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris 7, CNRS/IN2P3, LPNHE, Paris (France); Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Grell, B.R.; Habib, S.; Haidt, D.; Helebrant, C.; Kleinwort, C.; Kogler, R.; Kraemer, M.; Levonian, S.; Lipka, K.; List, B.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Piec, S.; Pitzl, D.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [Univ. Paris-Sud, CNRS/IN2P3, LAL, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [Ecole Polytechnique, CNRS/IN2P3, LLR, Palaiseau (France); Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I. [Univ. of Belgrade, Vinca Inst. of Nuclear Sciences, Belgrade (RS); Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D. [Univ. of Birmingham, (United Kingdom); Bruncko, D.; Cerny, V.; Ferencei, J. [Slovak Academy of Sciences, Kosice (Slovakia)] [and others

    2012-03-15

    Deep-inelastic positron-proton scattering events at low photon virtuality, Q {sup 2}, with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples, differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, {delta}{phi}, between the forward jet and the scattered positron in bins of the rapidity distance, Y, between them. The data are compared to predictions of Monte Carlo generators based on different evolution approaches as well as to next-to-leading order calculations in order to test the sensitivity to QCD evolution mechanisms. (orig.)

  11. Measurement of F_2^ccbar and F_2^bbbar at High Q^2 using the H1 Vertex Detector at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Broker, H.-B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxeld, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Winter, G.-G.; Wissing, Ch.; Woehrling, E.-E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; Zomer, F.

    2004-01-01

    Measurements are presented of inclusive charm and beauty cross sections in e^+p collisions at HERA for values of photon virtuality Q^2 > 150 GeV^2 and of inelasticity 0.1 < y < 0.7. The charm and beauty fractions are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 vertex detector. The data are divided into four regions in Q^2 and Bjorken x, and values for the structure functions F_2^{c\\bar{c}} and F_2^{b\\bar{b}} are obtained. The results are found to be compatible with the predictions of perturbative quantum chromodynamics.

  12. Measurement of D* meson with two jets in photoproduction with the H1 detector at HERA

    International Nuclear Information System (INIS)

    Staykova, Zlatka

    2011-02-01

    Photoproduction events containing a charmed meson D *± and two jets are investigated with the H1 detector using the HERA II data sample. The measurement is based on e + p collisions during the period of 2006/2007 data taking and uses integrated luminosity of 113.14 pb -1 . The kinematic range of the measurement covers 100 GeV γp 2 2 . The D * mesons are reconstructed in the decay channel, D *± →D 0 π ± →K -+ π ± π ± . Jets were reconstructed using the inclusive k t algorithm and are selected if they have transverse momenta of p t (jet)>3.5 GeV. One of the jets has to be associated with the D * meson itself, such that the parent charmed quark can be tagged. The phase space of the measurement is limited within the central rapidity for the D * meson and the D * jet , vertical stroke η vertical stroke <1.5 while the second jet was measured within, -1.5<η<2.9. Single differential cross sections and double differential distributions were measured and compared to Leading Order Monte Carlo (MC) event generators, Pythia and Cascade and with the Next-to-Leading order MC generator MC rate at NLO. (orig.)

  13. Progress in the NNPDF global analysis and the impact of the legacy HERA combination

    NARCIS (Netherlands)

    Rojo, Juan

    2015-01-01

    The H1 and ZEUS collaborations have recently presented their final results for the combination of inclusive cross-section measurements taken during Run I and Run II at the HERA collider. In this contribution, following an overview of recent progress in the NNPDF framework, we quantify the impact of

  14. Associated jet production at HERA

    CERN Document Server

    Bartels, Julius; de Roeck, A; Graudenz, Dirk; Wüsthoff, M

    1996-01-01

    We compare the BFKL prediction for the associated production of forward jets at HERA with fixed-order matrix element calculations taking into account the kinematical cuts imposed by experimental conditions. Comparison with H1 data of the 1993 run favours the BFKL prediction. As a further signal of BFKL dynamics, we propose to look for the azimuthal dependence of the forward jets.

  15. Outer Measures on a Commutative Ring Induced by Measures on Its Spectrum

    Directory of Open Access Journals (Sweden)

    Dudzik Dariusz

    2017-09-01

    Full Text Available On a commutative ring R we study outer measures induced by measures on Spec(R. The focus is on examples of such outer measures and on subsets of R that satisfy the Carathéodory condition.

  16. Measurement of D{sup {+-}} and D{sup 0} production in deep inelastic scattering using a lifetime tag at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., IL (US)] (and others)

    2008-12-15

    The production of D{sup {+-}} and D{sup 0} mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb{sup -1}. The measurements cover the kinematic range 5Measurements are extrapolated to the full kinematic phase space in order to obtain the open-charm contribution, F{sup c} {sup anti} {sup c}{sub 2}, to the proton structure function, F{sub 2}. (orig.)

  17. Evaluation of the data of the HERA-B vertex detector with regards to the physical properties of the applied silicon strip counters

    International Nuclear Information System (INIS)

    Wagner, W.

    1999-01-01

    The HERA-B experiment at the DESY laboratory in Hamburg is dedicated to measuring CP-violation in the decays of neutral B-mesons. The primary purpose of the experiment in the measurement of the CP-asymmetry in the decay channel B 0 → J/ψK S 0 . In order to identify the B-mesons and to determine the time-dependent asymmetry, the decay length anti Δ anti l of the B-mesons must be measured to an accuracy of σ Δl ≤ 500 μm. To achieve this aim, HERA-B has a vertex detector which is based on double-sided silicon strip detectors mounted in a Roman pot system. One important specification of the vertex detector is to allow independent tracking with an efficiency above 95%. Therefore, it is required to select hits on the strip detectors with an efficiency above 99% and optimize the suppression of noise. This thesis describes a detailed investigation of the behaviour of the silicon strip detectors used in the vertex detector. The first part presents measurements performed in the laboratory using a tunable infrared dye laser to simulate the passage of charged particles through the detector. This includes measurements of the charge division between adjacent readout strips and mapping of the detector depletion. The results of the measurements agree excellently with the predictions from a detailed model calculation carried out in this thesis. The second part of the thesis the analysis of data recorded with the HERA-B vertex detector during the commissioning run of spring 1999. The analysis focusses on the investigation of cluster shapes and cluster sizes. In particular, the dependence of these distributions from the selection cuts is analyzed. Additionally, the differences between the two detector designs used, p-spray and p-stop detectors with intermediate strip or without respectively, are worked out. The measured distributions agree very well with the predictions from a model calculation taking all relevant detector parameters into account. The results of the data

  18. Combination of Differential D^{*\\pm} Cross-Section Measurements in Deep-Inelastic ep Scattering at HERA

    CERN Document Server

    Abramowicz, H.; Adamczyk, L.; Adamus, M.; Andreev, V.; Antonelli, S.; Aushev, V.; Aushev, Y.; Baghdasaryan, A.; Begzsuren, K.; Behnke, O.; Behrens, U.; Belousov, A.; Bertolin, A.; Bloch, I.; Boos, E.G.; Borras, K.; Boudry, V.; Brandt, G.; Brisson, V.; Britzger, D.; Brock, I.; Brook, N.H.; Brugnera, R.; Bruni, A.; Buniatyan, A.; Bussey, P.J.; Bylinkin, A.; Bystritskaya, L.; Caldwell, A.; Campbell, A.J.; Cantun Avila, K.B.; Capua, M.; Catterall, C.D.; Ceccopieri, F.; Cerny, K.; Chekelian, V.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Contreras, J.G.; Cooper-Sarkar, A.M.; Corradi, M.; Corriveau, F.; Cvach, J.; Dainton, J.B.; Daum, K.; Dementiev, R.K.; Devenish, R.C.E.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dolinska, G.; Dusini, S.; Eckerlin, G.; Egli, S.; Elsen, E.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Figiel, J.; Fleischer, M.; Fomenko, A.; Foster, B.; Gabathuler, E.; Gach, G.; Gallo, E.; Garfagnini, A.; Gayler, J.; Geiser, A.; Ghazaryan, S.; Gizhko, A.; Gladilin, L.K.; Goerlich, L.; Gogitidze, N.; Golubkov, Yu. A.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Grebenyuk, J.; Greenshaw, T.; Gregor, I.; Grindhammer, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Haidt, D.; Hain, W.; Henderson, R.C.W.; Hladky, J.; Hochman, D.; Hoffmann, D.; Hori, R.; Horisberger, R.; Hreus, T.; Huber, F.; Ibrahim, Z.A.; Iga, Y.; Ishitsuka, M.; Iudin, A.; Jacquet, M.; Janssen, X.; Januschek, F.; Jomhari, N.Z.; Jung, A.W.; Jung, H.; Kadenko, I.; Kananov, S.; Kapichine, M.; Karshon, U.; Kaur, M.; Kaur, P.; Kiesling, C.; Kisielewska, D.; Klanner, R.; Klein, M.; Klein, U.; Kleinwort, C.; Kogler, R.; Kondrashova, N.; Kononenko, O.; Korol, Ie.; Korzhavina, I.A.; Kostka, P.; Kotanski, A.; Kotz, U.; Kovalchuk, N.; Kowalski, H.; Kretzschmar, J.; Kruger, K.; Krupa, B.; Kuprash, O.; Kuze, M.; Landon, M.P.J.; Lange, W.; Laycock, P.; Lebedev, A.; Levchenko, B.B.; Levonian, S.; Levy, A.; Libov, V.; Limentani, S.; Lipka, K.; Lisovyi, M.; List, B.; List, J.; Lobodzinska, E.; Lobodzinski, B.; Lohr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O.Yu.; Makarenko, I.; Malinovski, E.; Malka, J.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Mergelmeyer, S.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Idris, F.Mohamad; Morozov, A.; Nasir, N.Muhammad; Muller, K.; Myronenko, V.; Nagano, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nobe, T.; Notz, D.; Nowak, G.; Nowak, R.J.; Olsson, J.E.; Onishchuk, Yu.; Ozerov, D.; Pahl, P.; Pascaud, C.; Patel, G.D.; Paul, E.; Perez, E.; Perlanski, W.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Pokrovskiy, N.S.; Polifka, R.; Przybycien, M.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roloff, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rubinsky, I.; Rusakov, S.; Ruspa, M.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Saxon, D.H.; Schioppa, M.; Schmidke, W.B.; Schmitt, S.; Schneekloth, U.; Schoeffel, L.; Schoning, A.; Schorner-Sadenius, T.; Sefkow, F.; Shcheglova, L.M.; Shevchenko, R.; Shkola, O.; Shushkevich, S.; Shyrma, Yu.; Singh, I.; Skillicorn, I.O.; Slominski, W.; Solano, A.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Stanco, L.; Steder, M.; Stefaniuk, N.; Stern, A.; Stopa, P.; Straumann, U.; Sykora, T.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tassi, E.; Thompson, P.D.; Tokushuku, K.; Tomaszewska, J.; Traynor, D.; Trofymov, A.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsurugai, T.; Turcato, M.; Turkot, O.; Turnau, J.; Tymieniecka, T.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Verbytskyi, A.; Viazlo, O.; Walczak, R.; Wan Abdullah, W.A.T.; Wegener, D.; Wichmann, K.; Wing, M.; Wolf, G.; Wunsch, E.; Yamada, S.; Yamazaki, Y.; Zacek, J.; Zakharchuk, N.; Zarnecki, A.F.; Zawiejski, L.; Zenaiev, O.; Zhang, Z.; Zhautykov, B.O.; Zhmak, N.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.; Zotkin, D.S.

    2015-01-01

    H1 and ZEUS have published single-differential cross sections for inclusive D^{*\\pm}-meson production in deep-inelastic ep scattering at HERA from their respective final data sets. These cross sections are combined in the common visible phase-space region of photon virtuality Q2 > 5 GeV2, electron inelasticity 0.02 1.5 GeV and pseudorapidity |eta(D^*)| 1.5 GeV2. Perturbative next-to-leadingorder QCD predictions are compared to the results.

  19. High transverse momentum dijet cross section measurements in photoproduction at HERA

    International Nuclear Information System (INIS)

    Dossanov, Aziz

    2013-06-01

    The measurement of high transverse momentum differential dijet cross sections in photoproduction at HERA in the γp center-of-mass energy 101 γp + p mode during the year 2006, collecting an integrated luminosity of 92.4 pb -1 . The results correspond to a kinematic range of photon virtualities Q 2 2 and inelasticities 0.1 perpendicular to algorithm, and a minimum transverse momentum of the two leading jets, P T,1st,2nd >15.0 GeV and pseudorapidities in the range of -0.5 1st,2nd 12 >40.0 GeV is required. Single differential dijet cross sections are measured, including cross sections in the direct and resolved photon enhanced regions. In order to study the contribution of partons interacting in the hard process, which are sensitive to the jet pseudorapidities, three different topologies of jets pseudorapidities are investigated. Single differential cross sections as a function of proton momentum fraction, taken by the interacting parton, x P , the fraction of photon momentum, x γ , the angle between the incoming and outgoing partons in the hard scatter, vertical stroke cos θ * vertical stroke are presented. Additionally, the cross sections as a function of the invariant mass of dijets, M 12 , anti η=(η 1st +η 2nd )/2, anti P T =(P T,1st +P T,2nd )/2 and P T,1st are also presented. The data are compared to predictions from the Pythia event generator, based on the LO matrix elements and parton showers, and to the NLO QCD calculations corrected for hadronization effects.

  20. Determination of the integrated luminosity at HERA using elastic QED Compton events

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Vazdik, Y.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H.; Barrelet, E.; Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Pandurovic, M.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D.; Bruncko, D.; Cerny, V.; Ferencei, J.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Lubimov, V.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Ceccopieri, F.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Roosen, R.; Staykova, Z.; Mechelen, P. van; Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R.; Chekelian, V.; Grindhammer, G.; Kiesling, C.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C.; Dobre, M.; Kogler, R.; Nowak, K.; Dodonov, V.; Povh, B.; Dossanov, A.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Feltesse, J.; Perez, E.; Schoeffel, L.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Grab, C.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Herrera, G.; Lopez-Fernandez, R.; Huber, F.; Pirumov, H.; Sauter, M.; Schoening, A.; Joensson, L.; Jung, H.; Kapichine, M.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Landon, M.P.J.; Rizvi, E.; Traynor, D.; Martyn, H.U.; Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P.; Soloviev, Y.; Stella, B.; Sykora, T.; Tsakov, I.; Wegener, D.

    2012-01-01

    A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep→eγp. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3 %. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process. (orig.)

  1. Determination of the integrated luminosity at HERA using elastic QED Compton events

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2012-04-15

    A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep{yields}e{gamma}p. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3%. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process.

  2. Study of elastic ρ0 photoproduction at HERA using the ZEUS leading proton spectrometer

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magil, S.

    1996-08-01

    The differential cross section dσ/dt for elastic ρ 0 photoproduction, γp→ρ 0 p(ρ 0 →π + π - ), has been measured in ep interactions at HERA. The squared four-momentum exchanged at the proton vertex, t, has been determined directly by measuring the momentum of the scattered proton using the ZEUS leading proton spectrometer (LPS), a large scale system of silicon micro-strip detectors operating close to the HERA proton beam. The LPS allows the measurement of the momentum of high energy protons scattered at small angles with accuracies of 0.4% for the longitudinal momentum and 5 MeV for the transverse momentum. Photoproduction of ρ 0 mesons has been investigated in the interval 0.073 2 , for photon virtualities q 2 2 and photon-proton centre-of-mass energies between 50 and 100 GeV. In the measured range, the t distribution exhibits an exponential shape with a slope parameter b=9.8±0.8(stat.)±1.1(syst.) GeV -2 . The use of the LPS eliminates the contamination from events with diffractive dissociation of the proton into low mass states. (orig.)

  3. An extraction of the skewing factor from DESY-HERA data

    International Nuclear Information System (INIS)

    Favart, Laurent; Machado, Magno V.T.; Schoeffel, Laurent

    2007-01-01

    In this contribution we present recent investigation on the extraction of the skewing factor, defined as the ratio of the imaginary parts of the amplitudes ImA (gamma * p → gamma * p) / ImA (gamma * p → gamma p). This factor is extracted from the data using the recent DVCS and the inclusive inelastic cross section measurements at DESY-HERA. We compare the results to the theoretical predictions for NLO QCD and the color dipole approach. (author)

  4. Study of charm production at HERA using the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Woudenberg, R van

    1995-09-26

    The subject of this thesis is charm production at HERA, especially in photoproduction (Q{sup 2}{approx}0). In lowest order, the production of heavy quarks proceeds via photo-gluon fusion. Thus a measurement of charm production provides a handle on the gluon structure of the proton. (Leading and next-to-leading order processes together result in a total cross section of {sigma}(ep{yields}ec anti cX){approx_equal}O(1.0 {mu}b)). (orig./HSI).

  5. Plasma density measurement with ring-type cutoff probe

    International Nuclear Information System (INIS)

    Kim, D.W.; You, S.J.; Na, B.K.; Kim, J.H.; Shin, Y.H.; Chang, H.Y.; Oh, W.Y.

