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Sample records for pseudo-scalar meson photoproduction

  1. Progress in pseudo-scalar meson photoproduction experiments at MAMI-C in Mainz.

    Energy Technology Data Exchange (ETDEWEB)

    Annand, John R.M; Hamilton, David J.; Howdle, David; Livingston, Ken; MacGregor, Ian James Douglas; Mancell, Joe; McNicoll, Eilidh; Robinson, Jamie; Rosner, Guenther [Department of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom)

    2009-07-01

    Since its upgrade in 2007, the Glasgow-Mainz spectrometer has provided a state-of-the-art photon tagger for a series of photo-production experiments at electron beam energies from 200 to 1508 MeV. We report on the operational status of the tagging spectrometer, refitted with a new focal-plane detector to extend its rate capability and improve its timing resolution by a factor 2. This complements the Crystal Ball and TAPS calorimeters, which provide almost 4{pi} detection of both neutral and charged particles. These systems have very high detection efficiency for multi-photon final states. Measurement of pseudo-scalar-meson photo production on the nucleon is a major component of the experimental programme. We have data on {pi}{sup 0}, {pi}{sup +}, {eta}, {eta}{sup '}, K{sup 0}, K{sup +} (single and multiple-meson) final states for {sup 1}H and {sup 2}H targets. The eventual goal is to make complete measurements of the helicity amplitudes, which require at least 8 observables chosen properly from unpolarised, single-spin and double-spin possibilities. The possibilities in Mainz will extend when polarised targets become available in 2009. In December 2008 the maximum MAMI-C energy was raised to 1557 MeV and data taken with an open trigger at tagged-photon energies from 80 to 1447 MeV. We show some first analyses of these tests.

  2. Polarization observables in the longitudinal basis for pseudo-scalar meson photoproduction using a density matrix approach

    Energy Technology Data Exchange (ETDEWEB)

    Biplab Dey, Michael E. McCracken, David G. Ireland, Curtis A. Meyer

    2011-05-01

    The complete expression for the intensity in pseudo-scalar meson photoproduction with a polarized beam, target, and recoil baryon is derived using a density matrix approach that offers great economy of notation. A Cartesian basis with spins for all particles quantized along a single direction, the longitudinal beam direction, is used for consistency and clarity in interpretation. A single spin-quantization axis for all particles enables the amplitudes to be written in a manifestly covariant fashion with simple relations to those of the well-known CGLN formalism. Possible sign discrepancies between theoretical amplitude-level expressions and experimentally measurable intensity profiles are dealt with carefully. Our motivation is to provide a coherent framework for coupled-channel partial-wave analysis of several meson photoproduction reactions, incorporating recently published and forthcoming polarization data from Jefferson Lab.

  3. Photoproduction of pseudo-scalar mesons on proton - Use of CLAS detector for E{sub {gamma}}< 1.8 GeV -; Photoproduction de mesons pseudo-scalaires sur le proton - Avec le detecteur CLAS pour E{sub {gamma}}< 1.8 GeV -

    Energy Technology Data Exchange (ETDEWEB)

    Girard, P

    2000-04-19

    The subject of this thesis is an experimental study of the pseudo-scalar mesons photoproduction on the proton in an energy range from {radical}S=1450 MeV to 2100 MeV. It has been realized with the 4{pi} CLAS detector of Th. Jefferson Laboratory. A software has been developed in order to perform the time calibration of the tagging system, and allowed us to measure a time resolution of 150 ps (FWHM). Gla Data have been analyzed. We determine CLAS energy resolution and show that these values are compatible with those given in the detector conceptual design report. Information from the analysis of the neutral mesons photoproduction channels and from the study of the p({gamma}, p{pi}{sup +}{pi}{sup -}) reaction has been used to develop correction methods, applied to raw data, in order to extract the differential cross-sections for the reactions p({gamma}, p){pi}{sup 0}. New data points are shown and compared to the VPI multipole analysis. A preliminary study of the p({gamma}, p){eta} is stated in order to establish the method limits. An anomaly has been found in the data at a total center of mass energy of {radical}s = 1790 MeV and is discussed. (author)

  4. Constraints in vector meson photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Kloet, W. M.; Tabakin, F

    2000-01-31

    Constraints are discussed for spin observables extracted from photoproduction of vector mesons. These constraints originate from positivity of the spin density matrix and should be part of any future analysis of experimental data. Spin observables need to be defined in the photon-nucleon c.m. frame.

  5. Constraints in Vector Meson Photoproduction

    Science.gov (United States)

    Kloet, W. M.; Tabakin, F.

    2000-01-01

    Constraints are discussed for spin observables extracted from photoproduction of vector mesons. These constraints originate from positivity of the spin density matrix and should be part of any future analysis of experimental data. Spin observables need to be defined in the photon-nucleon c.m. frame.

  6. On photoproduction of psi -mesons

    CERN Document Server

    Zakharov, V I; Okun, Lev Borisovich

    1975-01-01

    Possible causes of the smallness of the psi -meson photoproduction cross section are discussed: a) suppression due to smallness of the scattering cross section of a real psi -meson due to the small magnitude of the residue of the Pomeranchouk trajectory; b) suppression due to inability of a virtual psi -meson to produce a pomeron shower during a time E/sub gamma //m/sub psi //sup 2/ and hence the diffraction transition of a virtual psi with q/sup 2/=0 into a real one with q/sup 2/=m/sub psi //sup 2/ is small; c) suppression due to smallness of the transition psi to gamma ; in this case the vertex g/sub e/ psi /sub mu /e gamma /sub mu /e is primary and not due to a virtual photon. It is shown that a choice between these possibilities can be made by studying experimentally electroproduction of psi -mesons and their photoproduction by nuclei. (16 refs).

  7. Vector meson photoproduction — model independent aspects

    Science.gov (United States)

    Kloet, W. M.; Tabakin, F.

    2000-07-01

    The rich spin structure of vector meson photoproduction allows for a systematic analysis of the angular and energy dependence of the spin observables in the photon-nucleon c.m. frame. Constraints for spin observables based on positivity of the spin density matrix, are discussed and should be part of any future analysis of experimental data.

  8. Vector meson photoproduction - model independent aspects

    Energy Technology Data Exchange (ETDEWEB)

    Kloet, W. M.; Tabakin, F

    2000-07-31

    The rich spin structure of vector meson photoproduction allows for a systematic analysis of the angular and energy dependence of the spin observables in the photon-nucleon c.m. frame. Constraints for spin observables based on positivity of the spin density matrix, are discussed and should be part of any future analysis of experimental data.

  9. GlueX: Meson Spectroscopy in Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Carlos [Norfolk State University, JLAB; Smith, Elton S. [JLAB

    2014-03-01

    The goal of the GlueX experiment \\cite{gluex} is to provide crucial data to help understand the soft gluonic fields responsible for binding quarks in hadrons. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. Photoproduction is expected to be effective in producing exotic hybrids but there is little data on the photoproduction of light mesons. GlueX will use the new 12-GeV electron beam at Jefferson Lab to produce a 9-GeV beam of linearly polarized photons using the technique of coherent bremsstrahlung. A solenoid-based hermetic detector is under construction, which will be used to collect data on meson production and decays. These data will also be used to study the spectrum of conventional mesons, including the poorly understood excited vector mesons. This talk will give an update on the experiment as well as describe theoretical developments \\cite{Dudek:2011bn} to help understand how these data can provide insights into the fundamental theory of strong interactions.

  10. Constraints on vector meson photoproduction spin observables

    Science.gov (United States)

    Kloet, W. M.; Tabakin, Frank

    2000-01-01

    Extraction of spin observables from vector meson photoproduction on a nucleon target is described. Starting from density matrix elements in the vector meson's rest frame, we transform to spin observables in the photon-nucleon c.m. frame. Several constraints on the transformed density matrix and on the spin observables follow from requiring that the angular distribution and the density matrix be positive definite. A set of constraints that are required in order to extract meaningful spin observables from forthcoming data are enunciated.

  11. High-energy photoproduction of neutral mesons

    CERN Document Server

    Charity, Tim

    1987-01-01

    This thesis presents results from the first full period of data-taking of the experiment WA69 at the Omega^'^ectrometer, CERN, Geneva. The experiment used a tagged photon beam of energy 60-180 GeV incident on a liquid hydrogen target to study photoproduction of hadronic states. The various components of the experiment are described, with particular emphasis on the electromagnetic calorimeters, and the associated offline software for event reconstruction and acceptance calculation. The performance of the outer calorimeter is discussed, and the pi^0 detection and reconstruction efficiency is examined by comparison with pi^{+/- } production. Searches for photoproduction of neutral meson states reveal a clear signal for the pi^0, eta^0 , and omega^0 mesons. The cross-section for elastic omega^0 production is estimated, and found to be consistent with the established value of 1 mub. The cross-section for inclusive pi^0 and eta^0 production is studied using the variable Feynman-x (x_{F }), and pi^0 production as a ...

  12. Cross section of pseudoscalar meson photoproduction within the ELA

    Science.gov (United States)

    Quirós, J. J.; Tamayo, D. F.; Jaramillo, D. E.; Barbero, C.

    2015-10-01

    We study the contributions of background and resonance terms to the total cross section of photoproduction of mesons off the free nucleon. The model we use is consistent and based on an effective Lagrangian approach (ELA) which includes nucleon Born terms, vector meson exchange terms, and nucleon resonances. The interaction Lagrangians are chiral symmetric, gauge invariant and crossing symmetric. The results we obtain are compared to available experimental data and agreement is found in the energy region from threshold up to 0.55 GeV in the case of π photoproduction. We outline the possibility to extend this calculation to the case of η meson photoproduction.

  13. Photoproduction and Decay of Light Mesons in CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Amaryan, Moskov Jamalovich [Old Dominion University

    2013-08-01

    We present preliminary experimental results on photoproduction and decay of light mesons measured with CLAS setup at JLAB . This include Dalitz decay of pseudoscalar and vector mesons, radiative decay of pseudoscalar mesons as well hadronic decays of pseudoscalar and vector mesons. The collected high statistics in some of decay channels exceeds the world data by an order of magnitude and some other decay modes are observed for the first time. It is shown how the CLAS data will improve the world data on transition form factors of light mesons, Dalitz plot analyses, branching ratios of rare decay modes and other fundamental properties potentially accessible through the light meson decays.

  14. Photoproduction of Light and Exotic Mesons in Hall D

    Science.gov (United States)

    Meyer, Curtis

    2000-10-01

    The Jefferson Lab Hall D collaboration is proposing a program to search for and study gluonic excitations of mesons using 8-9 GeV linearly polarized photon beams. By extending the nearly non-existent meson data in photoproduction, as well as taking advantage of a spin 1 probe, we expect to be able to produce and study hybrid mesons with exotic, or non q-barq quantum numbers. The properties of these mesons yield information on the dynamic nature of gluons, and yield information on the issue of confinement.

  15. Photoproduction of vector mesons off nucleons near threshold

    Energy Technology Data Exchange (ETDEWEB)

    Friman, B. [Technische Hochschule Darmstadt (Germany). Inst. fuer Kernphysik; Soyeur, M. [Laboratoire National Saturne, Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1995-12-31

    A simple meson-exchange model is proposed for the photoproduction of {rho}- and {omega}-mesons off protons near threshold. This model provides a good description of the available data and implies a large {rho}-nucleon interaction in the scalar channel ({sigma}-exchange). This phenomenological interaction is applied to estimate the leading contribution to the self-energy of {rho}-mesons in matter. The implications of our calculation for experimental studies of the {rho}-meson mass in nuclei are discussed. (author). 28 refs.

  16. Latest results from meson photoproduction at ELSA and MAMI

    Directory of Open Access Journals (Sweden)

    Krusche B.

    2014-06-01

    Full Text Available Photoproduction of mesons plays a key role for the investigation of the excitation spectrum of the nucleon and thus for our understanding of the strong interaction in the non-perturbative regime. In this contribution we discuss recent results from the experiments at the tagged photon beams of the electron accelerators ELSA in Bonn and MAMI in Mainz. They include the measurement of cross sections and (double polarization observables for single meson production and production of meson pairs off free protons as well as of quasi-free nucleons bound in light nuclei (in particular the deuteron.

  17. {eta} meson photoproduction on deuterium; Photoproduction du meson {eta} sur le deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann-Rothe, P.

    1996-05-30

    Measurements of the total and differential cross sections for {eta}-meson photoproduction on a D{sub 2} liquid target from threshold to 1.2 GeV, have been taken using the tagged Bremsstrahlung photon beam produced by the electrons extracted from the ELSA storage ring at Bonn. The reaction was identified by detecting the eta decay products in the neutral meson spectrometer SPES0-2{pi}, while the recoil baryons (proton, neutron or deuteron) were detected by a variety of large angle scintillator detectors. We succeeded to identify completely the final states corresponding to the production of an {eta} meson on a Quasi-Free (QF) proton, a QF neutron and the coherent deuteron. The differential cross sections corresponding to the production of a coherent deuteron n the final state have been measured, from threshold to 800 MeV; they are 6 times smaller the only previous measurement reported by Anderson and Prepost in 1969. This is consistent with an Isoscalar part of the Amplitude much smaller than the Isovector one. The differential cross sections are in good agreement with the theoretical prediction on the impulse approximation mechanism; indicating in particular, fairly small contributions from rescattering terms. A direct measurement of the neutron to proton cross section ratios has been obtained by integrating the counting rates on the corresponding QF peaks and is 0.70 {+-} 0.03, from 700 MeV to 900 MeV, with a small angular dependence. These two results by comparison to the measured free proton data should allow to reconstruct the free neutron cross sections in a rather model-independent way. (authors). 56 refs., 90 figs., 13 tabs.

  18. Photoproduction of Mesons on Quasi–Free Nucleons

    Directory of Open Access Journals (Sweden)

    Keshelashvili I.

    2014-01-01

    Full Text Available The investigation of excited baryon states is important to understand the underling nature/symmetries of hadronic matter. Historically, the first nucleon excitation experiments have been done using charged pion and kaon secondary beams. Later the antiproton-proton scattering has also been involved. However, since the beginning of the 90’s meson photoproduction reactions have been considered as a powerful tool in baryon spectroscopy. In this contribution, we overview our experimental programs conducted at the bremsstrahlung photon beams of the MAMI accelerator in Mainz and the ELSA accelerator in Bonn. The results are differential and total cross sections for photoproduction of light neutral mesons and of meson pairs off quasi-free nucleons bound in the deuteron (and sometimes other light nuclei. The scientific programs of this experiments also include single and double polarization measurements as well.

  19. Spin information from vector-meson decay in photoproduction

    Science.gov (United States)

    Kloet, W. M.; Chiang, Wen-Tai; Tabakin, Frank

    1998-08-01

    For the photoproduction of vector mesons, all single and double spin observables involving vector-meson two-body decays are defined consistently in the γN center-of-mass frame. These definitions yield a procedure for extracting physically meaningful single and double spin observables that are subject to known rules concerning their angle and energy evolution. As part of this analysis, we show that measuring the two-meson decay of a photoproduced ρ or φ does not determine the vector meson's vector polarization, but only its tensor polarization. The vector meson decay into lepton pairs is also insensitive to the vector meson's vector polarization, unless one measures the spin of one of the leptons. Similar results are found for all double spin observables which involve observation of vector-meson decay. To access the vector meson's vector polarization, one therefore needs to either measure the spin of the decay leptons, make an analysis of the background interference effects, or relate the vector meson's vector polarization to other accessible spin observables.

  20. Spin information from vector-meson decay in photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Kloet, W.M. [Department of Physics Astronomy, Rutgers University, Piscataway, New Jersey 08855-0849 (United States); Chiang, W.; Tabakin, F. [Department of Physics Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)

    1998-08-01

    For the photoproduction of vector mesons, all single and double spin observables involving vector-meson two-body decays are defined consistently in the {gamma}N center-of-mass frame. These definitions yield a procedure for extracting physically meaningful single and double spin observables that are subject to known rules concerning their angle and energy evolution. As part of this analysis, we show that measuring the two-meson decay of a photoproduced {rho} or {phi} does not determine the vector meson{close_quote}s vector polarization, but only its tensor polarization. The vector meson decay into lepton pairs is also insensitive to the vector meson{close_quote}s vector polarization, unless one measures the spin of one of the leptons. Similar results are found for all double spin observables which involve observation of vector-meson decay. To access the vector meson{close_quote}s vector polarization, one therefore needs to either measure the spin of the decay leptons, make an analysis of the background interference effects, or relate the vector meson{close_quote}s vector polarization to other accessible spin observables. {copyright} {ital 1998} {ital The American Physical Society}

  1. Exclusive photoproduction of gamma mesons at HERA

    NARCIS (Netherlands)

    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, 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.; Samson, U.; Schoenberg, V.; Shehzadi, R.; Wlasenko, M.; Brook, N. H.; Heath, G. P.; Kaur, M.; Kaur, P.; Singh, I.; Capua, M.; Fazio, S.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Tassi, E.; Kim, J. Y.; Ibrahim, Z. A.; Idris, F. Mohamad; Kamaluddin, B.; Abdullah, W. A. T. Wan; Ning, Y.; Ren, Z.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Galas, A.; Olkiewicz, K.; Pawlik, B.; Stopa, P.; Zawiejski, L.; Adamczyk, L.; Bold, T.; Grabowska-Bold, I.; Kisielewska, D.; Lukasik, J.; Przybycien, M.; Suszycki, L.; Kotanski, A.; Slominski, W.; Behnke, O.; Behr, J.; Behrens, U.; Blohm, C.; Borras, K.; Ciesielski, R.; Coppola, N.; Geiser, A.; Goettlicher, R.; Grebenyuk, J.; Gregor, I.; Haas, T.; Hain, W.; Huettmann, A.; Januschek, F.; Kahle, B.; Katkov, I. I.; Klein, U.; Koetz, U.; Kowalski, H.; Lisovyi, M.; Lobodzinska, E.; Loehr, B.; Mankel, R.; Melzer-Pellmann, I. -A.; Miglioranzi, S.; Montanari, A.; Namsoo, T.; Notz, D.; Parenti, A.; Roloff, P.; Rubinsky, I.; Schneekloth, U.; Spiridonov, A.; Szuba, D.; Szuba, J.; Theedt, T.; Tomaszewska, J.; 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.; Forrest, M.; Saxon, D. H.; Skillicorn, I. O.; Gialas, I.; Papageorgiu, K.; Holm, U.; Klanner, R.; Lohrmann, E.; Perrey, H.; Schleper, R.; 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.; Kuprash, O.; Libov, V.; Lontkovskyi, D.; Makarenko, I.; Sorokin, Iu.; Verbytskyi, A.; Volynets, O.; Zolko, M.; Son, D.; de Favereau, J.; Piotrzkowski, K.; Barreiro, F.; Glasman, C.; Jimenez, M.; del Peso, J.; Ron, E.; Terron, J.; Uribe-Estrada, C.; Corriveau, F.; Schwartz, J.; 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.; Kooijman, R.; Pellegrino, A.; Tiecke, H.; Vazquez, M.; 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.; Gwenlan, C.; Horton, K.; Oliver, K.; Robertson, A.; Walczak, R.; Bertolin, A.; Dal Corso, F.; Dusini, S.; Longhin, A.; Stanco, L.; Brugnera, R.; Carlin, R.; Garfagnini, A.; Limentani, S.; Oh, B. Y.; Raval, A.; Whitmore, J. J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cole, J. E.; Hart, J. C.; Abramowicz, H.; Ingbir, R.; Kananov, S.; Stern, A.; Kuze, M.; Maeda, J.; Hori, R.; Kagawa, S.; Okazaki, N.; Tawara, T.; Hamatsu, R.; Kaji, H.; Kitamura, S.; Ota, O.; Ri, Y. D.; Costa, M.; Ferrero, M. I.; Monaco, V.; Sacchi, R.; Sola, V.; Solano, A.; Arneodo, M.; Ruspa, M.; Fourletov, S.; Stewart, T. P.; Boutle, S. K.; Butterworth, J. M.; Jones, T. W.; Loizides, J. H.; Wing, M.; Brzozowska, B.; Ciborowski, J.; Grzelak, G.; Kulinski, P.; Luzniak, P.; Malka, J.; Nowak, R. J.; Pawlak, J. M.; Perlanski, W.; Zarnecki, A. F.; Adamus, M.; Plucinski, P.; Tymieniecka, T.; Eisenberg, Y.; Hochman, D.; Karshon, U.; Brownson, E.; Reeder, D. D.; Savin, A. A.; Smith, W. H.; Wolfe, H.; Bhadra, S.; Catterall, C. D.; Hartner, G.; Menary, S.; Noor, U.; Standage, J.; Whyte, J.

    2009-01-01

    The exclusive photoproduction reaction gamma p -> gamma 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. Incoherent photoproduction of {eta} mesons from the deuteron near threshold

    Energy Technology Data Exchange (ETDEWEB)

    Sibirtsev, A.; Elster, Ch.; Haidenbauer, J.; Speth, J.

    2001-08-01

    Incoherent photoproduction of the {eta} meson on the deuteron is studied for photon energies from threshold to 800 MeV. The dominant contribution, the {gamma}N-{eta}N amplitude, is described within an isobar model. The final state interaction derived from the CD-Bonn potential is included and found to be important for the description of the production cross section close to threshold. Possible effects from the {eta}N final state interaction are discussed.

  3. 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

  4. Photoproduction of ɛ'-mesons from the Proton

    Science.gov (United States)

    Elster, Ch.; Sibirtsev, A.; Krewald, S.; Speth, J.

    2004-08-01

    The presently available data for the reaction γp → η' p are analyzed in terms of a model in which the dominant production mechanism is the exchange of the vector mesons ω and ρ. To describe the data at photon energies close to the production threshold we introduce a resonance contribution due to the well established S11(1535) resonance. Finally we study the contributions due to nucleon exchange to the η' photoproduction and find, that those contributions can be seen at large angles in the differential cross section.

  5. Diffractive Photoproduction of Psi(2S) Mesons 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.; 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.; 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.; Wolf, E.A.De; 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.; 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.; 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.; 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.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Samson, J.; 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.; Strauch, I.; Straumann, U.; Swart, M.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vest, A.; Vichnevski, A.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; 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

    Results on diffractive photoproduction of psi(2S) mesons are presented using data collected between 1996 and 2000 with the H1 detector at the HERA ep collider. The data correspond to an integrated luminosity of 77 pb^(-1). The energy dependence of the diffractive psi(2S) cross section is found to be similar to or possibly somewhat steeper than that for J/psi mesons. The dependences of the elastic and proton dissociative psi(2S) photoproduction cross sections on the squared momentum transfer t at the proton vertex are measured. The t-dependence of the elastic channel, parametrised as e^(bt), yields b_(el)^(psi(2S))=(4.31+-0.57+-0.46) GeV^(-2), compatible with that of the J/psi. For the proton dissociative channel the result b_(pd)^(psi(2S))=(0.59+-0.13+-0.12) GeV^(-2) is 2.3 standard deviations smaller than that measured for the J/psi. With proper account of the individual wavefunctions theoretical predictions based on perturbative QCD are found to describe the measurements well.

  6. Photoproduction of $\\pi^+ \\pi^-$ meson pairs on the proton

    Energy Technology Data Exchange (ETDEWEB)

    Battaglieri, Marco A. [Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Genova; DeVita, Raffaella [Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Genova; Szczepaniak, Adam P. [Indiana Univ., Bloomington, IN (United States)

    2009-10-01

    The exclusive reaction $\\gamma p \\to p \\pi^+ \\pi^-$ was studied in the photon energy range 3.0 - 3.8 GeV and momentum transfer range $0.4<-t<1.0$ GeV$^2$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range the integrated luminosity was about 20 pb$^{-1}$. The reaction was isolated by detecting the $\\pi^+$ and proton in CLAS, and reconstructing the $\\pi^-$ via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the $S$, $P$, and $D$-waves in the $M_{\\pi^+\\pi^-}$ mass range $0.4-1.4$ GeV were derived performing a partial wave expansion of the extracted moments. Besides the dominant contribution of the $\\rho(770)$ meson in the $P$-wave, evidence for the $f_0(980)$ and the $f_2(1270)$ mesons was found in the $S$ and $D$-waves, respectively. The differential production cross sections $d\\sigma/dt$ for individual waves in the mass range of the above-mentioned mesons were extracted. This is the first time the $f_0(980)$ has been measured in a photoproduction experiment.

  7. Recent Results from Photoproduction of Mesons in A2

    Directory of Open Access Journals (Sweden)

    Walford Natalie

    2016-01-01

    Full Text Available Recent experiments using the Crystal Ball/TAPS setup at the MAMI accelerator in Mainz, Germany continue to study the properties and the excitation spectrum of the nucleon with meson photoproduction. Electromagnetic excitations of the proton and neutron are essential for understanding their isospin decomposition. The electromagnetic coupling of photons to protons is different than that of neutrons in certain states. Hence, a complete partial wave analysis (PWA can assist in yielding more information about any reaction, but gains from polarization observables constraining the fits. Polarization observables play a crucial role as they are essential in disentangling the contributing resonant and non-resonant amplitudes, whereas cross-section data alone is not sufficient for separating resonances. Preliminary results of polarization observables (E, T, and F of η and double π production off a polarized neutron (dButanol target are shown with comparison to predictions of recent multipole analyses. These results will allow for developing the world database.

  8. The FOREST detector for meson photoproduction experiments at ELPH

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, T., E-mail: ishikawa@lns.tohoku.ac.jp [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); Fujimura, H.; Fukasawa, H.; Hashimoto, R.; Ishida, T.; Kaida, S.; Kasagi, J. [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); Kawano, A. [Department of Information Science, Tohoku Gakuin University, Sendai 981–3193 (Japan); Kuwasaki, S. [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); Maeda, K. [Department of Physics, Tohoku University, Sendai 980–8578 (Japan); Miyahara, F.; Mochizuki, K.; Nakabayashi, T.; Nakamura, A.; Nawa, K.; Ogushi, S.; Okada, Y.; Okamura, K.; Onodera, Y.; Saito, Y. [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); and others

    2016-10-01

    An electromagnetic calorimeter complex, FOREST, has been constructed for meson photoproduction experiments at the Research Center for Electron Photon Science, Tohoku University. It consists of three types of calorimeters, which are made of pure cesium-iodide crystals, lead scintillating-fiber modules, and lead glass Cherenkov counters. Each calorimeter is equipped with a plastic scintillator hodoscope to identify charged particles. The design and performance of FOREST are described. The energy responses of test calorimeters have been investigated by using 100–800 MeV positron beams. The energy resolutions of the three calorimeters are found to be approximately 3%, 7%, and 5% for 1-GeV photons, respectively. A cryogenic hydrogen/deuterium target system fitted to the FOREST experiments and a newly developed data acquisition system are also presented.