    2013-01-01

    We proposed a cutoff probe with a ring-type detection tip enclosing a bar-type radiation tip. A comparative study between a proposed ring-type cutoff (RTC) probe and a conventional bar-type cutoff (BTC) probe showed that the RTC probe solved the problem of the BTC probe, the large measurement uncertainty of the electron density in a capacitively coupled plasma source. This improved characteristics of the RTC probe might have originated from the geometrical structure of the RTC probe concerning the monopole antennae radiation. This proposed cutoff probe can be expected to expand the applicable diagnostic range and to enhance the sensitivity of the cutoff probe. - Highlights: ► A cutoff probe with a ring type detection tip is proposed. ► Comparative experiment and simulation were conducted. ► The proposed probe showed a small uncertainty of measured plasma density. ► Improved characteristics might be originated from the geometrical structure

  6. Measurement of D{sup +} and {lambda}{sub c}{sup +} production in deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ (Israel). Raymond and Beverly Sackler Faculty of Exact Sciences; Max Planck Institute, Munich (Germany); Abt, I. [Max Planck Institut, Muenchen (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2010-06-15

    Charm production in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 120 pb{sup -1}. The hadronic decay channels D{sup +} {yields} K{sub S}{sup 0}{pi}{sup +}, {lambda}{sub c}{sup +} {yields} pK{sub S}{sup 0} and {lambda}{sub c}{sup +}{yields}{lambda}{pi}{sup +}, and their charge conjugates, were reconstructed. The presence of a neutral strange hadron in the final state reduces the combinatorial background and extends the measured sensitivity into the low transverse momentum region. The kinematic range is 0< p{sub T}(D{sup +}, {lambda}{sub c}{sup +})<10 GeV, vertical stroke {eta}(D{sup +}, {lambda}{sub c}{sup +}) vertical stroke <1.6, 1.5 < Q{sup 2}<1000 GeV{sup 2} and 0.02

  7. Measurement of jet production in deep-inelastic ep scattering at HERA

    International Nuclear Information System (INIS)

    Kogler, Roman

    2011-02-01

    In this thesis, precision measurements of inclusive jet, dijet and trijet cross sections in neutral current (NC) deep-inelastic ep scattering at a centre-of-mass energy of √(s)≅319 GeV are presented. The analysis is based on data collected by the H1 detector during the HERA-2 running phase in the years 2003-07, corresponding to an integrated luminosity of 351.5 pb -1 . The kinematic phase space of the measurement is defined by 150 2 2 and 0.2 2 and y are the negative four-momentum transfer squared and the inelasticity respectively. Jets are measured in the pseudorapidity range -1.0 lab T >7 GeV for the inclusive jet measurement and P T >7 GeV for the dijet and trijet measurements. In the case of the dijet and trijet measurements, the invariant mass of the two jets with the highest transverse momenta is required to be greater than 16 GeV. A large part of this work is devoted to the improvement of the reconstruction of the hadronic final state. This is achieved by a separation of showers originating from electromagnetically and hadronically interacting particles in the liquid argon calorimeter of the H1 detector on a statistical basis. A novel method to calibrate the hadronic final state, which is reconstructed with an energy-flow-algorithm, is developed. This calibration is based on the probability of a shower resulting from electromagnetically interacting particles and it is shown to improve the absolute energy scale uncertainty at high jet transverse momenta to 1%. Improvements of the resolution of the jet energy measurement with respect to the standard reconstruction of about 10% are reported. The new calibration in combination with improvements of the reconstruction algorithms by the H1 collaboration leads to a precision measurement of inclusive jet, dijet and trijet cross sections with average uncertainties of 4%, 5,2% and 7.2%, respectively. Measurements of jet cross sections normalised to the inclusive NC cross sections are then performed, which reduce

  8. Exclusive diffractive processes at HERA within the dipole picture

    International Nuclear Information System (INIS)

    Kowalski, H.; Motkyka, L.; Uniwersytet Jagiellonski, Krakow; Watt, G.; Univ. College London

    2006-08-01

    We present a simultaneous analysis, within an impact parameter dependent saturated dipole model, of exclusive diffractive vector meson (J/ψ, φ and ρ) production, deeply virtual Compton scattering and the total γ * p cross section data measured at HERA. Various cross sections measured as a function of the kinematic variables Q 2 , W and t are well described, with little sensitivity to the details of the vector meson wave functions. We determine the properties of the gluon density in the proton in both longitudinal and transverse dimensions, including the impact parameter dependent saturation scale. The overall success of the description indicates universality of the emerging gluon distribution and proton shape. (orig.)

  9. Inclusive charged particle cross sections in photoproduction at HERA

    International Nuclear Information System (INIS)

    Abt, I.

    1994-03-01

    Cross sections are presented for the inclusive production of charged particles measured in electron-proton collisions at low Q 2 with the H1 detector at HERA. The transverse momentum distribution extends up to 8 GeV/c. Its shape is found to be harder than that observed in anti pp collisions at comparable centre-of-mass energies √s γp ∼√s anti pp∼200 GeV, and also harder than in γp collisions at lower energies √s γp ∼18 GeV. Results from quantum chromodynamics (QCD) calculations agree with the measured transverse momentum and pseudorapidity cross sections. (orig.)

  10. Parton distributions with the combined HERA charm production cross sections

    International Nuclear Information System (INIS)

    Bertone, Valerio; Rojo, Juan

    2013-01-01

    Heavy quark structure functions from HERA provide a direct handle on the medium and small-x gluon PDF. In this contribution, we discuss ongoing progress on the implementation of the FONLL General-Mass scheme with running heavy quark masses, and of its benchmarking with the HOPPET and OpenQCDrad codes, and then present the impact of the recently released combined HERA charm production cross sections in the NNPDF 2.3 analysis. We find that the combined charm data contribute to constraining the gluon and quarks at small values of Bjorken-x.

  11. Parton distributions with the combined HERA charm production cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Bertone, Valerio [Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg i. B (Germany); Rojo, Juan [PH Department, TH Unit, CERN, CH-1211 Geneva 23 (Switzerland)

    2013-04-15

    Heavy quark structure functions from HERA provide a direct handle on the medium and small-x gluon PDF. In this contribution, we discuss ongoing progress on the implementation of the FONLL General-Mass scheme with running heavy quark masses, and of its benchmarking with the HOPPET and OpenQCDrad codes, and then present the impact of the recently released combined HERA charm production cross sections in the NNPDF 2.3 analysis. We find that the combined charm data contribute to constraining the gluon and quarks at small values of Bjorken-x.

  12. Measurement of D*± production at low Q2 with the beam-pipe calorimeter of ZEUS at HERA

    International Nuclear Information System (INIS)

    Irrgang, P.

    2004-12-01

    The production of D* mesons in deep-inelastic ep-scattering has been studied using the ZEUS detector at HERA. The total D* production cross-section and the differential cross-sections as functions of Q 2 , y, p t (D*) and η(D*) have been measured at low Q 2 . The data sample used was collected during the period 1998-2000 and amounts to an integrated luminosity of 82.2 pb -1 . The low Q 2 region could be reached using the beam-pipe calorimeter which measures the scattered electron at very small angles. Therefore special emphasis was put on the calibration of the BPC in order to reconstruct events in the kinematic range 0.05 2 2 and 0.02 * +→K - π + π - and the charged conjugated decay in the kinematic region 1.5 t (D*) 2 in agreement with the corresponding perturbative QCD predictions. (orig.)

  13. Measurement of charm and beauty dijet cross sections in photoproduction at HERA using the H1 vertex detector

    Science.gov (United States)

    Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Flucke, G.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Marti, L.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A. J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, M.; Usik, A.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-09-01

    A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. Events are selected with two or more jets of transverse momentum pt jet1(2)>11(8) GeV in the central range of pseudo-rapidity -0.9<ηjet1(2)<1.3. The fractions of events containing charm and beauty quarks are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 central vertex detector. Differential dijet cross sections for charm and beauty, and their relative contributions to the flavour inclusive dijet photoproduction cross section, are measured as a function of the transverse momentum of the leading jet, the average pseudo-rapidity of the two jets and the observable xγ obs. Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, while the predicted cross sections for beauty production are somewhat lower than the measurement.

  14. Selectron and squark production in ep collisions at HERA

    International Nuclear Information System (INIS)

    Bartels, J.; Hollik, W.

    1988-01-01

    For the SUSY Standard Model we give a detailed discussion how HERA can be used for disentangling the mixing structure in the neutralino sector. We present 3-dimensional plots for the total cross section and for the polarization asymmetry for selectron-squark production, varying both the sfermion masses and a mixing parameter. The main results are: (I) production rates at HERA are reasonably large for a wide range of mixing parameters; (II) the polarization asymmetry depends only weakly upon the sfermion masses and thus is a very useful tool in determining mixing parameters or mass splittings between left and right handed selectron masses. (orig.)

  15. Unpolarized neutral current e{sup {+-}}p cross section measurements at the H1 experiment, HERA

    Energy Technology Data Exchange (ETDEWEB)

    Habib, Shiraz Z.

    2009-11-15

    Measurements of the unpolarized inclusive neutral current reduced cross section in e{sup {+-}}p scattering at a center of mass energy {radical}(s) {approx_equal} 319 GeV are presented. The data was collected by the H1 detector during the HERA II running phase, after the 2000 luminosity upgrade, and corresponds to an integrated luminosity of 145 pb{sup -1} and 167 pb{sup -1} for the e{sup -}p and e{sup +}p periods respectively. The cross section measurements were made for the negative four-momentum transfer squared range 65{<=} Q{sup 2}{<=}30000 GeV{sup 2} and Bjorken-x range 0.00085{<=}x{<=}0.65. Dedicated measurements at inelasticity y=0.75 and Q{sup 2}{<=}800 GeV{sup 2} are also made. The details of the analysis are presented here. The cross section measurements presented here are found to agree with previously published data as well as predictions determined from various NLO QCD fits. Scaling violation of the F{sub 2} structure function as well differences between the e{sup -} and e{sup +} cross sections at high Q{sup 2} due to the xF{sub 3} structure function have been observed. The cross sections in the range Q{sup 2}{<=}800 GeV{sup 2} at inelasticity y=0.75 suggest non-zero values of the longitudinal structure function F{sub L}. (orig.)

  16. Prompt photon production in photoproduction at HERA

    International Nuclear Information System (INIS)

    Nowak, Krzysztof

    2010-03-01

    This thesis presents measurement of the production of prompt photons in photoproduction with the H1 experiment at HERA. The analysis is based on the data taken in the years 2004-2007, with a total integrated luminosity of 340 pb -1 . The main difficulty of the measurement comes from the high background of neutral mesons decaying into photons. It is accounted for with the help of multivariate analysis. Prompt photon cross sections are measured with the low negative four-momentum transfer squared Q 2 2 and in the inelasticity range 0.1 T γ γ γ and x p of the incident photon and proton carried by the constituents participating in the hard scattering process. Additionally, the transverse correlation between the photon and the jet is studied. The results are compared with predictions of a next-to-leading order calculation and a calculation based on the k T factorisation approach. Neither of calculations is able to describe all the aspects of the measurement. (orig.)

  17. Photoproduction of jets at HERA

    International Nuclear Information System (INIS)

    Chyla, J.

    1993-01-01

    The intimate relation between the direct and resolved photon interactions, due to the factorization mechanism, is elucidated. It is argued that recent data from HERA do not provide a direct evidence for the latter component, but should rather be interpreted as a manifestation of the O(α s 2 ) term in γp and, via the Weizsaecker-Williams approximation, in ep interactions. 5 figs., 12 refs

  18. A 110 m long prototype helium transfer line for the HERA project

    International Nuclear Information System (INIS)

    Horvath, I.; Ming, P.; Von Burg, M.; Horlitz, G.; Sindt, H.

    1986-01-01

    A prototype helium transfer line of 110-m length was designed and constructed at SIN for the HERA project. This rendered a study of the assembly and handling processes as well as the determination of the heat losses into the transfer line. In this paper the transfer line structure is described and first results of heat transfer measurement for the specially developed super-insulation are presented

  19. The Hadronic Final State in Deep Inelastic ep Scattering at Low Bjorken-x at HERA

    International Nuclear Information System (INIS)

    Goerlich, L.M.

    2006-01-01

    The electron-proton collider HERA with centre of mass system energy of about 300 GeV has extended the available kinematic regime in deep inelastic scattering to low values of Bjorken-x (10 -5 -10 -3 ) and made possible studies of the QCD dynamics in this region. The processes in which partons carry a very small fraction of the proton momentum may show deviations from the standard DGLAP dynamics and it is believed that their correct description is provided by the BFKL evolution formalism. Low x phenomena have been initially studied with the HERA data on F 2 structure function and later with more exclusive measurements of the hadronic final state. In this report recent results of these studies and especially dedicated measurements of jets and π 0 mesons, produced close to the proton remnant, are reviewed. The data are used to discriminate between QCD models with different parton evolution approximations. For completeness, measurements at e + e - and p-p colliders sensitive to the BFKL dynamics are also described. (author)

  20. From HERA to the Tevatron: A scaling law in hard diffraction

    International Nuclear Information System (INIS)

    Goulianos, K.

    1997-01-01

    Results on hard diffraction from CDF are reviewed and compared with predictions based on the diffractive structure function of the proton measured in deep inelastic scattering at HERA. The predictions are generally larger than the measured rates by a factor of ∼ 6, suggesting a breakdown of conventional factorization. Correct predictions are obtained by scaling the rapidity gap probability distribution of the diffractive structure function to the total integrated gap probability. The scaling of the gap probability is traced back to the pomeron flux renormalization hypothesis, which was introduced to unitarize the soft diffraction amplitude

  1. Hard x-ray measurements of the hot-electron rings in EBT-S

    International Nuclear Information System (INIS)

    Hillis, D.L.

    1982-06-01

    A thorough understanding of the hot electron rings in ELMO Bumpy Torus-Scale (EBT-S) is essential to the bumpy torus concept of plasma production, since the rings provide bulk plasma stability. The hot electrons are produced via electron cyclotron resonant heating using a 28-GHz cw gyrotron, which has operated up to power levels of 200 kW. The parameters of the energetic electron rings are studied via hard x-ray measurement techniques and with diamagnetic pickup coils. The hard x-ray measurements have used collimated NaI(Tl) detectors to determine the electron temperature T/sub e/ and electron density n/sub e/ for the hot electron annulus. Typical values of T/sub e/ are 400 to 500 keV and of n/sub e/ 2 to 5 x 10 11 cm -3 . The total stored energy of a single energetic electron ring as measured by diamagnetic pickup loops approaches approx. 40 J and is in good agreement with that deduced from hard x-ray measurements. By combining the experimental measurements from hard x-rays and the diamagnetic loops, an estimate can be obtained for the volume of a single hot electron ring. The ring volume is determined to be approx. 2.2 litres, and this volume remains approximately constant over the T-mode operating regime. Finally, the power in the electrons scattered out of the ring is measured indirectly by measuring the x-ray radiation produced when those electrons strike the chamber walls. The variation of this radiation with increasing microwave power levels is found to be consistent with classical scattering estimates

  2. SUSY signals at DESY HERA in the no-scale flipped SU(5) supergravity model

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, J.L.; Nanopoulos, D.V.; Wang, X.; Zichichi, A. (Center for Theoretical Physics, Department of Physics, Texas A M University, College Station, Texas 77843-4242 (United States) Astroparticle Physics Group, Houston Advanced Research Center (HARC), The Woodlands, Texas 77381 (United States) CERN, Geneva (Switzerland))

    1993-11-01

    Sparticle production and detection at DESY HERA are studied within the recently proposed no-scale flipped SU(5) supergravity model. Among the various reaction channels that could lead to sparticle production at HERA, only the following are within its limit of sensitivity in this model: [ital e][sup [minus

  3. Measurement of the Υ meson productin cross section in ep scattering at HERA

    International Nuclear Information System (INIS)

    Rubinskiy, Igor

    2009-04-01

    This thesis presents a measurement of Υ meson production in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 468 pb -1 . The Υ mesons were identified using the decay channel Υ→μ + μ - . The measurements were performed for exclusive diffractive production in the kinematic range Q 2 2 , 60 2 2 , 60 2 is virtuality of the exchanged photon and W is the photon-proton centre-of-mass energy. A feasibility study for the Υ meson inelastic production has also been performed. The measured cross sections are compared to and agree well with theoretical predictions within the perturbative QCD framework such as Martin-Ryskin-Teubner two gluon exchange and NRQCD. As the technical part of this thesis, work related to the commissioning of the Straw Tube Tracker (STT) and to the Zeus Event Visualisation (ZEVIS) software package are presented. STT developments include: the STT DSP (Digital Signal Processor) quality monitor was developed, the pattern recognition algorithm was optimised for speed, and used in the Third Level Trigger (TLT) in order to reduce the accepted event rate by rejecting non-physics background. The TLT Charge Current(CC) slot rate was reduced by an order of magnitude, offering a rate reduction for the total accepted TLT rate by ∼2%. ZEVIS developments include: the STT hit visualisation scheme in 2D, 3D and tan(θ)-φ view, and a user-friendly interface called ''EasyTool'' for global ZEUS track and hit visualisation for all ZEUS components. (orig.)

  4. Scaled momentum distributions of charged particles in dijet photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-04-01

    The scaled momentum distributions of charged particles in jets have been measured for dijet photoproduction with the ZEUS detector at HERA using an integrated luminosity of 359 pb -1 . The distributions are compared to predictions based on perturbative QCD carried out in the framework of the modified leading-logarithmic approximation (MLLA) and assuming local parton-hadron duality (LPHD). The universal MLLA scale, Λ eff , and the LPHD parameter, κ ch , are extracted. (orig.)

  5. Results from the H1 experiment at HERA

    International Nuclear Information System (INIS)

    Roeck, A. de

    1994-01-01

    New results from the H1 experiment at HERA on photoproduction, deep inelastic scattering and search for exotic particles are presented. Clear evidence is found for hard scattering in photoproduction interactions. Jets have been observed and used to examine the x γ distribution, indicating the need for a gluonic component in the photon. Hadronic final states and jet cross sections have been measured in deep inelastic scattering. A class of deep inelastic events with diffractive characteristics has been observed. The proton structure function F 2 (x, Q 2 ) has been measured in the new Bjorken-x region 10 -4 -2 and is found to rise with decreasing x. New limits for leptoquarks, squarks and excited electrons have been deduced. (orig.)

  6. Leading neutron energy and p{sub T} distributions in deep inelastic scattering and photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2007-02-15

    The production of energetic neutrons in ep collisions has been studied with the ZEUS detector at HERA. The neutron energy and p{sub T}{sup 2} distributions were measured with a forward neutron calorimeter and tracker in a 40 pb{sup -1} sample of inclusive deep inelastic scattering (DIS) data and a 6 pb{sup -1} sample of photoproduction data. The neutron yield in photoproduction is suppressed relative to DIS for the lower neutron energies and the neutrons have a steeper p{sub T}{sup 2} distribution, consistent with the expectation from absorption models. The distributions are compared to HERA measurements of leading protons. The neutron energy and transverse-momentum distributions in DIS are compared to Monte Carlo simulations and to the predictions of particle exchange models. Models of pion exchange incorporating absorption and additional secondary meson exchanges give a good description of the data. (orig.)

  7. Review of searches for rare processes and physics beyond the Standard Model at HERA

    International Nuclear Information System (INIS)

    South, David M.; Turcato, Monica

    2016-01-01

    The electron-proton collisions collected by the H1 and ZEUS experiments at HERA comprise a unique particle physics data set, and a comprehensive range of measurements has been performed to provide new insight into the structure of the proton. The high centre of mass energy at HERA has also allowed rare processes to be studied, including the production of W and Z 0 bosons and events with multiple leptons in the final state. The data have also opened up a new domain to searches for physics beyond the Standard Model including contact interactions, leptoquarks, excited fermions and a number of supersymmetric models. This review presents a summary of such results, where the analyses reported correspond to an integrated luminosity of up to 1 fb -1 , representing the complete data set recorded by the H1 and ZEUS experiments. (orig.)

  8. Events with an Isolated Lepton and Missing Transverse Momentum and Measurement of {\\boldmath $W$} Production at HERA

    CERN Document Server

    Aaron, F.D.; H1 and ZEUS Collaborations; Abt, I.; Adamczyk, L.; Adamus, M.; Aldaya Martin, M.; Alexa, C.; Andreev, V.; Antonelli, S.; Antonioli, P.; Antonov, A.; Antunovic, B.; Arneodo, M.; Aushev, V.; Bachynska, O.; Backovic, S.; Baghdasaryan, A.; Bamberger, A.; Barakbaev, A.N.; Barbagli, G.; Bari, G.; Barreiro, F.; Barrelet, E.; Bartel, W.; Bartsch, D.; Basile, M.; Begzsuren, K.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Belousov, A.; Bertolin, A.; Bhadra, S.; Bindi, M.; Bizot, J.C.; Blohm, C.; Bold, T.; Boos, E.G.; Borodin, M.; Borras, K.; Boscherini, D.; Bot, D.; Boudry, V.; Boutle, S.K.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Brock, I.; Brownson, E.; Brugnera, R.; Brummer, N.; Bruncko, D.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bunyatyan, A.; Buschhorn, G.; Bussey, P.J.; Butterworth, J.M.; Bylsma, B.; Bystritskaya, L.; Caldwell, A.; Campbell, A.J.; Cantun Avila, K.B.; Capua, M.; Carlin, R.; Catterall, C.D.; Cerny, K.; Cerny, V.; Chekanov, S.; Chekelian, V.; Cholewa, A.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Contreras, J.G.; Cooper-Sarkar, A.M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; D'Agostini, G.; Dainton, J.B.; Dal Corso, F.; Daum, K.; Deak, M.; de Favereau, J.; Delcourt, B.; Del Degan, M.; del Peso, J.; Delvax, J.; Dementiev, R.K.; De Pasquale, S.; Derrick, M.; Devenish, R.C.E.; De Wolf, E.A.; Diaconu, C.; Dobur, D.; Dodonov, V.; Dolgoshein, B.A.; Dossanov, A.; Doyle, A.T.; Drugakov, V.; Dubak, A.; Durkin, L.S.; Dusini, S.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eisenberg, Y.; Eliseev, A.; Elsen, E.; Ermolov, P.F.; Eskreys, A.; Falkiewicz, A.; Fang, S.; Favart, L.; Fazio, S.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrando, J.; Ferrero, M.I.; Figiel, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Forrest, M.; Foster, B.; Fourletov, S.; Gabathuler, E.; Galas, A.; Gallo, E.; Garfagnini, A.; Gayler, J.; Geiser, A.; Ghazaryan, S.; Gialas, I.; Gladilin, L.K.; Gladkov, D.; Glasman, C.; Glazov, A.; Glushkov, I.; Goerlich, L.; Gogitidze, N.; Golubkov, Yu.A.; Gottlicher, P.; Gouzevitch, M.; Grab, C.; Grabowska-Bold, I.; Grebenyuk, J.; Greenshaw, T.; Gregor, I.; Grell, B.R.; Grigorescu, G.; Grindhammer, G.; Grzelak, G.; Gwenlan, C.; Haas, T.; Habib, S.; Haidt, D.; Hain, W.; Hamatsu, R.; Hart, J.C.; Hartmann, H.; Hartner, G.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hilger, E.; Hiller, K.H.; Hochman, D.; Hoffmann, D.; Holm, U.; Hori, R.; Horisberger, R.; Horton, K.; Hreus, T.; Huttmann, A.; Iacobucci, G.; Ibrahim, Z.A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jacquet, M.; Jakob, H.P.; Janssen, X.; Januschek, F.; Jimenez, M.; Jones, T.W.; Jonsson, L.; Jung, A.W.; Jung, H.; Jungst, M.; Kadenko, I.; Kahle, B.; Kamaluddin, B.; Kananov, S.; Kanno, T.; Kapichine, M.; Karshon, U.; Karstens, F.; Katkov, I.I.; Katzy, J.; Kaur, M.; Kaur, P.; Kenyon, I.R.; Keramidas, A.; Khein, L.A.; Kiesling, C.; Kim, J.Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, M.; Klein, U.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Koffeman, E.; Kogler, R.; Kollar, D.; Kooijman, P.; Korol, Ie.; Korzhavina, I.A.; Kostka, P.; Kotanski, A.; Kotz, U.; Kowalski, H.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kulinski, P.; Kuprash, O.; Kutak, K.; Kuze, M.; Kuzmin, V.A.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lee, A.; Leibenguth, G.; Lendermann, V.; Levchenko, B.B.; Levonian, S.; Levy, A.; Li, G.; Libov, V.; Limentani, S.; Ling, T.Y.; Lipka, K.; Liptaj, A.; Lisovyi, M.; List, B.; List, J.; Lobodzinska, E.; Lohmann, W.; Lohr, B.; Lohrmann, E.; Loizides, J.H.; Loktionova, N.; Long, K.R.; Longhin, A.; Lontkovskyi, D.; Lopez-Fernandez, R.; Lubimov, V.; Lukasik, J.; Lukina, O.Yu.; Luzniak, P.; Maeda, J.; Magill, S.; Makankine, A.; Makarenko, I.; Malinovski, E.; Malka, J.; Mankel, R.; Marage, P.; Margotti, A.; Marini, G.; Marti, Ll.; Martin, J.F.; Martyn, H.U.; Mastroberardino, A.; Matsumoto, T.; Mattingly, M.C.K.; Maxfield, S.J.; Mehta, A.; Melzer-Pellmann, I.A.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Miglioranzi, S.; Mikocki, S.; Milcewicz-Mika, I.; Mohamad Idris, F.; Monaco, V.; Montanari, A.; Moreau, F.; Morozov, A.; Morris, J.D.; Morris, J.V.; Mozer, M.U.; Mudrinic, M.; Muller, K.; Murin, P.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Naumann, Th.; Newman, P.R.; Nicholass, D.; Niebuhr, C.; Nigro, A.; Nikiforov, A.; Nikitin, D.; Ning, Y.; Noor, U.; Notz, D.; Nowak, G.; Nowak, K.; Nowak, R.J.; Nozicka, M.; Nuncio-Quiroz, A.E.; Oh, B.Y.; Okazaki, N.; Oliver, K.; Olivier, B.; Olkiewicz, K.; Olsson, J.E.; Onishchuk, Yu.; Osman, S.; Ota, O.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Papageorgiu, K.; Parenti, A.; Pascaud, C.; Patel, G.D.; Paul, E.; Pawlak, J.M.; Pawlik, B.; Pejchal, O.; Pelfer, P.G.; Pellegrino, A.; Perez, E.; Perlanski, W.; Perrey, H.; Petrukhin, A.; Picuric, I.; Piec, S.; Piotrzkowski, K.; Pitzl, D.; Placakyte, R.; Plucinski, P.; Pokorny, B.; Pokrovskiy, N.S.; Polifka, R.; Polini, A.; Povh, B.; Proskuryakov, A.S.; Przybycien, M.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Raval, A.; Ravdandorj, T.; Reeder, D.D.; Reimer, P.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y.D.; Rizvi, E.; Robertson, A.; Robmann, P.; Roland, B.; Roloff, P.; Ron, E.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rubinsky, I.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Ruspa, M.; Sacchi, R.; Salek, D.; Salii, A.; Samson, U.; Sankey, D.P.C.; Sartorelli, G.; Sauter, M.; Sauvan, E.; Savin, A.A.; Saxon, D.H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W.B.; Schmitt, S.; Schneekloth, U.; Schoeffel, L.; Schonberg, V.; Schoning, A.; Schorner-Sadenius, T.; Schultz-Coulon, H.C.; Schwartz, J.; Sciulli, F.; Sefkow, F.; Shaw-West, R.N.; Shcheglova, L.M.; Shehzadi, R.; Shimizu, S.; Shtarkov, L.N.; Shushkevich, S.; Singh, I.; Skillicorn, I.O.; Sloan, T.; Slominski, W.; Smiljanic, I.; Smith, W.H.; Sola, V.; Solano, A.; Soloviev, Y.; Son, D.; Sopicki, P.; Sorokin, Iu.; Sosnovtsev, V.; South, D.; Spaskov, V.; Specka, A.; Spiridonov, A.; Stadie, H.; Stanco, L.; Staykova, Z.; Steder, M.; Stella, B.; Stern, A.; Stewart, T.P.; Stifutkin, A.; Stoicea, G.; Stopa, P.; Straumann, U.; Suchkov, S.; Sunar, D.; Susinno, G.; Suszycki, L.; Sykora, T.; Sztuk, J.; Szuba, D.; Szuba, J.; Tapper, A.D.; Tassi, E.; Tchoulakov, V.; Terron, J.; Theedt, T.; Thompson, G.; Thompson, P.D.; Tiecke, H.; Tokushuku, K.; Toll, T.; Tomasz, F.; Tomaszewska, J.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsurugai, T.; Turcato, M.; Turnau, J.; Tymieniecka, T.; Urban, K.; Uribe-Estrada, C.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vazquez, M.; Verbytskyi, A.; Viazlo, V.; Vinokurova, S.; Vlasov, N.N.; Volchinski, V.; Volynets, O.; von den Driesch, M.; Walczak, R.; Wan Abdullah, W.A.T.; Wegener, D.; Whitmore, J.J.; Whyte, J.; Wiggers, L.; Wing, M.; Wissing, Ch.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Wunsch, E.; Yagues-Molina, A.G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zacek, J.; Zalesak, J.; Zarnecki, A.F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhang, Z.; Zhautykov, B.O.; Zhokin, A.; Zhou, C.; Zichichi, A.; Zimmermann, T.; Zohrabyan, H.; Zolko, M.; Zomer, F.; Zotkin, D.S.; Zus, R.; 10.1007/JHEP03(2010)035

    2010-01-01

    A search for events containing an isolated electron or muon and missing transverse momentum produced in $e^{\\pm}p$ collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994--2007 and correspond to an integrated luminosity of 0.98 fb$^{-1}$. The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single $W$ production.In the $e^{+}p$ data, at large hadronic transverse momentum $P_{T}^{X}>25$ GeV, a total of 23 events are observed compared to a prediction of $14.0 \\pm 1.9$. % The total single $W$ boson production cross section is measured as $1.06 \\pm 0.16 ({\\rm stat.}) \\pm 0.07 ({\\rm sys.})$ pb, in agreement with an SM expectation of $1.26 \\pm 0.19$ pb.

  9. INMS measures an influx of molecules from Saturn's rings

    Science.gov (United States)

    Perry, M. E.

    2017-12-01

    In 1984, Connerney and Waite proposed water influx from Saturn's rings to explain the low electron densities measured during Pioneer and Voyager radio occultation experiments. Charge exchange with this minor species depleted the H+ ions and provided a faster path to electron recombination. With ice the primary constituent of the rings, water was the most likely in-falling molecule. During the Grand Finale orbits, Cassini's Ion and Neutral Mass Spectrometer (INMS) detected and quantified an influx from the rings. Unexpectedly, the primary influx molecules are CH4 and a heavier carbon-bearing species. Water was detected, but quantities were factors of ten lower than these other species. Distribution in both altitude and latitude are consistent with a ring influx. The concentration of the minor species in Saturn's atmosphere shows that they enter Saturn's atmosphere from the top. Both molecules have their highest concentrations at the highest altitudes, with concentrations >0.4% at 3,500 km altitude and only 0.02% at 2,700 km. Molecules from the rings deorbit to Saturn's atmosphere at altitudes near 4,000 km, consistent with the INMS measurements. The latitudinal dependence of the minor species indicates that their source is near the equatorial plane. At high altitudes, the minor species were observed primarily at zero latitude, where the 28u species was six times more concentrated than at 5° latitude. At lower altitudes, the peaking ratio was 1, indicating that the species had diffused and was fully mixed into Saturn's H2 atmosphere. The lighter molecule, CH4, diffuses more rapidly than the 28u species. INMS also detected both of these species during the earlier F-ring passes, finding that the neutrals were centered at the ring plane and extended 3,000 km (half width, half max) north and south.

  10. The fast trigger electronics of the lead/scintillating fiber calorimeter SpaCal of the H1 experiment at HERA: accomplishment, results of test beam measurements at CERN and first results at HERA

    International Nuclear Information System (INIS)

    Spielmann, Stephan

    1996-01-01

    The studies presented in this thesis cover parts of the project to improve the H1 detector at the electron-proton collider HERA. The main goal of this improvement was to build a lead/scintillating fiber calorimeter (SpaCal) and its associate trigger and read-out electronics. The description and the analysis of measurements with a calorimeter prototype and its electronics are presented with respect to the performance requirements for the project. This measurement realized at a CERN test beam facility have shown that an on-line selection of physics events out of background events can be achieved with a time-of-flight measurement. The efficiency of the trigger is higher than 99 percent independent of the particles' impact points. The feasibility of electron/pion separation on the one percent level is also shown. In 1995 the SpaCal calorimeter was integrated in the H1 detector. A detailed description of its associate electronics is given and the results on the trigger's performance for the first year of data taking are presented. (author) [fr

  11. Biomarkers and biometric measures of adherence to use of ARV-based vaginal rings.

    Science.gov (United States)

    Stalter, Randy M; Moench, Thomas R; MacQueen, Kathleen M; Tolley, Elizabeth E; Owen, Derek H

    2016-01-01

    Poor adherence to product use has been observed in recent trials of antiretroviral (ARV)-based oral and vaginal gel HIV prevention products, resulting in an inability to determine product efficacy. The delivery of microbicides through vaginal rings is widely perceived as a way to achieve better adherence but vaginal rings do not eliminate the adherence challenges exhibited in clinical trials. Improved objective measures of adherence are needed as new ARV-based vaginal ring products enter the clinical trial stage. To identify technologies that have potential future application for vaginal ring adherence measurement, a comprehensive literature search was conducted that covered a number of biomedical and public health databases, including PubMed, Embase, POPLINE and the Web of Science. Published patents and patent applications were also searched. Technical experts were also consulted to gather more information and help evaluate identified technologies. Approaches were evaluated as to feasibility of development and clinical trial implementation, cost and technical strength. Numerous approaches were identified through our landscape analysis and classified as either point measures or cumulative measures of vaginal ring adherence. Point measurements are those that give a measure of adherence at a particular point in time. Cumulative measures attempt to measure ring adherence over a period of time. Approaches that require modifications to an existing ring product are at a significant disadvantage, as this will likely introduce additional regulatory barriers to the development process and increase manufacturing costs. From the point of view of clinical trial implementation, desirable attributes would be high acceptance by trial participants, and little or no additional time or training requirements on the part of participants or clinic staff. We have identified four promising approaches as being high priority for further development based on the following measurements

  12. Measurement of K{sup *{+-}}(892) production in deep inelastic ep scattering with the H1 detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Sunar, Deniz

    2009-07-15

    A first measurement is presented of K{sup *}(892){sup {+-}} vector mesons, observed through the decay chain K{sup *}(892){sup {+-}} {yields} K{sup 0}{sub S}{pi}{sup {+-}} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup {+-}}; in neutral current deep-inelastic ep scattering. The data were taken at the HERA collider in the years 2005.2007 with centre of mass energy {radical}(s)=319 GeV using the H1 detector and correspond to an integrated luminosity of approximately 302 pb{sup -1}. The measurement of differential cross section was performed in the kinematic range which covers the photon virtuality 51 GeV and pseudorapidity -1.5<{eta}(K{sup *{+-}})<1.5. The results are compared to predictions of leading order Monte Carlo models matched with the parton showers. Persbericht (orig.)

  13. Measurement of Feynman-x spectra of photons and neutrons in the very forward direction in deep-inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Andreev, V.; Baghdasaryan, A.; Begzsuren, K.

    2014-03-01

    Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to the proton beam direction in deep-inelastic ep scattering at HERA are presented as a function of the Feynman variable x F and of the centre-of-mass energy of the virtual photon-proton system W. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 131 pb -1 . The measurement is restricted to photons and neutrons in the pseudorapidity range η > 7.9 and covers the range of negative four momentum transfer squared at the positron vertex 6 2 2 , of inelasticity 0.05 F dependent cross sections is investigated. Predictions of deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections.

  14. Photon structure as seen at HERA

    International Nuclear Information System (INIS)

    Butterworth, J.M.

    1995-03-01

    At HERA, the electron-proton collider at DESY, Hamburg, the large flux of almost on-shell photons accompanying the lepton beam is being used to shed new light on the structure of the photon. Recent results are reviewed and discussed, with emphasis on those aspects of the photon's nature which should be understandable using perturbative QCD. (orig.)

  15. Photon structure as seen at HERA

    International Nuclear Information System (INIS)

    Butterworth, J.M.

    1995-01-01

    At HERA, the lepton-proton collider at DESY, Hamburg, the large flux of almost on-shell photons accompanying the lepton beam is being used to shed new light on the structure of the photon. Recent results are reviewed and discussed, with emphasis on those aspects of the photon's nature which should be understandable using perturbative QCD. (author)

  16. Measurement of Charm and Beauty Dijet Cross Sections in Photoproduction at HERA using the H1 Vertex Detector

    CERN Document Server

    Aktas, A.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Flucke, G.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Marti, L.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A.J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Traynor, D.; Truol, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, Marcel; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-01-01

    A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. Events are selected with two or more jets of transverse momentum $p_t^{jet}_{1(2)}>11(8)$ GeV in the central range of pseudo-rapidity $-0.9<\\eta^{jet}_{1(2)}<1.3$. The fractions of events containing charm and beauty quarks are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 central vertex detector. Differential dijet cross sections for charm and beauty, and their relative contributions to the flavour inclusive dijet photoproduction cross section, are measured as a function of the transverse momentum of the leading jet, the average pseudo-rapidity of the two jets and the observable $x_{\\gamma}^{obs}$. Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, while the predicted cross sections for beauty production are somewhat lo...

  17. Photoproduction of Dijets with High Transverse Momenta at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A.J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sedlak, K.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Steder, M.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truol, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, Marcel; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-01-01

    Differential dijet cross sections are measured in photoproduction in the region of photon virtualities Q^2 < 1 GeV^2 with the H1 detector at the HERA ep collider using an integrated luminosity of 66.6 pb^{-1}. Jets are defined with the inclusive k_T algorithm and a minimum transverse momentum of the leading jet of 25 GeV is required. Dijet cross sections are measured in direct and resolved photon enhanced regions separately. Longitudinal proton momentum fractions up to 0.7 are reached. The data compare well with predictions from Monte Carlo event generators based on leading order QCD and parton showers and with next-to-leading order QCD calculations corrected for hadronisation effects.

  18. Photoproduction of dijets with high transverse momenta at HERA

    Science.gov (United States)

    H1 Collaboration; Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bähr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; de Roeck, A.; Desch, K.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kückens, J.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A. J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sedlák, K.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, M.; Usik, A.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-07-01

    Differential dijet cross sections are measured in photoproduction in the region of photon virtualities Q<1 GeV with the H1 detector at the HERA ep collider using an integrated luminosity of 66.6 pb-1. Jets are defined with the inclusive k algorithm and a minimum transverse momentum of the leading jet of 25 GeV is required. Dijet cross sections are measured in direct and resolved photon enhanced regions separately. Longitudinal proton momentum fractions up to 0.7 are reached. The data compare well with predictions from Monte Carlo event generators based on leading order QCD and parton showers and with next-to-leading order QCD calculations corrected for hadronisation effects.