  9. The Evolution of t dependence in Meson Photoproduction

    Science.gov (United States)

    Puentes, Daniel; Raue, Brian; Guo, Lei; Freese, Adam

    2016-03-01

    Studies of single-meson photoproduction off the proton over the past few decades have yielded tremendous amounts of data on differential cross sections. The wealth of data can be used to understand the exchange mechanisms responsible for the production of specific final-state hadrons. At low momentum transfer the differential cross section dσ / dt can be parameterized by the t-slope parameter b, where dσ / dt ~e-bt . We have determined b as a function of photon beam energy for the reactions γp -->K+Σ0 , γp -->K+ Λ , γp -->p ω , γp -->p η , γp -->pη' , γp -->pρ0 , γp -->pπ0 , and γp -->p ϕ . Preliminary results will be presented.

  10. Photoproduction of scalar mesons using CLAS at JLab

    Science.gov (United States)

    Chandavar, Shloka; Hicks, Kenneth; Weygand, Dennis; CLAS Collaboration

    2014-09-01

    The search for glueballs has been ongoing for decades. The lightest glueball has been predicted by quenched lattice QCD to have a mass in the range of 1.0-1.7 GeV and JPC =0++ . The mixing of glueball states with neighbouring meson states complicates their identification. The f0 (1500) is one of several candidates for the lightest glueball, whose presence in the Ks0 Ks0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. This is done by studying the reaction, γp -->fJ p -->Ks0> Ks0p --> 2 (π+π-) p using data from the g12 experiment. A brief description of this analysis, along with a preliminary partial wave analysis results will be presented. The search for glueballs has been ongoing for decades. The lightest glueball has been predicted by quenched lattice QCD to have a mass in the range of 1.0-1.7 GeV and JPC =0++ . The mixing of glueball states with neighbouring meson states complicates their identification. The f0 (1500) is one of several candidates for the lightest glueball, whose presence in the Ks0Ks0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. This is done by studying the reaction, γp -->fJ p -->Ks0 Ks0p --> 2 (π+π-) p using data from the g12 experiment. A brief description of this analysis, along with a preliminary partial wave analysis results will be presented. NSF.

  11. Photoproduction of mesons on the nucleon at intermediate energies; Photoproduction de mesons sur le nucleon aux energies intermediaires

    Energy Technology Data Exchange (ETDEWEB)

    Guidal, M

    1997-01-01

    In this work a model is proposed to simulate the photoproduction of pseudoscalar mesons ('PI' and K) on the nucleon at high energy. This model is based on the exchange of mesonic or baryonic Regge trajectories, it is gauge invariant and it uses a Feynman diagram formalism inspired from isobaric models. The measurements concerning the following reactions {gamma}p {yields} n{pi}{sup +}, {gamma}n {yields} p{pi}{sup -}, {gamma}p {yields} p{pi}{sup 0} and {gamma}n {yields} n{pi}{sup 0} are reviewed and the new model is confronted to the experimental results. The model gives a reasonable and coherent description of these 4 reactions. The model has also been applied to the photoproduction of strange mesons and of {lambda} and {sigma} baryons and has been extrapolated at low energy to the threshold of the reaction, the model matches the results even up to E{sub {gamma}} = 2 GeV for differential cross-sections and recoil polarization. An attempt has been made to associate a Regge based description, which is valid with low transfers, with perturbative quantum chromodynamics which is valid with high transfers. The model relies on the saturation of trajectories in the high transfer region and on the counting laws that give the right variation of the cross-section. It seems that a model based on linear trajectories can be reliable up to 4 GeV. The domain of high transfer has been too little investigated to provide enough experimental data to validate the model. An experiment whose purpose is to study the photoproduction of {phi} at high transfer, is proposed. This experiment requires an accelerator with high useful cycle because of the smallness of the expected cross-section. The CEBAF (continuous electron beam accelerator facility) as well as the CLAS 4{pi} detector is presented. The study of {gamma}p {yields} p{phi} and {gamma}p {yields} K{lambda}{sup *} (1520) requires the discrimination of kaons from pions so the measurement of 180 ps as time resolution allows the

  12. Experimental study of $\\eta$ meson photoproduction reaction at MAMI

    CERN Document Server

    Kashevarov, V L

    2015-01-01

    New data for the differential cross sections, polarization observables $T$, $F$, and $E$ in the reaction of $\\eta$ photoproduction on proton from the threshold up to a center-of-mass energy of W=1.9 GeV are presented. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. The polarization measurements were made using a frozen-spin butanol target and circularly polarized photon beam. The results are compared to existing experimental data and different PWA predictions. The data solve a long-standing problem related the angular dependence of older $T$ data close to threshold. The unexpected relative phase motion between $s$- and $d$-wave amplitudes required by the old data is not confirmed. At higher energies, all model predictions fail to reproduce the new polarization data indicating a significant impact on our understanding of the underlying dynamics of $\\eta$ meson photoproduction. Furthermore, we present a fit of the new data and e...

  13. Experimental study of η meson photoproduction reaction at MAMI

    Science.gov (United States)

    Kashevarov, V. L.

    2015-06-01

    New data for the differential cross sections, polarization observables T, F, and E in the reaction of η photoproduction on proton from the threshold up to a center-of-mass energy of W=1.9 GeV are presented. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. The polarization measurements were made using a frozen-spin butanol target and circularly polarized photon beam. The results are compared to existing experimental data and different PWA predictions. The data solve a long-standing problem related the angular dependence of older T data close to threshold. The unexpected relative phase motion between s- and d-wave amplitudes required by the old data is not confirmed. At higher energies, all model predictions fail to reproduce the new polarization data indicating a significant impact on our understanding of the underlying dynamics of η meson photoproduction. Furthermore, we present a fit of the new data and existing data from GRAAL for ∑ asymmetry based on an expansion in terms of associated Legendre polynomials. A Legendre decomposition shows the sensitivity to small partialwave contributions. The sensitivity of the Legendre coefficients to the nucleon resonance parameters is shown using the ηMAID isobar model.

  14. Experimental study of η meson photoproduction reaction at MAMI

    Directory of Open Access Journals (Sweden)

    Kashevarov V. L.

    2015-01-01

    Full Text Available New data for the differential cross sections, polarization observables T, F, and E in the reaction of η photoproduction on proton from the threshold up to a center-of-mass energy of W=1.9 GeV are presented. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. The polarization measurements were made using a frozen-spin butanol target and circularly polarized photon beam. The results are compared to existing experimental data and different PWA predictions. The data solve a long-standing problem related the angular dependence of older T data close to threshold. The unexpected relative phase motion between s- and d-wave amplitudes required by the old data is not confirmed. At higher energies, all model predictions fail to reproduce the new polarization data indicating a significant impact on our understanding of the underlying dynamics of η meson photoproduction. Furthermore, we present a fit of the new data and existing data from GRAAL for ∑ asymmetry based on an expansion in terms of associated Legendre polynomials. A Legendre decomposition shows the sensitivity to small partialwave contributions. The sensitivity of the Legendre coefficients to the nucleon resonance parameters is shown using the ηMAID isobar model.

  15. Inelastic Photoproduction of J/Psi Mesons 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.; 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.; 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.; 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.; 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.; 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.; Nozicka, M.; 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.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Samson, J.; 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.; Strauch, I.; Straumann, U.; Swart, M.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vest, A.; Vichnevski, A.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; 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

    An analysis of inelastic photoproduction of J/Psi mesons is presented using data collected at the ep collider HERA corresponding to an integrated luminosity of above 80pb-1. Differential and double differential cross sections are measured in a wide kinematic region: 60meson in the rest frame of the target proton. Cross sections at z<0.3 are presented for the first time. Theoretical calculations within the Colour Singlet Model at NLO for direct photon processes are shown to give a good description of the data in the medium z region (0.3

  16. Determining pseudoscalar meson photoproduction amplitudes from complete experiments

    Science.gov (United States)

    Sandorfi, A. M.; Hoblit, S.; Kamano, H.; Lee, T.-S. H.

    2011-05-01

    A new generation of complete experiments is focused on a high precision extraction of pseudoscalar meson photoproduction amplitudes. Here, we review the development of the most general analytic form of the cross section, dependent upon the three polarization vectors of the beam, target and recoil baryon, including all single-, double- and triple-polarization terms involving 16 spin-dependent observables. We examine the different conventions that have been used by different authors, and we present expressions that allow the direct numerical calculation of any pseudoscalar meson photoproduction observables with arbitrary spin projections from the Chew-Goldberger-Low-Nambu amplitudes. We use this numerical tool to clarify apparent sign differences that exist in the literature, in particular with the definitions of six double-polarization observables. We also present analytic expressions that determine the recoil baryon polarization, together with examples of their potential use with quasi-4π detectors to deduce observables. As an illustration of the use of the consistent machinery presented in this review, we carry out a multipole analysis of the γp → K+Λ reaction and examine the impact of recently published polarization measurements. When combining data from different experiments, we utilize the Fierz identities to fit a consistent set of scales. In fitting multipoles, we use a combined Monte Carlo sampling of the amplitude space, with gradient minimization, and find a shallow χ2 valley pitted with a very large number of local minima. This results in broad bands of multipole solutions that are experimentally indistinguishable. While these bands have been noticeably narrowed by the inclusion of new polarization measurements, many of the multipoles remain very poorly determined, even in sign, despite the inclusion of data on eight different observables. We have compared multipoles from recent PWA codes with our model-independent solution bands and found that such

  17. Photoproduction of the f1(1285 ) meson

    Science.gov (United States)

    Dickson, R.; Schumacher, R. A.; Adhikari, K. P.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Badui, R. A.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Holtrop, M.; Hicks, K.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mattione, P.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Markov, N.; Mokeev, V.; Moriya, K.; Munevar, E.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Salgado, C.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, E. S.; Smith, G. D.; Sober, D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Stankovic, I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weygand, D.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.; CLAS Collaboration

    2016-06-01

    The f1(1285 ) meson with mass 1281.0 ±0.8 MeV/c2 and width 18.4 ±1.4 MeV (full width at half maximum) was measured for the first time in photoproduction from a proton target using CLAS at Jefferson Lab. Differential cross sections were obtained via the η π+π-,K+K¯0π- , and K-K0π+ decay channels from threshold up to a center-of-mass energy of 2.8 GeV. The mass, width, and an amplitude analysis of the η π+π- final-state Dalitz distribution are consistent with the axial-vector JP=1+ f1(1285 ) identity, rather than the pseudoscalar 0- η (1295 ) . The production mechanism is more consistent with s -channel decay of a high-mass N* state and not with t -channel meson exchange. Decays to η π π go dominantly via the intermediate a0±(980 ) π∓ states, with the branching ratio Γ [a0π (noK ¯K )] /Γ [η π π (all)] =0.74 ±0.09 . The branching ratios Γ (K K ¯π ) /Γ (η π π ) =0.216 ±0.033 and Γ (γ ρ0) /Γ (η π π ) =0.047 ±0.018 were also obtained. The first is in agreement with previous data for the f1(1285 ) , while the latter is lower than the world average.

  18. Revealing transversity GPDs through the photoproduction of a photon and a ρ meson

    Directory of Open Access Journals (Sweden)

    Boussarie R.

    2016-01-01

    Full Text Available Photoproduction of a pair of particles with large invariant mass is a natural extension of collinear QCD factorization theorems which have been much studied for deeply virtual Compton scattering and deeply virtual meson production. We discuss the production of a photon and a meson, where the wide angle Compton scattering on a meson subprocess factorizes from generalized parton distribution. We calculate at dominant twist and leading order in αs, the production cross-section of a transversely polarized ρ meson which is sensitive to chiral-odd GPDs, and show that it may be measurable in near future JLab experiments.

  19. phi-meson photoproduction on Hydrogen in the neutral decay mode

    Energy Technology Data Exchange (ETDEWEB)

    Seraydaryan, Helena [ODU; Amaryan, Moscov J. [ODU; Gavalian, Gagik [JLAB; Baghdasaryan, Hovhannes A. [UVA; Weinstein, Larry [ODU

    2014-05-01

    We report the first measurement of the photoproduction cross section of the $\\phi$ meson in its neutral decay mode in the reaction $\\gamma p \\to p\\phi(K_SK_L)$. The experiment was performed with a tagged photon beam of energy $1.6 \\le E_\\gamma \\le 3.6$ GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The $p \\phi$ final state is identified via reconstruction of $K_S$ in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction $\\gamma p \\to p K_S X$ to be $K_L$. The presented results significantly enlarge the existing data on $\\phi$-photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of $\\phi$ photoproduction.

  20. 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

  1. Inclusive photoproduction of {rho}{sup 0}, K{sup *0} and {phi} mesons 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 Physical Inst., Moscow (RU)] (and others)

    2008-12-15

    Inclusive non-diffractive photoproduction of {rho}(770){sup 0}, K{sup *}(892){sup 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

  2. Photoproduction of the eta prime meson in the effective Lagrangian approach

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, N.C.; Zhang, J.F. [Rensselaer Polytechnic Inst., Troy, NY (United States); Benmerrouche, M. [Univ. of Saskatchewan, Saskaton (Canada)

    1994-04-01

    In the framework of the effective Lagrangian approach, the authors study the {eta}{prime} photoproduction off protons, of great interest at CEBAF I and II. They calculate the contributions from the leading nucleon Born terms, vector meson exchanges, and estimate the resonance contributions, using the transition amplitudes from the recent quark model estimates by Capstick and Roberts. They discuss implications for the CEBAF experiments.

  3. Photoproduction of the f1(1285)/η(1295) Mesons using CLAS at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, Ryan [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2011-07-18

    This work presents the results of analysis of a meson mass mx =1281.0 ± 0.8 MeV/ c2 and a FWHM of Γx = 18.4 ± 1.4 MeV/ c2 seen in CLAS at Jefferson Lab in photoproduction off the proton, γp → xp.

  4. Elastic Photoproduction of $J/\\psi$ and $\\Upsilon$ 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.; Hauschildt, T.; 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.; Hilton, C.D.; 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.; Kolanoski, H.; 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.; List, B.; 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, A.; 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, D.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Negri, I.; 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.; Schleif, S.; 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.; zur Nedden, M.

    2000-01-01

    Cross sections for elastic photoproduction of J/Psi and Upsilon mesons are presented. For J/Psi mesons the dependence on the photon-proton centre-of-mass energy W_gammap is analysed in an extended range with respect to previous measurements of 26<=W_gammap<= 285 GeV. The measured energy dependence is parameterized as sigma_gammap proportional W_gammap^delta with delta=0.83+-0.07. The differential cross section dsigma/dt for J/Psi mesons is derived, its dependence on W_gammap and on t is analysed and the effective trajectory (in terms of Regge theory) is determined to be alpha(t)=(1.27+-0.05)+(0.08+-0.17)*t/GeV^2. Models based on perturbative QCD and on pomeron exchange are compared to the data.

  5. Photoproduction de Mesons sur le Nucleon aux Energies Intermediaire (in French) [Photoproduction of mesons on the nucleon at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Guidal, Michel [Univ. of Paris, Orsay (France)

    1996-12-13

    One object of this thesis is to propose a model taking account of low transfer reaction mechanisms for a series of photoproduction reactions on nucleons for photon energies ≳4 GeV. If our comprehension of processes with low transfers is correct, then extrapolating our model in the domain of large transfers and the comparison with data supplied will give us information on the domains in energy and transfers from which an interpretation of reactions in terms of the "soft" process ceases to be valid. In the domain of large transfers, only one approach in terms of "hard" process can then explain the data. We are interested in electromagnetic photoproduction reactions because the probe, firstly, interacts with the target via an exact and well known mechanism (described by the QED theory) and also eliminates the interaction phenomena in the initial state. No probe is as well known as the photon. The extraction of reaction mechanisms, amplitudes and coupling constants match is made easier than in the case of hadronic probes. The energy domain Eγ >4 GeV studied is particularly interesting because it is from this energy of incident photons that can be expected to achieve large enough pulse transfers to hope for emergence of hard processes and therefore see the cessation of validity of interpretation of hadron models. Also, resonance effects are minor and do not interfere with our interpretations. Experimentally, this area is widely unexplored and the new generation accelerators of a large duty cycle (CEBAF, MAMI, ESRF, ELF, ...) combined with 4π detectors will allow to precisely measure low cross sections reactions of a large transfer. We first study pion photoproduction reactions on nucleon because they are the most experimentally accessible reactions and many data of high energy and low transfers exist. This will require strong constraints on the model parameters of the numerous analyses performed previously. Then we'll move on to kaon photoproduction

  6. Baryon Spectroscopy Through Partial-Wave Analysis and Meson Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Manley, D. Mark [Kent State Univ., Kent, OH (United States)

    2016-09-08

    The principal goal of this project is the experimental and phenomenological study of baryon spectroscopy. The PI's group consists of himself and three graduate students. This final report summarizes research activities by the PI's group during the period 03/01/2015 to 08/14/2016. During this period, the PI co-authored 11 published journal papers and one proceedings article and presented three invited talks. The PI's general interest is the investigation of the baryon resonance spectrum up to masses of ~ 2 GeV. More detail is given on two research projects: Neutral Kaon Photoproduction and Partial-Wave Analyses of γp → η p, γn → η n, and γp → K⁺ Λ.

  7. Exclusive $\\rho^0$ Meson Photoproduction with a Leading Neutron at HERA

    CERN Document Server

    Andreev, V.; Begzsuren, K.; Belousov, A.; Bolz, A.; Boudry, V.; Brandt, G.; Brisson, V.; Britzger, D.; Buniatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; 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.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Haidt, D.; Henderson, R.C.W.; Hladký, 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.; Krüger, 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.; Müller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nowak, G.; Olsson, J.E.; Ozerov, D.; 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.; Rusakov, S.; Šálek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schöning, A.; 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.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkárová, A.; Vallée, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wünsch, E.; Žáček, J.; Zhang, Z.; Žlebčík, R.; Zohrabyan, H.; Zomer, F.

    2016-01-23

    A first measurement is presented of exclusive photoproduction of $\\rho^0$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years $2006$ and $2007$ at a centre-of-mass energy of $\\sqrt{s}=319$ GeV and correspond to an integrated luminosity of $1.16$ pb$^{-1}$. The $\\rho^0$ mesons with transverse momenta $p_T0.35$, are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality $Q^2 < 2$ GeV$^2$, the total energy of the photon-proton system $20 < W_{\\gamma p} < 100$ GeV and the polar angle of the leading neutron $\\theta_n < 0.75$ mrad. The cross section of the reaction $\\gamma p \\to \\rho^0 n \\pi^+$ is measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a $\\rho^0$ meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross se...

  8. Photoproduction of the rho^0 Meson on the Proton at Large Momentum Transfer

    Energy Technology Data Exchange (ETDEWEB)

    M. Battaglieri; E. Anciant; M. Anghinolfi; R. De Vita; E. Golovach; J. M. Laget; V. Mokeev; M. Ripani; G. Adams; M. J. Amaryan; D. S. Armstrong; B. Asavapibhop; G. Asryan; G. Audit; T. Auger; H. Avakian; S. Barrow; K. Beard; M. Bektasoglu; B. L. Berman; N. Bianchi; A. S. Biselli; S. Boiarinov; D. Branford; W. J. Briscoe; W. K. Brooks; V. D. Burkert; J. R. Calarco; G. P. Capitani; D. S. Carman; B. Carnahan; A. Cazes; C. Cetina; P. L. Cole; A. Coleman; D. Cords; P. Corvisiero; D. Crabb; H. Crannell; J. P. Cummings; E. DeSanctis; P. V. Degtyarenko; R. Demirchyan; H. Denizli; L. Dennis; K. V. Dharmawardane; K. S. Dhuga; C. Djalali; G. E. Dodge; D. Doughty; P. Dragovitsch; M. Dugger; S. Dytman; M. Eckhause; H. Egiyan; K. S. Egiyan; L. Elouadrhiri; L. Farhi; R. J. Feuerbach; J. Ficenec; T. A. Forest; A. P. Freyberger; V. Frolov; H. Funsten; S. J. Gaff; M. Gai; S. Gilad; G. P. Gilfoyle; K. L. Giovanetti; K. Griffioen; M. Guidal; M. Guillo; V. Gyurjyan; D. Hancock; J. Hardie; D. Heddle; F. W. Hersman; K. Hicks; R. S. Hicks; M. Holtrop; C. E. Hyde-Wright; M. M. Ito; K. Joo; J. H. Kelley; M. Khandaker; W. Kim; A. Klein; F. J. Klein; M. Klusman; M. Kossov; L. H. Kramer; Y. Kuang; S. E. Kuhn; D. Lawrence; M. Lucas; K. Lukashin; R. W. Major; J. J. Manak; C. Marchand; S. McAleer; J. McCarthy; J. W. C. McNabb; B. A. Mecking; M. D. Mestayer; C. A. Meyer; K. Mikhailov; R. Minehart; M. Mirazita; R. Miskimen; V. Muccifora; J. Mueller; G. S. Mutchler; J. Napolitano; S. O. Nelson; B. B. Niczyporuk; R. A. Niyazov; J. T. O' Brien; A. K. Opper; G. Peterson; S. A. Philips; N. Pivnyuk; D. Pocanic; O. Pogorelko; E. Polli; B. M. Preedom; J. W. Price; D. Protopopescu; L. M. Qin; B. A. Raue; A. R. Reolon; G. Riccardi; G. Ricco; B. G. Ritchie; F. Ronchetti; P. Rossi; D. Rowntree; P. D. Rubin; K. Sabourov; C. Salgado; M. Sanzone-Arenhovel; V. Sapunenko; R. A. Schumacher; V. S. Serov; A. Shafi; Y. G. Sharabian; J. Shaw; A. V. Skabelin; E. S. Smith; T. Smith; L. C. Smith; D. I. Sober; M. Spraker; A. Stavinsky; S. Stepanyan; P. Stoler; M. Taiuti; S. Taylor; D. J. Tedeschi; L. Todor; R. Thompson; M. F. Vineyard; A. V. Vlassov; L. B. Weinstein; A. Weisberg; H. Weller; D. P. Weygand; C. S. Whisnant; E. Wolin; M. Wood; A. Yegneswaran; J. Yun; B. Zhang; J. Zhao; Z. Zhou

    2001-10-01

    The differential cross section, d{sigma}/dt, for p0 meson photoproduction on the proton above the resonance region was measured up to a momentum transfer -t = 5 GeV2 using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The p0 channel was extracted from the measured two charged-pion cross sections by fitting the {pi}+{pi}- and p{pi}+ invariant masses. The low momentum transfer region shows the typical diffractive pattern expected from Reggeon exchange. The flatter behavior at large -t cannot be explained solely in terms of QCD-inspired two-gluon exchange models. The data indicate that other processes, like quark interchange, are important to fully describe p photoproduction.

  9. {eta}N final-state interaction in incoherent photoproduction of {eta}-mesons from the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, S.; Sibirtsev, A.; Haidenbauer, J.; Krewald, S.; Speth, J. [Institut fuer Kernphysik, Forschungszentrum Juelich, D-52425, Juelich (Germany); Elster, C. [Institut fuer Kernphysik, Forschungszentrum Juelich, D-52425, Juelich (Germany); Institute of Nuclear and Particle Physics, Ohio University, OH 45701, Athens (United States)

    2003-11-01

    An analysis of incoherent photoproduction of {eta}-mesons from the deuteron is presented. We concentrate here on the threshold region. The dominant contribution, the {gamma}N-{eta}N amplitude is described within an isobar model. Effects of the final-state interaction in the NN as well as the {eta}N systems are included by employing models derived within a meson-exchange approach. (orig.)

  10. Quasi-free photoproduction of {eta}-mesons off {sup 3}He nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Witthauer, L.; Werthmueller, D.; Keshelashvili, I.; Dieterle, M.; Jaegle, I.; Kaeser, A.; Krusche, B.; Maghrbi, Y.; Oberle, M.; Pheron, F.; Rostomyan, T. [University of Basel, Department of Physics, Basel (Switzerland); Aguar-Bartolome, P.; Ahrens, J.; Arends, H.J.; Heid, E.; Jahn, O.; Martinez, M.; Ostrick, M.; Rost, M.; Thomas, A. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Annand, J.R.M.; Hamilton, D.; Howdle, D.; Livingston, K.; MacGregor, I.J.D.; Mancell, J.; McGeorge, J.C.; McNicoll, E.; Robinson, J.; Rosner, G. [University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); Bantawa, K.; Manley, D.M. [Kent State University, Kent, Ohio (United States); Beck, R.; Nikolaev, A.; Schumann, S.; Unverzagt, M. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Bekrenev, V.; Kruglov, S.P.; Kulbardis, A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Braghieri, A.; Mushkarenkov, A.; Pedroni, P. [INFN, Pavia (Italy); Branford, D.; Glazier, D.I.; Jude, T.C.; Sikora, M.H.; Watts, D.P. [University of Edinburgh, School of Physics, Edinburgh (United Kingdom); Briscoe, W.J.; Demissie, B.; Marinides, Z. [The George Washington University, Institute for Nuclear Studies, Washington, DC (United States); Brudvik, J.; Nefkens, B.M.K.; Starostin, A. [University of California Los Angeles, Los Angeles, California (United States); Cherepnya, S.; Fil' kov, L.V. [Lebedev Physical Institute, Moscow (Russian Federation); Downie, E.J. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); The George Washington University, Institute for Nuclear Studies, Washington, DC (United States); Drexler, P.; Metag, V.; Novotny, R. [University of Giessen, II. Physikalisches Institut, Giessen (Germany); Fix, A. [Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation); Hornidge, D.; Middleton, D.G. [Mount Allison University, Sackville (Canada); Huber, G.M. [University of Regina, Regina (Canada); Kashevarov, V.L. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Lebedev Physical Institute, Moscow (Russian Federation); Kondratiev, R.; Lisin, V.; Polonski, A. [Institute for Nuclear Research, Moscow (Russian Federation); Korolija, M.; Supek, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Oussena, B. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); The George Washington University, Institute for Nuclear Studies, Washington, DC (United States); Prakhov, S. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); The George Washington University, Institute for Nuclear Studies, Washington, DC (United States); University of California Los Angeles, Los Angeles, California (United States); Sober, D. [The Catholic University of America, Washington, DC (United States); Thiel, M. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Giessen, II. Physikalisches Institut, Giessen (Germany); Collaboration: Crystal Ball/TAPS experiment at MAMI, the A2 Collaboration

    2013-12-15

    Quasi-free photoproduction of {eta}-mesons has been measured off nucleons bound in {sup 3}He nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost 4{pi} covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The {eta}-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the S{sub 11}(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron results. On an absolute scale the cross sections for both quasi-free protons and neutrons are suppressed with respect to the deuteron target pointing to significant nuclear final-state interaction effects. (orig.)