  19. Some models of spin coherence and decoherence in storage rings

    International Nuclear Information System (INIS)

    Heinemann, K.

    1997-09-01

    I present some simple exactly solvable models of spin diffusion caused by synchrotron radiation noise in storage rings. I am able to use standard stochastic differential equation and Fokker-Planck methods and I thereby introduce, and exploit, the polarization density. This quantity obeys a linear evolution equation of the Bloch type, which is, like the Fokker-Planck equation, universal in the sense that it is independent of the state of the system. I also briefly consider Bloch equations for other local polarization quantities derived from the polarization density. One of the models chosen is of relevance for some existing and proposed low energy electron (positron) storage rings which need polarization. I present numerical results for a ring with parameters typical of HERA and show that, where applicable, the results of my approach are in satisfactory agreement with calculations using SLIM. These calculations provide a numerical check of a basic tenet of the conventional method of calculating depolarization using the n-vector-axis. I also investigate the equilibrium behaviour of the spin ensemble when there is no synchrotron radiation. Finally, I summarize other results which I have obtained using the polarization density and which will be published separately. (orig.)

  20. Production of excited charm and charm-strange mesons at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.; Musgrave, B.; Nicholass, D.; Repond, J.; Yoshida, R.; Mattingly, M.C.K.; Antonioli, P.; Bari, G.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cindolo, F.; Corradi, M.; Iacobucci, G.; Margotti, A.; Nania, R.; Polini, A.; Antonelli, S.; Basile, M.; Bindi, M.; Cifarelli, L.; Contin, A.; De Pasquale, S.; Sartorelli, G.; Zichichi, A.; Bartsch, D.; Brock, I.; Hartmann, H.; Hilger, E.; Jakob, H.P.; Juengst, M.; Nuncio-Quiroz, A.E.; Paul, E.; Samson, U.; Schoenberg, V.; Shehzadi, R.; Wlasenko, M.; Brook, N.H.; Heath, G.P.; Morris, J.D.; Capua, M.; Fazio, S.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Tassi, E.; Kim, J.Y.; Ibrahim, Z.A.; Kamaluddin, B.; Wan Abdullah, W.A.T.; Ning, Y.; Ren, Z.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Galas, A.; Gil, M.; Olkiewicz, K.; Stopa, P.; Zawiejski, L.; Adamczyk, L.; Bold, T.; Grabowska-Bold, I.; Kisielewska, D.; Lukasik, J.; Przybycien, M.; Suszycki, L.; Kotanski, A.; Slominski, W.; Behrens, U.; Blohm, C.; Bonato, A.; Borras, K.; Ciesielski, R.; Coppola, N.; Fang, S.; Fourletova, J.; Geiser, A.; Goettlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T.; Hain, W.; Huettmann, A.; Januschek, F.; Kahle, B.; Katkov, I.I.; Klein, U.; Koetz, U.; Kowalski, H.; Lobodzinska, E.; Loehr, B.; Mankel, R.; Melzer-Pellmann, I.A.; Miglioranzi, S.; Montanari, A.; Namsoo, T.; Notz, D.; Parenti, A.; Rinaldi, L.; Roloff, P.; Rubinsky, I.; Santamarta, R.; Schneekloth, U.; Spiridonov, A.; Szuba, D.; Szuba, J.; Theedt, T.; Wolf, G.; Wrona, K.; Yaguees Molina, A.G.; Youngman, C.; Zeuner, W.; Drugakov, V.; Lohmann, W.; Schlenstedt, S.; Barbagli, G.; Gallo, E.; Pelfer, P.G.; Bamberger, A.; Dobur, D.; Karstens, F.; Vlasov, N.N.; Bussey, P.J.; Doyle, A.T.; Dunne, W.; Forrest, M.; Rosin, M.; Saxon, D.H.; Skillicorn, I.O.; Gialas, I.; Papageorgiu, K.; Holm, U.; Klanner, R.; Lohrmann, E.; Schleper, P.; Schoerner-Sadenius, T.; Sztuk, J.; Stadie, H.; Turcato, M.; Foudas, C.; Fry, C.; Long, K.R.; Tapper, A.D.; Matsumoto, T.; Nagano, K.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Barakbaev, A.N.; Boos, E.G.; Pokrovskiy, N.S.; Zhautykov, B.O.; Aushev, V.; Bachynska, O.; Borodin, M.; Kadenko, I.; Kozulia, A.; Libov, V.; Lisovyi, M.; Lontkovskyi, D.; Makarenko, I.; Sorokin, I.; Verbytskyi, A.; Volynets, O.; Son, D.; Favereau, J. de; Piotrzkowski, K.; Barreiro, F.; Glasman, C.; Jimenez, M.; Labarga, L.; Peso, J. del; Ron, E.; Soares, M.; Terron, J.; Zambrana, M.; Corriveau, F.; Liu, C.; Schwartz, J.; Walsh, R.; Zhou, C.; Tsurugai, T.; Antonov, A.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S.; Dementiev, R.K.; Ermolov, P.F.; Gladilin, L.K.; Golubkov, Yu.A.; Khein, L.A.; Korzhavina, I.A.; Kuzmin, V.A.; Levchenko, B.B.; Lukina, O.Yu.; Proskuryakov, A.S.; Shcheglova, L.M.; Zotkin, D.S.; Abt, I.; Caldwell, A.; Kollar, D.; Reisert, B.; Schmidke, W.B.; Grigorescu, G.; Keramidas, A.; Koffeman, E.; Kooijman, P.; Pellegrino, A.; Tiecke, H.; Vazquez, M.; Wiggers, L.; Bruemmer, N.; Bylsma, B.; Durkin, L.S.; Lee, A.; Ling, T.Y.; Allfrey, P.D.; Bell, M.A.; Cooper-Sarkar, A.M.; Devenish, R.C.E.; Ferrando, J.; Foster, B.; Korcsak-Gorzo, K.; Oliver, K.; Robertson, A.; Uribe-Estrada, C.; Walczak, R.; Bertolin, A.; Dal Corso, F.; Dusini, S.; Longhin, A.; Stanco, L.; Bellan, P.; Brugnera, R.; Carlin, R.; Garfagnini, A.; Limentani, S.; Oh, B.Y.; Raval, A.; Ukleja, J.; Whitmore, J.J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cole, J.E.; Hart, J.C.

    2009-01-01

    The production of excited charm, D 1 (2420) 0 and D 2 * (2460) 0 , and charm-strange, D s 1(2536) ± , mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb -1 . Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D 2 * (2460) 0 and D s1 (2536) ± branching fractions. A search for the radially excited charm meson, D *' (2640) ± , was also performed. The results are compared with those measured previously and with theoretical expectations. (orig.)

  1. Production of excited charm and charm-strange mesons at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-07-01

    The production of excited charm, D 1 (2420) 0 and D * 2 (2460) 0 , and charm-strange, D s1 (2536) ± , mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb -1 . Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D * 2 (2460) 0 and D s1 (2536) ± branching fractions. A search for the radially excited charm meson, D *' (2640) ± , was also performed. The results are compared with those measured previously and with theoretical expectations. (orig.)

  2. Magnetic measurements on the ring dipoles and quadrupoles for the Los Alamos proton storage ring

    International Nuclear Information System (INIS)

    Schermer, R.I.; Blind, B.; Jason, A.J.; Sawyer, G.A.

    1985-01-01

    This paper discusses magnetic measurements and shimming performed on the ring dipoles and quadrupoles for the Los Alamos Proton Storage Ring (PSR). For the dipoles, point-by-point field maps were obtained using a search coil that could be scanned over a three-dimensional grid. By appropriate machining of removable end blocks, all magnet lengths were adjusted to within 0.01% of a nominal value and all integrated multipoles were set within tolerance. Integrated fields of 20 PSR quadrupoles were measured using a rotating ''Morgan Coil'' and a digital spectrum analyzer. The magnets were shimmed to specifications by adjusting steel bolts threaded through the field clamps. 3 refs., 5 figs., 4 tabs

  3. Scaled momentum distributions of charged particles in dijet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-04-15

    The scaled momentum distributions of charged particles in jets have been measured for dijet photoproduction with the ZEUS detector at HERA using an integrated luminosity of 359 pb{sup -1}. The distributions are compared to predictions based on perturbative QCD carried out in the framework of the modified leading-logarithmic approximation (MLLA) and assuming local parton-hadron duality (LPHD). The universal MLLA scale, {lambda}{sub eff}, and the LPHD parameter, {kappa}{sup ch}, are extracted. (orig.)

  4. Measurement of beauty photoproduction at threshold using di-electron events with the H1 detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Sauter, Michel David

    2009-12-15

    The cross section of b anti b photoproduction in ep collisions has been measured with the H1 detector at HERA. Events containing b-quarks were identified through detection of two low momentum electrons in the nal state. Semileptonic decays b anti b{yields}eeX were exploited in the kinematic range of the photon virtuality Q{sup 2}<1 GeV{sup 2}, the inelasticity 0.2measured differential b-quark production cross section as a function of the transverse b-quark momentum extends the previously experimentally accessible phase space towards the b-quark production threshold. The results are compared to other b-quark cross section measurements, as well as to leading-order and next-to-leading-order QCD predictions. The extension to lower b-quark momenta became possible with a dedicated low momentum electron trigger in the data period 2007, which combines track (Fast Track Trigger) and calorimeter information (Jet Trigger), and by mastering the experimental challenges of low p{sub T}-electron identification. (orig.)

  5. Cross section measurement of vector meson quasi-photoproduction at high four-momentum transfer using the ZEUS detector at the HERA collider

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, K.H.

    2001-11-01

    Photoproduction of vector mesons, {gamma}p {yields} VY, where Y is the system into which the proton dissociates, has been measured in e{sup +}p interactions with the ZEUS detector at HERA using an integrated luminosity of 24 pb{sup -1}. The data were taken at a photon-proton center-of-mass energy W {approx_equal} 100 GeV and extend up to -t = 10 GeV{sup 2}, where t is the square of the four-momentum transferred to the vector meson. The differential cross section d{sigma}/dt for {rho}{sup 0}, {phi} and J/{psi} production are compared to the expectations of phenomenological models. (orig.)

  6. What one can learn about QCD from nuclear beams at HERA?

    International Nuclear Information System (INIS)

    Strikman, M.

    1996-01-01

    Overview is given of the theoretical issues of the physics which can be addressed with nuclear beams circulating in HERA. It is shown that such experiments widen considerably the horizon for probing QCD compared to that from free nucleon targets. They would allow to study nonlinear QCD phenomena at small x, understand dynamics of nuclear shadowing, as well as the the origin of diffraction in deep inelastic scattering. Interplay between the physics to be studied at HERA and in AA collisions at RHIC and LHC is also discussed. (author)

  7. Measurement of beauty and charm photoproduction using semi-muonic decays in dijet events at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2012-04-15

    Measurements of cross sections for beauty and charm events with dijets and a muon in the photoproduction regime at HERA are presented. The data were collected with the H1 detector and correspond to an integrated luminosity of 179 pb{sup -1}. Events with dijets of transverse momentum P{sup jet1}{sub T}>7 GeV and P{sup jet2}{sub T}>6 GeV in the pseudorapidity range -1.5<{eta}{sup jet}<2.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q{sup 2}<2.5 GeV{sup 2} and inelasticity 0.22.5 GeV in the pseudorapidity range -1.3<{eta}{sup {mu}}<1.5. The fractions of beauty and charm events are determined using the impact parameters of the muon tracks with respect to the primary vertex and their transverse momentum relative to the axis of the associated jet. Both variables are reconstructed using the H1 vertex detector. The measurements are in agreement with QCD predictions at leading and next-to-leading order.

  8. Measurement of beauty and charm photoproduction using semi-muonic decays in dijet events at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Inst., Yerevan (Armenia); Barrelet, E. [CNRS/IN2P3, LPNHE, Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris 7, Paris (France); Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [CNRS/IN2P3, LAL, Univ. Paris-Sud, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [CNRS/IN2P3, LLR, Ecole Polytechnique, Palaiseau (France); Bozovic-Jelisavcic, I.; Pandurovic, M. [Univ. of Belgrade, Vinca Inst. of Nuclear Sciences, Belgrade (RS); Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D. [Univ. of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Bruncko, D.; Cerny, V.; Ferencei, J. [Slovak Academy of Sciences, Kosice (Slovakia)] [and others

    2012-06-15

    Measurements of cross sections for beauty and charm events with dijets and a muon in the photoproduction regime at HERA are presented. The data were collected with the H1 detector and correspond to an integrated luminosity of 179 pb{sup -1}. Events with dijets of transverse momentum P{sub T}{sup jet1}> 7 GeV and P{sub T}{sup jet2}> 6 GeV in the pseudorapidity range -1.5<{eta}{sup jet}<2.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q{sup 2}<2.5 GeV{sup 2} and inelasticity 0.2 2.5 GeV in the pseudorapidity range -1.3<{eta}{sup {mu}}<1.5. The fractions of beauty and charm events are determined using the impact parameters of the muon tracks with respect to the primary vertex and their transverse momentum relative to the axis of the associated jet. Both variables are reconstructed using the H1 vertex detector. The measurements are in agreement with QCD predictions at leading and next-to-leading order. (orig.)

  9. An Extended Octagonal Ring Dynamometer for Measurement of ...

    African Journals Online (AJOL)

    The analysis, design, construction, evaluation and use of an extended octagonal ring dynamometer for measurement of draught, vertical force and moment on a simple tillage tool are presented. The dynamometer was used to measure tool forces as functions of depth, rake angle and speed, for a wide plane blade.

  10. Beam Profile Measurement with Flying Wires at the Fermilab Recycler Ring

    CERN Document Server

    Hu, Martin; Krider, John; Lorman, Eugene; Marchionni, Alberto; Pishchalnikov, Yu M; Pordes, Stephen; Slimmer, David; Wilson, Peter R; Zagel, James

    2005-01-01

    The Fermilab Recycler Ring is a high vacuum fixed energy antiproton storage ring with stochastic and electron cooling systems. Flying wires were installed at the Fermilab Recycler Ring for transverse beam profile measurement. The following note describes the system configuration, calibration and resolution of the flying wire system, as well as analysis of the transverse beam profile in the presence of both cooling systems.

  11. Charged particle multiplicities in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Aid, S.; Anderson, M.; Andreev, V.

    1996-08-01

    Using the H1 detector at HERA, charged particle multiplicity distributions in deep inelastic e + p scattering have been measured over a large kinematical region. The evolution with W and Q 2 of the multiplicity distribution and of the multiplicity moments in pseudorapidity domains of varying size is studied in the current fragmentation region of the hadronic centre-of-mass frame. The results are compared with data from fixed target lepton-nucleon interactions, e + e - annihilations and hadron-hadron collisions as well as with expectations from QCD based parton models. Fits to the negative binomial and lognormal distributions are presented. (orig.)

  12. Forward jet production in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Aktas, A.; Andreev, V.; Anthonis, T.

    2005-08-01

    The production of forward jets has been measured in deep inelastic ep collisions at HERA. The results are presented in terms of single differential cross sections as a function of the Bjorken scaling variable (x Bj ) and as triple differential cross sections d 3 σ/dx Bj dQ 2 dp t,jet 2 , where Q 2 is the four momentum transfer squared and p t,jet 2 is the squared transverse momentum of the forward jet. Also cross sections for events with a di-jet system in addition to the forward jet are measured as a function of the rapidity separation between the forward jet and the two additional jets. The measurements are compared with next-to-leading order QCD calculations and with the predictions of various QCD-based models. (orig.)

  13. Forward Jet Production in Deep Inelastic Scattering at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxeld, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A.J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sedlak, K.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-01-01

    The production of forward jets has been measured in deep inelastic ep collisions at HERA. The results are presented in terms of single differential cross sections as a function of the Bjorken scaling variable (x_{Bj}) and as triple differential cross sections d^3 \\sigma / dx_{Bj} dQ^2 dp_{t,jet}^2, where Q^2 is the four momentum transfer squared and p_{t,jet}^2 is the squared transverse momentum of the forward jet. Also cross sections for events with a di-jet system in addition to the forward jet are measured as a function of the rapidity separation between the forward jet and the two additional jets. The measurements are compared with next-to-leading order QCD calculations and with the predictions of various QCD-based models.

  14. Phenomenology of leading nucleon production in e p collisions at HERA in the framework of fracture functions

    Science.gov (United States)

    Shoeibi, Samira; Taghavi-Shahri, F.; Khanpour, Hamzeh; Javidan, Kurosh

    2018-04-01

    In recent years, several experiments at the e-p collider HERA have collected high precision deep-inelastic scattering (DIS) data on the spectrum of leading nucleon carrying a large fraction of the proton's energy. In this paper, we have analyzed recent experimental data on the production of forward protons and neutrons in DIS at HERA in the framework of a perturbative QCD. We propose a technique based on the fractures functions framework, and extract the nucleon fracture functions (FFs) M2(n /p )(x ,Q2;xL) from global QCD analysis of DIS data measured by the ZEUS Collaboration at HERA. We have shown that an approach based on the fracture functions formalism allows us to phenomenologically parametrize the nucleon FFs. Considering both leading neutron as well as leading proton production data at HERA, we present the results for the separate parton distributions for all parton species, including valence quark densities, the antiquark densities, the strange sea distribution, and the gluon distribution functions. We proposed several parametrizations for the nucleon FFs and open the possibility of these asymmetries. The obtained optimum set of nucleon FFs is accompanied by Hessian uncertainty sets which allow one to propagate uncertainties to other observables interest. The extracted results for the t -integrated leading neutron F2LN (3 )(x ,Q2;xL) and leading proton F2LP (3 )(x ,Q2;xL) structure functions are in good agreement with all data analyzed, for a wide range of fractional momentum variable x as well as the longitudinal momentum fraction xL.

  15. Measurement of the energy dependence of the total photon-proton cross section at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). Raymond and Beverly Sackler Faculty of Exact Sciences; Univ. Coll. London (United Kingdom); Krakow Univ. of Technology (Poland). Faculty of Physics, Mathematics and Applied Computer Science; Abt, I. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2010-10-15

    The energy dependence of the photon-proton total cross section, {sigma}{sub tot}{sup {gamma}}{sup p}, was determined from e{sup +}p scattering data collected with the ZEUS detector at HERA at three values of the center-of-mass energy, W, of the {gamma}p system in the range 194

  16. The ZEUS uranium-scintillator calorimeter for HERA

    International Nuclear Information System (INIS)

    Hilger, E.