  11. Quasi-free photoproduction of eta-mesons off 3He nuclei

    CERN Document Server

    Witthauer, L; Keshelashvili, I; Aguar-Bartolome, P; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Beck, R; Bekrenev, V; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Demissie, B; Dieterle, M; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Glazier, D I; Hamilton, D; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jaegle, I; Jahn, O; Jude, T C; Kaeser, A; Kashevarov, V L; Kondratiev, R; Korolija, M; Kruglov, S P; Krusche, B; Kulbardis, A; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; Martinez, M; McGeorge, J C; McNicoll, E; Metag, V; Middleton, D G; Mushkarenkov, A; Nefkens, B M K; Nikolaev, A; Novotny, R; Oberle, M; Ostrick, M; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S; Robinson, J; Rosner, G; Rost, M; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D; Starostin, A; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P

    2013-01-01

    Quasi-free photoproduction of $\\eta$-mesons has been measured off nucleons bound in $^3$He nuclei for incident photon energies from the threshold region up to 1.4 GeV. The experiment was performed at the tagged photon facility of the Mainz MAMI accelerator with an almost $4\\pi$ covering electromagnetic calorimeter, combining the TAPS and Crystal Ball detectors. The $\\eta$-mesons were detected in coincidence with the recoil nucleons. This allowed a comparison of the production cross section off quasi-free protons and quasi-free neutrons and a full kinematic reconstruction of the final state, eliminating effects from nuclear Fermi motion. In the $S_{11}$(1535) resonance peak, the data agree with the neutron/proton cross section ratio extracted from measurements with deuteron targets. More importantly, the prominent structure observed in photoproduction off quasi-free neutrons bound in the deuteron is also clearly observed. Its parameters (width, strength) are consistent with the expectations from the deuteron r...

  12. Exclusive ρ{sup 0} meson photoproduction with a leading neutron 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. [Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bolz, A.; Huber, F.; Radescu, V.; 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.; Kleinwort, C.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; 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. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Moscow Institute of Physics and Technology, Moscow (Russian Federation); Bystritskaya, L.; Fedotov, 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); Cerny, K.; Pokorny, B.; 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.; Hladka, 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. [Fachbereich C, Universitaet Wuppertal, Wuppertal (Germany); Universitaet Wuppertal, Rechenzentrum, 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. [Paul Scherrer Institut, Villigen (Switzerland); Favart, L.; Grebenyuk, A.; Hreus, T.; Janssen, X.; Roosen, R.; Van Mechelen, P. [Inter-University Institute for High Energies ULB-VUB, Brussels and Universiteit Antwerpen, Antwerp (Belgium); Feltesse, J.; Schoeffel, L. [Irfu/SPP, CE Saclay, Gif-sur-Yvette Cedex (France); Ferencei, J. [Slovak Academy of Sciences, Institute of Experimental Physics, Kosice (Slovakia); Goerlich, L.; Mikocki, S.; Nowak, G.; Sopicki, P.; Turnau, J. [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, Lancaster (United Kingdom); Jung, H. [Inter-University Institute for High Energies ULB-VUB, Brussels and Universiteit Antwerpen, Antwerp (Belgium); DESY, Hamburg (Germany); Kapichine, M.; Morozov, A.; Spaskov, V. [Joint Institute for Nuclear Research, Dubna (RU); Kogler, R. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (DE); Landon, M.P.J.; Rizvi, E.; Traynor, D. [Queen Mary, University of London, School of Physics and Astronomy, London (GB); Lange, W.; Naumann, T. [DESY, Zeuthen (DE); Martyn, H.U. [I. Physikalisches Institut der RWTH, Aachen (DE); Meyer, H. [Fachbereich C, Universitaet Wuppertal, Wuppertal (DE); Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P. [Physik-Institut der Universitaet Zuerich, Zurich (CH); Perez, E. [CERN, Geneva (CH); Picuric, I.; Raicevic, N. [University of Montenegro, Faculty of Science, Podgorica (ME); Polifka, R. [Charles University, Faculty of Mathematics and Physics, Prague (CZ); University of Toronto, Department of Physics, Toronto, ON (CA); Povh, B. [Max-Planck-Institut fuer Kernphysik, Heidelberg (DE); 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, CNRS/IN2P3, LAPP, Annecy-le-Vieux (FR); Soloviev, Y. [DESY, Hamburg (DE); Lebedev Physical Institute, Moscow (RU); Stella, B. [Universita di Roma Tre, Dipartimento di Fisica, Rome (IT); INFN Roma 3 (IT); Sykora, T. [Inter-University Institute for High Energies ULB-VUB, Brussels and Universiteit Antwerpen, Antwerp (BE); Charles University, Faculty of Mathematics and Physics, Prague (CZ); Tsakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (BG); Tseepeldorj, B. [Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (MN); Ulaanbaatar University, Ulaanbaatar (MN); Wegener, D. [TU Dortmund, Institut fuer Physik, Dortmund (DE); Collaboration: H1 Collaboration

    2016-01-15

    A first measurement is presented of exclusive photoproduction of ρ{sup 0} mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of √(s) = 319 GeV and correspond to an integrated luminosity of 1.16 pb{sup -1}. The ρ{sup 0} mesons with transverse momenta p{sub T} < 1 GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, x{sub L} > 0.35, are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality Q{sup 2} < 2 GeV{sup 2}, the total energy of the photon.proton system 20 < W{sub γp} < 100 GeV and the polar angle of the leading neutron θ{sub n} < 0.75 mrad. The cross section of the reaction γp → ρ{sup 0}nπ{sup +} is measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a ρ{sup 0} meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering, σ{sup el}(γπ{sup +} → ρ{sup 0}π{sup +}), is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction γp → ρ{sup 0}nπ{sup +}. (orig.)

  13. 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 100meson differential cross sections are measured 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.)

  14. 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 100meson differential cross sections are measured 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.)

  15. Primordial GWs from universality classes of pseudo-scalar inflation

    Science.gov (United States)

    Pieroni, M.

    2017-05-01

    In this contribution we discuss the possibility of generating an observable gravitational wave (GW) background by coupling a pseudo-scalar inflaton to some Abelian gauge fields. This analysis is performed by dividing inflationary models into universality classes. We find that of the most promising scenario is a Starobinsky-like model, which may lead to the generation of observational signatures both in upcoming CMB detectors as well as for direct GW detectors. The signal which can be produced in these models would both be observable in ground-based detectors, such as advanced LIGO, and in space-based detectors, such as LISA. The complementarity between the CMB and direct GW detection may be used to extract informations on the microphysics of inflation. Interestingly the mechanism discussed in this contribution may also be relevant for the generation of Primordial Black Holes (PBHs).

  16. Photoproduction of $D^{*\\pm}$ mesons associated with a leading neutron

    CERN Document Server

    Abramowicz, H; Adamus, M; Adler, V; Aghuzumtsyan, G; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M; Bellagamba, L; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Catterall, C D; Chekanov, S; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cloth, P; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Cottrell, A; D'Agostini, Giulio; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Deshpande, A A; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fricke, U; Fusayasu, T; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Gliga, S; Goers, S; Golubkov, Yu A; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Grijpink, S; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, P; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karstens, F; Kataoka, M; Katkov, I I; Kcira, D; Khein, L A; Kim, J Y; Kim, Y K; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhav--, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kowalski, T; Krakauer, D A; Kramberger, G; Kreisel, A; Krumnack, N; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lainesse, J; Lammers, S; Lee, J H; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukina, O Yu; Luzniak, P; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; McCubbin, N A; Mellado, B; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Mus, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Paganis, S; Palmonari, F; Parenti, A; Park, I H; Patel, S; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Riveline, U Karshon M; Robins, S; Rosin, M; Rurua, L; Ruspa, M; Sacchi, R; Salehi, H; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Vázquez, M; Velthuis, J J; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Weber, A; Whitmore, J J; Wichmann, K; Wick, K; Wiggers, L; Wing, M; Wolf, G; Yamada, S; Yamashita, T; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Wolf, E; Del Peso, J

    2004-01-01

    The photoproduction of $D^{*\\pm} (2010)$ mesons associated with a leading neutron has been observed with the ZEUS detector in $ep$ collisions at HERA using an integrated luminosity of 80 pb$^{-1}$. The neutron carries a large fraction, {$x_L>0.2$}, of the incoming proton beam energy and is detected at very small production angles, {$\\theta_n 1.9$ GeV}, which is large compared to the average transverse momentum of the neutron of 0.22 GeV. The ratio of neutron-tagged to inclusive $D^*$ production is $8.85\\pm 0.93({\\rm stat.})^{+0.48}_{-0.61}({\\rm syst.})\\%$ in the photon-proton center-of-mass energy range {$130

  17. Vector meson-baryon dynamics in photoproduction reactions around 2 GeV

    Directory of Open Access Journals (Sweden)

    Ramos A.

    2014-01-01

    Full Text Available We investigate the role of vector mesons and coupled-channel unitarization on photoproduction reactions o_ the proton at energies around 2 GeV. We explain the sudden drop on the γp → K0Σ+ cross section, observed recently by the CBELSA/TAPS collaboration, by a delicate interference between amplitudes having K*Λ and K*Σ intermediate states modulated by the presence of a nearby N* resonance produced by our model, a feature that we have employed to predict its properties. We also show the importance of coupled-channel unitarization in the γp → K*0Σ+ reaction, measured recently by CBELSA/TAPS and CLAS with conflicting results.

  18. Studies of Final-State Interactions via Helicity Asymmetries in Exclusive Pseudoscalar Meson Photoproduction off Deuteron

    Science.gov (United States)

    Ilieva, Yordanka

    2017-05-01

    Exclusive meson photoproduction off deuteron is a great tool to study final-state interactions (FSI) between the hadrons produced in the scattering of the incident photon off one of the target nucleons and the spectator nucleon. FSI in the reaction γ d→ K^+Λ n allow to access the dynamics of Λ n elastic scattering and provide a method of studying the hyperon-nucleon ( YN) interaction. Also, as deuteron is often used as a neutron target, FSI contribute to the reaction dynamics in addition to the quasi-free mechanism and their understanding is critical for the estimate of observables off the free neutron. Here we show preliminary results for beam-helicity asymmetries for the reactions {γ } d→ K^+Λ n and {γ } d→ pπ ^+π ^- n and their evolution over the spectator-nucleon momentum. The data were obtained with the CEBAF Large Acceptance Spectrometer at Thomas Jefferson National Accelerator Facility (JLab). We show how to kinematically select an event sample dominated by a specific FSI mechanism. We also discuss a method to extract polarization observables for photoproduction off the free nucleon using the helicity asymmetries for reactions off the deuteron.

  19. Coherent photoproduction of {pi}{sup 0}- and {eta}-mesons off {sup 7}Li

    Energy Technology Data Exchange (ETDEWEB)

    Maghrbi, Y.; Krusche, B.; Boillat, B.; Jaegle, I.; Keshelashvili, I.; Pheron, F.; Werthmueller, D.; Zehr, F. [University of Basel, Department of Physics, Basel (Switzerland); Ahrens, J.; Arends, H.J.; Heid, E.; Jahn, O.; Krambrich, D.; Martinez, M.; Ostrick, M.; Rost, M.; Thomas, A. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Annand, J.R.M.; Codling, R.F.B.; Livingston, K.; MacGregor, I.J.D.; McGeorge, J.C.; Rosner, G. [University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); Beck, R.; Lang, M.; Nikolaev, A.; Schumann, S.; Unverzagt, M. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Bekrenev, V. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Braghieri, A.; Pedroni, P.; Rostomyan, T. [INFN, Sezione di Pavia, Pavia (Italy); Branford, D.; Glazier, D.I.; Tarbert, C.M.; Watts, D.P. [University of Edinburgh, School of Physics, Edinburgh (United Kingdom); Briscoe, W.J. [The George Washington University, Center for Nuclear Studies, Washington, DC (United States); Brudvik, J.; Nefkens, B.M.K.; Prakhov, S.; Price, J.W.; Starostin, A. [University of California Los Angeles, Los Angeles, California (United States); Cherepnya, S.; Fil' kov, L.V. [Lebedev Physical Institute, Moscow (Russian Federation); Downie, E.J. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); The George Washington University, Center for Nuclear Studies, Washington, DC (United States); Drexler, P.; Gregor, R.; Lugert, S.; Metag, V.; Novotny, R.; Schadmand, S. [University of Giessen, II. Physikalisches Institut, Giessen (Germany); Fix, A. [Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation); Hornidge, D. [Mount Allison University, Sackville (Canada); Kashevarov, V.L. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Lebedev Physical Institute, Moscow (Russian Federation); Knezevic, A.; Korolija, M.; Mekterovic, D.; Supek, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Kondratiev, R.; Lisin, V.; Polonski, A. [Institute for Nuclear Research, Moscow (Russian Federation); Manley, D.M. [Kent State University, Kent, Ohio (United States); Sober, D. [The Catholic University of America, Washington, DC (United States); Collaboration: The Crystal Ball at MAMI, TAPS, and A2 Collaborations

    2013-03-15

    Coherent photoproduction of {pi}{sup 0}-mesons from threshold (E{sub th} {approx} 136 MeV) throughout the {Delta}-resonance region and of {eta}-mesons close to the production threshold (E{sub th} {approx} 570 MeV) for {eta} has been measured for {sup 7}Li nuclei. The experiment was performed using the tagged-photon beam of the Mainz MAMI accelerator with the Crystal Ball and TAPS detectors combined to give an almost 4 {pi} solid-angle electromagnetic calorimeter. The reactions were identified by a combined invariant-mass and missing-energy analysis. A comparison of the pion data to plane-wave impulse modelling tests the nuclear mass form factor. So far coherent {eta} production had been only identified for the lightest nuclear systems ({sup 2}H and {sup 3}He). For {sup 3}He a large enhancement of the cross section above plane-wave approximations had been reported, indicating the formation of a quasi-bound state. The present Li data for {eta} production agree with a plane-wave approximation. Contrary to {sup 3}He, neither a threshold enhancement of the total cross section nor a deviation of the angular distributions from the expected form factor dependence were observed. (orig.)

  20. Coherent photoproduction of pi^0- and eta-mesons off 7Li

    CERN Document Server

    Maghrbi, Y; Ahrens, J; Annand, J R M; Arends, H J; Beck, R; Bekrenev, V; Boillat, B; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Codling, R F B; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Glazier, D I; Gregor, R; Heid, E; Hornidge, D; Jaegle, I; Jahn, O; Kashevarov, V L; Keshelashvili, I; Knezevic, A; Kondratiev, R; Korolija, M; Krambrich, D; Lang, M; Lisin, V; Livingston, K; Lugert, S; MacGregor, I J D; Manley, D M; Martinez, M; McGeorge, J C; Mekterovic, D; Metag, V; Nefkens, B M K; Nikolaev, A; Novotny, R; Ostrick, M; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S; Price, J W; Rosner, G; Rost, M; Rostomyan, T; Schadmand, S; Schumann, S; Sober, D; Starostin, A; Supek, I; Tarbert, C M; Thomas, A; Unverzagt, M; Watts, D P; Werthmueller, D; Zehr, F

    2013-01-01

    Coherent photoproduction of $\\pi^0$-mesons from threshold ($E_{th} \\approx$ 136 MeV) throughout the $\\Delta$-resonance region and of $\\eta$-mesons close to the production threshold ($E_{th} \\approx$ 570 MeV for $\\eta$) has been measured for $^7$Li nuclei. The experiment was performed using the tagged-photon beam of the Mainz MAMI accelerator with the Crystal Ball and TAPS detectors combined to give an almost 4$\\pi$ solid-angle electromagnetic calorimeter. The reactions were identified by a combined invariant-mass and missing-energy analysis. A comparison of the pion data to plane-wave impulse modelling tests the nuclear mass form factor. So far coherent $\\eta$-production had been only identified for the lightest nuclear systems ($^2$H and $^3$He). For $^3$He a large enhancement of the cross section above plane-wave approximations had been reported, indicating the formation of a quasi-bound state. The present Li-data for $\\eta$-production agree with a plane-wave approximation. Contrary to $^3$He, neither a thr...

  1. Photoproduction of Scalar Mesons Using the CEBAF Large Acceptance Spectrometer (CLAS)

    Science.gov (United States)

    Chandavar, Shloka K.

    The search for glueballs has been ongoing for several decades. The lightest glueball has been predicted by quenched lattice QCD to have mass in the range of 1.0--1.7 GeV and JPC = 0++ . The mixing of glueball states with neighbouring meson states complicates their identification and hence several experiments have been carried out over the years to study the glueball candidates. By analyzing the decay channels and production mechanisms of these candidates, their glueball content can theoretically be determined. In reality, a lot of confusion still exists about the status of these glueball candidates. The f0(1500) is one of several contenders for the lightest glueball, which has been extensively studied in several different kinds of experiments. However, there exists no photoproduction data on this particle. In the analysis presented in this dissertation, the presence of the f0(1500) in the KS 0KS0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility, also called Jefferson Lab (JLab). This is done by studying the reaction, gammap → fJp → KS0 KS0p → 2(pi +pi-)p using data from the g12 experiment. A clear peak is seen at 1500 MeV in the background subtracted data. This is enhanced if the momentum transfer is restricted to be less than 1 GeV2. Comparing with simulations, it is seen that this peak is associated with t channel production mechanism. The f 2'(1525) has a mass of 1525 MeV and a width of 73 MeV, and hence there is a possibility of it contributing to the peak observed in our data. A moments analysis seems to suggest some presence of a D wave, however, the low acceptance at forward and backward angles prohibits a definitive conclusion.

  2. Elastic and proton-dissociative photoproduction of J/{psi} mesons 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.; Tseepeldorj, B. [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. [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 [Inter-University Institute for High Energies ULB-VUB, Brussels (Belgium); Universiteit Antwerpen, 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, 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. [Inter-University Institute for High Energies ULB-VUB, Brussels (Belgium); Universiteit Antwerpen, 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. [Universita di Roma Tre (Italy); INFN Roma 3, Dipartimento di Fisica, Roma (Italy); Sykora, T. [Inter-University Institute for High Energies ULB-VUB, Brussels (Belgium); Universiteit Antwerpen, 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

    2013-06-15

    Cross sections for elastic and proton-dissociative photoproduction of J/{psi} mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at ep centre-of-mass energies {radical}(s) {approx} 318 GeV and {radical}(s) {approx} 225 GeV, corresponding to integrated luminosities of L = 130 pb{sup -1} and L = 10.8 pb{sup -1}, respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25 < W{sub {gamma}p} < 110 GeV. Differential cross sections d {sigma}/dt, where t is the squared four-momentum transfer at the proton vertex, are measured in the range vertical stroke t vertical stroke < 1.2 GeV{sup 2} for the elastic process and vertical stroke t vertical stroke <8 GeV{sup 2} for proton dissociation. The results are compared to other measurements. The W{sub {gamma}p} and t-dependences are parametrised using phenomenological fits. (orig.)

  3. Photoproduction of D$*^{\\pm}$ mesons in electron-proton collisions at HERA

    CERN Document Server

    Aïd, S

    1996-01-01

    At the electron-proton collider HERA the inclusive D^{*\\pm} meson photoproduction cross section has been measured with the H1 detector in two different, but partly overlapping, kinematical regions. For the first, where \\langle W_{\\gamma p}\\rangle \\approx 200\\ GeV and Q^2 < 0.01\\,\\gev^2, the result is \\sigma(\\gamma p \\rightarrow c \\bar{c} X) = (13.2 \\pm 2.2 ^{+2.1}_{-1.7}\\, ^{+9.9}_{-4.8})\\,\\mu b. The second measurement for Q^2 < 4\\,\\gev^2 yields \\sigma(\\gamma p \\rightarrow c \\bar{c} X) = ( 9.3 \\pm 2.1 ^{+1.9}_{-1.8}\\, ^{+6.9}_ {-3.2} )\\,\\mu b at \\langle W_{\\gamma p}\\rangle \\approx 142\\,GeV and \\sigma(\\gamma p \\rightarrow c \\bar{c} X) = ( 20.6 \\pm 5.5 ^ {+4.3}_{-3.9}\\, ^{+15.4}_{-7.2})\\,\\mu b at \\langle W_{\\gamma p} \\rangle \\approx 230\\,GeV, respectively. The third error accounts for an additional uncertainty due to the proton and photon parton density parametrizations. Differential cross sections are presented as a function of the D^{*\\pm} transverse momentum and rapidity. The results compare reasonably...

  4. Photoproduction of pi0-mesons off neutrons in the nucleon resonance region

    CERN Document Server

    Dieterle, M; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Bartolome, P A; Beck, R; Bekrenev, V; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Demissie, B; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Glazier, D I; Hamilton, D; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jaegle, I; Jahn, O; Jude, T C; Kaeser, A; Kashevarov, V L; Kondratiev, R; Korolija, M; Kruglov, S P; Krusche, B; Kulbardis, A; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; Martinez, M; McGeorge, J C; McNicoll, E; Mekterovic, D; Metag, V; Micanovic, S; Middleton, D G; Mushkarenkov, A; Nefkens, B M K; Nikolaev, A; Novotny, R; Oberle, M; Ostrick, M; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S N; Robinson, J; Rosner, G; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D; Starostin, A; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P; Werthmueller, D; Witthauer, L

    2014-01-01

    Precise angular distributions have been measured for the first time for the photoproduction of $\\pi^{0}$-mesons off neutrons bound in the deuteron. The effects from nuclear Fermi motion have been eliminated by a complete kinematic reconstruction of the final state. The influence of final-state-interaction effects has been estimated by a comparison of the reaction cross section for quasi-free protons bound in the deuteron to the results for free protons and then applied as a correction to the quasi-free neutron data. The experiment was performed at the tagged photon facility of the Mainz Microtron MAMI with the Crystal Ball and TAPS detector setup for incident photon energies between $0.45$~GeV and $1.4$~GeV. The results are compared to the predictions from reaction models and partial-wave analyses based on data from other isospin channels. The model predictions show large discrepancies among each other and the present data will provide much tighter constraints. This is demonstrated by the results of a new ana...

  5. Photoproduction of η mesons from the neutron: Cross sections and double polarization observable E

    Energy Technology Data Exchange (ETDEWEB)

    Witthauer, L.; Dieterle, M.; Challand, T.; Kaeser, A.; Keshelashvili, I.; Krusche, B.; Rostomyan, T.; Walford, N.K.; Werthmueller, D. [University of Basel, Department of Physics, Basel (Switzerland); Afzal, F.; Beck, R.; Boese, S.; Funke, C.; Gottschall, M.; Gruener, M.; Hammann, C.; Hartmann, J.; Hoffmeister, P.; Honisch, C.; Kaiser, D.; Kalinowsky, H.; Kalischewski, F.; Klassen, P.; Koop, K.; Lang, M.; Mahlberg, P.; Mueller, J.; Muellers, J.; Piontek, D.; Schmidt, C.; Seifen, T.; Sokhoyan, V.; Spieker, K.; Thiel, A.; Thoma, U.; Urban, M.; Pee, H. van; Walther, D.; Wendel, C.; Winnebeck, A. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn, Bonn (Germany); Anisovich, A.V.; Bayadilov, D.; Nikonov, V.; Sarantsev, A. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn, Bonn (Germany); Petersburg Nuclear Physics Institute, National Research Centre ' ' Kurchatov Institute' ' , Gatchina (Russian Federation); Bantes, B.; Dutz, H.; Eberhardt, H.; Elsner, D.; Ewald, R.; Fornet-Ponse, K.; Frommberger, F.; Goertz, S.; Hammann, D.; Hannappel, J.; Hillert, W.; Jude, T.; Kammer, S.; Kleber, V.; Klein, F.; Schmieden, H. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Bichow, M.; Meyer, W.; Reicherz, G. [Ruhr-Universitaet Bochum, Institut fuer Experimentalphysik I, Bochum (Germany); Brinkmann, K.T.; Gutz, E. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn, Bonn (Germany); Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Crede, V. [Florida State University, Department of Physics, Tallahassee, FL (United States); Friedrich, S.; Makonyi, K.; Metag, V.; Nanova, M. [Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Gridnev, A.; Lopatin, I. [Petersburg Nuclear Physics Institute, National Research Centre ' ' Kurchatov Institute' ' , Gatchina (Russian Federation); Wilson, A. [Helmholtz-Institut fuer Strahlen- und Kernphysik der Universitaet Bonn, Bonn (Germany); Florida State University, Department of Physics, Tallahassee, FL (United States); Collaboration: The CBELSA/TAPS Collaboration

    2017-03-15

    Results from measurements of the photoproduction of η mesons from quasifree protons and neutrons are summarized. The experiments were performed with the CBELSA/TAPS detector at the electron accelerator ELSA in Bonn using the η → 3π{sup 0} → 6γ decay. A liquid deuterium target was used for the measurement of total cross sections and angular distributions. The results confirm earlier measurements from Bonn and the MAMI facility in Mainz about the existence of a narrow structure in the excitation function of γn → nη. The current angular distributions show a forward-backward asymmetry, which was previously not seen, but was predicted by model calculations including an additional narrow P{sub 11} state. Furthermore, data obtained with a longitudinally polarized, deuterated butanol target and a circularly polarized photon beam were analyzed to determine the double polarization observable E. Both data sets together were also used to extract the helicity-dependent cross sections σ{sub 1/2} and σ{sub 3/2}. The narrow structure in the excitation function of γn → nη appears associated with the helicity-1/2 component of the reaction. (orig.)

  6. Diffractive Photoproduction of J/psi Mesons with Large Momentum Transfer at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Beglarian, A.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, C.; 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.; 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; 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.; 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.; Gorbounov, S.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Haidt, D.; Hajduk, L.; Haller, J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; 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.; Jacquet, 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.; Katzy, J.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; 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.; Kueckens, 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.; Lytkin, L.; Makankine, A.; 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.; 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.; Nikitin, D.; 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.; Povh, B.; Raicevic, N.; 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.; 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.; 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.; Wessling, B.; Winde, M.; Winter, G.G.; Wissing, C.; 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 diffractive photoproduction of J/psi mesons is measured with the H1 detector at the ep collider HERA using an integrated luminosity of 78 pb^-1. The differential cross section d sigma(gamma p -> J/psi Y) / d t is studied in the range 2 < |t| < 30 GeV^2, where t is the square of the four-momentum transferred at the proton vertex. The cross section is also presented as a function of the photon-proton centre-of-mass energy W in three t intervals, spanning the range 50 < W < 200 GeV. A fast rise of the cross section with W is observed for each t range and the slope for the effective linear Pomeron trajectory is measured to be alpha^\\prime= -0.0135 \\pm 0.0074 (stat.) \\pm 0.0051 (syst.) GeV^-2. The measurements are compared with perturbative QCD models based on BFKL and DGLAP evolution. The data are found to be compatible with s-channel helicity conservation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Salvaire, F.

    2007-09-15

    The first analysis of inelastic J/{psi} meson production in photoproduction (Q{sup 2}<2.5 GeV{sup 2}) of the H1 experiment for the second phase of HERA (HERA II) is presented. The analysis is carried out at low and medium elasticities. The production of heavy quarks (charm, or bottom) is of special interest since the mass of the quarks provides a hard scale for the application of perturbative QCD. The muonic decay channel is used to select the J/{psi} mesons. The data was collected by the H1 detector during the period 2003-2005, and corresponds to an integrated luminosity of 133 pb{sup -1}. However only a subset of this data could be analysed. At the start of HERA II the trigger system was affected by a sizeable background. Then a fault was introduced in the trigger software during the summer 2004 and was only discovered and solved in April 2006. This means that approximately 80 % of the triggered events at medium elasticities and 65 % at low elasticities was lost during this period. Moreover during the first half of 2005 the muon trigger was affected by faulty power supplies. Consequently two good data taking periods are analysed: a first period with an integrated luminosity of 23 pb{sup -1} collected in 2004, and a second period of 60 pb{sup -1} collected during the second half of 2005, which is however strongly affected by the malfunction of the trigger software. In the medium elasticity region the total photoproduction cross section as a function of the photon-proton centre-of-mass energy W and the single differential cross sections as functions of the transverse momentum squared of the J/{psi} meson Pt{sup 2}{sub t,{psi}} and the elasticity z are extracted. The analysis covers the kinematic range 0.3{<=}z{<=}0.9, 60{<=}W{sub {gamma}}{sub p}{<=}240 GeV, and Pt{sup 2}{sub t,{psi}}>1 GeV{sup 2}. The same analysis is performed at low elasticity for the kinematic region 0.05{<=}z{<=}0.45, 120{<=}W{sub {gamma}}{sub p}{<=}260 GeV, and Pt{sup 2}{sub t,{psi}}>1 Ge

  8. High-Energy Photoproduction of the $\\rho$ and $\\rho^{\\prime}$ Vector Mesons

    Energy Technology Data Exchange (ETDEWEB)

    Bronstein, John Michael [Univ. of Illinois, Urbana, IL (United States)

    1977-01-01

    In an experiment in the broad band photon beam at Fermilab we observe diffractive production of 2$\\pi^{\\pm}$ and 4$\\pi^{\\pm}$ states from Be, Al. Cu and Pb target~. The 2$\\pi^{\\pm}$data is dominated by the $\\rho$(770) and the 4$\\pi^{\\pm}$is dominated by the $\\rho^{\\prime}$(1500). We measure the energy dependence of $\\rho$ photo production from Be and see no evidence for energy variation of the forward cross section in the range 30 to 160 GeV. The forward cross section is consistent with its average value $d\\sigma$/dt$\\mid_{0}$= 3.42 $\\pm$ 0.28 $\\mu b$/$GeV^2$ over the entire range. We obtain for the p' a mass of 1487± 20 MeV and a width of 675 $\\pm$ 60 MeV. All quoted errors are statistical. A standard optical model analysis of the A dependence of the $\\rho$ and $\\rho^{\\prime}$ photoproduction yields the following results. $f^2_{\\rho^{\\prime}}$ = 3.7 $\\pm$ 0.7 $\\sigma_{\\rho^{\\prime}}$/$\\sigma_{\\rho}$ = 1. 05 $\\pm$ 0.18 Our results for the photon coupling constants are in good agreement with GVMD and with the $e^+e^-$ storage ring results. The approximate equality of the $\\rho$-nucleon and $\\rho^{\\prime}$-nucleon total cross sections is inconsistent with the diagonal version of GVMD and provides strong motivation for including transitions between different vector mesons in GVMD.

  9. Measurement of inclusive and DiJet D{sup *}-meson photoproduction at the H1-experiment at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Urban, K.

    2009-03-15

    In the present analysis the production mechanism of charm quarks in electron proton scattering at the HERA collider is investigated using 30.68 pb{sup -1}, 68.23 pb{sup -1} and 93.39 pb{sup -1} of data collected with the H1 experiment. Events containing charm quarks are detected by the reconstruction of D{sup *} mesons in the kinematic domain of photoproduction. For the first time D{sup *} mesons are selected on the basis of the third level of the H1 Fast Track Trigger. Compared to the previous analysis the phase space studied was extended significantly and the data statistics increased by a factor of eight. The investigated kinematic region covers photons of virtuality of Q{sup 2}<2 GeV{sup 2} and photon-proton center-of-mass energies in the range of 100mesons are measured with transverse momenta of at least 1.8 GeV and pseudorapidities vertical stroke {eta} vertical stroke <1.5. The measurement in photoproduction and low p{sub t}(D{sup *}) is of particular interest since it allows the test of different theoretical models at the limit of applicability of pertubative QCD. In a further measurement, which is based on the events with D{sup *} mesons, at least two jets are selected. Jets with p{sub t}>4 GeV and p{sub t}>3 GeV, are studied in the pseudorapidity range of vertical stroke {eta} vertical stroke <1.5, where one of the selected jets is associated with the D{sup *} meson. The investigation of two hard partons, by means of the jets, results in an improved understanding of the production mechanism of charm quarks. This measurement demonstrates that resolved photon processes play an important role in the photoproduction of charm quarks. Single and double differential cross sections of both event samples are compared to predictions of perturbative QCD in leading and next to leading order. (orig.)

  10. Two component WIMP-FImP dark matter model with singlet fermion, scalar and pseudo scalar

    Energy Technology Data Exchange (ETDEWEB)

    Dutta Banik, Amit; Pandey, Madhurima; Majumdar, Debasish [Saha Institute of Nuclear Physics, HBNI, Astroparticle Physics and Cosmology Division, Kolkata (India); Biswas, Anirban [Harish Chandra Research Institute, Allahabad (India)

    2017-10-15

    We explore a two component dark matter model with a fermion and a scalar. In this scenario the Standard Model (SM) is extended by a fermion, a scalar and an additional pseudo scalar. The fermionic component is assumed to have a global U(1){sub DM} and interacts with the pseudo scalar via Yukawa interaction while a Z{sub 2} symmetry is imposed on the other component - the scalar. These ensure the stability of both dark matter components. Although the Lagrangian of the present model is CP conserving, the CP symmetry breaks spontaneously when the pseudo scalar acquires a vacuum expectation value (VEV). The scalar component of the dark matter in the present model also develops a VEV on spontaneous breaking of the Z{sub 2} symmetry. Thus the various interactions of the dark sector and the SM sector occur through the mixing of the SM like Higgs boson, the pseudo scalar Higgs like boson and the singlet scalar boson. We show that the observed gamma ray excess from the Galactic Centre as well as the 3.55 keV X-ray line from Perseus, Andromeda etc. can be simultaneously explained in the present two component dark matter model and the dark matter self interaction is found to be an order of magnitude smaller than the upper limit estimated from the observational results. (orig.)

  11. 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 GeVmesons are reconstructed in the decay channel, D{sup *{+-}}{yields}D{sup 0}{pi}{sup {+-}}{yields}K{sup -+}{pi}{sup {+-}}{pi}{sup {+-}}. Jets were reconstructed using the inclusive k{sub t} algorithm and are selected if they have transverse momenta of p{sub t}(jet)>3.5 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.)

  12. High-energy two-body photoproduction

    CERN Document Server

    Salin, P

    1974-01-01

    Considers three aspects of two-body photoproduction reactions: vector meson production as a tool to investigate properties of diffractive reactions; the occurrence of a possible J=0 fixed pole in the Compton amplitude; and pseudoscalar meson photoproduction. (73 refs).

  13. 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.

  14. Investigating the impact of the gluon saturation effects on the momentum transfer distributions for the exclusive vector meson photoproduction in hadronic collisions

    Directory of Open Access Journals (Sweden)

    V.P. Gonçalves

    2017-05-01

    Full Text Available The exclusive vector meson production cross section is one of the most promising observables to probe the high energy regime of the QCD dynamics. In particular, the squared momentum transfer (t distributions are an important source of information about the spatial distribution of the gluons in the hadron and about fluctuations of the color fields. In this paper we complement previous studies on exclusive vector meson photoproduction in hadronic collisions presenting a comprehensive analysis of the t-spectrum measured in exclusive ρ, ϕ and J/Ψ photoproduction in pp and PbPb collisions at the LHC. We compute the differential cross sections taking into account gluon saturation effects and compare the predictions with those obtained in the linear regime of the QCD dynamics. Our results show that gluon saturation suppresses the magnitude of the cross sections and shifts the position of the dips towards smaller values of t.

  15. Coherent photoproduction of J/ψ and ϒ mesons in pp and PbPb ultraperipheral collisions from dynamical gluon distributions

    Science.gov (United States)

    Fu, Qiang; Chen, Xurong

    2017-11-01

    We present calculations of coherent photoproduction of vector mesons (J/ψ and ϒ) with leading-order parton distribution functions to check new kinds of corrections of the DGLAP equations and nuclear modifications. The input gluon distribution of the proton is the dynamical parton model from the DGLAP equations with GLR-MQ-ZRS (Gribov-Levin-Ryskin, Mueller-Qiu, Zhu-Ruan-Shen) modifications. From comparison between several other gluon distribution models, we find that the dynamical gluon distribution fits with the results of meson photoproduction experiments in the high energy region. The calculation of the differential cross sections using dynamical and other gluon distributions is compared with the experimental data from the HERA, ZEUS and LHCb Collaborations. Although there is little data for the rapidity distribution of vector meson photoproduction near zero rapidity, the dynamical gluon distribution works well with the data in the large rapidity region. Supported by Key Research Program of Frontier Sciences, CAS, under the Grants Number NO. QYZDY-SSW-SLH006 of Chinese Academy of Sciences

  16. All the states of the nucleon. Nucleon spectroscopy through the production of mesons; Le nucleon dans tous ses etats. Etude de la spectroscopie du nucleon via la photoproduction de mesons

    Energy Technology Data Exchange (ETDEWEB)

    Rebreyend, D

    2006-10-15

    The photoproduction of mesons on the nucleon gives a direct access to its spectroscopy and is a promising way for the study of the structure of the nucleon. The GRAAL experiment uses a tagged and polarized photon beam produced through the Compton diffusion of laser photons on the electrons circulating in the ESRF storage ring. The combination of this photon beam and an efficient detection system has allowed a series of measurements concerning the photoproduction of light mesons on the proton and on the neutron. The first 4 chapters are dedicated to the nucleon spectroscopy: the nucleon models and their consequences on the excited levels are recalled, the experimental technique used is described and the difficulties due to the extraction of relevant data are presented. Highly accurate measurements of cross-sections, {sigma} asymmetry beams and resonance parameters have been performed. The last part is dedicated to the principle of the measurement of the electric dipole momentum of the neutron. (A.C.)

  17. Inelastic Production of J/psi Mesons in Photoproduction and Deep Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.; 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, 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.; 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.; 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, J.; 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.; 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.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Raspiareza, A.; 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.; 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.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; 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

    A measurement is presented of inelastic photo- and electroproduction of J/psi mesons in ep scattering at HERA. The data were recorded with the H1 detector in the period from 2004 to 2007. Single and double differential cross sections are determined and the helicity distributions of the J/psi mesons are analysed. The results are compared to theoretical predictions in the colour singlet model and in the framework of non-relativistic QCD. Calculations in the colour singlet model using a k_T factorisation ansatz are able to give a good description of the data, while colour singlet model calculations to next-to-leading order in collinear factorisation underestimate the data.

  18. Inelastic production of J/{psi} mesons in photoproduction and deep inelastic scattering 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 Physical Inst., Moscow (RU)] (and others)

    2009-12-15

    A measurement is presented of inelastic photo- and electroproduction of J/{psi} mesons in ep scattering at HERA. The data were recorded with the H1 detector in the period from 2004 to 2007. Single and double differential cross sections are determined and the helicity distributions of the J/{psi} mesons are analysed. The results are compared to theoretical predictions in the colour singlet model and in the framework of non-relativistic QCD. Calculations in the colour singlet model using a k{sub T} factorisation ansatz are able to give a good description of the data, while colour singlet model calculations to next-to-leading order in collinear factorisation underestimate the data. (orig.)

  19. Determining the dominant partial wave contributions from angular distributions of single- and double-polarization observables in pseudoscalar meson photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Y.; Afzal, F.; Thiel, A.; Beck, R. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)

    2017-05-15

    This work presents a simple method to determine the significant partial wave contributions to experimentally determined observables in pseudoscalar meson photoproduction. First, fits to angular distributions are presented and the maximum orbital angular momentum L{sub max} needed to achieve a good fit is determined. Then, recent polarization measurements for γp → π{sup 0}p from ELSA, GRAAL, JLab and MAMI are investigated according to the proposed method. This method allows us to project high-spin partial wave contributions to any observable as long as the measurement has the necessary statistical accuracy. We show, that high precision and large angular coverage in the polarization data are needed in order to be sensitive to high-spin resonance states and thereby also for the finding of small resonance contributions. This task can be achieved via interference of these resonances with the well-known states. For the channel γp → π{sup 0}p, those are the N(1680)(5)/(2){sup +} and Δ(1950)(7)/(2){sup +}, contributing to the F-waves. (orig.)

  20. N⁎→Nη′ decays from photoproduction of η′-mesons off protons

    Directory of Open Access Journals (Sweden)

    A.V. Anisovich

    2017-09-01

    Full Text Available A study of the partial-wave content of the γp→η′p reaction in the fourth resonance region is presented, which has been prompted by new measurements of polarization observables for that process. Using the Bonn–Gatchina partial-wave formalism, the incorporation of new data indicates that the N(18951/2−, N(19003/2+, N(21001/2+, and N(21203/2− are the most significant contributors to the photoproduction process. New results for the branching ratios of the decays of these more prominent resonances to Nη′ final states are provided; such branches have not been indicated in the most recent edition of the Review of Particle Properties. Based on the analysis performed here, predictions for the helicity asymmetry E for the γp→η′p reaction are presented.

  1. 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 60

  2. Photoproduction opportunities at CEBAF: Meson spectroscopy and the physics of flying {phi}`s

    Energy Technology Data Exchange (ETDEWEB)

    Dzierba, A.R. [Indiana Univ., Bloomington, IN (United States)

    1994-04-01

    The availability of high-intensity photon beams with an efficient duty-factor and with energies in the range 10 to 12 GeV makes possible studies in meson spectroscopy, rare decays and possibly symmetry tests such as CP and CPT. Indeed, with a 6 GeV tagged photon beam, realizable in the near future at CEBAF, measurements of rare radiative decays of the {phi}`s will be made. At higher energies, a photon beam could be used to answer a number of questions in meson spectroscopy. An even more exciting possibility is the use of photon beams to produce an intense source of {phi}`s. The physics contemplated at e{sup +}e{sup {minus}} {phi} factories, such as CP and CPT tests, might be also studied at CEBAF with completely different and complementary systematics; e.g. having the {phi}`s decay in flight may offer distinct advantages over {phi}`s produced at rest.

  3. Extraction of the Pomeron Trajectory from a Global Fit to Exclusive $\\rho^0$ Meson Photoproduction Data

    CERN Document Server

    List, Benno

    2009-01-01

    Based on data on elastic $\\rho^0$ photoproduction from the H1, Omega and ZEUS collaborations, a fit has been performed to extract the value $\\alpha_P (t)$ of the pomeron trajectory at fixed values of t from the W dependence of the differential $\\gamma p$ cross section $d \\sigma_{\\gamma p} (W) / d t$. The data used in the fit cover the range of $8.3 \\le W \\le 94 GeV$ in $\\gamma p$ centre-of-mass energy and $0.01 \\le |t| \\le 0.95 GeV^2$ in momentum transfer. A linear fit to the resulting values of $\\alpha_P (t)$ yields $\\alpha_{P,0} =1.0871 \\pm 0.0026 (stat.) \\pm 0.0030 (syst.)$ for the intercept and $\\alpha'_P = 0.126 \\pm 0.013 (stat.) \\pm 0.012 (syst.) GeV^{-2}$ for the slope of the pomeron trajectory. The data are also compatible with the Donnachie-Landshoff trajectory $\\alpha_P (t) = 1.0808 + 0.25 GeV^{-2}\\cdot t$ at low values $|t| \\lesssim 0.3 GeV^2$ and with a constant value of $\\alpha_P (t)$ at larger values of $|t|$.

  4. Search for the decay of the Higgs boson into two nMSSM pseudo-scalar particles

    CERN Document Server

    Janus, Michel; The ATLAS collaboration

    2017-01-01

    The next-to-minimal supersymmetric Standard Model (nMSSM) predicts the existence of a light pseudo-scalar boson "$a$" and the decay of the Higgs boson into a pair of such particles. This particle is searched for in several final states sensitive to different decay modes and mass ranges of the hypothetical pseudo-scalar, using ATLAS data amounting to either $20.3$ fb$^{-1}$ of $p$-$p$ collisions at $\\sqrt{s} = 8 \\,$ TeV or between $3.2$ fb$^{-1}$ and $36.1$ fb$^{-1}$ at $\\sqrt{s} = 13 \\,$ TeV.

  5. CrossRef Photoproduction of vector mesons in ultra-peripheral p–Pb and Pb–Pb collisions at the LHC with the ALICE experiment

    CERN Document Server

    Broz, Michal

    2015-01-01

    Vector mesons are copiously produced in ultra-peripheral collisions. In these collisions, the impact parameter is larger than the sum of the radii of the two projectiles, implying that electromagnetic processes become dominant. The cross section of production of vector mesons is expected to be sensitive to the gluon distribution and can therefore probe nuclear gluon shadowing (Pb–Pb) and the gluon structure function in the nucleon (p-Pb). The ALICE Collaboration has performed the first measurements of the production of ρ0, J/ψ and ψ/(2S) in Pb–Pb ultra-peripheral collision as well as the cross section for exclusive J/ψ photoproduction off protons in ultra-peripheral proton-lead collisions at the LHC. The results are compared to the STARLIGHT Monte Carlo and to QCD based models.

  6. Quark mass dependence of pseudo-scalar masses and coupling constants qq+q Collaboration

    Science.gov (United States)

    Farchioni, F.; Gebert, C.; Montvay, I.; Scholz, E.; Scorzato, L.

    2004-03-01

    The dependence of pseudo-scalar masses and decay constants on the sea and valence quark masses is investigated in the pseudo- Goldstone boson sector of QCD with two light quark flavours. The sea quark masses are at present in the range {1}/{3}m s ≤ m ud ≤ {2}/{3}m s whereas the valence quark masses satisfy {1}/{2}m sea ≤ m val ≤ 2m sea. The values of the Gasser-Leutwyler low energy constants L4, L5, L6 and L8 are estimated. The computation is done with the Wilson-quark lattice action at gauge coupling β = 5.1 on 16 4 lattices. O(a) effects are taken into account by applying chiral perturbation theory for the Wilson lattice action as proposed by Rupak and Shoresh.

  7. Measurement of diffractive D{sup *{+-}}-meson production in deep-inelastic ep-scattering and photoproduction at HERA; Messung diffractiver D{sup *{+-}}-Meson Produktion in tief-inelastischer ep-Streuung und Photoproduktion bei HERA

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, R.

    2006-07-19

    Measurements are presented of diffractive D* meson production in deep-inelastic scattering (DIS) and photoproduction ({gamma}p) at HERA. The event topology is given by ep{yields}eXY where a central system X contains at least one D{sup *{+-}} meson and is well separated by a large rapidity gap from a leading low-mass proton remnant system Y. The analyzed data were collected with the H1 detector in the years 1999 and 2000 and correspond to an integrated luminosity of 47.0 pb{sup -1}. The measurements are compared to QCD predictions in NLO, based on diffractive parton density functions previously obtained from a QCD analysis of the diffractive structure function F{sub 2}{sup D(3)} at H1. A good agreement is observed in the full kinematic regime, which supports the validity of QCD factorization in DIS and {gamma}p. (orig.)

  8. ALICE results on vector meson photoproduction in ultra-peripheral p-Pb and Pb-Pb collisions

    CERN Document Server

    Kryshen, E L

    2014-01-01

    Lead nuclei, accelerated at the LHC, are sources of strong electromagnetic fields that can be used to measure photon-induced interactions in a new kinematic regime. These interactions can be studied in ultra-peripheral p-Pb and Pb-Pb collisions where impact parameters are larger than the sum of the nuclear radii and hadronic interactions are strongly suppressed. Heavy quarkonium photoproduction is of particular interest since it is sensitive to the gluon distribution in the target. The ALICE Collaboration has studied J/psi and psi(2S) photoproduction in ultra-peripheral Pb-Pb collisions and exclusive J/psi photoproduction off protons in ultra-peripheral p-Pb collisions at the LHC. Implications for the study of gluon density distributions and nuclear gluon shadowing are discussed. Recent ALICE results on rho photoproduction are also presented.

  9. Probing the BFKL dynamics in the vector meson photoproduction at large-t in pPb collisions at the CERN LHC

    Science.gov (United States)

    Gonçalves, V. P.; Sauter, W. K.

    2018-01-01

    The photoproduction of vector mesons in pPb collisions at LHC energies is investigated assuming that the color singlet t-channel exchange carries a large momentum transfer t. The rapidity distributions and total cross sections for the process Pb p → Pb ⊗ V ⊗ jet + X, with V = ρ , J / Ψ and ⊗ representing a rapidity gap in the final state, are estimated considering the non-forward solution of the BFKL equation at high energy and large-t. A comparison with the predictions obtained at the Born level also is presented. We predict a large enhancement of the cross sections associated to the BFKL dynamics in the kinematical range probed by the LHCb Collaboration. Moreover, our results indicate that the experimental identification can be feasible at the LHC and that this process can be used to probe the BFKL dynamics.

  10. Measurement of the total cross section for the photoproduction of omega mesons on the proton; Messung des totalen Wirkungsquerschnitts fuer die Photoproduktion von Omegamesonen am Proton

    Energy Technology Data Exchange (ETDEWEB)

    Hoeffgen, S.K.

    2007-06-15

    The photoproduction of omega mesons on the proton ({gamma}p {yields} {omega}p) directly at the production threshold was investigated during the first phase of the CB-ELSA experiment in Bonn. In experiments directly at the threshold the protons are strongly focussed in forward direction due to kinematic reasons. Therefore the forward detector, a large area time of flight detector, plays a prominent role and there is a detailed description of the reconstruction and measuring capabilities of this spectrometer. Thereafter follows the extraction of the total cross section of the reaction {gamma}p {yields} {omega}p in the decay channel with {omega} {yields} {pi}{sup 0}{pi}{sup +}{pi}{sup -} directly at the production threshold with previously unequaled accuracy. (orig.)

  11. Photoproduction of the f1(1285) meson

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, R.; Schumacher, R. A.; Adhikari, K. P.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Badui, R. A.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D' Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Holtrop, M.; Hicks, K.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mattione, P.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Markov, N.; Mokeev, V.; Moriya, K.; Munevar, E.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Salgado, C.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, E. S.; Smith, G. D.; Sober, D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Stankovic, I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weygand, D.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.

    2016-06-01

    The f(1)(1285) meson withmass 1281.0 +/- 0.8MeV/c(2) and width 18.4 +/- 1.4MeV (full width at half maximum) was measured for the first time in photoproduction from a proton target using CLAS at Jefferson Lab. Differential cross sections were obtained via the eta pi(+)pi(-), K+(K) over bar (0) pi(-), and (K-K0)pi(+) decay channels from threshold up to a center-of-mass energy of 2.8 GeV. The mass, width, and an amplitude analysis of the eta pi(+)pi(-) final-state Dalitz distribution are consistent with the axial-vector J(P) = 1(+) f(1)(1285) identity, rather than the pseudoscalar 0(-) eta(1295). The production mechanism is more consistent with s-channel decay of a high-mass N* state and not with t-channel meson exchange. Decays to eta pi pi go dominantly via the intermediate a(0)(+/-) (980)pi(-/+) states, with the branching ratio Gamma [a(0)pi (no (K) over barK)]/Gamma[eta pi pi (all)] = 0.74 +/- 0.09. The branching ratios Gamma (K (K) over bar pi)/Gamma(eta pi pi) = 0.216 +/- 0.033 and Gamma (gamma rho(0))/Gamma(eta pi pi) = 0.047 +/- 0.018 were also obtained. The first is in agreement with previous data for the f(1)(1285), while the latter is lower than the world average.

  12. Photoproduction of the f1(1285) meson

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, Ryan [Carnegie Mellon Univ., Pittsburgh, PA (United States); Schumacher, Reinhard A. [Carnegie Mellon Univ., Pittsburgh, PA (United States); Adhikari, K. P.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Badui, R. A.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D' Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Holtrop, M.; Hicks, K.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mattione, P.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Markov, N.; Mokeev, V.; Moriya, K.; Munevar, E.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Salgado, C.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, E. S.; Smith, G. D.; Sober, D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Stankovic, I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weygand, D.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.

    2016-06-01

    The $f_1(1285)$ meson with mass $1281.0 \\pm 0.8$ MeV/$c^2$ and width $18.4 \\pm 1.4$ MeV (FWHM) was measured for the first time in photoproduction from a proton target using CLAS at Jefferson Lab. Differential cross sections were obtained via the $\\eta\\pi^{+}\\pi^{-}$, $K^+\\bar{K}^0\\pi^-$, and $K^-K^0\\pi^+$ decay channels from threshold up to a center-of-mass energy of 2.8 GeV. The mass, width, and an amplitude analysis of the $\\eta\\pi^{+}\\pi^{-}$ final-state Dalitz distribution are consistent with the axial-vector $J^P=1^+$ $f_1(1285)$ identity, rather than the pseudoscalar $0^-$ $\\eta(1295)$. The production mechanism is more consistent with $s$-channel decay of a high-mass $N^*$ state, and not with $t$-channel meson exchange. Decays to $\\eta\\pi\\pi$ go dominantly via the intermediate $a_0^\\pm(980)\\pi^\\mp$ states, with the branching ratio $\\Gamma(a_0\\pi \\text{ (no} \\bar{K} K\\text{)}) / \\Gamma(\\eta\\pi\\pi \\text{(all)}) = 0.74\\pm0.09$. The branching ratios $\\Gamma(K \\bar{K} \\pi)/\\Gamma(\\eta\\pi\\pi) = 0.216\\pm0.033$ and $\\Gamma(\\gamma\\rho^0)/\\Gamma(\\eta\\pi\\pi) = 0.047\\pm0.018$ were also obtained. The first is in agreement with previous data for the $f_1(1285)$, while the latter is lower than the world average.

  13. Photoproduction of charmed hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, R. [Univ. of Illinois, Urbana, IL (United States)

    1994-10-01

    Photoproduction data can be used to test QCD production mechanisms. In this paper the authors present results on the single-inclusive p{sub t}{sup 2} distributions of charm mesons and baryons, correlations between fully reconstructed charm pairs, and production asymmetries between charm and anticharm particles.

  14. Study of photoproduction of vector mesons on deuterium by 5. 5 GeV linearly polarized photons

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, V.P.

    1974-12-01

    The experimental results of a deuterium bubble chamber photoproduction study of half a million pictures at 5.5 GeV are presented. This experiment has been performed using a monoenergetic and linearly polarized photon beam facility at SLAC. At 5.5 GeV the beam polarization is greater than 90%, and the average FWHM of the beam energy spectrum is 0.6 GeV. The reaction ..gamma..d ..-->.. ..pi../sup +/..pi../sup -/d has been studied in detail. A clear sample of ..gamma..d ..-->.. rho/sup 0/d channel was obtained and from the rho/sup 0/ decay distribution in terms of an extended density matrix which includes correlation with the beam polarization, nine independent density matrix parameters were determined. The study of rho/sup 0/ production and decay in the reaction channel ..gamma..d ..-->.. rho/sup 0/d was found to proceed almost completely through natural parity exchanges; the contribution from unnatural parity exchanges being only (5.3 +- 4.5)% for momentum transfer absolute value t less than or equal to 0.25 GeV/sup 2/. For the rho/sup 0/ mass and width, the values (766 +- 5) and (139 +- 11) MeV, respectively were obtained. The rho/sup 0/ production cross section in this channel has been determined to be (9.1 +- 0.8) ..mu..b.