    1987-01-01

    The high resolution calorimeter for the ZEUS detector at HERA is presented. The choice of a sandwich calorimeter from depleted uranium plates and plastic scintillator was made to accomplish compensation and thus the best possible energy resolution for hadrons and jets. The calorimeter is segmented transversely into towers and longitudinally into an electromagnetic and one or two hadronic sections. It is divided in a forward, barrel and rear part which surround hermetically the interaction region and the inner detectors. The expected energy resolutions are for electrons σ(E)/E = 0.15/√E, and for hadrons σ(E)/E = 0.35/√E, with a constant term of maximum 2% added in quadrature. First results from calorimeter test measurements are presented. (orig.)

  17. Measurement of the proton structure from high-Q2 neutral current events in e+p deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Schnurbusch, H.

    2002-09-01

    Inclusive Neutral Current cross sections in e + p deep inelastic scattering yielding the generalised structure function F 2 have been measured in the regime of Q 2 > 185 GeV 2 . The data sample of 63.2 pb -1 was collected in the 1999/2000 data-taking period of the ZEUS experiment at the HERA collider. The centre-of-mass energy was √(s) = 318 GeV. Statistical and systematic uncertainties have been calculated throughout the kinematical range of the data. Systematic uncertainties were studied including photoproduction background, first-level trigger efficiency and the hadronic final state in the Forward Tracking Devices of the detector. The structure function F 2 was measured more precisely than in earlier measurements due to the larger data set and due to increased knowledge about systematic effects. The results are in good agreement with the Standard Model evaluated with the CTEQ5D parton distribution functions. (orig.)

  18. Photoproduction of isolated photons, inclusively and with a jet, at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2013-12-01

    The photoproduction of isolated photons, both inclusive and together with a jet, has been measured with the ZEUS detector at HERA using an integrated luminosity of 374 pb -1 . Differential cross sections are presented in the isolated-photon transverse-energy and pseudorapidity ranges 6 T γ γ T jet jet 2 2 . Differential cross sections are also presented for inclusive isolated photon production as functions of the transverse energy and pseudorapidity of the photon. Higher-order theoretical calculations are compared to the results.

  19. A stochastic model of depolarization enhancement due to large energy spread in electron storage rings

    International Nuclear Information System (INIS)

    Buon, J.

    1988-10-01

    A new semiclassical and stochastic model of spin diffusion is used to obtain numerical predictions for depolarization enhancement due to beam energy spread. It confirms the results of previous models for the synchrotron sidebands of isolated spin resonances. A satisfactory agreement is obtained with the width of a synchrotron satellite observed at SPEAR. For HERA and LEP, at Z 0 energy, the depolarization enhancement is of the order of a few units and increases very rapidly with the energy spread. Large reduction of polarization degree is expected in these rings

  20. Analytic calculation of depolarization due to large energy spread in high-energy electron storage rings

    International Nuclear Information System (INIS)

    Buon, J.

    1989-08-01

    A new semiclassical and stochastic model of spin diffusion is used to obtain numerical predictions for depolarization enhancement due to beam energy spread. It confirms the results of previous models for the synchrotron sidebands of spin resonances. A satisfactory agreement is obtained with the width of a synchrotron satellite observed at SPEAR. For HERA, TRISTAN, and LEP at Z 0 energy, the depolarization enhancement is of the order of a few units and increases very rapidly with the energy spread. Large reduction of polarization degree is expected in these rings

  1. Diffractive photoproduction of dijets in ep collisions at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-09-01

    Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb -1 . The measurements were made in the kinematic range Q 2 2 , 0.20 P 2 is the photon virtuality, y is the inelasticity and x P is the fraction of the proton momentum taken by the diffractive exchange. The two jets with the highest transverse energy, E jet T , were required to satisfy E jet T >7.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5 jet <1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton. (orig.)

  2. Precision measurement of the cross section of charged-current and neutral current processes at large Q{sup 2} at HERA with the polarized-electron beam; Mesures de precision de la section efficace des processus courant charge et courant neutre a grand Q{sup 2} a HERA avec le faisceau d'electrons polarises

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Trong Hieu

    2011-04-15

    The inclusive cross sections for both charged and neutral current processes have been measured in interactions of longitudinally polarized electrons (positrons) with unpolarized protons using the full data samples collected by H1 at HERA-II. The data taken at a center-of-mass energy of 319 GeV correspond to an integrated luminosity of 149.1 pb{sup -1} and 180.0 pb{sup -1} for e{sup -}p and e{sup +}p collisions, representing an increase in statistics of a factor of 10 and 2, respectively, over the data from HERA-I. The measured double differential cross sections d{sup 2}{sigma}/dxdQ{sup 2} cover more than two orders of magnitude in both Q{sup 2}, the negative four-momentum transfer squared, up to 30000 GeV{sup 2}, and Bjorken x, down to 0.003. The cross section data are compared to predictions of the Standard Model which is able to provide a good description of the data. The polarization asymmetry as a function of Q{sup 2} is measured with improved precision, confirming the previous observation of P violation effect in neutral current ep scattering at distances down to 10{sup -18} m. The total cross sections of the charged current process, for Q{sup 2} > 400 GeV{sup 2} and inelasticity y < 0.9 are measured for 4 independent data samples with e{sup {+-}} beams and different polarization values. Together with the corresponding cross section obtained from the previously published unpolarized data, the polarization dependence of the charged current cross section is measured and found to be in agreement with the Standard Model prediction with the absence of right-handed charged current. The cross sections are combined with previously published data from H1 to obtain the most precise unpolarized measurements. These are used to extract the structure function xF{sub 3}{sup {gamma}}{sup Z} which is sensitive to the valence quark distributions down to low x values. The new cross sections have also been used in a combined electroweak and QCD fit to significantly improve the

  3. Production of excited charm and charm-strange mesons at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2008-07-15

    The production of excited charm, D{sub 1}(2420){sup 0} and D{sup *}{sub 2}(2460){sup 0}, and charm-strange, D{sub s1}(2536){sup {+-}}, mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb{sup -1}. Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D{sup *}{sub 2}(2460){sup 0} and D{sub s1}(2536){sup {+-}} branching fractions. A search for the radially excited charm meson, D{sup *'}(2640){sup {+-}}, was also performed. The results are compared with those measured previously and with theoretical expectations. (orig.)

  4. Measurement of the neutral current reaction at high Q{sup 2} in the H1 experiment at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Shushkevich, Stanislav

    2012-12-15

    This thesis presents inclusive e{sup {+-}}p double and single differential cross section measurements for neutral current deep inelastic scattering of longitudinally polarized leptons on protons as a function of the negative four-momentum transfer squared Q{sup 2} and the Bjorken variable x. The data were collected in the years 2003-2007 in the H1 experiment at HERA with positively and negatively longitudinally polarized lepton beams of 27 GeV and a proton beam of 920 GeV corresponding to the centre-of-mass energy of {radical}(s)=319 GeV. The integrated luminosity is about 330 pb{sup -1}. An overview of the phenomenology of the deep inelastic scattering is given and the experimental apparatus is described. The NC cross section measurement procedure is presented and discussed in details. The measured cross sections are used to investigate electroweak effects at high Q{sup 2}. The proton structure function xF{sub 3}, sensitive to the valence quarks in the proton, is measured. The polarization effects sensitive to the chiral structure of neutral currents are investigated. The Standard Model predictions are found to be in a good agreement with the measurement.

  5. Measurement of high-Q{sup 2} charged current cross sections in e{sup +}p deep inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Rautenberg, J

    2004-06-01

    Cross sections for charged current deep inelastic scattering have been measured in e{sup +}p collisions at a center-of-mass energy of 318 GeV. The data collected with the ZEUS detector at HERA in the running periods 1999 and 2000 correspond to an integrated luminosity of 61 pb{sup -1}. Single differential cross sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy have been measured for Q{sup 2}>200 GeV{sup 2}, as well as the double differential reduced cross section d{sup 2}{sigma}/dxdQ{sup 2} in the kinematic range 280 GeV{sup 2}measurements of e{sup -}p charged current deep inelastic scattering cross sections. The helicity structure is investigated in particular. The mass of the space-like W boson propagator has been determined from a fit to d{sigma}/dQ{sup 2}. (orig.)

  6. Measurement of D^{*\\pm} Meson Production and Determination of F_2^{ccbar} at low Q2 in Deep-Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boenig, M.O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, A.W.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Kogler, R.; Kostka, P.; Kraemer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lopez-Fernandez, R.; Lubimov, V.; Makankine, A.; Malinovski, E.; Marage, P.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mudrinic, M.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Tabasco, J.E.Ruiz; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, I.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Toll, T.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2011-01-01

    Inclusive production of D* mesons in deep-inelastic ep scattering at HERA is studied in the range 5 1.25 GeV and |eta(D*)| < 1.8. The data sample corresponds to an integrated luminosity of 348 pb^{-1} collected with the H1 detector. Single and double differential cross sections are measured and the charm contribution F_2^{ccbar} to the proton structure function F_2 is determined. The results are compared to perturbative QCD predictions at next-to-leading order implementing different schemes for the charm mass treatment and with Monte Carlo models based on leading order matrix elements with parton showers.

  7. Dijet angular distributions in direct and resolved photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1996-05-01

    Jet photoproduction, where the two highest transverse energy (E T jet ) jets have E T jet above 6 GeV and a jet-jet invariant mass above 23 GeV, has been studied with the ZEUS detector at the HERA ep collider. Resolved and direct photoproduction samples have been separated. The cross section as a function of the angle between the jet-jet axis and the beam direction in the dijet rest frame has been measured for the two samples. The measured angular distributions differ markedly from each other. They agree with the predictions of QCD calculations, where the different angular distributions reflect the different spins of the quark and gluon exchanged in the hard subprocess. (orig.)

  8. Measurement of jet production in deep-inelastic ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Kogler, Roman

    2011-02-15

    In this thesis, precision measurements of inclusive jet, dijet and trijet cross sections in neutral current (NC) deep-inelastic ep scattering at a centre-of-mass energy of {radical}(s){approx_equal}319 GeV are presented. The analysis is based on data collected by the H1 detector during the HERA-2 running phase in the years 2003-07, corresponding to an integrated luminosity of 351.5 pb{sup -1}. The kinematic phase space of the measurement is defined by 150measured in the pseudorapidity range -1.0<{eta}{sub lab}<2.5 in the laboratory rest frame. The jet transverse momentum in the Breit frame of reference is required to be P{sub T}>7 GeV for the inclusive jet measurement and P{sub T}>7 GeV for the dijet and trijet measurements. In the case of the dijet and trijet measurements, the invariant mass of the two jets with the highest transverse momenta is required to be greater than 16 GeV. A large part of this work is devoted to the improvement of the reconstruction of the hadronic final state. This is achieved by a separation of showers originating from electromagnetically and hadronically interacting particles in the liquid argon calorimeter of the H1 detector on a statistical basis. A novel method to calibrate the hadronic final state, which is reconstructed with an energy-flow-algorithm, is developed. This calibration is based on the probability of a shower resulting from electromagnetically interacting particles and it is shown to improve the absolute energy scale uncertainty at high jet transverse momenta to 1%. Improvements of the resolution of the jet energy measurement with respect to the standard reconstruction of about 10% are reported. The new calibration in combination with improvements of the reconstruction algorithms by the H1 collaboration leads to a precision measurement of inclusive jet, dijet and

  9. Photoproduction of isolated photons, inclusively and with a jet, at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Barakbaev, A.N.; Bartosik, N.; Behnke, O.; Behr, J.; Behrens, U.; Bertolin, A.; Bhadra, S.; Bloch, I.; Bokhonov, V.; Boos, E.G.

    2014-01-01

    The photoproduction of isolated photons, both inclusive and together with a jet, has been measured with the ZEUS detector at HERA using an integrated luminosity of 374 pb −1 . Differential cross sections are presented in the isolated-photon transverse-energy and pseudorapidity ranges 6 T γ γ T jet jet 2 2 . Differential cross sections are also presented for inclusive isolated-photon production as functions of the transverse energy and pseudorapidity of the photon. Higher-order theoretical calculations are compared to the results

  10. Multiple parton interactions in photoproduction at HERA/H1

    Energy Technology Data Exchange (ETDEWEB)

    Magro, Lluis Marti

    2009-02-15

    Photoproduction data of HERA-I are analysed by requiring dijets with transverse momenta of at least 5 GeV. The two jets define in azimuth a towards region (leading jet), an away region (usually the 2nd jet) and transverse regions between them. The charged particle and jet with low transverse momentum multiplicity, so called minijets, are measured in these regions as a function of the variables x{sup obs}{sub {gamma}} and P{sup Jet{sub 1T}} (leading jet). The measurement is compared to predictions including parton showers and matrix elements at leading order in {alpha}{sub s}. Some predictions include contributions from multiple parton interactions and use different parton evolution equations. It was found that existing MC programs do not fully describe the measurements but the description can be improved by including multiple parton interactions. (orig.)

  11. Elastic J/Psi Production at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Flucke, G.; Fomenko, A.; Foresti, I.; Franke, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Portheault, B.; Povh, B.; Prideaux, P.; Rahmat, A.J.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Schilling, F.-P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sedlak, K.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wigmore, C.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-01-01

    Cross sections for elastic production of J/Psi mesons in photoproduction and electroproduction are measured in electron proton collisions at HERA using an integrated luminosity of 55 pb^{-1}. Results are presented for photon virtualities Q^2 up to 80 GeV^2. The dependence on the photon-proton centre of mass energy W_{gamma p} is analysed in the range 40 < \\Wgp < 305 GeV in photoproduction and 40 < \\Wgp < 160 GeV in electroproduction. The \\Wgp dependences of the cross sections do not change significantly with Q^2 and can be described by models based on perturbative QCD. Within such models, the data show a high sensitivity to the gluon density of the proton in the domain of low Bjorken x and low Q^2. Differential cross sections d\\sigma/dt, where t is the squared four-momentum transfer at the proton vertex, are measured in the range |t|<1.2 GeV^2 as functions of \\Wgp and Q^2. Effective Pomeron trajectories are determined for photoproduction and electroproduction. The J/Psi production and decay ang...

  12. Spin-orbit maps and electron spin dynamics for the luminosity upgrade project at HERA

    International Nuclear Information System (INIS)

    Berglund, G.Z.M.

    2001-09-01

    HERA is the high energy electron(positron)-proton collider at deutsches elektronen-synchrotron (DESY) in Hamburg. Following eight years of successful running, five of which were with a longitudinally spin polarized electron(positron) beam for the HERMES experiment, the rings have now been modified to increase the luminosity by a factor of about five and spin rotators have been installed for the H1 and ZEUS experiments. The modifications involve nonstandard configurations of overlapping magnetic fields and other aspects which have profound implications for the polarization. This thesis addresses the problem of calculating the polarization in the upgraded machine and the measures needed to maintain the polarization. A central topic is the construction of realistic spin-orbit transport maps for the regions of overlapping fields and their implementation in existing software. This is the first time that calculations with such fields have been possible. Using the upgraded software, calculations are presented for the polarization that can be expected in the upgraded machine and an analysis is made of the contributions to depolarization from the various parts of the machine. It is concluded that about 50% polarization should be possible. The key issues for tuning the machine are discussed. The last chapter deals with a separate topic, namely how to exploit a simple unitary model of spin motion to describe electron depolarization and thereby expose a misconception appearing in the literature. (orig.)

  13. Measurement of the {upsilon} meson productin cross section in ep scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Rubinskiy, Igor

    2009-04-15

    This thesis presents a measurement of {upsilon} meson production in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 468 pb{sup -1}. The {upsilon} mesons were identified using the decay channel {upsilon}{yields}{mu}{sup +}{mu}{sup -}. The measurements were performed for exclusive diffractive production in the kinematic range Q{sup 2}<1 GeV{sup 2}, 60measured cross sections are compared to and agree well with theoretical predictions within the perturbative QCD framework such as Martin-Ryskin-Teubner two gluon exchange and NRQCD. As the technical part of this thesis, work related to the commissioning of the Straw Tube Tracker (STT) and to the Zeus Event Visualisation (ZEVIS) software package are presented. STT developments include: the STT DSP (Digital Signal Processor) quality monitor was developed, the pattern recognition algorithm was optimised for speed, and used in the Third Level Trigger (TLT) in order to reduce the accepted event rate by rejecting non-physics background. The TLT Charge Current(CC) slot rate was reduced by an order of magnitude, offering a rate reduction for the total accepted TLT rate by {approx}2%. ZEVIS developments include: the STT hit visualisation scheme in 2D, 3D and tan({theta})-{phi} view, and a user-friendly interface called ''EasyTool'' for global ZEUS track and hit visualisation for all ZEUS components. (orig.)

  14. Multi-lepton production at high transverse momentum at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-06-15

    A search for events containing two or more high-transverse-momentum isolated leptons has been performed in ep collisions with the ZEUS detector at HERA using the full collected data sample, corresponding to an integrated luminosity of 480 pb{sup -1}. The number of observed events has been compared with the prediction from the Standard Model, searching for possible deviations, especially for multi- lepton events with invariant mass larger than 100 GeV. Good agreement with the Standard Model has been observed. Total and differential cross sections for di-lepton production have been measured in a restricted phase space dominated by photon-photon collisions. (orig.)

  15. Multi-lepton production at high transverse momentum at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-06-01

    A search for events containing two or more high-transverse-momentum isolated leptons has been performed in ep collisions with the ZEUS detector at HERA using the full collected data sample, corresponding to an integrated luminosity of 480 pb -1 . The number of observed events has been compared with the prediction from the Standard Model, searching for possible deviations, especially for multi- lepton events with invariant mass larger than 100 GeV. Good agreement with the Standard Model has been observed. Total and differential cross sections for di-lepton production have been measured in a restricted phase space dominated by photon-photon collisions. (orig.)

  16. DESY: HERA superconducting magnets OK; Theory workshop

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The HERA electron-proton collider being built at the DESY Laboratory in Hamburg is the first accelerator using superconducting magnets manufactured by industry on a large scale. For this pioneering step several potential problems now seem to be all well under control, with important contributions coming from both the manufacturers and DESY's accelerator specialists

  17. The color class condensate RHIC and HERA

    CERN Document Server

    McLerran, L

    2002-01-01

    In this talk, I discuss a universal form of matter, the color glass condensate. It is this matter which composes the low x part of all hadronic wavefunctions. The experimental programs at RHIC and HERA, and future programs at LHC and RHIC may allow us to probe and study the properties of this matter. (8 refs).

  18. The Use of the Time Average Visibility for Analyzing HERA-19 Commissioning Data: Effects of Non-Redundancy

    Science.gov (United States)

    Benefo, Roshan; Gallardo, Samavarti; Aguirre, James; La Plante, Paul; HERA Collaboration

    2018-01-01

    The Hydrogen Epoch of Reionization Array (HERA) is a radio telescope situated in South Africa designed to observe the universe from redshifts 13 through 6, in order to detect the emission of the 21 cm line from the hydrogen spin-flip transition. We perform 21 cm cosmology due to its relation with reionization; by detecting this emission line, we can identify the timing of reionization, and understand more about the nature of the universe during the birth of the first stars and galaxies. With that, we can understand the heating conditions of the initial universe, providing us a larger picture of the conditions that created the large-scale structure of the universe we observe today. The HERA array currently consists of 19 antennas, spaced in a hexagonal grid pattern. We consider a robust observable, the time-averaged visibility (TAV), which is in principle sensitive to variations in the beam pattern between antenna elements and is easier to measure than the beam pattern itself. We use this TAV to explore the non-redundancy of baselines in the HERA array due either to cross-coupling between antennas (probed by antenna location in the array) or non-uniformity in their manufacture. The TAV may provide a simple way of verifying improvements in antenna element redundancy.