  15. Simulation and calibration of the specific energy loss of the central jet chambers of the H1 detector and measurement of the inclusive D{sup *{+-}} meson cross section in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Hennekemper, Eva

    2011-12-15

    In this thesis the photoproduction of D{sup *} mesons in ep collisions at HERA is analysed. D{sup *} mesons are detected in the 'golden' decay channel D{sup *} {yields} K{pi}{pi}{sub s} with the H1 detector. Compared to earlier analyses, the systematic uncertainty is reduced due to two main improvements. Firstly, the simulation of the Fast Track Trigger, which is based on tracks measured within the central jet chambers, allows the trigger efficiency dependence of various kinematic variables to be evaluated. Secondly, the use of specific energy loss provides the possibility to suppress the non-resonant background. In order to use particle identification with the specific energy loss in the analysis, the simulation of the specific energy loss in the central jet chambers of the H1 detector is improved and the necessary correction functions and calibrations have been determined. This improved final H1 detector simulation is used to determine the cross section of photoproduction of D{sup *} mesons in the HERA II data sample, which corresponds to an integrated luminosity of 113 pb{sup -1}. The measurement was performed in the kinematic region of Q{sup 2}<2 GeV for the photon virtuality and photon-proton center of mass energies of 100mesons with transverse momenta above 1.8 GeV and in the central pseudorapidity range of vertical stroke {eta}(D{sup *}) vertical stroke <1.5 are determined and are compared to leading and next to leading order QCD predictions. (orig.)

  16. Eta meson photoproduction on hydrogen from threshold up to 1100 MeV: Measurement of the {Sigma} beam asymmetry; Photoproduction du meson eta sur l`hydrogene du seuil jusqu`a 1100 MeV: Mesure de l`asymetrie faisceau {Sigma}

    Energy Technology Data Exchange (ETDEWEB)

    Ajaka, Jassem [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1997-12-12

    The photoproduction of {eta} meson on hydrogen has been measured from threshold to 1100 MeV in GRAAL experiment performed in 1996 - 1997 at the ESRF in Grenoble by a collaboration of Italian, French and Russian groups. A tagged and linearly polarized photon beam has been produced by back-scattering a laser beam on the 6 GeV electron beam of the ESRF ring. The target was a liquid hydrogen target of 3 cm. A 4{pi} detection system was used. It is composed of three layers of detectors: wire chambers, scintillator counters and calorimeters. We had in charge to install and calibrate a double wall of scintillator bars (3 x 3 m) designed to detect at forward angles (1 deg. - 25 deg.) the charged particles and to measure their loss of energy and their time of flight. We analyzed the results of the reaction {gamma}p {yields} {eta}p by identifying the {eta} in the lateral calorimeter which is a BGO ball and by detecting the proton in the scintillation counters. The {Sigma} beam asymmetry was extracted from {phi} distribution of {eta} meson and was plotted against {theta}{sub CM} of {eta} for 6 intervals of energy between the threshold and 1100 MeV. The interpretation of {Sigma} beam asymmetry was performed in the frame of the isobaric model. The use of two resonances S11(1535) and D13(1520) to explain our results was not sufficient. We had to take into account in addition the excitation of the resonances P13(1720), D15(1675) and P13(1880). The last being missing in the table of resonances and recently revealed by quark models. (author) 94 refs., 56 figs., 20 tabs.

  17. Pseudo-scalar Higgs boson production at N{sup 3}LO{sub A}+N{sup 3}LL{sup '}

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Taushif; Rana, Narayan; Ravindran, V. [The Institute of Mathematical Sciences, Chennai (India); Bonvini, Marco; Rottoli, Luca [University of Oxford, Rudolf Peierls Centre for Theoretical Physics, Oxford (United Kingdom); Kumar, M.C. [Indian Institute of Technology Guwahati, Department of Physics, Guwahati (India); Mathews, Prakash [Saha Institute of Nuclear Physics, Kolkata (India)

    2016-12-15

    We consider the production of a pseudo-scalar particle A at the LHC, and present accurate theoretical predictions for its inclusive cross section in gluon fusion. The prediction is based on combining fixed-order perturbation theory and all-order threshold resummation. At fixed order we include the exact next-to-next-to-leading order (NNLO) plus an approximate next-to-next-to-next-to-leading order (N{sup 3}LO{sub A}) which is based on the recent computation at this order for the scalar case. We then add threshold resummation at next-to-next-to-next-to leading logarithmic accuracy (N{sup 3}LL{sup '}). Various forms of threshold resummation are considered, differing by the treatment of subleading terms, allowing a robust estimate of the theoretical uncertainties due to missing higher orders. With particular attention to pseudo-scalar masses of 200 and 750 GeV, we also observe that perturbative convergence is much improved when resummation is included. Additionally, results obtained with threshold resummation in direct QCD are compared with analogous results as computed in soft-collinear effective theory, which turn out to be in good agreement. We provide precise predictions for pseudo-scalar inclusive cross section at 13 TeV LHC for a wide range of masses. The results are available through updated versions of the public codes ggHiggs and TROLL. (orig.)

  18. Photoproduction of the J/{psi} meson at HERA at next-to-leading order within the framework of nonrelativistic QCD

    Energy Technology Data Exchange (ETDEWEB)

    Butenschoen, Mathias

    2009-06-15

    Nonrelativistic QCD (NRQCD) provides a rigorous factorization scheme which describes the production and decay of heavy quarkonia. It has been a desire for 13 years to know the NRQCD NLO predictions for both J/{psi} hadroproduction and photoproduction, in order to be able to check the universality of the color octet long distance matrix elements (MEs) by comparing Tevatron and HERA data. In this work we calculate for the rst time the NRQCD NLO prediction for direct photoproduction at HERA and compare our result with recent H1 data. Our results show clear evidence that the color octet mechanism of NRQCD is indeed realized in J/{psi} photoproduction at HERA. We solved a number of open conceptual problems, probably the most important one being the issue of Coulomb singularities. We found a way to evaluate the virtual corrections without having to deal with them. (orig.)

  19. Coherent photo-production of ρ0 mesons in ultra-peripheral Pb-Pb collisions at the LHC measured by ALICE

    Directory of Open Access Journals (Sweden)

    Mayer Christoph

    2014-01-01

    Full Text Available We present the differential cross section for coherent ρ0 photo-production at mid-rapidity (−0.5 < y < 0.5 measured by the ALICE experiment in Pb-Pb collisions at √sNN = 2.76 TeV at the LHC, as well as the total ρ0 cross section obtained by modelbased extrapolation to all rapidities. These cross sections are compared to various model predictions, as well as to earlier measurements at RHIC. In addition, we present results on nuclear breakup in coincidence with coherent ρ0 photo-production.

  20. Exotic meson spectroscopy with CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Adams, G.; Napolitano, J. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1994-04-01

    The identification and study of mesons with explicit gluonic degrees of freedom will provide major constraints on nonperturbative QCD and models thereof. CLAS will provide a unique opportunity for studying these resonances by measuring photoproduction of multi-meson final states.

  1. Coherent diffractive photoproduction of ρ0 mesons on gold nuclei at 200 GeV/nucleon-pair at the Relativistic Heavy Ion Collider

    Science.gov (United States)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, B.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Klein, S. R.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, W.; Li, Y.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, H.; Liu, P.; Liu, Y.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, Y. G.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, C.; Yang, S.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, X. P.; Zhang, J. B.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, S.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

    2017-11-01

    The STAR Collaboration reports on the photoproduction of π+π- pairs in gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair. These pion pairs are produced when a nearly real photon emitted by one ion scatters from the other ion. We fit the π+π- invariant-mass spectrum with a combination of ρ0 and ω resonances and a direct π+π- continuum. This is the first observation of the ω in ultraperipheral collisions, and the first measurement of ρ -ω interference at energies where photoproduction is dominated by Pomeron exchange. The ω amplitude is consistent with the measured γ p →ω p cross section, a classical Glauber calculation, and the ω →π+π- branching ratio. The ω phase angle is similar to that observed at much lower energies, showing that the ρ -ω phase difference does not depend significantly on photon energy. The ρ0 differential cross section d σ /d t exhibits a clear diffraction pattern, compatible with scattering from a gold nucleus, with two minima visible. The positions of the diffractive minima agree better with the predictions of a quantum Glauber calculation that does not include nuclear shadowing than with a calculation that does include shadowing.

  2. Inclusive photoproduction of D{sup *{+-}} mesons at next-to-leading order in the general-mass variable-flavor-number scheme

    Energy Technology Data Exchange (ETDEWEB)

    Kniehl, B.A.; Kramer, G. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Schienbein, I. [Univ. Joseph Fourier/CNRS-IN2P3, INPG, Grenoble (France). Lab. de Physique Subatomique et de Cosmologie; Spiesberger, H. [Mainz Univ. (Germany). Inst. fuer Physik

    2009-02-15

    We discuss the inclusive production of D{sup *{+-}} mesons in {gamma}p collisions at DESY HERA, based on a calculation at next-to-leading order in the general-mass variable-flavor-number scheme. In this approach, MS subtraction is applied in such a way that large logarithmic corrections are resummed in universal parton distribution and fragmentation functions and finite mass terms are taken into account. We present detailed numerical results for a comparison with data obtained at HERA and discuss various sources of theoretical uncertainties. (orig.)

  3. Central production of two-pseudoscalar meson systems at the COMPASS experiment at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Austregesilo, Alexander

    2014-10-20

    COMPASS is a fixed-target experiment at the CERN SPS which recorded a data set with an incident proton beam impinging on a liquid hydrogen target in order to study the central production of light scalar mesons. We select events with two protons and two pseudo-scalar mesons in the final state and decompose their angular distribution in terms of partial-wave amplitudes. Fits to the mass-dependence of these amplitudes are used to determine the Breit-Wigner parameters of scalar resonances.

  4. Medium modifications of mesons. Chiral symmetry restoration, in-medium QCD sum rules for D and ρ mesons, and Bethe-Salpeter equations

    Energy Technology Data Exchange (ETDEWEB)

    Hilger, Thomas Uwe

    2012-04-11

    The interplay of hadron properties and their modification in an ambient nuclear medium on the one hand and spontaneous chiral symmetry breaking and its restoration on the other hand is investigated. QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D- anti D and B- anti B mesons as a function of the nuclear matter density and investigate the impact of various condensates in linear density approximation. The analysis also includes D{sub s} and D{sup *}{sub 0} mesons. QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive the corresponding Weinberg type sum rules. Based on QCD sum rules we explore the consequences of a scenario for the ρ meson, where the chiral symmetry breaking condensates are set to zero whereas the chirally symmetric condensates remain at their vacuum values. The complementarity of mass shift and broadening is discussed. An alternative approach which utilizes coupled Dyson-Schwinger and Bethe-Salpeter equations for quark-antiquark bound states is investigated. For this purpose we analyze the analytic structure of the quark propagators in the complex plane numerically and test the possibility to widen the applicability of the method to the sector of heavy-light mesons in the scalar and pseudo-scalar channels, such as the D mesons, by varying the momentum partitioning parameter. The solutions of the Dyson-Schwinger equation in the Wigner-Weyl phase of chiral symmetry at nonzero bare quark masses are used to investigate a scenario with explicit but without dynamical chiral symmetry breaking.

  5. Heavy quark fragmentation functions for D-wave quarkonium and charmed beauty mesons

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, K. [Texas Univ., Austin, TX (United States). Center for Particle Physics; Yuan, T.C. [Univ. of California, Davis, CA (United States). Davis Inst. for High Energy Physics

    1995-09-01

    At the large transverse momentum region, the production of heavy-heavy bound-states such as charmonium, bottomonium, and {anti b}c mesons in high energy e{sup +}e{sup {minus}} and hadronic collisions is dominated by parton fragmentation. The authors calculate the heavy quark fragmentation functions into the D-wave quarkonium and {anti b}c mesons to leading order in the strong coupling constant and in the non-relativistic expansion. In the {anti b}c meson case, one set of its D-wave states is expected to lie below the open flavor threshold. The total fragmentation probability for a {anti b} antiquark to split into the D-wave {anti b}c mesons is about 2 {times} 10{sup {minus}5}, which implies that only 2% of the total pseudo-scalar ground state B{sub c} comes from the cascades of these orbitally excited states.

  6. and electro-production of mesons with arbitrary spins

    Indian Academy of Sciences (India)

    parity sπ. Let us consider photo-production of a meson with spin-parity sπ and isospin Im at. c.m. energy W. Let k and q denote respectively the photon and meson momenta in c.m. frame. We use a right-handed frame with z-axis chosen along k ...

  7. Phases, quantum interferences and effective vector meson masses in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Soyeur, M.

    1996-12-31

    We discuss the prospects for observing the mass of {rho}- and {omega}-mesons around nuclear matter density by studying their coherent photoproduction in nuclear targets and subsequent in-medium decay into e{sup +}e{sup -}pairs. The quantum interference of {rho} and {omega}-mesons in the e{sup +}e{sup -}channel and the interference between Bethe-Heitler pairs and dielectrons from vector meson decays are of particular interest. (author). 21 refs.

  8. Search for medium effects on light vector mesons

    Energy Technology Data Exchange (ETDEWEB)

    Djalali, C; Nasseripour, R; Weygand, D P; Wood, M H

    2007-02-01

    The photoproduction of vector mesons on various nuclei has been studied using the Cebaf Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. The rho, omega, and phi mesons are observed via their decay to e+e. The rho spectral function is extracted from the data on carbon, iron, and titanium. We observe no effects on the mass of the rho meson, some widening in titanium and iron is observed consistent with standard collisional broadening.

  9. The Effect of Vector Meson Decays on Dihadron Fragmentation Functions

    Directory of Open Access Journals (Sweden)

    Matevosyan Hrayr H.

    2014-03-01

    Full Text Available Dihadron Fragmentation Functions (DFF provide a vast amount of information on the intricate details of the parton hadronization process. Moreover, they provide a unique access to the “clean” extraction of nucleon transversity parton distribution functions in semi inclusive deep inelastic two hadron production process with a transversely polarised target. On the example of the u → π+π−, we analyse the properties of unpolarised DFFs using their probabilistic interpretation. We use both the NJL-jet hadronization model and PYTHIA 8.1 event generator to explore the effect of the strong decays of the vector mesons produced in the quark hadronization process on the pseudoscalar DFFs. Our study shows that, even though it is less probable to produce vector mesons in the hadronization process than pseudo scalar mesons of the same charge, the products of their strong decays drastically affect the DFFs for pions because of the large combinatorial factors. Thus, an accurate description of both vector meson production and decays are crucial for theoretical understanding of DFFs.

  10. Search for gluonic excitations in light unconventional mesons

    Energy Technology Data Exchange (ETDEWEB)

    Paul Eugenio

    2007-07-01

    Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenologicalmodels for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by a discussion of plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.

  11. In-medium properties of light vector mesons

    Energy Technology Data Exchange (ETDEWEB)

    C. Djalali; R. Nasseripour; D. P. Weygand; M. H. Wood

    2007-08-01

    The photoproduction of vector mesons on various nuclei has been studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. All three vector mesons ρ, ω and phi are observed via their decay to e+e-. The possible in-medium effects on the properties of the ρ meson are of particular interest. The ρ spectral function is extracted from the data on carbon, iron and titanium, and compared to the spectrum from liquid deuterium, which is relatively free of nuclear effects. We observe no effects on the mass of the ρ meson, some widening in titanium and iron is observed consistent with the collisional broadening.

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

    OpenAIRE

    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.

    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 pred...

  13. {eta}-Photoproduction in a gauge-invariant chiral unitary framework

    Energy Technology Data Exchange (ETDEWEB)

    Ruic, Dino [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, D-53115 Bonn (Germany); Mai, Maxim, E-mail: mai@hiskp.uni-bonn.de [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, D-53115 Bonn (Germany); Meissner, Ulf-G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, D-53115 Bonn (Germany); Forschungszentrum Juelich, Institut fuer Kernphysik, Institute for Advanced Simulation, and Juelich Center for Hadron Physics, D-52425 Juelich (Germany)

    2011-10-25

    We analyze photoproduction of {eta} mesons off the proton in a gauge-invariant chiral unitary framework. The interaction kernel for meson-baryon scattering is derived from the leading order chiral effective Lagrangian and iterated in a Bethe-Salpeter equation. The recent precise threshold data from the Crystal Ball at MAMI can be described rather well and the complex pole corresponding to the S{sub 11}(1535) is extracted. An extension of the kernel is also discussed.

  14. Measurements of inelastic J/psi and psi' photoproduction at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Musgrave, B; 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, Luisa; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Giusti, P; Iacobucci, G; Margotti, A; Nania, R; Palmonari, F; Pesci, A; Sartorelli, G; Zichichi, A; Aghuzumtsyan, G; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Irrgang, P; Jakob, H P; Kappes, A; Katz, U F; Kind, O; Paul, E; Rautenberg, J; Renner, R; Schnurbusch, H; Stifutkin, A; Tandler, J; Voss, K C; Wang, M; Weber, A; 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; Kim, J Y; Kim, Y K; Lee, J H; Lim, I T; Pac, M Y; Caldwell, A; Helbich, M; Liu, X; Mellado, B; Ning, Y; Paganis, S; Ren, Z; Schmidke, W B; Sciulli, F; Chwastowski, J; Eskreys, Andrzej; Figiel, J; Olkiewicz, K; Stopa, P; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Kowal, A M; Kowal, M; Kowalski, T; Przybycien, M B; Suszycki, L; Szuba, D; Szuba, J; Kotanski, Andrzej; Slominski, W; Bauerdick, L A T; Behrens, U; Bloch, I; Borras, K; Chiochia, V; Dannheim, D; Derrick, Malcolm; Drews, G; Fourletova, J; Fox-Murphy, A; Fricke, U; Geiser, A; Göbel, F; Göttlicher, P; Gutsche, O; Haas, T; Hain, W; Hartner, G F; Hillert, S; Kötz, U; Kowalski, H; Kramberger, G; Labes, H; Lelas, D; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Moritz, M; Notz, D; Petrucci, M C; Polini, A; Raval, A; Schneekloth, U; Selonke, F; Wessoleck, H; Wichmann, R; Wolf, G; Youngman, C; Zeuner, W; López-Duran-Viani, A; Meyer, A; Schlenstedt, S; Barbagli, G; Gallo, E; Genta, C; Pelfer, P G; Bamberger, Andreas; Benen, A; Coppola, N; Bell, M; Bussey, Peter J; Doyle, A T; Glasman, C; Hanlon, S; Lee, S W; Lupi, A; McCance, G J; Saxon, D H; Skillicorn, Ian O; Gialas, I; Bodmann, B; Carli, T; Holm, U; Klimek, K; Krumnack, N; Lohrmann, E; Milite, M; Salehi, H; Stonjek, S; Wick, K; Ziegler, A; Collins-Tooth, C; Foudas, C; Goncalo, R; Long, K R; Metlica, F; Tapper, A D; 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; Lim, H; Son, D; Barreiro, F; González, O; Labarga, L; Del Peso, J; Redondo, I; Tassi, E; Terron, J; Vázquez, M; Barbi, M; Bertolin, A; Corriveau, F; Ochs, A; Padhi, S; Stairs, D G; Saint-Laurent, M G; Tsurugai, T; Antonov, A; Danilov, P; Dolgoshein, B A; Gladkov, D; Sosnovtsev, V V; Suchkov, S; Dementev, R K; Ermolov, P F; Golubkov, Yu A; Katkov, I I; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Vlasov, N N; Zotkin, S A; Bokel, C; Engelen, J; Grijpink, S; Koffeman, E; Kooijman, P M; Maddox, E; Pellegrino, A; Schagen, S; Tiecke, H G; Tuning, N; Velthuis, J J; Wiggers, L; De Wolf, E; Brümmer, N; Bylsma, B; Durkin, L S; Ling, T Y; Boogert, S; Cooper-Sarkar, A M; Devenish, R C E; Ferrando, J; Grzelak, G; 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; Heaphy, E A; Oh, B Y; Saull, P R B; Whitmore, J J; Iga, Y; D'Agostini, Giulio; Marini, G; Nigro, A; Cormack, C; Hart, J C; McCubbin, N A; Heusch, C A; Park, I H; Pavel, N; Abramowicz, H; Gabareen, A; Kananov, S; Kreisel, A; Levy, A; Abe, T; Fusayasu, T; Kagawa, S; Kohno, T; Tawara, T; Yamashita, T; Hamatsu, R; Hirose, T; Inuzuka, M; Kitamura, S; Matsuzawa, K; Nishimura, T; Arneodo, M; Ferrero, M I; Monaco, V; Ruspa, M; Sacchi, R; Solano, A; Galea, R; Koop, T; Levman, G M; Martin, J F; Mirea, A; Sabetfakhri, A; Butterworth, J M; Gwenlan, C; Hall-Wilton, R; Jones, T W; Lightwood, M S; Loizides, J H; West, B J; Ciborowski, J; Ciesielski, R; Nowak, R J; Pawlak, J M; Smalska, B; Sztuk, J; Tymieniecka, T; Ukleja, A; Ukleja, J; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Gladilin, L K; Hochman, D; Karshon, U; Kcira, D; Lammers, S; Li, L; Reeder, D D; Savin, A A; Smith, W H; Deshpande, A A; Dhawan, S; Hughes, V W; Straub, P B; Bhadra, S; Catterall, C D; Fourletov, S; Menary, S R; Soares, M; Standage, J

    2003-01-01

    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 38.0 pb-1. The events were required to have 0.1 0.4 is compared to leading-order QCD predictions.

  15. Light meson decays from photon-induced reactions with CLAS

    Directory of Open Access Journals (Sweden)

    Kunkel Michael C.

    2016-01-01

    Full Text Available Photoproduction experiments with the CEBAF Large Acceptance Spectrometer CLAS at the Thomas Jefferson National Facility produce data sets with competitive statistics of light mesons. With these data sets, measurements of transition form factors for η, ω, and η′ mesons via conversion decays can be performed using the invariant mass distribution of the final state dileptons. Tests of fundamental symmetries and information on the light quark mass difference can be performed using a Dalitz plot analysis of the meson decay. An overview of preliminary results, from existing CLAS data, and future prospects within the newly upgraded CLAS12 apparatus are given.

  16. Hard photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier / CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble (France)

    2007-07-01

    In view of possible photoproduction studies in ultra-peripheral heavy-ion collisions at the LHC, we briefly review the present theoretical understanding of photons and hard photoproduction processes at HERA, discussing the production of jets, light and heavy hadrons, quarkonia, and prompt photons. We address in particular the extraction of the strong coupling constant from photon structure function and inclusive jet measurements, the infrared safety and computing time of jet definitions, the sensitivity of di-jet cross sections on the parton densities in the photon, factorization breaking in diffractive di-jet production, the treatment of the heavy-quark mass in charm production, the relevance of the color-octet mechanism for quarkonium production, and isolation criteria for prompt photons. (author)

  17. Quasar polarization with ultralight (pseudo-)scalars

    Indian Academy of Sciences (India)

    Abstract. Recently, it was shown that the absence of circular polarization of visible light from quasars severely constrains the interpretation of axion-like particles (ALPs) as a solution for the generation of linear polarization. Furthermore, the new observation of linear polarization in radio wavelength from quasars, similar to ...

  18. Quasar polarization with ultralight (pseudo-) scalars

    Indian Academy of Sciences (India)

    Recently, it was shown that the absence of circular polarization of visible light from quasars severely constrains the interpretation of axion-like particles (ALPs) as a solution for the generation of linear polarization. Furthermore, the new observation of linear polarization in radio wavelength from quasars, similar to the earlier ...

  19. K-Kbar photoproduction from protons

    Energy Technology Data Exchange (ETDEWEB)

    A. Sibirtsev; J. Haidenbauer; S. Krewald; Ulf-G. Meissner; A.W. Thomas

    2007-02-01

    We study the contribution of the Drell mechanism driven by K{sup +} and K{sup -} exchange to the reaction {gamma} N {yields} K-{bar K}N. Our calculation implements the full KN and {bar K}N reaction amplitudes in the form of partial wave amplitudes taken from a meson-exchange model (KN) and a partial wave analysis ({bar K}N), respectively. Comparing our results to data of the LAMP2 collaboration we observe that the Drell mechanism alone cannot describe the large {Lambda}(1520) photoproduction rate observed experimentally. We argue that the discrepancy could be due to significant contributions from K*-meson exchange with subsequent excitation of the {Lambda} (1520) resonance. After adding such contributions to our model a good agreement of the LAMP2 experiment is achieved. When applying the same model to the recent SAPHIR data we find an excellent description of the K{sup +}p spectrum and can determine the parameters of the {Lambda} (1600) P{sub 01} resonance, M{sub R} = 1617 {+-} 2 MeV and {Gamma}{sub R} = 117 {+-} 4 MeV, from the K{sup -} p mass distribution.

  20. Scattering vector mesons in D4-D8 holographic QCD

    Energy Technology Data Exchange (ETDEWEB)

    Boschi-Filho, Henrique; Braga, Nelson; Ballon Bayona, C.A.; Torres, Marcus A.C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

    2009-07-01

    Full text. Sakai and Sugimoto authored one of the most successful string top-down models in describing real QCD, the D4-D8 brane model of holographic QCD. This model succeeds in exhibiting chiral symmetry breaking and confinement.A drawback of this model is that all massive hadrons have their masses set by the Kaluza-Klein compactification scale and we would have to work at energy scales below 1 GeV in order to describe a four dimensional physics. Still, they were able to find pion form factors and pion in agreement with experiment at scale of 1 GeV and above. They also calculate pion quadratic square radius in check with experiment, from a formula that depends on the entire Kaluza-Klein tower of excited pion states. Their model also realizes vector meson dominance (VMD) in electromagnetic interaction as proposed by Sakurai in the sixties. 5D gauge fields from flavor symmetry provides a zoo of mesons (scalar, pseudo-scalar, vector and pseudo-vector) and instanton configurations of such fields are interpreted as baryon fields. Inspired by the results of pion form factors and pion quadratic radius predicted in close agreement with experiment, we further calculate vector and axial vector mesons {psi}(z) wave functions, form factors, we discuss about its Q{sup -2} power behavior at large virtuosity (Q{sup 2}), and we check necessary relations between coupling constants and masses (superconvergence) that grants such power behavior of form factors. We compare our results with what is found in bottom-up hard wall and soft wall models and discuss the problems of the D4-D8 model. (author)

  1. Photoproduction of neutral pions

    OpenAIRE

    Fuhrer, Andreas

    2009-01-01

    The pion and nucleon mass differences generate a very pronounced cusp in the photoproduction reaction of a single neutral pion on the proton. A nonrelativistic effective field theory to describe this reaction is constructed. The approach is rigorous in the sense that it is an effective field theory with a consistent power counting scheme. Expressions for the S- and P-wave multipole amplitudes at one loop are given. The relation of the phase of the electric multipole E_0+ to the phase of the S...

  2. Measurements of the Mass, Total Width and Two-Photon Partial Width of the $\\eta_{c}$ Meson

    CERN Document Server

    Brandenburg, G; Gao, Y S; Kim, D Y J; Wilson, R; Browder, T E; Li, Y; Rodríguez, J L; Yamamoto, H; Bergfeld, T; Eisenstein, B I; Ernst, J; Gladding, G E; Gollin, G D; Hans, R M; Johnson, E; Karliner, I; Marsh, M A; Palmer, M; Plager, C; Sedlack, C; Selen, M; Thaler, J J; Williams, J; Edwards, K W; Janicek, R; Patel, P M; Sadoff, A J; Ammar, R; Bean, A; Besson, D; Davis, R; Kwak, N; Zhao, X; Anderson, S; Frolov, V V; Kubota, Y; Lee, S J; Mahapatra, R; O'Neill, J J; Poling, R A; Riehle, T; Smith, A; Stepaniak, C J; Urheim, J; Ahmed, S; Alam, M S; Athar, S B; Jian, L; Ling, L; Saleem, M; Timm, S; Wappler, F; Anastassov, A; Duboscq, J E; Eckhart, E; Gan, K K; Gwon, C; Hart, T; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pedlar, T K; Schwarthoff, H; Thayer, J B; Von Törne, E; Zoeller, M M; Richichi, S J; Severini, H; Skubic, P L; Undrus, A; Chen, S; Fast, J; Hinson, J W; Lee, J; Miller, D H; Shibata, E I; Shipsey, I P J; Pavlunin, V; Cronin-Hennessy, D; Lyon, A L; Thorndike, E H; Jessop, C P; Marsiske, H; Perl, Martin Lewis; Savinov, V; Ugolini, D W; Zhou, X; Coan, T E; Fadeev, V; Maravin, Y; Narsky, I; Stroynowski, R; Ye, J; Wlodek, T; Artuso, M; Ayad, R; Boulahouache, C; Bukin, K; Dambasuren, E; Karamov, S; Majumder, G; Moneti, G C; Mountain, R; Schuh, S; Skwarnicki, T; Stone, S; Viehhauser, G; Wang, J C; Wolf, A; Wu, J; Kopp, S E; Mahmood, A H; Csorna, S E; Danko, I; McLean, K W; Marka, S; Xu, Z; Godang, R; Kinoshita, K; Lai, I C; Schrenk, S; Bonvicini, G; Cinabro, D; McGee, S; Perera, L P; Zhou, G J; Lipeles, E; Pappas, S P; Schmidtler, M; Shapiro, A; Sun, W M; Weinstein, A J; Würthwein, F; Jaffe, D E; Masek, G E; Paar, H P; Potter, E M; Prell, S; Sharma, V; Asner, D M; Eppich, A; Hill, T S; Morrison, R J; Briere, R A; Ferguson, T; Vogel, H; Behrens, B H; Ford, W T; Gritsan, A; Roy, J D; Smith, J G; Alexander, J P; Baker, R; Bebek, C; Berger, B E; Berkelman, K; Blanc, F; Boisvert, V; Cassel, David G; Dickson, M; Drell, P S; Ecklund, K M; Ehrlich, R; Foland, A D; Gaidarev, P B; Galik, R S; Gibbons, L K; Gittelman, B; Gray, S W; Hartill, D L; Heltsley, B K; Hopman, P I; Jones, C D; Kreinick, D L; Lohner, M; Magerkurth, A; Meyer, T O; Mistry, N B; Nordberg, E; Patterson, J R; Peterson, D; Riley, D; Thayer, J G; Thies, P G; Urner, D; Valant-Spaight, B L; Warburton, A; Avery, P; Prescott, C; Rubiera, A I; Yelton, J; Zheng, J

    2000-01-01

    Using 13.4 $fb^{-1}$ of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudo-scalar charmonium in the decay $\\eta_c$ -> $K_S K^{\\mp} \\pi^{\\pm}$. We have measured the $\\eta_c$ mass to be (2980.4 +- 2.3 (stat) +- 0.6 (sys)) MeV and its full width as (27.0 +- 5.8 (stat) +- 1.4 (sys)) MeV. We have determined the two-photon partial width of the $\\eta_c$ meson to be (7.6 +- 0.8 (stat) +- 0.4 (sys) +- 2.3 (br)) keV, with the last uncertainty associated with the decay branching fraction.

  3. SEARCH FOR IN-MEDIUM MODIFICATIONS OF THE ρ MESON

    Energy Technology Data Exchange (ETDEWEB)

    WEYGAND, D P; DJALALI, C; NASSERIPOUR, R; WOOD, M

    2007-01-01

    The photoproduction of vector mesons on various nuclei has been studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory, and here we present preliminary results. All three vector mesons, ρ, ω,and φ, are observed via their decay to e+e-, in order to reduce the effects of final state interactions in the nucleus. Of particular interest is possible in-medium effects on the properties of the ρ meson. The ρ spectral function is extracted from the data on various nuclei, carbon, iron, and titanium, and compared to the spectrum from liquid deuterium, which is relatively free of nuclear effects. We observe no effects on the mass of the ρ meson, however, there is some widening of the resonance in titanium and iron, which is consistent with expected collisional broadening.

  4. Search for medium modification of the $\\rho$ meson

    Energy Technology Data Exchange (ETDEWEB)

    R. Nasseripour; M. H. Wood; C. Djalali; D. P. Weygand; C. Tur; U. Mosel; P. Muehlich; CLAS Collaboration

    2007-08-01

    The photoproduction of vector mesons on various nuclei has been studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. The vector mesons, $\\rho$, $\\omega$, and $\\phi$, are observed via their decay to $e^+e^-$, in order to reduce the effects of final state interactions in the nucleus. Of particular interest are possible in-medium effects on the properties of the $\\rho$ meson. The $\\rho$ spectral function is extracted from the data on various nuclei, carbon, iron, and titanium, and compared to the spectrum from liquid deuterium, which is relatively free of nuclear effects. We observe no significant mass shift for the $\\rho$ meson; however, there is some widening of the resonance in titanium and iron, which is consistent with expected collisional broadening.

  5. Hybrid Mesons

    CERN Document Server

    Ketzer, Bernhard

    2012-01-01

    The SU(3)_flavor constituent quark model has been quite successful to explain the properties as well as the observed spectrum of mesons with pseudoscalar and vector quantum numbers. Many radial and orbital excitations of quark-antiquark systems predicted by the model, however, have not yet been observed experimentally or assigned unambiguously. In addition, a much richer spectrum of mesons is expected from QCD, in which quarks interact which each other through the exchange of colored self-interacting gluons. Owing to this particular structure of QCD, configurations are allowed in which an excited gluonic field contributes to the quantum numbers J^{PC} of the meson. States with a valence color-octet qqbar' pair neutralized in color by an excited gluon field are termed hybrids. The observation of such states, however, is difficult because they will mix with ordinary qqbar' states with the same quantum numbers, merely augmenting the observed spectrum for a given J^{PC}. Since the gluonic field may carry quantum ...

  6. 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.

  7. Diffractive photoproduction of D{sup *{+-}}(2010) at HERA

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-03-15

    Diffractive photoproduction of D{sup *{+-}}(2010) mesons was measured with the ZEUS detector at the ep collider HERA, using an integrated luminosity of 78.6 pb{sup -1}. The D{sup *} mesons were reconstructed in the kinematic range: transverse momentum p{sub T}(D{sup *})>1.9 GeV and pseudorapidity vertical stroke {eta}(D{sup *}) vertical stroke <1.6, using the decay D{sup *+} {yields} D{sup 0}{pi}{sup +}{sub s} followed by D{sup 0} {yields} K{sup -}{pi}{sup +}(+c.c.). Diffractive events were identified by a large gap in pseudorapidity between the produced hadronic state and the outgoing proton. Cross sections are reported for photon-proton centre-of-mass energies in the range 130photoproduction cross section is about 6%. The data are in agree- ment with perturbative QCD calculations based on various parameterisations of diffractive parton distribution functions. The results are consistent with diffractive QCD factorisation. (orig.) ZEUS Collaboration

  8. DD correlations in photoproduction

    Science.gov (United States)

    Alvarez, M. P.; Barate, R.; Bloch, D.; Bonamy, P.; Borgeaud, P.; Burchell, M.; Burmeister, H.; Brunet, J. M.; Calvino, F.; Cattaneo, M.; Crespo, J. M.; D'Almagne, B.; David, M.; di Ciaccio, L.; Dixon, J.; Druet, P.; Duane, A.; Engel, J. P.; Ferrer, A.; Filippas, T. A.; Fokitis, E.; Forty, R. W.; Foucault, P.; Gazis, E. N.; Gerber, J. P.; Giomataris, Y.; Hofmokl, T.; Katsoufis, E. C.; Koratzinos, M.; Krafft, C.; Lefievre, B.; Lemoigne, Y.; Lopez, A.; Lui, W. K.; Magneville, C.; Maltezos, A.; McEwen, J. G.; Papadopoulou, T.; Pattison, B.; Poutot, D.; Primout, M.; Rahmani, H.; Roudeau, P.; Seez, C.; Six, J.; Strub, R.; Treille, D.; Triscos, P.; Tristram, G.; Villet, G.; Volte, A.; Wayne, M.; Websdale, D. M.; Wormser, G.; Zolnierowski, Y.

    1992-03-01

    Kinematic correlations between the charmed D and D mesons produced by a photon beam of mean energy 100 GeV/c have been measured by the NA14/2 experiment at CERN using a sample of almost background-free fully reconstructed DD events. The observed D and DD distributions are compared to the predictions of production models using different parameters for the charm fragmentation function and for the intrinsic transverse momentum of the partons.

  9. Eta-photoproduction in a gauge-invariant chiral unitary framework

    OpenAIRE

    Ruić, Dino; Mai, Maxim; Meißner, Ulf-G.

    2011-01-01

    We analyze photoproduction of η mesons off the proton in a gauge-invariant chiral unitary framework. The interaction kernel for meson–baryon scattering is derived from the leading order chiral effective Lagrangian and iterated in a Bethe–Salpeter equation. The recent precise threshold data from the Crystal Ball at MAMI can be described rather well and the complex pole corresponding to the S11(1535)S11(1535) is extracted. An extension of the kernel is also discussed.

  10. 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.)

  11. Measurement of the Exclusive and Inclusive Branching Fractions of $B^{0}_{s} \\to D^{(*)+}_{s}D^{(*)-}_{s}$ Decays at CDF and its Implications on the Decay Width Difference in the $B^{0}_{s}-B^{-0}_{s}$ Meson System

    Energy Technology Data Exchange (ETDEWEB)

    Horn, Dominik [Karlsruhe Inst. of Technology (KIT) (Germany)

    2011-01-01

    The purpose of this thesis is threefold: Firstly, new measurements of both the exclusive and semi-inclusive partial decay widths of $B^{0}_{s} \\to D^{(*)+}_{s}D^{(*)-}_{s}$ meson decays are presented. Secondly, the feasibility of extracting the unknown polarization components in $B^{0}_{s} \\to D^{(*)+}_{s}D^{(*)-}_{s}$ by partial reconstruction of this pseudo-scalar to vector-vector decay in a Monte Carlo driven analysis scheme is studied. Finally, based on the suggestions contributed by the theory community this study discusses how a measurement of the branching fraction of semi-inclusive decays $B^{0}_{s} \\to D^{(*)+}_{s}D^{(*)-}_{s}$ can contribute to gain insight about the relative decay width di erence in the B$0\\atop{s}$--B$0\\atop{s}$ meson system.

  12. Exclusive vector mesons at high energies: from photon-proton to proton-proton and nucleus-nucleus collisions

    Directory of Open Access Journals (Sweden)

    Schäfer Wolfgang

    2012-12-01

    Full Text Available Photoproduction of vector mesons has been studied since the 1960’s and was instrumental in establishing the hadronic structure of the photon and the concept of vectormeson dominance. More recently our knowledge on vector meson photoproduction has been furthered by experiments at the HERA accelerator. Total cross sections ans well as a number of kinematical distributions have been measured from light to heavy vector mesons. These experiments have been a testbed of ideas on the production mechanism, the QCD Pomeron exchange. In particular in varying the mass of the vector meson we can study the Pomeron exchange from the soft to the perturbatively hard regimes. The production mechanism also contains information on the quark-antiquark wave function of the produced meson. High energy protons or ions are the source of a flux of Weizsäcker-Williams photons, which can be utilized to study the photoproduction of vector mesons also at the Tevatron and LHC colliders. We discuss how information on the small-x gluon distribution in protons in nuclei can be obtained. Besides this intrinsic interest in vector meson production, a precise knowledge thereof is also necessary for odderon searches. In this regard, we discuss also transverse momentum distributions including absorption effects.

  13. Photoproduction of the K+ K-(1750)

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Ryan Edward [Univ. of Tennessee, Knoxville, TN (United States)

    2003-01-01

    While photoproduction has often been advertised as an important environment in which to study light meson spectroscopy, solid experimental results are sparse. In fact, beyond the relatively straightforward photoproduction of the ρ, ω, and Ψ mesons, the few results of exclusive photoproduction that do exist are poorly understood, and several, perhaps, have even been misinterpreted. After extensively reviewing the sometimes tenuous history of the exclusive photoproduction of the ''ρ1(1600)'', the ''ωπ0(1250)'', the ''ω(1650)'', and the ''K+K-(1750)'', new results from the E831/FOCUS photoproduction experiment at Fermilab are presented which address the interpretation of the K+K-(1750). This enhancement in low-pT K+K- pairs at a mass near 1750 MeV/c2 has been observed by several previous photoproduction experiments, but, despite several apparent inconsistencies, it has always been interpreted as the JPC = 1-- ρ(1680) meson. With nearly two orders of magnitude more events than any previous observation of the K+K-(1750), and based on precise measurements of its mass and width, and its absence from the K*K final state, the FOCUS data can finally render this interpretation implausible. In addition, several steps have been taken towards establishing a new interpretation. Based on limited angular analyses of its decay and the beam energy dependence of its production, they argue that, in the absence of any wild interference scenarios, the K+K-(1750) has JPC ≠ 1--, and, in fact, the most likely assignment appears to be 2++. It is hoped that this work can help set the stage for future reevaluations and new insights in photoproduction.

  14. Meson Spectroscopy in the Light Quark Sector

    Energy Technology Data Exchange (ETDEWEB)

    De Vita, R.; Lunardi, S.; Bizzeti, P. G.; Bucci, C.; Chiari, M.; Dainese, A.; Di Nezza, P.; Menegazzo, R.; Nannini, A.; Signorini, C.; Valiente-Dobon, J. J.

    2014-01-01

    Understanding the hadron spectrum is one of the fundamental issues in modern particle physics. We know that existing hadron configurations include baryons, made of three quarks, and mesons, made of quark-antiquark pairs. However most of the mass of the hadrons is not due to the mass of these elementary constituents but to their binding force. Studying the hadron spectrum is therefore a tool to understand one of the fundamental forces in nature, the strong force, and Quantum Chromo Dynamics (QCD), the theory that describes it. This investigation can provide an answer to fundamental questions as what is the origin of the mass of hadrons, what is the origin of quark confinement, what are the relevant degrees of freedom to describe these complex systems and how the transition between the elementary constituents, quarks and gluons, and baryons and mesons occurs. In this field a key tool is given by meson spectroscopy. Mesons, being made by a quark and an anti-quark, are the simplest quark bound system and therefore the ideal benchmark to study the interaction between quarks and understand what the role of gluons is. In this investigation, it is fundamental to precisely determine the spectrum and properties of mesons but also to search for possible unconventional states beyond the configuration q{anti q} as tetraquarks (qq{anti qq}), hybrids (q{anti q}g) and glueballs. These states can be distinguished unambiguously from regular mesons when they have exotic quantum numbers, i.e. combinations of total angular momentum, spin and parity that are not allowed for q{anti q} states. These are called exotic quantum numbers and the corresponding states are referred to as exotics. The study of the meson spectrum and the search for exotics is among the goals of several experiments in the world that exploit different reaction processes, as e{sup +}e{sup -} annihilation, p{anti p} annihilation, pion scattering, proton-proton scattering and photo-production, to produce meson states

  15. Kaon photoproduction off proton

    Directory of Open Access Journals (Sweden)

    Skoupil Dalibor

    2016-01-01

    Full Text Available We have recently constructed our version of the Regge-plus-resonance (RPR model and two variants of an isobar model for photoproduction of kaons on the proton, utilizing new experimental data from CLAS, LEPS, and GRAAL collaborations for adjusting free parameters of the models. Higher-spin nucleon (3/2 and 5/2 and hyperon (3/2 resonances were included using the consistent formalism by Pascalutsa and found to play an important role in data description. The set of chosen nucleon resonances in our new isobar models agrees well with the set of the most probable contributing states determined in the Bayesian analysis with the RPR model whilst only 6 out of 10 N*’s selected in the RPR fit of ours overlap with the nucleon resonant states in the Bayesian analysis. Results of two versions of the isobar model are compared to the new version of the RPR model and experimental data in the third-resonance region and their properties are discussed. We place an emphasis on the choice of resonances, the predictions in the forward- and backward-angle region as well as the choice of the hadron form factor.

  16. Biological hydrogen photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Nemoto, Y. [Univ. of Miami, FL (United States)

    1995-09-01

    Following are the major accomplishments of the 6th year`s study of biological hydrogen photoproduction which were supported by DOE/NREL. (1) We have been characterizing a biological hydrogen production system using synchronously growing aerobically nitrogen-fixing unicellular cyanobacterium, Synechococcus sp. Miami BG 043511. So far it was necessary to irradiate the cells to produce hydrogen. Under darkness they did not produce hydrogen. However, we found that, if the cells are incubated with oxygen, they produce hydrogen under the dark. Under 80% argon + 20% oxygen condition, the hydrogen production activity under the dark was about one third of that under the light + argon condition. (2) Also it was necessary so far to incubate the cells under argon atmosphere to produce hydrogen in this system. Argon treatment is very expensive and should be avoided in an actual hydrogen production system. We found that, if the cells are incubated at a high cell density and in a container with minimum headspace, it is not necessary to use argon for the hydrogen production. (3) Calcium ion was found to play an important role in the mechanisms of protection of nitrogenase from external oxygen. This will be a clue to understand the reason why the hydrogen production is so resistant to oxygen in this strain. (4) In this strain, sulfide can be used as electron donor for the hydrogen production. This result shows that waste water can be used for the hydrogen production system using this strain.

  17. Isospin violating decays of positive parity B{sub s} mesons in HMχPT

    Energy Technology Data Exchange (ETDEWEB)

    Fajfer, Svjetlana [University of Ljubljana, Department of Physics, Ljubljana (Slovenia); J. Stefan Institute, Jamova 39, P. O. Box 3000, Ljubljana (Slovenia); Prapotnik Brdnik, Anita [J. Stefan Institute, Jamova 39, P. O. Box 3000, Ljubljana (Slovenia); University of Maribor, Faculty of Civil Engineering, Transportation Engineering and Architecture, Maribor (Slovenia)

    2016-10-15

    Recent lattice QCD results suggest that the masses of the first two positive parity B{sub s} mesons lie below the BK threshold, similar to the case of D{sup *}{sub s0}(2317){sup +} and D{sub s1}(2460){sup +} mesons. The mass spectrum of B{sub s} mesons seems to follow the pattern of a D{sub s} mass spectrum. As in the case of charmed mesons, the structure of positive parity B{sub s} mesons is very intriguing. To shed more light on this issue, we investigate the strong isospin violating decays B{sub s0}{sup *0} → B{sub s}{sup 0}π{sup 0}, B{sub s1}{sup 0} → B{sub s}{sup *0}π{sup 0}, and B{sub s1}{sup 0} → B{sub s}{sup 0}ππ within heavy meson chiral perturbation theory. The two-body decay amplitude arises at tree level and we show that the loop corrections give significant contributions. On the other hand, in the case of three-body decay B{sub s1}{sup 0} → B{sub s}{sup 0}ππ the amplitude occurs only at loop level. We find that the decay widths for these decays are Γ(B{sub s1}{sup 0} → B{sub s}{sup 0}ππ) ∝ 10{sup -3} keV, and Γ(B{sub s0}{sup *0} → B{sub s}{sup 0}π{sup 0}) ≤ 55 keV, Γ(B{sub s1}{sup 0} → B{sub s}{sup *0}π{sup 0}) ≤ 50 keV. More precise knowledge of the coupling constant describing the interaction of positive and negative parity heavy mesons with light pseudo-scalar mesons would help to increase the accuracy of our calculation. (orig.)

  18. Measurement of $J/\\psi$ photoproduction in UPC of PbPb at 5 TeV

    CERN Document Server

    Dobishuk, Vasyl

    2017-01-01

    A first look at $J/\\psi$ photoproduction in ultra-peripheral PbPb collisions at center-of-mass energy $\\sqrt{s_{NN}} = 5\\, \\mathrm{TeV}$ with the LHCb experiment is presented. The measurement is based on a low multiplicity data sample of $J/\\psi$ mesons, decaying through the dimuon channel. An analysis of signal contamination as well as a method of two stage fit to obtain yield of coherent $J/\\psi$ is described.

  19. Recent results from Fermilab E-687, charm particle decays, lifetimes and photoproduction dynamics: A compilation results presented at DPF 1994

    Energy Technology Data Exchange (ETDEWEB)

    E687 Collaboration

    1994-10-01

    This report contains papers on the following topics: Recent results on the semi-leptonic decay Decay D{sup 0} {yields} K{sup {minus}}{mu}{sup +}{nu}{sub {mu}}; charmed mesons; observation of the Decay {Omega}{sub c}{sup 0}{Sigma}{sup +}K{sup {minus}}K{sup {minus}}{phi}{sup +}; the physics of charm lifetimes; and photoproduction of charmed hadrons. These papers have been cataloged separately.

  20. Prompt photon production in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Krzysztof

    2010-03-15

    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{sup -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{sup 2} < 1GeV{sup 2} and in the inelasticity range 0.1 < y < 0.7 for photons with a transverse energy 6 < E{sub T}{sup {gamma}} < 15GeV and in the pseudorapidity range.1.0 < {eta}{sup {gamma}} < 2.4 as a function of photons transverse energy and its pseudorapidity. Cross sections for prompt photon events with an additional hadronic jet are measured as a function of the transverse energy and pseudorapidity of the jet and of the momentum fractions x{sub {gamma}} and x{sub 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{sub T} factorisation approach. Neither of calculations is able to describe all the aspects of the measurement. (orig.)

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

    CERN Document Server

    Chekanov, S; Abt, I; Adamczyk, L; Adamus, M; Adler, V; Allfrey, P D; Antonelli, S; Antonioli, P; Antonov, A; Arneodo, M; Bamberger, A; Barakbaev, A N; Barbagli, G; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P; Bertolin, A; Bhadra, S; Bindi, M; Bloch, I; Blohm, C; Bold, T; Bonato, A; Boos, E G; Borras, K; Boscherini, D; Boutle, S K; Brock, I; Brook, N H; Brownson, E; Brugnera, R; Bruni, A; Bruni, G; Brzozowska, B; Brümmer, N; Bussey, P J; Butterworth, J M; Bylsma, B; Büttner, C; Caldwell, A; Capua, M; Carlin, R; Catterall, C D; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, L; Cindolo, F; Cole, J E; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danielson, T; De Favereau, J; De Pasquale, S; Del Peso, J; Dementiev, R K; Derrick, M; Devenish, R C E; Dobur, D; Dolgoshein, B A; Dossanov, A; Doyle, A T; Dunne, W; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, A; Estrada; Everett, A; Fazio, S; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Gialas, I; Gil, M; Giller, I; Gladilin, L K; Gladkov, D; Glasman, C; Goers, S; Gosau, T; Grabowska-Bold, I; Gregor, I; Grigorescu, G; Grzelak, G; Gwenlan, C; Göttlicher, P; Haas, T; Hain, W; Hamatsu, R; Hart, J C; Hartmann, H; Hartner, G; Heath, G P; Hilger, E; Hochman, D; Holm, U; Hori, R; Horn, C; Iacobucci, G; Ibrahim, Z A; Iga, Y; Ingbir, R; Jakob, H P; Jechow, M; Jiménez, M; Jones, T W; Jüngst, M; Kagawa, S; Kahle, B; Kaji, H; Kamaluddin, B; Kananov, S; Karshon, U; Karstens, F; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O M; Kisielewska, D; Kitamura, S; Klanner, R; Klein, U; Koffeman, E; Kollar, D; Kooijman, P; Korcsak-Gorzo, K; Korzhavina, I A; Kotanski, A; Kowalski, H; Kulinski, P; Kuze, M; Kuzmin, V A; Kötz, U; Labarga, L; Lee, A; Levchenko, B B; Levy, A; Limentani, S; Ling, T Y; Liu, C; Lobodzinska, E; Lohmann, W; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Löhr, B; Ma, K J; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsumoto, T; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S; Miglioranzi, S; Monaco, V; Montanari, A; Morris, J D; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nicholass, D; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Okazaki, N; Olkiewicz, K; Ota, O; Patel, S; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Roberfroid, V; Robertson, A; Ron, E; Rosin, M; Rubinsky, I; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Samson, U; San, R; Sartorelli, G; Savin, A A; Saxon, D H; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schonberg, V; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Shehzadi, R; Shimizu, S; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V; Spiridonov, A; Stadie, H; Stanco, L; Standage, J; Stifutkin, A; Stopa, P; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Theedt, T; Tiecke, H; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Uribe-, C; Vlasov, N N; Vázquez, M; Walczak, R; Walsh, R; Wan-Abdullah, W A T; Whitmore, J J; Whyte, J; Wichmann, K; Wick, 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; Zambrana, M; Zarnecki, A F; Zaw, I; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Zotkin, D S; Zotkin, S A

    2007-01-01

    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.

  2. Photoproduction of exotic baryon resonances

    Directory of Open Access Journals (Sweden)

    Marek Karliner

    2016-01-01

    Full Text Available We point out that the new exotic resonances recently reported by LHCb in the J/ψp channel are excellent candidates for photoproduction off a proton target. This test is crucial to confirming the resonant nature of such states, as opposed to their being kinematical effects. We specialize to an interpretation of the heavier narrow state as a molecule composed of Σc and D¯⁎, and estimate its production cross section using vector dominance. The relevant photon energies and fluxes are well within the capabilities of the GlueX and CLAS12 detectors at Thomas Jefferson National Accelerator Facility (JLAB. A corresponding calculation is also performed for photoproduction of an analogous resonance which is predicted to exist in the ϒp channel.