  19. The status of polarization studies at HERA

    International Nuclear Information System (INIS)

    Boege, M.

    1993-01-01

    In August 1992 a vertical electron beam polarization of nearly 60% at 26.7 GeV (spin tune=60.5) was obtained at HERA. This was achieved by optimizing the energy and orbit tunes and by applying harmonic corrections to the closed orbit. The polarization level was reproducible from fill to fill and the calibration of the Compton polarimeter was confirmed by measuring the polarization build up curve. The polarization measurements were made with currents of one to two milliamps. Much higher currents are expected for the 1993 luminosity run (∼ 30 mA were obtained in May 1993). The high polarization level was reproduced at high current. Further polarization studies in parallel with e-p operation are planned. In 1993/94 a pair of spin rotators will be installed in the East straight section so that longitudinal polarization is available at the East interaction point. Simulations with the spin tracking program SITROS are in qualitative agreement with the measurements. Calculations with SITROS show that longitudinal polarizations of up to 50% could then still be achieved

  20. Some topics in ep scattering at HERA. Pt. 2

    International Nuclear Information System (INIS)

    Abramowicz, H.; Krawczyk, M.; Maor, U.

    1991-06-01

    The theoretical and experimental situation related to the photon structure function is reviewed. The existing parton distributions of the resolved photon are disucssed in view of their need for the study of various processes at HERA. (orig.)

  1. Charm Production and QCD Analysis at HERA and LHC

    CERN Document Server

    Zenaiev, Oleksandr; Foster, Brian; McNulty, Ronan

    2015-01-01

    In this thesis the study of charm production in ep and pp collisions is presented. The heavy- quark masses provide a hard scale, allowing the application of perturbative QCD. A measurement of D + -meson production in deep inelastic scattering with the ZEUS detector at HERA is presented. The analysis was performed using a data sample with an integrated luminosity of 354 pb-1. Di erential cross sections were measured as a function of virtuality Q 2 , inelasticity y , transverse momentum and pseudorapidity of the D + mesons. Lifetime infor- mation was used to reduce the combinatorial background significantly. Next-to-leading-order QCD predictions in the fixed-flavour-number scheme were compared to the data. This measurement was combined with other H1 and ZEUS measurements of charm produc- tion. The combination was performed at inclusive level for the reduced charm cross sections, which were obtained from the measured visible cross sections, extrapolated to the full phase space using the shape of the theoretical ...

  2. Measurement of the D± meson cross section in DIS with the H1 detector at HERA

    International Nuclear Information System (INIS)

    Pahl, Philipp

    2014-04-01

    The inclusive production of D ± mesons in deep inelastic scattering at √(s)=318 GeV at HERA is studied using data taken with the Hl detector during the high energy measurement period in the years 2006 and 2007 corresponding to an integrated luminosity of 202.6 pb -1 . The visible phase space is defined by 5 2 2 , 0.05 T (D ± ) and -1.5 ± ) 2 is the photon virtuality, y is the inelasticity and p T (D ± ) and η(D ± ) are the transverse momentum and rapidity of the D ± meson. Charm production events are identified by the reconstruction of the D ± →K -+ π ± π ± decay channel. The sample is enhanced by the application of a multi-variate analysis technique using a multilayer perceptron. The input variables of the classifier are based on the specific energy loss of the kaon decay particle candidate and the reconstructed decay length of the D ± meson. The single and double differential cross sections are compared to leading and next-to-leading order QCD predictions.

  3. Measurement of high-Q{sup 2} charged current deep inelastic scattering cross sections with a longitudinally polarised positron beam at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). Faculty of Exact Sciences, School of Physics; Max-Planck-Inst., Munich (Germany); Abt, I. [Max-Planck-Inst. fuer Physik, Muenchen (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2010-08-15

    Measurements of the cross sections for charged current deep inelastic scattering in e{sup +}p collisions with a longitudinally polarised positron beam are presented. The measurements are based on a data sample with an integrated luminosity of 132 pb{sup -1} collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is presented at positive and negative values of the longitudinal polarisation of the positron beams. The single-differential cross sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy are presented for Q{sup 2}>200 GeV{sup 2}. The reduced cross-section {sigma} is presented in the kinematic range 200measurements agree well with the predictions of the Standard Model. The results are used to determine a lower limit on the mass of a hypothetical right-handed W boson. (orig.)

  4. Measurement of photon production in the very forward direction in deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2011-06-15

    The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 126 pb{sup -1}. The analysis covers the range of negative four momentum transfer squared at the positron vertex 6measured for the most energetic photon with pseudorapidity {eta}>7.9 as a function of its transverse momentum p{sub T}{sup lead} and longitudinal momentum fraction of the incoming proton x{sub L}{sup lead}. In addition, the cross sections are studied as a function of the sum of the longitudinal momentum fraction x{sub L}{sup sum} of all photons in the pseudorapidity range {eta}>7.9. The cross sections are normalised to the inclusive deep-inelastic scattering cross section and compared to the predictions of models of deep-inelastic scattering and models of the hadronic interactions of high energy cosmic rays. (orig.)

  5. Measurement of photon production in the very forward direction in deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Podgorica (ME); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Inst. (Armenia); Barrelet, E. [Univ. Pierre et Marie Curie Paris 6, LPNHE, Paris (France); Univ. Denis Diderot Paris 7, CNRS/IN2P3, Paris (France); Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Grell, B.R.; Habib, S.; Haidt, D.; Helebrant, C.; Kleinwort, C.; Kogler, R.; Kraemer, M.; Levonian, S.; Lipka, K.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Piec, S.; Pitzl, D.; Schmitt, S.; Sefkow, F.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [Univ. Paris-Sud, CNRS/IN2P3, LAL, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [Ecole Polytechnique, CNRS/IN2P3, LLR, Palaiseau (France); Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I. [Univ. of Belgrade, Vinca Institute of Nuclear Sciences, Belgrade (RS); Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D. [Univ. of Birmingham (United Kingdom); Bruncko, D.; Cerny, V.; Ferencei, J. [Slovak Academy of Sciences, Inst. of Experimental Physics, Kosice (Slovakia)] [and others

    2011-10-15

    The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 126 pb{sup -1}. The analysis covers the range of negative four momentum transfer squared at the positron vertex 6measured for the most energetic photon with pseudorapidity {eta}>7.9 as a function of its transverse momentum p{sub T}{sup lead} and longitudinal momentum fraction of the incoming proton x{sub L}{sup lead}. In addition, the cross sections are studied as a function of the sum of the longitudinal momentum fraction x{sub L}{sup sum} of all photons in the pseudorapidity range {eta}>7.9. The cross sections are normalised to the inclusive deep-inelastic scattering cross section and compared to the predictions of models of deep-inelastic scattering and models of the hadronic interactions of high energy cosmic rays. (orig.)

  6. Dijet production in diffractive deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-08-01

    The production of dijets in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 61 pb -1 . The dijet cross section has been measured for virtualities of the exchanged virtual photon, 5 2 2 , and γ * p centre-of-mass energies, 100 T algorithm in the γ * p frame, were required to have a transverse energy E * T,jet >4 GeV and the jet with the highest transverse energy was required to have E * T,jet >5 GeV. All jets were required to be in the pseudorapidity range -3.5 * jet <0. The differential cross sections are compared to leading-order predictions and next-to-leading- order QCD calculations based on recent diffractive parton densities extracted from inclusive diffractive deep inelastic scattering data. (orig.)

  7. Study of {chi}{sub c} production using HERA-B data

    Energy Technology Data Exchange (ETDEWEB)

    Aleksandrov, Aleksandar

    2010-07-15

    In this thesis the production of the charmonium states {chi}{sub c1} and {chi}{sub c2} in protonnucleus collisions at a proton-nucleon center-of-mass energy {radical}(s)=41.6 GeV was studied. The data used for the analysis have been taken by the fixed-target experiment HERA-B that uses the HERA proton beam to scatter protons off the nuclei of different wire targets. About 122.10{sup 3} recorded muonic J/{psi} decays, J/{psi}{yields}{mu}{sup +}{mu}{sup -}, resulted in almost 10000 reconstructed {chi}{sub c}{yields}J/{psi}{gamma}. The ratio R{sub {chi}{sub c}}= sum {sub i=1,2}{sigma}({chi}{sub ci})Br({chi}{sub ci}{yields}J/{psi}{gamma})/{sigma}(J/{psi}), which is the ratio of J/{psi} from {chi}{sub c} decays to all produced J/{psi}, was measured in the kinematical range -0.35measured yielding R{sub 12}=1.30{sub -0.37}{sup +0.59} which corresponds to a production cross section ratio ({sigma}({chi}{sub c1}))/({sigma}({chi}{sub c2}))=0.74{sub -0.22}{sup +0.34}. By using the known J/{psi} production cross section, the {chi}{sub c1} and {chi}{sub c2} production cross sections are calculated to be {sigma}({chi}{sub c1})=(153{+-}27) nb/nucleon and {sigma}({chi}{sub c2})=(207{+-}39) nb/nucleon, respectively. All results were obtained under the assumption that both the J/{psi} and {chi}{sub c} states are produced without polarization. In addition a study of possible deviations of R{sub {chi}{sub c}} and R{sub 12} due to the polarization of J/{psi} and {chi}{sub c} was performed. By varying the polarization parameter, {lambda}{sub obs}, of all produced J/{psi} by 2{sigma} around the value measured by HERA-B, and assuming fully

  8. Studies of diffractive scattering of photons at large momentum transfer and of the VFPS detector at HERA

    International Nuclear Information System (INIS)

    Hreus, Tomas

    2008-09-01

    In this thesis, two studies of the diffractive phenomena in the electron proton collisions with the H1 detector at HERA are presented. The rst is the study of the inclusive elastic diffractive events ep → eXp in the regime of high photon virtuality (Q 2 >few GeV 2 ), with the scattered proton detected by the Very Forward Proton Spectrometer (VFPS). The VFPS detector, designed to measure diffractive scattered protons with high acceptance, has been installed in 2004 to benefit from the HERA II luminosity increase. The selected event sample of an integrated luminosity of 130.2 pb -1 was collected in years 2006-2007. Data sample distributions are compared to the prediction based on the diffractive parton distribution functions, as extracted from the H1 measurement of the diffractive structure function F D(3) 2 at HERA I. After the study of the VFPS efficiency, the VFPS acceptance as a function of x P is estimated and studied in relation to the forward proton beam optics. The second study leads to the cross section measurement of the diffractive scattering of quasi-real photons off protons, γp → γY, with the large momentum transfer, vertical stroke t vertical stroke. The final state photon is separated from the proton dissociation system, Y, by a large rapidity gap and has a large transverse momentum, p T > 2 GeV. Large p T imply the presence of the hard scale t (vertical stroke t vertical stroke ≅ p 2 T ) and allows predictions of the perturbative QCD to be applied. The measurement is based on an integrated luminosity 46.2 pb -1 of data collected in the 1999-2000 running period. Cross sections σ(W) as a function of the incident photon-proton centre of mass energy, W, and dσ/d vertical stroke t vertical stroke are measured in the range Q 2 2 , 175 2 and y P <0.05. The cross section measurements have been compared to predictions of LLA BFKL calculations. (orig.)

  9. Measurement of D* meson cross sections at HERA and determination of the gluon density in the proton using NLO QCD

    International Nuclear Information System (INIS)

    Adloff, C.; Anderson, M.; Andreev, V.; Andrieu, B.; Arkadov, V.; Arndt, C.; Ayyaz, I.; Babaev, A.; Baehr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Bate, P.; Beck, M.; Beglarian, A.; Behnke, O.; Behrend, H.-J.; Beier, C.; Belousov, A.; Berger, Ch.; Bernardi, G.; Bertrand-Coremans, G.; Biddulph, P.; Bizot, J.C.; Boudry, V.; Braunschweig, W.; Brisson, V.; Brown, D.P.; Brueckner, W.; Bruel, P.; Bruncko, D.; Buerger, J.; Buesser, F.W.; Buniatian, A.; Burke, S.; Burrage, A.; Buschhorn, G.; Calvet, D.; Campbell, A.J.; Carli, T.; Chabert, E.; Charlet, M.; Clarke, D.; Clerbaux, B.; Contreras, J.G.; Cormack, C.; Coughlan, J.A.; Cousinou, M.-C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; David, M.; Davidsson, M.; De Roeck, A.; De Wolf, E.A.; Delcourt, B.; Demirchyan, R.; Diaconu, C.; Dirkmann, M.; Dixon, P.; Dlugosz, W.; Donovan, K.T.; Dowell, J.D.; Droutskoi, A.; Ebert, J.; Eckerlin, G.; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Elsen, E.; Enzenberger, M.; Erdmann, M.; Fahr, A.B.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrarotto, F.; Fleischer, M.; Fluegge, G.; Fomenko, A.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Gaede, F.; Garvey, J.; Gassner, J.; Gayler, J.; Gerhards, R.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Gorelov, I.; Grab, C.; Graessler, H.; Greenshaw, T.; Griffiths, R.K.; Grindhammer, G.; Hadig, T.; Haidt, D.; Hajduk, L.; Haller, T.; Hampel, M.; Haustein, V.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herynek, I.; Hewitt, K.; Hiller, K.H.; Hilton, C.D.; Hladky, J.; Hoffmann, D.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C.; Jacquet, M.; Jaffre, M.; Jansen, D.M.; Joensson, L.; Johnson, D.P.; Jones, M.; Jung, H.; Kaestli, H.K.; Kander, M.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnik, O.; Katzy, J.; Kaufmann, O.; Kausch, M.; Kenyon, I.R.; Kermiche, S.; Keuker, C.; Kiesling, C.; Klein, M.; Kleinwort, C.; Knies, G.; Koehne, J.H.; Kolanoski, H.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Kraemerkaemper, T.; Krasny, M.W.; Krehbiel, H.; Kruecker, D.; Krueger, K.; Kuepper, A.; Kuester, H.; Kuhlen, M.; Kurca, T.; Lahmann, R.; Landon, M.P.J.; Lange, W.; Langenegger, U.; Lebedev, A.; Lehner, F.; Lemaitre, V.; Lendermann, V.; Levonian, S.; Lindstroem, M.; List, B.; Lobo, G.; Lobodzinska, E.; Lubimov, V.; Lueders, S.; Lueke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Krueger, H.; Malinovski, E.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martin, G.; Martyn, H.-U.; Martyniak, J.; Maxfield, S.J.; McMahon, T.R.; Mehta, A.; Meier, K.; Merkel, P.; Metlica, F.; Meyer, A.; Meyer, A.; Meyer, H.; Meyer, J.; Meyer, P.-O.; Mikocki, S.; Milstead, D.; Moeck, J.; Mohr, R.; Mohrdieck, S.; Moreau, F.; Morris, J.V.; Mueller, D.; Mueller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, Th.; Negri, I.; Newman, P.R.; Nguyen, H.K.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Niedzballa, Ch.; Niggli, H.; Nikitin, D.; Nix, O.; Nowak, G.; Nunnemann, T.; Oberlack, H.; Olsson, J.E.; Ozerov, D.; Palmen, P.; Panassik, V.; Pascaud, C.; Passaggio, S.; Patel, G.D.; Pawletta, H.; Perez, E.; Phillips, J.P.; Pieuchot, A.; Pitzl, D.; Poeschl, R.; Pope, G.; Povh, B.; Rabbertz, K.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Rick, H.; Riess, S.; Rizvi, E.; Robmann, P.; Roosen, R.; Rosenbauer, K.; Rostovtsev, A.; Rouse, F.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Schacht, P.; Scheins, J.; Schilling, F.-P.; Schleif, S.; Schleper, P.; Schmidt, D.; Schmidt, D.; Schoeffel, L.; Schroeder, V.; Schultz-Coulon, H.-C.; Schwab, B.; Sefkow, F.; Semenov, A.; Shekelyan, V.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sirois, Y.; Sloan, T.; Smirnov, P.; Smith, M.; Solochenko, V.; Soloviev, Y.; Spaskov, V.; Specka, A.; Spiekermann, J.; Spitzer, H.; Squinabol, F.; Steffen, P.; Steinberg, R.; Steinhart, J.; Stella, B.; Stellberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Sutton, J.P.; Swart, M.; Tapprogge, S.; Tasevsky, M.; Tchernshov, V.; Tchetchelnitski, S.; Theissen, J.; Thompson, G.; Thompson, P.D.; Tobien, N.; Todenhagen, R.; Truoel, P.; Tsipolitis, G.; Turnau, J.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Esch, P.; Van Haecke, A.; Van Mechelen, P.; Vazdik, Y.; Villet, G.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Wegner, A.; Wengler, T.; Werner, M.; West, L.R.; Wiesand, S.; Wilksen, T.; Willard, S.; Winde, M.; Winter, G.-G.; Wittek, C.; Wittmann, E.; Wobisch, M.; Wollatz, H.; Wuensch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zini, P.; Zomer, F.; Zsembery, J.; zurNedden, M.

    1999-01-01

    With the H1 detector at the ep collider HERA, D * meson production cross sections have been measured in deep inelastic scattering with four-momentum transfers Q 2 > 3 GeV 2 and in photoproduction at energies around W γp ∼ 88 GeV and 194 GeV. Next-to-Leading Order QCD calculations are found to describe the differential cross sections within theoretical and experimental uncertainties. Using these calculations, the NLO gluon momentum distribution in the proton, x g g(x g ), has been extracted in the momentum fraction range 7.5 x 10 -4 g -2 at average scales μ 2 = 25 to 50 GeV 2 . The gluon momentum fraction x g has been obtained from the measured kinematics of the scattered electron and the D * meson in the final state. The results compare well with the gluon distribution obtained from the analysis of scaling violations of the proton structure function F 2

  10. QCD expectations for deep inelastic scattering at small x and their phenomenological implications for HERA

    International Nuclear Information System (INIS)

    Kwiecinski, J.

    1994-05-01

    The basic QCD expectations concerning the deep inelastic scattering at low x where x is the Bjorken scaling variable are reviewed. This includes discussion of the BFKL equation which sums the leading powers of ln (1/x) and the shadowing effects. Phenomenological implications of the theoretical expectations for the deep inelastic lepton-hadron scattering in the small x region which has become accessible at the HERA ep collider are described. We give predictions for structure functions F 2 which are based on the BFKL equation and the high energy k T factorization theorem. These predictions are compared with the results of structure function analysis based on Altarelli-Parisi evolution equations and confronted with the recent data from HERA. We discuss jet production and transverse energy flow in deep inelastic lepton scattering as the measurements which may be particularly suitable for revealing the QCD dynamics at small x. (author). 37 refs, 4 figs

  11. Saue - Hera ja Heraklese kaitse all / Jüri Kuuskemaa

    Index Scriptorium Estoniae

    Kuuskemaa, Jüri, 1942-

    2003-01-01

    Saue mõisa ajaloost, omanikest, härrastemajast (arhitekt Johann Schultz), selle restaureeritud ja hästi säilinud ruumidest, inglispärasest tagaaiast, barokipäraselt regulaarse kujundusega eesaiast, Heraklese ja jumalanna (Hera, Juno) kujust aias, pargipaviljonist. 12 ill

  12. Muon Pair Production in ep Collisions at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, C.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.O.; Boudry, V.; Bracinik, J.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cousinou, M.C.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dowell, J.D.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Haidt, D.; Hajduk, L.; Haller, J.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Heuer, R.D.; Hildebrandt, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, C.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Knutsson, A.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kroseberg, J.; Kuckens, J.; Kuhr, T.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luders, S.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martisikova, M.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milcewicz, I.; Milstead, D.; Moreau, F.; Morozov, A.; Morozov, I.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Newman, Paul R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Ossoskov, G.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Poschl, R.; Portheault, B.; Povh, B.; Raicevic, N.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Trevino, A.Vargas; Vassiliev, S.; Vazdik, Y.; Veelken, C.; Vest, A.; Vichnevski, A.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Waugh, B.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Winde, M.; Winter, G.G.; Wissing, C.; Woehrling, E.E.; Wunsch, E.; Yan, W.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2003-01-01

    Cross sections for the production of two isolated muons up to high di-muon masses are measured in ep collisions at HERA with the H1 detector in a data sample corresponding to an integrated luminosity of 71 pb^-1 at a centre of mass energy of sqrt{s} = 319 GeV. The results are in good agreement with Standard Model predictions, the dominant process being photon-photon interactions. Additional muons or electrons are searched for in events with two high transverse momentum muons using the full data sample corresponding to 114 pb^-1, where data at sqrt{s} = 301 GeV and sqrt{s} = 319 GeV are combined. Both the di-lepton sample and the tri-lepton sample agree well with the predictions.

  13. Measurement of Charm and Beauty Production in Deep Inelastic Scattering at HERA and Test Beam Studies of ATLAS Pixel Sensors

    CERN Document Server

    Libov, Vladyslav; Klanner, Robert; Haller, Johannes; Geiser, Achim

    A measurement of charm and beauty production in Deep Inelastic Scattering at HERA is presented. The analysis is based on the data sample collected by the ZEUS detector in the period from 2003 to 2007 corresponding to an integrated luminosity of 354 pb 1 . The kinematic region of the measurement is given by 5 4 : 2(5) GeV for charm (beauty) and 1 : 6 < jet < 2 : 2 for both charm and beauty, where E jet T and jet are the transverse energy and pseudorapidity of the jet, respectively. The signicance of the decay length and the invariant mass of charged tracks associated with the secondary vertex are used as discriminating variables to distinguish between signal and background. Dierential cross sections of jet production in charm and beauty events as a function of Q 2 , y , E jet T and jet are measured. Results are compared to Next-to-Leading Order (NLO) predictions from Quantum Chromodynamics (QCD) in the xed avour number scheme. Good agreement between data and theory is observed. Contributions of the char...

  14. Measurement of Feynman-x spectra of photons and neutrons in the very forward direction in deep-inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Vazdik, Y. [Lebedev Physical Institute, Moscow (Russian Federation); Baghdasaryan, A.; Zohrabyan, H. [Yerevan Physics Institute, Yerevan (Armenia); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Belov, P.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Dodonov, V.; Eckerlin, G.; Elsen, E.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Haidt, D.; Kleinwort, C.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Petrukhin, A.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Boudry, V.; Specka, A. [LLR, Ecole Polytechnique, CNRS/IN2P3, Palaiseau (France); Brandt, G. [Oxford University, Department of Physics, Oxford (United Kingdom); Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F. [LAL, Universite Paris-Sud, CNRS/IN2P3, Orsay (France); Buniatyan, A.; Huber, F.; Sauter, M.; Schoening, A. [Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Rostovtsev, A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Cantun Avila, K.B.; Contreras, J.G. [CINVESTAV, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Ceccopieri, F.; Favart, L.; Grebenyuk, A.; Hreus, T.; Janssen, X.; Roosen, R.; Mechelen, P. van [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Chekelian, V.; Grindhammer, G.; Kiesling, C. [Max-Planck-Institut fuer Physik, Munich (Germany); Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kostka, P.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D. [University of Liverpool, Department of Physics, Liverpool (United Kingdom); Daum, K.; Meyer, H. [Fachbereich C, Universitaet Wuppertal, Wuppertal (Germany); Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C. [CPPM, Aix-Marseille Univ, CNRS/IN2P3, Marseille (France); Dobre, M.; Rotaru, M. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Dossanov, A. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Max-Planck-Institut fuer Physik, Munich (Germany); Egli, S.; Horisberger, R. [Paul Scherrer Institut, Villigen (Switzerland); Feltesse, J.; Perez, E.; Schoeffel, L. [CEA, DSM/Irfu, CE-Saclay, Gif-sur-Yvette (France); Ferencei, J. [Slovak Academy of Sciences, Institute of Experimental Physics, Kosice (Slovakia); Goerlich, L.; Mikocki, S.; Nowak, G.; Sopicki, P.; Turnau, J. [Institute for Nuclear Physics, Cracow (Poland); Grab, C. [Institut fuer Teilchenphysik, ETH, Zurich (Switzerland); Henderson, R.C.W. [University of Lancaster, Department of Physics, Lancaster (United Kingdom); Herbst, M.; Schultz-Coulon, H.C. [Kirchhoff-Institut fuer Physik, Universitaet Heidelberg, Heidelberg (Germany); Hladky, J.; Reimer, P. [Academy of Sciences of the Czech Republic, Institute of Physics, Prague (Czech Republic); Jung, H. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (Belgium); DESY, Hamburg (Germany); Kapichine, M.; Lytkin, L.; Morozov, A.; Spaskov, V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kogler, R.; Nowak, K. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (Germany); Landon, M.P.J.; Rizvi, E.; Traynor, D. [University of London, School of Physics and Astronomy, Queen Mary, London (GB); Lange, W.; Naumann, T. [DESY, Zeuthen (DE); Martyn, H.U. [I. Physikalisches Institut der RWTH, Aachen (DE); Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P. [Physik-Institut der Universitaet Zuerich, Zurich (CH); Newman, P.R.; Thompson, P.D. [School of Physics and Astronomy, University of Birmingham, Birmingham (GB); Picuric, I.; Raicevic, N. [University of Montenegro, Faculty of Science, Podgorica (ME); Povh, B. [Max-Planck-Institut fuer Kernphysik, Heidelberg (DE); Sankey, D.P.C. [STFC, Rutherford Appleton Laboratory, Didcot, Oxfordshire (GB); Soloviev, Y. [DESY, Hamburg (DE); Lebedev Physical Institute, Moscow (RU); Stella, B. [Dipartimento di Fisica Universita di Roma Tre (IT); INFN Roma 3, Rome (IT); Sykora, T. [Brussels and Universiteit Antwerpen, Inter-University Institute for High Energies ULB-VUB, Antwerp (BE); Charles University, Faculty of Mathematics and Physics, Prague (CZ); Tsakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (BG); Wegener, D. [Institut fuer Physik, TU Dortmund, Dortmund (DE); Collaboration: H1 Collaboration

    2014-06-15

    Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to the proton beam direction in deep-inelastic ep scattering at HERA are presented as a function of the Feynman variable x{sub F} and of the centre-of-mass energy of the virtual photon-proton system W. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 131 pb{sup -1}. The measurement is restricted to photons and neutrons in the pseudorapidity range η > 7.9 and covers the range of negative four momentum transfer squared at the positron vertex 6 < Q{sup 2} < 100 GeV{sup 2}, of inelasticity 0.05 < y < 0.6 and of 70 < W < 245 GeV. To test the Feynman scaling hypothesis the W dependence of the x{sub F} dependent cross sections is investigated. Predictions of deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections. (orig.)

  15. Development of stress relaxation measurement by a small size C-ring specimen method

    International Nuclear Information System (INIS)

    Shimanuki, Shizuka; Nakata, Kiyotomo; Kasahara, Shigeki; Kuniya, Jiro

    2002-01-01

    A stress relaxation measurement method has been developed by using C-ring specimens, and a specimen size effect has been evaluated taking radiation-induced stress relaxation into consideration. C-ring specimens were stressed by forcing a wedge in the gap. Giving an appropriate eccentric configuration in the half of the ring opposite the gap, the stress gradient along the circumference was eliminated in the section and the stress level could be varied by changing the gap spacing. The validity of the C-ring test method was confirmed by thermally stress relaxation experiments at annealing temperatures from 300 to 600degC for 1 min to 200 h in carbon steel: considerable stress relaxation could be measured for all levels of applied stress even at relatively low annealing temperatures. The relaxation results obtained from the C-ring test were in good agreement with those from a uniaxial tensile stress relaxation test. The smaller C-ring specimen with about 40 mm diameter, which is required for radiation-induced stress relaxation test, also showed adequate accuracy on stress relaxation at 600 to 830degC in stainless steel, compared with the large size C-ring specimen test. (author)

  16. Elastic and proton-dissociative photoproduction of J/ψ mesons at HERA

    International Nuclear Information System (INIS)

    Alexa, C.; Dobre, M.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Vazdik, Y.; Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H.; Bartel, W.; Belov, P.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Boudry, V.; Specka, A.; Bozovic-Jelisavcic, I.; Pandurovic, M.; Brandt, G.; Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F.; Buniatyan, A.; Huber, F.; Pirumov, H.; Sauter, M.; Schoening, A.; Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Lubimov, V.; Rostovtsev, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Ceccopieri, F.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Roosen, R.; Staykova, Z.; Mechelen, P. van; Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R.; Chekelian, V.; Grindhammer, G.; Kiesling, C.; Cvach, J.; Hladky, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C.; Dodonov, V.; Dossanov, A.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Feltesse, J.; Perez, E.; Schoeffel, L.; Ferencei, J.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Grab, C.; Henderson, R.C.W.; Hennekemper, E.; Herbst, M.; Schultz-Coulon, H.C.; Herrera, G.; Lopez-Fernandez, R.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Joensson, L.; Jung, H.; Kapichine, M.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Kogler, R.; Nowak, K.; Landon, M.P.J.; Rizvi, E.; Traynor, D.; Martyn, H.U.; Morris, J.V.; Sankey, D.P.C.; Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P.; Newman, P.R.; Thompson, P.D.; Picuric, I.; Raicevic, N.; Soloviev, Y.; Stella, B.; Sykora, T.; Tsakov, I.; Wegener, D.

    2013-01-01

    Cross sections for elastic and proton-dissociative photoproduction of J/ψ mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at ep centre-of-mass energies √(s) ∼ 318 GeV and √(s) ∼ 225 GeV, corresponding to integrated luminosities of L = 130 pb -1 and L = 10.8 pb -1 , respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25 γp 2 for the elastic process and vertical stroke t vertical stroke 2 for proton dissociation. The results are compared to other measurements. The W γp and t-dependences are parametrised using phenomenological fits. (orig.)

  17. Measurement of D*± meson production and determination of F2cantic at low Q2 in deep-inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H.; Barrelet, E.; Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Grell, B.R.; Habib, S.; Haidt, D.; Helebrant, C.; Kleinwort, C.; Kogler, R.; Kraemer, M.; Levonian, S.; Lipka, K.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Piec, S.; Pitzl, D.; Schmitt, S.; Sefkow, F.; South, D.; Staykova, Z.; Steder, M.; Toll, T.; Wuensch, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boenig, M.O.; Wegener, D.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D.; Bruncko, D.; Cerny, V.; Ferencei, J.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Shushkevich, S.; Bystritskaya, L.; Fedotov, A.; Lubimov, V.; Ozerov, D.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Ceccopieri, F.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Roosen, R.; Mechelen, P. van; Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C.; Dobre, M.; List, B.; Placakyte, R.; Dodonov, V.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Feltesse, J.; Perez, E.; Schoeffel, L.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Grab, C.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Urban, K.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Herrera, G.; Lopez-Fernandez, R.; Huber, F.; Pirumov, H.; Radescu, V.; Sauter, M.; Schoening, A.; Joensson, L.; Jung, H.; Kapichine, M.; Makankine, A.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Landon, M.P.J.; Rizvi, E.; Traynor, D.; Martyn, H.U.; Mueller, K.

    2011-01-01

    Inclusive production of D * mesons in deep-inelastic ep scattering at HERA is studied in the range 5 2 2 of the photon virtuality and 0.02 * meson is p T (D * ) >1.25 GeV and vertical stroke η(D * ) vertical stroke -1 collected with the H1 detector. Single and double differential cross sections are measured and the charm contribution F 2 c anti c to the proton structure function F 2 is determined. The results are compared to perturbative QCD predictions at next-to-leading order implementing different schemes for the charm mass treatment and with Monte Carlo models based on leading order matrix elements with parton showers. (orig.)

  18. Measurement of D{sup *} meson with two jets in photoproduction with the H1 detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Staykova, Zlatka

    2011-02-15

    Photoproduction events containing a charmed meson D{sup *{+-}} and two jets are investigated with the H1 detector using the HERA II data sample. The measurement is based on e{sup +}p collisions during the period of 2006/2007 data taking and uses integrated luminosity of 113.14 pb{sup -1}. The kinematic range of the measurement covers 100 GeV3.5 GeV. One of the jets has to be associated with the D{sup *} meson itself, such that the parent charmed quark can be tagged. The phase space of the measurement is limited within the central rapidity for the D{sup *} meson and the D{sup *}{sub jet}, vertical stroke {eta} vertical stroke <1.5 while the second jet was measured within, -1.5<{eta}<2.9. Single differential cross sections and double differential distributions were measured and compared to Leading Order Monte Carlo (MC) event generators, Pythia and Cascade and with the Next-to-Leading order MC generator MC rate at NLO. (orig.)

  19. Beauty photoproduction using decays into muons at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Samson, U.

    2008-05-15

    Inclusive cross-sections for the production of open beauty in ep collisions at HERA are measured. The data were recorded with the ZEUS detector between 1996 and 2000. The measurements are restricted to photoproduction processes, i.e. collision events with small four-momentum transfer squared, Q{sup 2}{approx}0. Two jets with transverse momentum p{sub T}>7(6) GeV and pseudo-rapidities vertical stroke {eta} vertical stroke <2.5 are required. The flavour is tagged by the identification of muons from semi-leptonic decays of the beauty quark. The variable used to discriminate between beauty and background is the transverse momentum of the muon with respect to the jet axis. The fraction of beauty is determined by a fit of Monte Carlo templates to the data. Cross-sections have been measured as a function of the muon and jet variables as well as a function of dijet correlation variables. Dijet correlations in beauty production have been measured for the first time in ZEUS and are found in agreement with QCD NLO predictions. (orig.)

  20. Beauty photoproduction using decays into muons at HERA

    International Nuclear Information System (INIS)

    Samson, U.

    2008-05-01

    Inclusive cross-sections for the production of open beauty in ep collisions at HERA are measured. The data were recorded with the ZEUS detector between 1996 and 2000. The measurements are restricted to photoproduction processes, i.e. collision events with small four-momentum transfer squared, Q 2 ∼0. Two jets with transverse momentum p T >7(6) GeV and pseudo-rapidities vertical stroke η vertical stroke <2.5 are required. The flavour is tagged by the identification of muons from semi-leptonic decays of the beauty quark. The variable used to discriminate between beauty and background is the transverse momentum of the muon with respect to the jet axis. The fraction of beauty is determined by a fit of Monte Carlo templates to the data. Cross-sections have been measured as a function of the muon and jet variables as well as a function of dijet correlation variables. Dijet correlations in beauty production have been measured for the first time in ZEUS and are found in agreement with QCD NLO predictions. (orig.)

  1. Measurement of αs from jet rates in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-10-01

    Jet production in deep inelastic scattering for 120 2 2 has been studied using data from an integrated luminosity of 3.2 pb -1 collected with the ZEUS detector at HERA. Jets are identified with the JADE algorithm. A cut on the angular distribution of parton emission in the γ-parton centre-of-mass system minimises the experimental and theoretical uncertainties in the determination of the jet rates. The jet rates, when compared to OMIKRON (α s 2 ) perturbative QCD calculations, allow a precise determination of α s (Q) in three Q 2 -intervals. The values are consistent with a running of α s (Q), as expected from QCD. Extrapolating to Q=M (Z 0 ) yields α s (M Z 0 )=0.117±0.005(stat) -0.005 +0.004 (syst exp )±0. 007(syst theory ). (orig.)

  2. Charm photoproduction using electron taggers with the Zeus detector at HERA

    International Nuclear Information System (INIS)

    Aghuzumtsyan, G.

    2006-07-01

    Charm production has been studied at a centre-of-mass energy of √(s)=318 GeV in the ZEUS experiment at the electron-proton collider HERA. The data from the years 1998-2000 are used. Photoproduction is identified by reconstructing the D * (2010) meson via the decay chain D *+ →K - π + π + (+c.c.) and by selecting the scattered electron in one of the dedicated electron taggers located 44m and 35m away from the interaction point. The total visible cross section and differential cross sections as a function of p T (D * ), η(D * ) and W were measured in the restricted phase space: -1.0 * ) T (D * )>1.5 GeV, 80 GeV 2 2 in case of the 44m tagger sample, and -1.5 * ) T (D * )>2.0 GeV, 200 GeV 2 2 in case of the 35m tagger sample. Next-to-leading-order QCD predictions were calculated in the same kinematic region as the data. The comparison of the theoretical predictions with the data shows good agreement within the theoretical uncertainties. Total charm cross sections were calculated by extrapolating the visible cross sections in the limited (p T (D * ), η(D * )) phase space to the full kinematic region. The measurements with the 35m tagger overlap with previous untagged data while the 44m tagger data are used to study a new intermediate region 80 GeV 44m <120 GeV between fixed target and and the other HERA measurements. The comparison of the NLO QCD predictions with the data shows good agreement. (orig.)

  3. an extended octagonal ring dynamometer for measurement of forces

    African Journals Online (AJOL)

    NIJOTECH

    The analysis, design, construction, evaluation and use of an extended octagonal ring dynamometer for ... For tillage applications, it has been used ..... confirmed that the dynamometer and the measurement system were capable of indicating.