  3. Study of charm photoproduction mechanisms

    Science.gov (United States)

    Alvarez, M. P.; Barate, R.; Bloch, D.; Bonamy, P.; Borgeaud, P.; Burchell, M.; Burmeister, H.; Brunet, J. M.; Calvino, F.; Cattaneo, M.; Crespo, J. M.; D'Almagne, B.; David, M.; di Ciaccio, L.; Druet, P.; Duane, A.; Engel, J. P.; Ferrer, A.; Filippas, T. A.; Fokitis, E.; Forty, R. W.; Foucault, P.; Gazis, E. N.; Gerber, J. P.; Giomataris, Y.; Hall, G.; Hofmokl, T.; Katsoufis, E. C.; Koratzinos, M.; Krafft, C.; Lefievre, B.; Lemoigne, Y.; Lopez, A.; Lui, W. K.; Magneville, C.; Maltezos, A.; McEwen, J. G.; Papadopoulou, Th.; Pattison, B.; Poutot, D.; Primout, M.; Rahmani, H.; Roudeau, P.; Seez, C.; Six, J.; Strub, R.; Treille, D.; Triscos, P.; Tristram, G.; Villet, G.; Volte, A.; Wayne, M.; Websdale, D. M.; Wormser, G.; Zolnierowski, Y.

    1993-03-01

    This paper presents results on charm photoproduction in the energy interval 40 to 160 GeV, obtained from the high-statistics charm samples of the NA 14/2 experiment at CERN. We measure the charm cross-section, the distributions in x F and p {2/ T } and various production ratios and charge asymmetries. The total non-diffractive open-charm cross-section per nucleon is measured to beσ _{(γ N to cbar cX)} at =100 GeV. We discuss the photoproduction of charm in terms of theoretical and phenomenological models. We compare the measured p {2/ T } and x F distributions with first-order QCD calculations of photon-gluon fusion and obtain a value for the charm-quark mass of m c =1.5{+0.2/-0.1}GeV/c2.

  4. 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.

  5. Measurement of $D*{+-}$ meson production in ep scattering at low $Q^{2}$

    CERN Document Server

    Chekanov, S; Abt, I; Adamczyk, L; Adamus, M; Adler, V; Allfrey, P D; Antonelli, S; Antonioli, P; Antonov, A; Arneodo, M; Bamberger, A; Barakbaev, A N; Barbagli, G; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P; Bertolin, A; Bhadra, S; Bindi, M; Bloch, I; Blohm, C; Bold, T; Bonato, A; Boos, E G; Borras, K; Boscherini, D; Boutle, S K; Brock, I; Brook, N H; Brownson, E; Brugnera, R; Bruni, A; Bruni, G; Brzozowska, B; Brümmer, N; Bussey, P J; Butterworth, J M; Bylsma, B; Büttner, C; Caldwell, A; Capua, M; Carlin, R; Catterall, C D; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, L; Cindolo, F; Cole, J E; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danielson, T; De Favereau, J; De Pasquale, S; Del Peso, J; Dementiev, R K; Derrick, M; Devenish, R C E; Dobur, D; Dolgoshein, B A; Dossanov, A; Doyle, A T; Dunne, W; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, A; Estrada; Everett, A; Fazio, S; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Gialas, I; Gil, M; Giller, I; Gladilin, L K; Gladkov, D; Glasman, C; Goers, S; Gosau, T; Grabowska-Bold, I; Gregor, I; Grigorescu, G; Grzelak, G; Gwenlan, C; Göttlicher, P; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hart, J C; Hartmann, H; Hartner, G; Heath, G P; Hilger, E; Hochman, D; Holm, U; Hori, R; Horn, C; Iacobucci, G; Ibrahim, Z A; Iga, Y; Ingbir, R; Irrgang, P; Jakob, H P; Jechow, M; Jiménez, M; Jones, T W; Jüngst, M; Kagawa, S; Kahle, B; Kaji, H; Kamaluddin, B; Kananov, S; Karshon, U; Karstens, F; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O M; Kisielewska, D; Kitamura, S; Klanner, R; Klein, U; Koffeman, E; Kollar, D; Kooijman, P; Korcsak-Gorzo, K; Korzhavina, I A; Kotanski, A; Kowalski, H; Kulinski, P; Kuze, M; Kuzmin, V A; Kötz, U; Labarga, L; Lee, A; Levchenko, B B; Levy, A; Limentani, S; Ling, T Y; Liu, C; Lobodzinska, E; Lohmann, W; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Löhr, B; Ma, K J; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsumoto, T; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S; Miglioranzi, S; Monaco, V; Montanari, A; Morris, J D; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nicholass, D; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Okazaki, N; Olkiewicz, K; Ota, O; Patel, S; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Roberfroid, V; Robertson, A; Ron, E; Rosin, M; Rubinsky, I; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Samson, U; Santamarta, R; Sartorelli, G; Savin, A A; Saxon, D H; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schonberg, V; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Shehzadi, R; Shimizu, S; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V; Spiridonov, A; Stadie, H; Stanco, L; Standage, J; Stifutkin, A; Stopa, P; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Theedt, T; Tiecke, H; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Uribe-, C; Vlasov, N N; Vázquez, M; Walczak, R; Walsh, R; Wan-Abdullah, W A T; Whitmore, J J; Whyte, J; Wichmann, K; Wick, 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; Zambrana, M; Zarnecki, A F; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Zotkin, D S; Zotkin, S A

    2007-01-01

    The production of D*+-(2010) mesons in ep scattering in the range of exchanged photon virtuality 0.05 D0 pi+ with D0 -> K- pi+ and corresponding antiparticle decay were used to identify D* mesons and the ZEUS beampipe calorimeter was used to identify the scattered electron. Differential D* cross sections as functions of Q^2, inelasticity, y, transverse momentum of the D* meson, p_T(D*), and pseudorapidity of the D* meson, eta(D*), have been measured in the kinematic region 0.02 < y < 0.85, 1.5 < p_T(D*) < 9.0 GeV and |eta(D*)| < 1.5. The measured differential cross sections are in agreement with two different NLO QCD calculations. The cross sections are also compared to previous ZEUS measurements in the photoproduction and DIS regimes.

  6. 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 50mesons were identified through their decay into muon pairs. The polar and azimuthal angles of the {mu}{sup +} were measured in the J/{psi} rest frame and compared to theoretical predictions at leading and next-to-leading order in QCD. (orig.)

  7. Interference phenomena in the JP = 1/2- wave in η photoproduction

    Science.gov (United States)

    Anisovich, A. V.; Klempt, E.; Krusche, B.; Nikonov, V. A.; Sarantsev, A. V.; Thoma, U.; Werthmüller, D.

    2015-06-01

    The recent precise experimental results for the photoproduction of η-mesons off the neutron measured with the Crystal Ball/TAPS calorimeter at the MAMI accelerator have been investigated in detail in the framework of the Bonn-Gatchina coupled-channel model. The main result is that the narrow structure observed in the excitation function of γη → nη can be reproduced fully with a particular interference pattern in the J P = 1/2- partial wave. Introduction of the narrow resonance N(1685) with the properties reported in earlier publications deteriorates the quality of the fit.

  8. Inelastic Leptoproduction of J/Psi Mesons 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.; 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.; 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.; 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.; 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.; 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.; Nozicka, M.; 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.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Samson, J.; 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.; Strauch, I.; Straumann, U.; Swart, M.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vest, A.; Vichnevski, A.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; 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

    The leptoproduction of J/psi mesons is studied in inelastic reactions for four momentum transfers 2photoproduction are made and the polarisation of the produced J/psi meson is analysed.

  9. Further Results on the Production of Neutral Mesons by Photons

    Science.gov (United States)

    Panofsky, W. K. H.; Steinberger, J.; Steller, J.

    1951-10-01

    Further measurements have been made on the photoproduction of neutral mesons using the gamma-gamma coincidence technique. New data have been obtained on the gamma-gamma correlation curves in beryllium. The angular distribution of the photo mesons in Be has been determined and found to be strongly peaked forward. The dependence on the atomic number A of production has been found to obey an A{sup 2/3} law. Some data obtained for production in hydrogen show that the pi-zero and pi-plus production cross sections are comparable and that the pi-zero excitation curve starts more slowly from threshold than does the pi-plus photo excitation curve.

  10. SUITABILITY OF A NEW CALORIMETER FOR EXOTIC MESON SEARCHES

    Energy Technology Data Exchange (ETDEWEB)

    Bookwalter, C.; Ostrovidov, A.; Eugenio, P.

    2007-01-01

    Exotic mesons, particles that have quantum numbers that are inaccessible to conventional quark-model mesons, are predicted by quantum chromodynamics (QCD), but past experiments seeking to identify exotic candidates have produced controversial results. The HyCLAS experiment (E04005) at Thomas Jefferson National Accelerator Facility (TJNAF) proposes the use of the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) in Hall B to study the photoproduction of exotic mesons. However, the base detector package at CLAS is not ideal for observing and measuring neutral particles, particularly at forward angles. The Deeply Virtual Compton Scattering (DVCS) experiment at TJNAF has commissioned a new calorimeter for detecting small-angle photons, but studies must be performed to determine its suitability for a meson spectroscopy experiment. The ηπ system has been under especial scrutiny in the community as a source for potential exotics, so the new calorimeter’s ability at reconstructing these resonances must be evaluated. To achieve this, the invariant mass of showers in the calorimeter are reconstructed. Also, two electroproduction reaction channels analogous to photoproduction channels of interest to HyCLAS are examined in DVCS data. It is found that, while not ideal, the new calorimeter will allow access to additional reaction channels, and its inclusion in HyCLAS is warranted. Results in basic shower reconstruction show that the calorimeter has good effi ciency in resolving π° decays, but its η reconstruction is not as strong. When examining ep → epπ°η, preliminary reconstruction of the ηπ° system shows faint signals in the a0(980) region. In the ep → e n π+ η channel, preliminary reconstruction of the ηπ+ system gave good signals in the a0(980) and a2(1320) regions, but statistics were poor. While more analyses are necessary to improve statistics and remove background, these preliminary results support the claim

  11. Theoretical study of incoherent {phi} photoproduction on a deuteron target

    Energy Technology Data Exchange (ETDEWEB)

    Sekihara, T. [Kyoto University, Department of Physics, Graduate School of Science, Kyoto (Japan); Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); Martinez Torres, A.; Jido, D. [Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); Oset, E. [Institutos de Investigacion de Paterna, Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Valencia (Spain)

    2012-01-15

    We study the photoproduction of {phi} mesons in deuteron, paying attention to the modification of the cross-section from bound protons to the free ones. For this purpose we take into account Fermi motion in single scattering and rescattering of {phi} to account for {phi} absorption on a second nucleon as well as the rescattering of the proton on the neutron. We find that the contribution of the double scattering for {phi} is much smaller than the typical cross-section of {gamma}p{yields}{phi}p in free space, which implies a very small screening of the {phi} production in deuteron. The contribution from the proton rescattering, on the other hand, is found to be not negligible compared to the cross-section of {gamma}p{yields}{phi}p in free space, and leads to a moderate reduction of the {phi} photoproduction cross-section on a deuteron at forward angles if the LEPS set-up is taken into account. The Fermi motion allows contribution of the single scattering in regions forbidden by phase-space in the free case. In particular, we find that for momentum transfer squared close to the maximum value, the Fermi motion changes drastically the shape of d{sigma}/dt, to the point that the ratio of this cross-section to the free one becomes very sensitive to the precise value of t chosen, or the size of the bin used in an experimental analysis. Hence, this particular region of t does not seem to be the most indicated to find effects of a possible {phi} absorption in the deuteron. This reaction is studied theoretically as a function of t and the results are contrasted with recent experiments at LEPS and Jefferson Lab. The effect of the experimental angular cuts at LEPS is also discussed, providing guidelines for future experimental analyses of the reaction. (orig.)

  12. Vector-meson dominance revisited

    Directory of Open Access Journals (Sweden)

    Terschlüsen Carla

    2012-12-01

    Full Text Available The interaction of mesons with electromagnetism is often well described by the concept of vector-meson dominance (VMD. However, there are also examples where VMD fails. A simple chiral Lagrangian for pions, rho and omega mesons is presented which can account for the respective agreement and disagreement between VMD and phenomenology in the sector of light mesons.

  13. Danti D correlations in photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, M.P.; Calvino, F.; Crespo, J.M. (Univ. Autonoma Barcelona, Bellaterra (Spain)); Barate, R.; Burmeister, H.; Di Ciaccio, L.; Ferrer, A.; Giomataris, Y.; Pattison, B.; Treille, D.; Zolnierowski, Y. (CERN, Geneva (Switzerland)); Bloch, D.; Engel, J.P.; Foucault, P.; Gerber, J.P.; Strub, R.; Websdale, D.M. (CRN, IN2P3-CNRS, 67 - Strasbourg (France) Univ. Louis Pasteur, 67 - Strasbourg (France)); Bonamy, P.; Borgeaud, P.; David, M.; Lemoigne, Y.; Magneville, C.; Primout, M.; Villet, G. (DPhPE, CEN-Saclay, 91 - Gif-sur-Yvette (France)); Burchell, M.; Cattaneo, M.; Dixon, J.; Duane, A.; Forty, R.W.; Seez, C. (Blackett Lab., Imperial Coll., London (United Kingdom)); Brunet, J.M.; Lefievre, B.; Poutot, D.; Triscos, P.; Tristram, G.; Volte, A. (Coll. de France, 75 - Paris (France)); Almagne, B. d' ; Druet, P.; Krafft, C.; Roudeau, P.; Six, J.; Wayne, M.; Wormser, G. (LAL, IN2P3-CNRS, 91 - Orsay (France) Univ. Paris-Sud, 91 - Orsay (France)); Filippas, T.A.; Fokitis, E.; Gazis, E.N

    1992-03-26

    Kinematic correlations between the charmed D and anti D mesons produced by a photon beam of mean energy 100 GeV/c have been measured by the NA14/2 experiment at CERN using a sample of almost background-free fully reconstructed Danti D events. The observed D and Danti D distributions are compared to the predictions of production models using different parameters for the charm fragmentation function and for the intrinsic transverse momentum of the partons. (orig.).

  14. Photoproduction of the Xi Hyperons

    Energy Technology Data Exchange (ETDEWEB)

    John Price; J. Ducote; and BFK Nefkens

    2003-05-01

    Very little is known about the doubly-strange Xi hyperons. SU(3){sub F} symmetry, based on QCD, implies the existence of many Xi states yet to be found. A complete study of the excited Xi spectrum can also be used to study other related areas of nuclear physics, such as the s - d quark mass difference and Xi p scattering. We will report on a new approach to Xi physics, using the photoproduction process gamma p --> K{sup +} K{sup +} Xi{sup -}, in which the Xi is cleanly tagged by the missing mass of the (K{sup +}K{sup +}) system. We show the current status of this study with the CLAS detector at Jefferson Laboratory, and discuss how it relates to the above topics. We also comment on the future of this program.

  15. Properties of Bc meson

    Indian Academy of Sciences (India)

    The mass spectrum of c¯b meson is investigated with an effective quark– antiquark potential of the form −αc r. + Arν with ν varying from 0.5 to 2.0. The S and. P-wave masses, pseudoscalar decay constant, weak decay partial widths in spectator model and the lifetime of Bc meson are computed. The properties calculated ...

  16. 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.)

  17. The meson spectroscopy program with CLAS12 at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, Alessandro [Univ. of Rome Tor Vergata (Italy)

    2016-06-01

    The study of the hadronic spectrum is one of the most powerful tools to investigate the mechanism at the basis of quark confinement within hadrons. A precise determination of the spectrum allows not only to assess the properties of the hadrons in their fundamental and excited states, but also to investigate the existence of states resulting from alternative configurations of quarks and gluons, such as the glue-balls, hybrid hadrons and many-quarks configurations. The study of the mesonic part of the spectrum can play a central role in this investigation thanks to the strong signature that the hybrid mesons are expected to have: the presence of explicit gluonic degrees of freedom in such states may result in JPC configurations not allowed for the standard q ¯ q states. From the experimental side the expected high-multiplicity decays of the hybrid mesons require an apparatus with high performances in terms of rate-capability, resolution and acceptance. The CLAS12 experiment (formally MesonEx) is one of new-generation experiments at Thomas Jefferson National Laboratory (JLAB) for which an unprecedented statistics of events, with fully reconstructed kinematics for large particle multiplicity decays, will be available. A wide scientific program that will start in 2016 has been deployed for meson spectrum investigation with the CLAS12 apparatus in Hall B at energies up to 11 GeV. One of the main parts of the program is based on the use of the Forward Tagger apparatus, which will allow CLAS12 experiment to extend the study of meson electro-production to the quasi-real photo-production kinematical region (very low Q2), where the production of hybrid mesons is expected to be favoured. The data analysis which is required to extract the signal from hybrid states should go beyond the standard partial wave analysis techniques and a new analysis framework is being set up through the international network Haspect. The Haspect Network gathers people involved into theoretical and

  18. Measurement of double polarisation asymmetries in ω-photoproduction

    Directory of Open Access Journals (Sweden)

    H. Eberhardt

    2015-11-01

    Full Text Available The first measurements of the beam-target-helicity-asymmetries E and G in the photoproduction of ω-mesons off protons at the CBELSA/TAPS experiment are reported. E (G was measured using circularly (linearly polarised photons and a longitudinally polarised target. E was measured over the photon energy range from close to threshold (Eγ=1108 MeV to Eγ=2300 MeV and G at a single energy interval of 1108

  19. Photoproduction ofeta-pi pairs off nucleons and deuterons

    CERN Document Server

    Kaeser, A; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Bartolome, P A; Beck, R; Braghieri, A; Briscoe, W J; Cherepnya, S; Costanza, S; Dieterle, M; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Garni, S; Glazier, D I; Hamilton, D; Hornidge, D; Howdle, D; Huber, G M; Jaegle, I; Jude, T C; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; McGeorge, J C; McNicoll, E; Mekterovic, D; Metag, V; Micanovic, S; Middleton, D G; Mushkarenkov, A; Nikolaev, A; Novotny, R; Oberle, M; Ostrick, M; Otte, P; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S; Robinson, J; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D; Starostin, A; Strub, Th; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Walford, N K; Watts, D P; Werthmueller, D; Witthauer, L

    2016-01-01

    Quasi-free photoproduction of $\\pi\\eta$-pairs has been investigated from threshold up to incident photon energies of 1.4 GeV, respectively up to photon-nucleon invariant masses up to 1.9 GeV. Total cross sections, angular distributions, invariant-mass distributions of the $\\pi\\eta$ and meson-nucleon pairs, and beam-helicity asymmetries have been measured for the reactions $\\gamma p\\rightarrow p\\pi^0\\eta$, $\\gamma n\\rightarrow n\\pi^0\\eta$, $\\gamma p\\rightarrow n\\pi^+\\eta$, and $\\gamma n\\rightarrow p\\pi^-\\eta$ from nucleons bound inside the deuteron. For the $\\gamma p$ initial state data for free protons have also been analyzed. Finally, the total cross sections for quasi-free production of $\\pi^0\\eta$ pairs from nucleons bound in $^3$He nuclei have been investigated in view of final state interaction (FSI) effects. The experiments were performed at the tagged photon beam facility of the Mainz MAMI accelerator using an almost $4\\pi$ covering electromagnetic calorimeter composed of the Crystal Ball and TAPS dete...

  20. J /Ψ photoproduction in peripheral A A collisions

    Science.gov (United States)

    Gay Ducati, M. B.; Martins, S.

    2017-09-01

    The exclusive photoproduction of the heavy vector mesons J /Ψ is investigated in the context of peripheral lead-lead collisions for the energies available at the LHC, √{s }=2.76 TeV and √{s }=5.02 TeV . Using the light-cone color dipole formalism, the rapidity distribution was calculated in two centrality bins at 50%-70% and 70%-90% in order to evaluate its robustness in extrapolating down to a smaller impact parameter. A modified photon flux is introduced, without change in the photonuclear cross section in relation to the ultraperipheral (UPC) case. Results were obtained for the two regions analyzed, which presented a maximum difference of 27% in frontal rapidity for the two regions. Comparing the results for √{s }=2.76 TeV and √{s }=5.02 TeV , an increase was verified of approximately half the one obtained in the ultraperipheral regime in the central rapidity region.

  1. Devlopments of components for the detector driving system of the PANDA calorimeter and studies on the photoproduction of excited η mesons with the CB/ELSA experiment; Entwicklung von Komponenten fuer das Detektorsteuersystem des PANDA-Kalorimeters und Studien zur Photoproduktion angeregter η-Mesonen mit dem CB/ELSA-Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Triffterer, Tobias

    2016-01-28

    This PhD thesis (written in German language) consists of two parts: The first part describes developments for the Detector Control System of the electromagnetic calorimeter of the PANDA detector. An alarm and current border regulation system has been developed for this to ensure the correct functioning of the detector and to prevent damages. In addition, a database system (endcap production database) has been created to accompany the construction of the forward endcap and archive the characteristics of the photodetectors. The second part deals with the investigation into excited η mesons using the data measured with the CB/ELSA experiment. The distribution of the η' production angle in the decay channel η'→ ηπ{sup 0}π{sup 0} has been calculated for the first time within the beam photo energy range of 2500 to 2950 MeV. Furthermore, the relative effective cross section of the η(1405) to the η' could be determined to 0.16±0.05 (3.2σ). This shows evidence for a more complex nature of the η(1405).

  2. Algal Systems for Hydrogen Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Ghirardi, Maria L [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-08

    The National Renewable Energy Laboratory (NREL), under the guidance of Drs. Michael Seibert (retired, Fellow Emeritus) and Maria Ghirardi (Fellow), led 15 years of research addressing the issue of algal H2 photoproduction. This project resulted in greatly increased rates and yields of algal hydrogen production; increased understanding of the H2 metabolism in the green alga, Chlamydomonas reinhardtii; expanded our knowledge of other physiological aspects relevant to sustained algal photosynthetic H2 production; led to the genetic identification, cloning and manipulation of algal hydrogenase genes; and contributed to a broader, fundamental understanding of the technical and scientific challenges to improving the conversion efficiencies in order to reach the U.S. Department of Energy’s Fuel Cell Technologies Office’s targets. Some of the tangible results are: (i) 64 publications and 6 patents, (ii) international visibility to NREL, (iii) reinvigoration of national and international biohydrogen research, and (iv) research progress that helped stimulate new funding from other DOE and non-DOE programs, including the AFOSR and the DOE Office of Science.

  3. Multijets in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Krastev, Kaloyan

    2008-11-15

    In the analysis jets in photoproduction are studied with data collected by the H1 detector in 2006. Events with at least two jets with transverse energy greater than 9 GeV and pseudorapidity in the range of -0.5 to 1.5 in the laboratory frame are selected for the dijet sample. For the trijet and fourjet scenarios, one and two additional jets with transverse energy greater than 6 GeV and pseudorapidity in the range of -0.5 to 2.4 are required. The aim of the analysis is to study the dynamics of multijet events (events with more than two jets). In the perturbative picture the jet rate increases due to additional parton emissions. The jet rate can also be affected by multiple parton interactions when several pairs of partons within the incoming particles interact. Differential cross sections as a function of various variables for the dijet, trijet and fourjet scenario are measured. In addition, the applicability of two currently established multiple interaction models is tested. The results show that current models are not correctly describing the properties of multijet events in the analyzed phase space. (orig.)

  4. 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.)

  5. 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 0.55meson and p{sub T} is the transverse momentum of the meson with respect to the beam axis. The J/{psi} cross sections were measured 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.

  6. Study of the Two-pion Photoproduction on the Deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Lewis P. [Univ. of South Carolina, Columbia, SC (United States)

    2012-12-01

    Understanding the structure of baryons in terms of the fundamental interaction of the constituent quarks and gluons is one of the primary challenges in strong interaction physics. This interaction is governed by Quantum Chromodynamics (QCD), which is a theory for understanding the dynamics of strong. QCD displays the asymptotic freedom of hadrons at very short distances and also the confinement of quarks and gluons inside hadrons. However, solutions of this QCD theory in the non-perturbative domain of the interaction are extremely difficult to achieve, mainly because confinement happens on the hadronic scale on which the coupling constant is large and prevents any perturbative approach. Thus leaving us with strategies such as lattice QCD or formulating QCD sum rules to get around this problem. In exclusive hadron production the yN interaction is recognized for being a powerful method for investigating hadrons and the mysteries that still exist within the strong interaction. From reactions with the nucleon, the strong interaction can be investigated through the transition amplitudes to the N and Delta resonances. More specifically, if an electromagnetic interaction is well known then the intermediate resonance states may be evaluated through meson photoproduction. To gain more detailed insight into this interaction, we look to probe the baryon structure of the nucleon and the photo-excited resonance decays through photon scattering off a deuteron producing two pions in the final state. This photoproduction process off the deuteron will be used to investigate known baryon resonances in the two pion channel. The two pion final state will be investigated for unraveling new information into the photo-coupling strengths. We want to explore final state interactions, search for properties of known resonances, and to explore the possibility of seeing missing states that are predicted by quark models but have not yet been found experimentally. Using the CEBAF Large

  7. Charmed mesons in nuclear matter

    NARCIS (Netherlands)

    Tolos, Laura; Gamermann, D.; Garcia-Recio, C.; Molina, R.; Nieves, J.; Oset, E.; M. Ramos, A.; Crede,; Eugenio, P; Ostrovidov, A

    2010-01-01

    We obtain the properties of charmed mesons in dense matter using a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We study the behaviour of dynamically-generated baryonic resonances together with the open-charm meson spectral

  8. Vector mesons in matter

    Indian Academy of Sciences (India)

    One consequence of the chiral restoration is the mixing of parity partners. We look for a possible signature of the mixing of vector and axial vector mesons in heavy-ion collisions. We suggest an experimental method for its observation. The dynamical evolution of the heavy-ion collision is described by a transport equation of ...

  9. Vector mesons in matter

    Indian Academy of Sciences (India)

    kfki.hu. Abstract. One consequence of the chiral restoration is the mixing of parity partners. We look for a possible signature of the mixing of vector and axial vector mesons in heavy- ion collisions. We suggest an experimental method for its ...

  10. Glueball-meson mixing

    Energy Technology Data Exchange (ETDEWEB)

    Vento, Vicente [Consejo Superior de Investigaciones Cientificas, Departamento de Fisica Teorica y Instituto de Fisica Corpuscular, Universidad de Valencia, Burjassot (Spain)

    2016-01-15

    Calculations in unquenched QCD for the scalar glueball spectrum have confirmed previous results of Gluodynamics finding a glueball at ∝1750 MeV. I analyze the implications of this discovery from the point of view of glueball-meson mixing in light of the experimental scalar spectrum. (orig.)