  4. Measurement of beauty quark production from dimuon events with the ZEUS detector at HERA II

    International Nuclear Information System (INIS)

    Bot, Danny

    2011-10-01

    In this thesis, a measurement of beauty quark production via the process ep→e'b anti bX→e'μμX in electron-proton collisions at HERA using a data sample recorded by the ZEUS detector in the years 2003-2007, corresponding to an integrated luminosity of 376 pb -1 , is presented. A low transverse momentum threshold for muon identification in combination with the large rapidity coverage of the ZEUS muon-detection system gives access to essentially the full phase space for beauty quark production. Dimuon charge correlations as well as hadronic isolation and the mass of the dimuon system were used to separate the beauty signal from backgrounds. Visible, differential and total cross sections for beauty quark production were measured and compared to next-to-leading order QCD calculations and previous measurements. In addition, a first search for QCD instanton-induced processes containing both a charm- and beauty-quark pair in dimuon events was performed. In order to differentiate between beauty and instanton events, discriminating observables sensitive to the hadronic final state, so-called event shape variables, were used in combination with the dimuon requirement. As technical part of this thesis, the reconstruction algorithm for so-called energy flow objects (EFOs) was modified. EFOs contain the combined information of primary and secondary vertex-fitted tracks as well as CAL energy measurements. The modification considers additional tracks close to but not fitted to the primary vertex and which fulfill reasonable track and impact parameter requirements. As a result, the efficiency to reconstruct muon candidates with high impact parameter values as energy flow objects was increased. (orig.)

  5. Measurement of beauty quark production from dimuon events with the ZEUS detector at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Bot, Danny

    2011-10-15

    In this thesis, a measurement of beauty quark production via the process ep{yields}e'b anti bX{yields}e'{mu}{mu}X in electron-proton collisions at HERA using a data sample recorded by the ZEUS detector in the years 2003-2007, corresponding to an integrated luminosity of 376 pb{sup -1}, is presented. A low transverse momentum threshold for muon identification in combination with the large rapidity coverage of the ZEUS muon-detection system gives access to essentially the full phase space for beauty quark production. Dimuon charge correlations as well as hadronic isolation and the mass of the dimuon system were used to separate the beauty signal from backgrounds. Visible, differential and total cross sections for beauty quark production were measured and compared to next-to-leading order QCD calculations and previous measurements. In addition, a first search for QCD instanton-induced processes containing both a charm- and beauty-quark pair in dimuon events was performed. In order to differentiate between beauty and instanton events, discriminating observables sensitive to the hadronic final state, so-called event shape variables, were used in combination with the dimuon requirement. As technical part of this thesis, the reconstruction algorithm for so-called energy flow objects (EFOs) was modified. EFOs contain the combined information of primary and secondary vertex-fitted tracks as well as CAL energy measurements. The modification considers additional tracks close to but not fitted to the primary vertex and which fulfill reasonable track and impact parameter requirements. As a result, the efficiency to reconstruct muon candidates with high impact parameter values as energy flow objects was increased. (orig.)

  6. Inclusive Photoproduction of rho^0, K^{*0} and phi Mesons at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Behnke, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eliseev, A.; Elsen, E.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.-J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Glazov, A.; Glushkov, I.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Helebrant, C.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Knutsson, A.; Kogler, R.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Mudrinic, M.; Muller, K.; Murin, P.; Naroska, B.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Pejchal, O.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rurikova, Z.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; von den Driesch, M.; Wegener, D.; Wissing, Ch.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2009-01-01

    Inclusive non-diffractive photoproduction of rho(770)^0, K^*(892)^0 and phi(1020) mesons is investigated with the H1 detector in ep collisions at HERA. The corresponding average \\gamma p centre-of-mass energy is 210 GeV. The mesons are measured in the transverse momentum range 0.5

  7. A measurement of multijet production in low-x{sub Bj} neutral current deep inelastic scattering with ZEUS at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Danielson, T.E.

    2007-12-15

    Inclusive dijet and trijet production in deep inelastic ep scattering has been measured for 10HERA ep collider with center-of-mass energy {radical}(s)=318 GeV using the ZEUS detector and correspond to an integrated luminosity of 82 pb{sup -1}. Jets were identified in the hadronic center-of-mass (HCM) frame using the k{sub T} cluster algorithm in the longitudinally invariant inclusive mode. Measurements of dijet and trijet differential cross sections are presented as functions of Q{sup 2}, x{sub Bj}, jet transverse energy, and jet pseudorapidity. As a further examination of low-x{sub Bj} dynamics, multi-differential cross sections as functions of the jet correlations in transverse momenta, azimuthal angles, and pseudorapidity are also presented. Calculations at O({alpha}{sup 3}{sub s}) generally describe the trijet data well and improve the description of the dijet data compared to the calculation at O({alpha}{sup 2}{sub s}). (orig.)

  8. Strangeness production at low Q2 in deep-inelastic ep scattering at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Preda, T.; Rotaru, M.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Sheviakov, I.; Shtarkov, L.N.; Smirnov, P.; Soloviev, Y.; Vazdik, Y.; Antunovic, B.; Aplin, S.; Bacchetta, A.; Bartel, W.; Beckingham, M.; Brandt, G.; Brinkmann, M.; Campbell, A.J.; Cholewa, A.; Deak, M.; Boer, Y. de; Roeck, A. de; Eckerlin, G.; Elsen, E.; Felst, R.; Fleischer, M.; Gayler, J.; Glazov, A.; Grell, B.R.; Haidt, D.; Helebrant, C.; Janssen, M.E.; Jung, H.; Katzy, J.; Kleinwort, C.; Klimkovich, T.; Knutsson, A.; Korbel, V.; Kraemer, M.; Krastev, K.; Kutak, K.; Levonian, S.; List, J.; Lucaci-Timoce, A.I.; Marti, Ll.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Niebuhr, C.; Nikiforov, A.; Nozicka, M.; Olsson, J.E.; Panagoulias, I.; Papadopoulou, T.; Peng, H.; Pitzl, D.; Placakyte, R.; Radescu, V.; Rurikova, Z.; Salvaire, F.; Schmidt, S.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Toll, T.; Vargas Trevino, A.; Vinokurova, S.; Wessels, M.; Wissing, C.; Wuensch, E.; Zhu, Y.C.; Asmone, A.; Stella, B.; Astvatsatourov, A.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roland, B.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Ghazaryan, S.; Hovhannisyan, A.; Volchinski, V.; Yeganov, V.; Zohrabyan, H.; Barrelet, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Behnke, O.; Berger, N.; Del Degan, M.; Eichler, R.; Grab, C.; Leibenguth, G.; Sauter, M.; Zimmermann, T.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Li, G.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boenig, M.O.; South, D.; Wegener, D.; Boudry, V.; Gouzevitch, M.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Faulkner, P.J.W.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Bruncko, D.; Cerny, V.; Ferencei, J.; Murin, P.; Tomasz, F.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Liptaj, A.; Olivier, B.; Raspiareza, A.; Shushkevich, S.; Tzamariudaki, E.; Bystritskaya, L.; Efremenko, V.; Essenov, S.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Petrukhin, A.; Rostovtsev, A.; Zhelezov, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cassol-Brunner, F.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Trinh, T.N.; Vallee, C.; Cerny, K.; Pejchal, O.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cozzika, G.; Feltesse, J.; Perez, E.; Schoeffel, L.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Rahmat, A.J.; Daum, K.; Meyer, H.; Dodonov, V.; Lytkin, L.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Glushkov, I.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Piec, S.; Tsurin, I.; Goettlich, M.; Habib, S.; Jemanov, V.; Lipka, K.; List, B.; Naroska, B.; Hansson, M.; Joensson, L.; Osman, S.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Jung, A.W.; Krueger, K.; Lendermann, V.; Meier, K.; Schultz-Coulon, H.C.; Urban, K.; Herrera, G.; Lopez-Fernandez, R.; Kapichine, M.; Makankine, A.; Morozov, A.; Palichik, V.; Spaskov, V.; Tchoulakov, V.; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Schmitz, C.; Straumann, U.; Truoel, P.; Nankov, K.; Tsakov, I.; Schoening, A.

    2009-01-01

    The production of neutral strange hadrons is investigated using deep-inelastic scattering events measured with the H1 detector at HERA. The measurements are made in the phase space defined by the negative four-momentum transfer squared of the photon 2 2 2 and the inelasticity 0.1 s 0 and Λ(anti Λ) production cross sections and their ratios are determined. K s 0 production is compared to the production of charged particles in the same region of phase space. The Λ- anti Λ asymmetry is also measured and found to be consistent with zero. Predictions of leading order Monte Carlo programs are compared to the data. (orig.)

  9. Planning and Prototyping for a Storage Ring Measurement of the Proton Electric Dipole Moment

    Energy Technology Data Exchange (ETDEWEB)

    Talman, Richard [Cornell Univ., Ithaca, NY (United States)

    2015-07-01

    Electron and proton EDM's can be measured in "frozen spin" (with the beam polarization always parallel to the orbit, for example) storage rings. For electrons the "magic" kinetic energy at which the beam can be frozen is 14.5 MeV. For protons the magic kinetic energy is 230 MeV. The currently measured upper limit for the electron EDM is much smaller than the proton EDM upper limit, which is very poorly known. Nevertheless, because the storage ring will be an order of magnitude cheaper, a sensible plan is to first build an all-electric electron storage ring as a prototype. Such an electron ring was successfully built at Brookhaven, in 1954, as a prototype for their AGS ring. This leaves little uncertainty concerning the cost and performance of such a ring. (This is documentedin one of the Physical Review papers mentioned above.)

  10. Energy dependence of the charged multiplicity in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-03-01

    The charged multiplicity distributions and the mean charged multiplicity have been investigated in inclusive neutral current deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of 38.6 pb -1 . The measurements were performed in the current region of the Breit frame, as well as in the current fragmentation region of the hadronic centre-of-mass frame. The KNO-scaling properties of the data were investigated and the energy dependence was studied using different energy scales. The data are compared to results obtained in e + e - collisions and to previous DIS measurements as well as to leading-logarithm parton-shower Monte Carlo predictions. (orig.)

  11. Measurement of spin motions in a storage ring outside the stable polarization direction

    International Nuclear Information System (INIS)

    Akchurin, N.; Badano, L.; Bravar, A.; Istituto Nazionale di Fisica Nucleare, Legnaro

    1993-06-01

    Polarized, stored beams are becoming a more and more important tool in nuclear and high energy physics. In order to measure the beam polarization in a storage ring the polarization vector of the stored beams has to aim, revolution for revolution, over a period of seconds to minutes, into the same, so-called ''stable'' direction. In this paper measurements at the Indiana University cooler ring (IUCF) are described in which for the first time in a storage ring oscillations of the polarization vector around this stable direction have been measured. The existence and the dynamics of such oscillations are, for instance, important for a new proposed technique for polarizing stored hadron beams

  12. Measurement of spin motions in a storage ring outside the stable polarization direction

    International Nuclear Information System (INIS)

    Akchurin, N.; McPherson, J.; Olchowski, F.; Onel, Y.; Badano, L.; Conte, M.; Bravar, A.; Penzo, A.; Hall, J.; Kreiser, H.

    1993-01-01

    Polarized, stored beams are becoming a more and more important tool in nuclear and high energy physics. In order to measure the beam polarization in a storage ring the polarization vector of the stored beam has to aim, revolution for revolution, over a period of seconds to minutes, into the same, so-called open-quote stableclose quotes, direction. In this paper measurements at the Indiana University Cooler Ring (IUCF) are described in which for the first time in a storage ring oscillations of the polarization vector around this stable direction have been measured. The existence and the dynamics of such oscillations are, for instance, important for a new proposed technique for polarizing stored hadron beams

  13. Measurement of high-Q2 neutral current deep inelastic e-p scattering cross sections with a longitudinally polarised electron beam at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-12-01

    Measurements of the neutral current cross sections for deep inelastic scattering in e - p collisions at HERA with a longitudinally polarised electron beam are presented. The single-differential cross-sections dσ/dQ 2 , dσ/dx and dσ/dy and the double-differential cross sections in Q 2 and x are measured in the kinematic region y 2 > 185GeV 2 for both positively and negatively polarised electron beams and for each polarisation state separately. The measurements are based on an integrated luminosity of 169.9 pb -1 taken with the ZEUS detector in 2005 and 2006 at a centre-of-mass energy of 318GeV. The structure functions xF 3 and xF 3 γZ are determined by combining the e - p results presented in this paper with previously measured e + p neutral current data. The asymmetry parameter A - is used to demonstrate the parity violating effects of electroweak interactions at large spacelike photon virtuality. The measurements agree well with the predictions of the Standard Model. (orig.)

  14. On the kinematic reconstruction of deep inelastic scattering at HERA: the Σmethod

    International Nuclear Information System (INIS)

    Bassler, U.; Bernardi, G.

    1994-12-01

    We review and compare the reconstruction methods of the inclusive deep inelastic scattering variables used at HERA. We introduce a new prescription, the Sigma (Σ) method, which allows to measure the structure function of the proton F 2 (x, Q 2 ) in a large kinematic domain, and in particular in the low x-low Q 2 region, with small systematic errors and small radiative corrections. A detailed comparison between the Σ method and the other methods is shown. Extensions of the Σ method are presented. The effect of QED radiation on the kinematic reconstruction and on the structure function measurement is discussed. (orig.)

  15. The outer tracker detector of the HERA-B experiment. Pt. 3. Operation and performance

    International Nuclear Information System (INIS)

    Albrecht, H.; Bauer, T.S.; Utrecht Univ.; Beck, M.

    2006-12-01

    In this paper we describe the operation and performance of the HERA-B Outer Tracker, a 112674 channel system of planar drift tube layers. The performance of the HERA-B Outer Tracker system fullfilled all requirements for stable and efficient operation in a hadronic environment, thus confirming the adequacy of the honeycomb drift tube technology and of the front-end readout system. The detector was stably operated with a gas gain of 3 . 10 4 in an Ar/CF 4 /CO 2 (65:35:5) gas mixture, yielding a good efficiency for triggering and track reconstruction, larger than 95 % for tracks with momenta above 5 GeV/c. The hit resolution of the drift cells was 300 to 320 μm and the relative momentum resolution can be described as: σ(p)/p(%) = (1.61 ± 0.02) + (0.0051 ± 0.0006) . p. At the end of the HERA-B running no aging effects in the Outer Tracker cells were observed. (orig.)

  16. Cavity ring-down technique for measurement of reflectivity of high ...

    Indian Academy of Sciences (India)

    Laser & Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085,. India. *Corresponding author. E-mail: gsridhar@barc.gov.in. Abstract. A simple, accurate and reliable method for measuring the reflectivity of laser- ... Keywords. Cavity ring-down method; reflectivity measurement; optical resonator.

  17. Elastic photoproduction of ρ0 mesons at HERA

    International Nuclear Information System (INIS)

    Aid, S.; Andreev, V.; Andrieu, B.

    1995-12-01

    The cross section for the elastic photoproduction of ρ 0 mesons (γp→ρ 0 p) has been measured with the H1 detector at HERA for two average photon-proton centre-of-mass energies of 55 and 187 GeV. The lower energy point was measured by observing directly the ρ 0 decay giving a cross section of 9.1±0.9 (stat.)±2.5 (syst.) μb. The logarithmic slope parameter of the differential cross section, dσ/dt, is found to be 10.9±2.4 (stat.)±1.1 (syst.) GeV -2 . The ρ 0 decay polar angular distribution is found to be consistent with s-channel helicity conservation. The higher energy cross section was determined from analysis of the lower part of the hadronic invariant mass spectrum of diffractive photoproduction and found to be 13.6±0.8 (stat.)±2.4 (syst.) μb. (orig.)

  18. Scaled momentum spectra in deep inelastic scattering at HERA

    NARCIS (Netherlands)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Aushev, V.; Aushev, Y.; Bachynska, O.; Bamberger, A.; Barakbaev, A. N.; Barbagli, G.; Bari, G.; Barreiro, F.; Bartsch, D.; Basile, M.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Bertolin, A.; Bhadra, S.; Bindi, M.; Blohm, C.; Bold, T.; Boos, E. G.; Borodin, M.; Borras, K.; Boscherini, D.; Boutle, S. K.; Brock, I.; Brownson, E.; Brugnera, R.; Bruemmer, N.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bussey, P. J.; Butterworth, J. M.; Bylsma, B.; Caldwell, A.; Capua, M.; Carlin, R.; Catterall, C. D.; Chekanov, S.; Chwastowski, J.; Ciborowski, J.; Pellegrino, A.

    Charged particle production has been studied in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 0.44 fb(-1). Distributions of scaled momenta in the Breit frame are presented for particles in the current fragmentation region. The evolution

  19. Jet photoproduction at HERA

    International Nuclear Information System (INIS)

    Frixione, S.

    1997-01-01

    We compute various kinematical distributions for one-jet and two-jet inclusive photoproduction at HERA. Our results are accurate to next-to-leading order in QCD. We use the subtraction method for the cancellation of infrared singularities. We perform a thorough study of the reliability of QCD predictions; in particular, we consider the scale dependence of our results and discuss the cases when the perturbative expansion might break down. We also deal with the problem of the experimental definition of the pointlike and hadronic components of the incident photon, and briefly discuss the sensitivity of QCD predictions upon the input parameters of the calculation, like α S and the parton densities. (orig.)

  20. The vibration measurements at the photon factory storage ring building

    International Nuclear Information System (INIS)

    Haga, K.; Nakayama, M.; Masuda, K.; Ishizaki, H.; Kura, M.; Meng, L.; Oku, Y.

    1999-01-01

    The Photon Factory is a 2.5 GeV electron storage ring and has been operating since 1982 as a dedicated SR source. At the Photon Factory, we have been pursuing the various sources of the beam instabilities which deteriorated the SR beam quality in the wide frequency range. Some of the sources were the vibrations of magnets and floor of the ring tunnel, temperature change of the cooling water and the elongation of the storage ring building roof due to sunshine that induced the diurnal motion of the SR beam axis. This article presents the results of the vibration measurements that have been performed at the Photon Factory storage ring building. (1) The vibrations of the ring tunnel floor and the experimental hall floor, comparing with the vibration of the ground surrounding the storage ring building, are same order in the 1 ∼ 5 Hz range, and 1/3 ∼ 1/5 in the 5 ∼ 100 Hz range, in the vertical and the horizontal direction. (2) The effects of the vibration arising from the operating eight air-conditioners can be seen in the Fourier spectrum of the vibration of the ring tunnel floor, experimental floor, Q-magnets and BPM vacuum duct. (3) The vibrations of the Q-magnet and girder at frequencies near their fundamental resonant frequencies have been amplified 100 limes in the lateral direction comparing to the floor vibration. (4) Correlation between the vibration of the BPM vacuum duct and the vibration of the electron beam motion is unknown for the lack of the precise data. (authors)