  11. Diffractive production of mesons

    Directory of Open Access Journals (Sweden)

    Schicker Rainer

    2014-01-01

    Full Text Available The interest in the study of diffractive meson production is discussed. The description of diffraction within Regge phenomenology is presented, and the QCD-based understanding of diffractive processes is given. Central production is reviewed, and the corresponding main results from the COMPASS experiment and from the experiments at the ISR, RHIC, TEVATRON and LHC collider are summarised.

  12. Mesonic Form Factors

    Energy Technology Data Exchange (ETDEWEB)

    Frederic D. R. Bonnet; Robert G. Edwards; George T. Fleming; Randal Lewis; David Richards

    2003-07-22

    We have started a program to compute the electromagnetic form factors of mesons. We discuss the techniques used to compute the pion form factor and present preliminary results computed with domain wall valence fermions on MILC asqtad lattices, as well as Wilson fermions on quenched lattices. These methods can easily be extended to rho-to-gamma-pi transition form factors.

  13. Gluonic Excitations in Mesons

    OpenAIRE

    Page, Philip R

    1998-01-01

    We report on some interesting recent theoretical and experimental advances on J^PC exotics and hybrid mesons. These are the decay selection rules governing J^PC exotic decay, the experimental evidence for a J^PC = 1^-+ exotic in eta pi and rho pi, and the production of charmonium hybrids at forthcoming B-factories.

  14. Properties of Bc meson

    Indian Academy of Sciences (India)

    antiquark potential of the form − c r + A r with varying from 0.5 to 2.0. The and -wave masses, pseudoscalar decay constant, weak decay partial widths in spectator model and the lifetime of c meson are computed. The properties calculated ...

  15. Cross sections for inelastic meson-meson scattering

    Science.gov (United States)

    Yang, Kai; Xu, Xiao-Ming; Weber, H. J.

    2017-12-01

    We study two kinds of inelastic meson-meson scattering. The first kind is inelastic 2-to-2 meson-meson scattering that is governed by quark interchange as well as quark-antiquark annihilation and creation. Cross-section formulas are provided to get unpolarized cross sections for π K →ρ K* for I =1 /2 , π K*→ρ K for I =1 /2 , π K*→ρ K* for I =1 /2 , and ρ K →ρ K* for I =1 /2 . Near threshold, quark interchange dominates the reactions near the critical temperature. The second kind is 2-to-1 meson-meson scattering with the process that a quark in an initial meson and an antiquark in another initial meson annihilate into a gluon and subsequently the gluon is absorbed by the other antiquark or quark. The transition potential for the process is derived. Four Feynman diagrams at tree level contribute to the 2-to-1 meson-meson scattering. Starting from the S -matrix element, the isospin-averaged unpolarized cross section with transition amplitudes is derived. The cross sections for π π →ρ and π K →K* decrease with increasing temperature.

  16. Impressions of the Meson Spectrum: Hybrids & Exotics, present and future

    Energy Technology Data Exchange (ETDEWEB)

    Pennington, Michael R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-03-25

    It has long been expected that the spectrum of hadrons in QCD would be far richer and extensive than experiment has so far revealed. While there have been experimental hints of this richness for some time, it is really only in the last few years that dramatic progress has been seen in the exploration both experimentally and in calculations on the lattice. Precision studies enabled by new technology both with detectors and high performance computations are converging on an understanding of the spectrum in strong coupling QCD. These methodologies are laying the foundation for a decade of potential discovery that electro and photoproduction experiments at Jefferson Lab, which when combined with key results on B and charmonium decays from both e+e? and pp colliders, should turn mere impressions of the light meson spectrum into a high definition picture.

  17. On relative contributions of fusion and fragmentation mechanisms in J/{psi} photoproduction at high energy

    Energy Technology Data Exchange (ETDEWEB)

    Saleev, V.A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Shipilova, A.V. [Samara State Univ. (Russian Federation). Dept. of Physics

    2006-12-15

    We study J/{psi} photoproduction via the fusion and fragmentation mechanisms at the HERA Collider within the frameworks of the collinear parton model and the quasi-multi-Regge kinematics approach using the factorization formalism of non-relativistic QCD at leading order in the strong-coupling constant {alpha}{sub s} and the relative velocity v of the bound quarks. It is shown that the fusion production mechanism dominates over the fragmentation production mechanism at the all relevant J/{psi} transverse momenta. The J/{psi} meson p{sub T}-spectra in the fragmentation and fusion production at the asymptotically large p{sub T} have equal slopes in the quasi-multi-Regge kinematics approach, opposite the collinear parton model. (orig.)

  18. The growth with energy of exclusive J/Ψ and ϒ photo-production cross-sections and BFKL evolution

    Science.gov (United States)

    Hentschinski, Martin

    2017-03-01

    We investigate whether NLO BFKL evolution is capable to describe the energy dependence of the exclusive photo-production cross-section of vector mesons J/Ψ and ϒ on protons. Our description is based on available NLO BFKL fits of the proton impact factor in inclusive DIS, which allow us to construct the necessary scattering amplitude at zero momentum transfer t = 0. Assuming an exponential drop-off with t, this result allows us to calculate the exclusive photoproduction cross-section. Comparing our results with both HERA data (measured by H1 and ZEUS collaborations in ep collision) and LHC data (measured by ALICE, CMS and LHCb collaborations in ultra-peripheral pp and pPb collision) we find that our framework provides a very good description of the energy dependence of the J/Ψ and ϒ photoproduction cross-section, providing therefore further evidence for BFKL evolution at the LHC. The available fits of the proton impact factor require on the other hand an adjustment in the overall normalization.

  19. Jet shapes in charm photoproduction and deeply inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Grell, Brian Rosenvold

    2010-09-15

    This analysis investigates charm production processes in photoproduction and deeply inelastic scattering. The analysed data was collected with the H1 detector at the HERA accelerator in the years 1999-2000 for photoproduction and 2004-2007 for deeply inelastic scattering, corresponding to integrated luminosities of 83 pb{sup -1}, respectively 348 pb{sup -1}. Dijet events are selected with jet transverse momenta of at least 5 GeV, respectively 4 GeV, in the central rapidity region. One jet is tagged by a D{sup *} meson to be initiated by a charm quark. The other is studied with respect to its mean integrated jet shape in order to deduce to which fraction it is initiated by a quark or a gluon. The jet shape is described by the fraction {psi}(r) of the jet energy inside a cone of radius r around the jet axis; it is found that for r=0:6, {psi}(r) is most sensitive to differences between charm and light quark or gluon jets. The shape is measured as a function of various kinematic variables such as the jet energy and pseudorapidity, photon virtuality and x{sub {gamma}}{sup obs}, the fraction of the photon momentum entering the hard interaction. The photoproduction data is compared to Pythia, the DIS data to RapGap Monte Carlo simulations. In the Monte Carlo calculation, direct and resolved photon processes are simulated separately to compare samples with an enriched fraction of quark, respectively gluon initiated jets. Deviations at low x{sub {gamma}}{sup obs} are observed for higher values of Q{sup 2}, where direct and resolved expectations are nearly identical, hinting at an overestimation of gluon initiated jets. In most regions of phase space though, the resolution of the measurement excels the difference between direct and resolved predictions, allowing a distinction of such event samples. (orig.)

  20. Photon beam asymmetry Σ for η and η′ photoproduction from the proton

    Directory of Open Access Journals (Sweden)

    P. Collins

    2017-08-01

    Full Text Available Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η′ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp→ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp→η′p reaction. For γp→ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp→η′p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn–Gatchina model strengthens the evidence for four nucleon resonances – the N(18951/2−, N(19003/2+, N(21001/2+ and N(21203/2− resonances – which presently lack the “four-star” status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.

  1. Photon beam asymmetry Σ for η and η‧ photoproduction from the proton

    Science.gov (United States)

    Collins, P.; Ritchie, B. G.; Dugger, M.; Anisovich, A. V.; Döring, M.; Klempt, E.; Nikonov, V. A.; Rönchen, D.; Sadasivan, D.; Sarantsev, A.; Adhikari, K. P.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Balossino, I.; Bashkanov, M.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, Frank Thanh; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Glazier, D. I.; Gleason, C.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wei, X.; Zachariou, N.; Zhang, J.

    2017-08-01

    Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η‧ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp → ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp →η‧ p reaction. For γp → ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp →η‧ p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn-Gatchina model strengthens the evidence for four nucleon resonances - the N (1895) 1 /2-, N (1900) 3 /2+, N (2100) 1 /2+ and N (2120) 3 /2- resonances - which presently lack the ;four-star; status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.

  2. Electromagnetic Polarizabilities of Mesons

    Science.gov (United States)

    Aleksejevs, A.; Barkanova, S.

    2016-04-01

    The Chiral Perturbation Theory (CHPT) has been very successful in describing low-energy hadronic properties in the non-perturbative regime of Quantum Chromodynamics. The results of ChPT, many of which are currently under active experimental investigation, provide stringent predictions of many fundamental properties of hadrons, including quantities such as electromagnetic polarizabilities. Yet, even for the simplest hadronic system, a pion, we still have a broad spectrum of polarizability measurements (MARK II, VENUS, ALEPH, TPC/2g, CELLO, Belle, Crystal Ball). The meson polarizability can be accessed through Compton scattering, so we can measure it through Primakoff reaction. This paper will provide an analysis of the CHPT predictions of the SU(3) meson electromagnetic polarizabilities and outline their relationship to the Primakoff cross section at the kinematics relevant to the planned JLab experiments.

  3. Photoproduction of ηπ pairs off nucleons and deuterons

    Energy Technology Data Exchange (ETDEWEB)

    Kaeser, A.; Mueller, F.; Dieterle, M.; Garni, S.; Jaegle, I.; Keshelashvili, I.; Krusche, B.; Maghrbi, Y.; Oberle, M.; Pheron, F.; Rostomyan, T.; Strub, T.; Walford, N.K.; Witthauer, L. [University of Basel, Department of Physics, Basel (Switzerland); Ahrens, J.; Arends, H.J.; Bartolome, P.A.; Ostrick, M.; Otte, P.; Thomas, A. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Annand, J.R.M.; Hamilton, D.; Howdle, D.; Livingston, K.; MacGregor, I.J.D.; Mancell, J.; McGeorge, J.C.; McNicoll, E.; Robinson, J. [University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); Bantawa, K.; Manley, D.M. [Kent State University, Kent, OH (United States); Beck, R.; Nikolaev, A.; Schumann, S.; Unverzagt, M. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Braghieri, A.; Costanza, S.; Mushkarenkov, A.; Pedroni, P. [INFN Sezione di Pavia, Pavia (Italy); Briscoe, W.J.; Marinides, Z. [The George Washington University, Center for Nuclear Studies, Washington (United States); Cherepnya, S.; Fil' kov, L.V. [Lebedev Physical Institute, Moscow (Russian Federation); Downie, E.J. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); The George Washington University, Center for Nuclear Studies, Washington (United States); Drexler, P.; Metag, V.; Novotny, R.; Thiel, M. [University of Giessen, II. Physikalisches Institut, Giessen (Germany); Fix, A. [Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation); Glazier, D.I. [University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); University of Edinburgh, SUPA School of Physics, Edinburgh (United Kingdom); Hornidge, D.; Middleton, D.G. [Mount Allison University, Sackville, New Brunswick (Canada); Huber, G.M. [University of Regina, Regina (Canada); Jude, T.C.; Sikora, M.H.; Watts, D.P. [University of Edinburgh, SUPA School of Physics, Edinburgh (United Kingdom); Kashevarov, V.L. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Lebedev Physical Institute, Moscow (Russian Federation); Kondratiev, R.; Lisin, V.; Polonski, A. [Institute for Nuclear Research, Moscow (Russian Federation); Korolija, M.; Mekterovic, D.; Micanovic, S.; Supek, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Oussena, B. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); The George Washington University, Center for Nuclear Studies, Washington (United States); Prakhov, S.; Starostin, A. [University of California Los Angeles, Los Angeles, California (United States); Sober, D. [The Catholic University of America, Washington (United States); Werthmueller, D. [University of Basel, Department of Physics, Basel (Switzerland); University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); Collaboration: The A2 Collaboration

    2016-09-15

    Quasi-free photoproduction of πη-pairs has been investigated from threshold up to incident photon energies of 1.4 GeV, respectively up to photon-nucleon invariant masses up to 1.9 GeV. Total cross sections, angular distributions, invariant-mass distributions of the πη and meson-nucleon pairs, and beam-helicity asymmetries have been measured for the reactions γp → pπ{sup 0}η, γn → nπ{sup 0}η, γp → nπ{sup +}η, and γn → pπ{sup -}η from nucleons bound inside the deuteron. For the γp initial-state data for free protons have also been analyzed. Finally, the total cross sections for quasi-free production of π{sup 0}η pairs from nucleons bound in {sup 3} He nuclei have been investigated in view of final state interaction (FSI) effects. The experiments were performed at the tagged photon beam facility of the Mainz MAMI accelerator using an almost 4π covering electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. The shapes of all differential cross section data and the asymmetries are very similar for protons and neutrons and agree with the conjecture that the reactions are dominated by the sequential Δ*3/2{sup -} → ηΔ(1232) → πηN decay chain, mainly with Δ(1700)3/2{sup -} and Δ(1940)3/2{sup -}. The ratios of the magnitude of the total cross sections also agree with this assumption. However, the absolute magnitudes of the cross sections are reduced by FSI effects with respect to free proton data. (orig.)

  4. Photoproduction of the coherent $J/\\psi$ accompanied by the forward neutron emission in ultra-peripheral PbPb collisions at 2.76~TeV

    CERN Document Server

    CMS Collaboration

    2014-01-01

    The cross section of coherent $J/\\psi$ photoproduction accompanied by forward neutrons is measured in ultra-peripheral PbPb collisions at $\\sqrt{s_{NN}} = 2.76$ TeV with the CMS experiment at the LHC. $J/\\psi$ mesons are reconstructed by their decay into muon pairs while the neutrons are measured by Zero Degree Calorimeters. The analysis is based on a data sample collected during the 2011 PbPb run, corresponding to an integrated luminosity of 159 $\\mu$b$^{-1}$. The cross section for coherent $J/\\psi$ photoproduction in the rapidity region 1.8~$<|y|<$~2.3, in association with at least one neutron, is measured to be $\\frac{d\\sigma^{coh}_{X_{n}0_{n}}}{dy}($J/\\psi$) = $ 0.37 $\\pm$ 0.04 (stat) $\\pm$ 0.04 (syst)~mb. This result is found to be in agreement with models that include nuclear gluon shadowing.

  5. Rare B Meson Decays With Omega Mesons

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei; /Colorado U.

    2006-04-24

    Rare charmless hadronic B decays are particularly interesting because of their importance in understanding the CP violation, which is essential to explain the matter-antimatter asymmetry in our universe, and of their roles in testing the ''effective'' theory of B physics. The study has been done with the BABAR experiment, which is mainly designed for the study of CP violation in the decays of neutral B mesons, and secondarily for rare processes that become accessible with the high luminosity of the PEP-II B Factory. In a sample of 89 million produced B{bar B} pairs on the BABAR experiment, we observed the decays B{sup 0} {yields} {omega}K{sup 0} and B{sup +} {yields} {omega}{rho}{sup +} for the first time, made more precise measurements for B{sup +} {yields} {omega}h{sup +} and reported tighter upper limits for B {yields} {omega}K* and B{sup 0} {yields} {omega}{rho}{sup 0}.

  6. Rare B Meson Decays With O Mesons

    CERN Document Server

    Zhang, L

    2004-01-01

    Rare charmless hadronic B decays are particularly interesting because of their importance in understanding the CP violation, which is essential to explain the matter-antimatter asymmetry in our universe, and of their roles in testing the “effective” theory of B physics. The study has been done with the BABAR experiment, which is mainly designed for the study of CP violation in the decays of neutral B mesons, and secondarily for rare processes that become accessible with the high luminosity of the PEP-II B Factory. In a sample of 89 million produced BB¯ pairs on the BABAR experiment, we observed the decays B 0 → ωK0 and B + → ωρ+ for the first time, made more precise measurements for B+ → ω h+ and reported tighter upper limits for B → ωK* and B 0 → ωρ0. The branching fractions measured are B (B+ → ωπ+) = (5.5 ± 0.9 ± 0.5)...

  7. MesonNet Workshop on Meson Transition Form Factors

    CERN Document Server

    Eidelman, S; Hanhart, C; Kubis, B; Kupsc, A; Leupold, S; Moskal, P; Schadmand, S

    2012-01-01

    The mini-proceedings of the Workshop on Meson Transition Form Factors held in Cracow from May 29th to 30th, 2012 introduce the meson transition form factor project with special emphasis on the interrelations between the various form factors (on-shell, single off-shell, double off-shell). Short summaries of the talks presented at the workshop follow.

  8. Pion photoproduction in a nonrelativistic theory

    OpenAIRE

    Fuhrer, Andreas

    2009-01-01

    The pion and nucleon mass differences generate a very pronounced cusp in the photoproduction reaction of a single pion on the nucleon. A nonrelativistic effective field theory to describe this reaction is constructed. The approach is rigorous in the sense that it is an effective field theory with a consistent power counting scheme. Expressions for the S- and P-wave multipole amplitudes for all four reaction channels at two loops are given.

  9. Pion photoproduction in a nonrelativistic theory

    Energy Technology Data Exchange (ETDEWEB)

    Fuhrer, Andreas, E-mail: afuhrer@physics.ucsd.ed [University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0319 (United States)

    2010-01-18

    The pion and nucleon mass differences generate a very pronounced cusp in the photoproduction reaction of a single pion on the nucleon. A nonrelativistic effective field theory to describe this reaction is constructed. The approach is rigorous in the sense that it is an effective field theory with a consistent power counting scheme. Expressions for the S- and P-wave multipole amplitudes for all four reaction channels at two loops are given.

  10. Photoproduction of Neutral Kaons on Deuterons

    Science.gov (United States)

    Beckford, Brian

    2006-11-01

    Experimentation to greater understand the strangeness production mechanism can be performed by observing the electromagnetic interaction that leads to Kaon photoproduction. The n (γ, K^0) λ reaction may assist in answering questions about the strangeness photo-production process. An experiment into the elementary Kaon photoproduction process was investigated in an experiment conducted at the Laboratory of Nuclear Science of Tohoku University (LNS) using the Neutral Kaon Spectrometer. (NKS). The experiment was conducted by the d (γ, K^0) reaction. K^0 will be measured in the K^0->π^+π^- decay chain by the NKS. The NKS implements many detectors working in coincidence: These ranging from the Tagged Photon Beam generated by the 1.2 GeV Electron beam via bremsstrahlung, an Inner Plastic Scintillator Hodoscope (IH), a Straw Drift Chamber (SDC), a Cylindrical Drift Chamber (CDC), and an Outer Plastic Scintillator Hodoscope. Due to the background produced through the γ-> e+e- process, electron veto counters (EV) were placed in the middle of the OH to reject charged particles in the horizontal plane of the beam line. Preliminary analysis of the data indicates the need for pulse height correction. This was achieved by analysis of the Inner and Outer hodoscopes, and determining the energy deposit in the scintillators.

  11. Polarization observables in ω photo-production

    Directory of Open Access Journals (Sweden)

    Vegna V.

    2014-06-01

    Full Text Available The total cross section of ω photo-production off proton shows several bumps in the incoming photon energy range 1.1–2.5 GeV, which can be ascribed to the contribution of intermediate proton excited states in the s-channel of the reaction. At the same time, differential cross sections show a diffractive behavior, which is interpreted in terms of t-channel exchange contributions. A complete understanding of the ω photo-production process requires a simultaneous investigation of both t-channel exchange terms and s-channel contributions. The measurement of the angular distributions of omega decay products allows to extract the values of the spin-density-matrix elements (SDME and to evaluate the contribution of natural/unnatural parity exchange terms. The use of polarized beam and/or target allows to measure polarization observables which can help to identify the intermediate proton excited states involved in the process. Results of SDME and polarization observables will be shown as an overview about ω photo-production.

  12. Exclusive Backward-Angle Omega Meson Electroproduction

    Energy Technology Data Exchange (ETDEWEB)

    Wenliang, Li [Univ. of Regina, Regina, SK (Canada)

    2017-10-01

    Exclusive meson electroproduction at different squared four-momenta of the exchanged virtual photon, Q2 , and at different four-momentum transfers, t and u, can be used to probe QCD's transition from hadronic degrees of freedom at the long distance scale to quark-gluon degrees of freedom at the short distance scale. Backward-angle meson electroproduction was previously ignored, but is anticipated to offer complimentary information to conventional forward-angle meson electroproduction studies on nucleon structure. This work is a pioneering study of backward-angle ω cross sections through the exclusive 1H(e, e'p)ω reaction using the missing mass reconstruction technique. The extracted cross sections are separated into the transverse (T), longitudinal (L), and LT, TT interference terms. The analyzed data were part of experiment E01-004 (Fπ-2), which used 2.6-5.2 GeV electron beams and HMS+SOS spectrometers in Jefferson Lab Hall C. The primary objective was to detect coincidence π in the forward-angle, where the backward-angle omega events were fortuitously detected. The experiment has central Q2 values of 1.60 and 2.45 GeV2 , at W = 2.21 GeV. There was significant coverage in phi and epsilon, which allowed separation of σT,L,LT,TT . The data set has a unique u coverage of -u ~ 0, which corresponds to -t > 4 GeV2 . The separated σT result suggest a flat ~ 1/Q1.33±1.21 dependence, whereas sigma_L seems to hold a stronger 1/Q9.43±6.28 dependence. The σL/σT ratio indicate σT dominance at Q2 = 2.45 GeV2 at the ~90% confidence level. After translating the results into the -t space of the published CLAS data, our data show evidence of a backward-angle omega electroproduction peak at both Q2 settings. Previously, this phenomenon showing both forward and backward-angle peaks was only observed in the meson

  13. Vector mesons in meson-baryon scattering and large-N{sub c} quantum chromodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Fuhrmann, Hans-Friedrich

    2016-02-11

    -vanishing spin. In particular we considered the vector meson photoproduction off the nucleon as it is currently studied by e.g. Jude (2015), Wilson (2015) or Sokhoyan (2015). A decomposition of on-shell production amplitudes into covariant partial wave amplitudes which are both free from kinematical constraints and compatible with the microcausality condition was achieved. A Mathematica code using the FeynCalc package was written and applied to some tree-level contact terms and s-, u- and t-channel processes.

  14. Meson Resonances from Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-06-01

    There has been recent, significant, advances in the determination of the meson spectrum of QCD. Current efforts have focused on the development and application of finite-volume formalisms that allow for the determination of scattering amplitudes as well as resonance behavior in coupled channel systems. I will review some of these recent developments, and demonstrate the viability of the method in meson systems.

  15. Meson resonances on the lattice

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-06-01

    There has been recent, significant, advances in the determination of the meson spectrum of QCD. Current efforts have focused on the development and application of finite-volume formalisms that allow for the determination of scattering amplitudes as well as resonance behavior in coupled channel systems. I will review some of these recent developments, and demonstrate the viability of the method in meson systems

  16. The light meson spectroscopy program

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Elton S. [JLAB

    2014-06-01

    Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.

  17. The Meson Mass System

    CERN Document Server

    Palazzi, Paolo

    2007-01-01

    The neglected 35 MeV/c2 particle mass quantization hypothesis has recently been reassessed for all known meson states. The rule is found to be statistically relevant, once the states are grouped by quark composition and JPC, with slightly different mass units for each group. In certain groups the mass unit is spin-dependent. Also the mass units are linearly quantized, with highly structured correlation patterns. The baryon masses are organized along similar lines. These results support an indication that hadrons might be shell-structured.

  18. Strong and radiative decays of excited vector mesons and predictions for a new ϕ (1930 ) resonance

    Science.gov (United States)

    Piotrowska, Milena; Reisinger, Christian; Giacosa, Francesco

    2017-09-01

    We study the phenomenology of two nonets of excited vector mesons, {ρ (1450 ),K*(1410 ),ω (1420 ),ϕ (1680 )} and {ρ (1700 ),K*(1680 ),ω (1650 ),ϕ (???)} , which (roughly) correspond to radially excited 2 3S1 and to orbitally excited 1 3D1 vector mesons. We evaluate the strong and radiative decays of these mesons into pseudoscalar and ground-state vector mesons by using an effective relativistic QFT model based on flavor symmetry. We compare decay widths and branching ratios with various experimental results listed in the PDG. An overall agreement of theory with experiment reinforces the standard quark-antiquark assignment of the resonances mentioned above. Predictions for not-yet-measured quantities are also made. In particular, we shall also make predictions for the not-yet-discovered s s ¯ state of the 1 3D1 nonet, denoted as ϕ (???) . Its mass can be estimated to be about 1930 MeV; hence we shall call this putative state ϕ (1930 ). Its main decays are into K K*(892 ) (about 200 MeV) and K K (about 100 MeV). Since this state couples also to γ η , it can be searched for in the near future in the photoproduction-based experiments GlueX and CLAS12 at Jefferson Lab.

  19. Meson Spectroscopy at COMPASS

    CERN Document Server

    Grube, Boris

    2015-01-01

    The COmmon Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS) is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron (SPS) aimed at studying the structure and spectrum of hadrons. The two-stage spectrometer has a good acceptance for charged as well as neutral particles over a wide kinematic range and thus allows to access a wide range of reactions. Light mesons are studied with negative (mostly $\\pi^-$) and positive ($p$, $\\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The spectrum of light mesons is investigated in various final states produced in diffractive dissociation reactions at squared four-momentum transfers to the target between 0.1 and 1.0 $(\\text{GeV}/c)^2$. The flagship channel is the $\\pi^-\\pi^+\\pi^-$ final state, for which COMPASS has recorded the currently largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new resonance-like signal, t...

  20. The Z Charmoniumlike Mesons

    Energy Technology Data Exchange (ETDEWEB)

    Gabareen Mokhtar, Arafat; /SLAC; Olsen, Stephen Lars; /Seoul Natl. U.

    2011-08-12

    A brief review of the experimental situation concerning the electrically charged charmoniumlike meson candidates, Z{sup -}, is presented. The Belle Collaboration reported peaks in the {psi}{prime}{pi}{sup -} and {chi}{sub c1}{pi}{sup -} invariant mass distributions in B {yields} {psi}{prime}{pi}{sup -}K and B {yields} {chi}{sub c1}{pi}{sup -}K, respectively. If these peaks are meson resonances, they would have a minimal quark substructure of c{bar c}d{bar u} and be unmistakeably exotic. However, even though the Belle signals have more than 5{sigma} statistical significance, the experimental situation remains uncertain in that none of these peaks have yet been confirmed by other experiments. An analysis by the BABAR Collaboration of B {yields} {psi}{prime}{pi}{sup -}K neither confirms nor contradicts the Belle claim for the Z(4430){sup -} {yields} {psi}{prime}{pi}{sup -}. In the BABAR analysis, B {yields} J/{psi}{pi}{sup -}K decays were also studied, and no evidence for Z(4430){sup -} {yields} J/{psi}{pi}{sup -} was found. In this paper, we review and compare Belle and BABAR results on searches for charged charmonium-like states.

  1. Meson spectroscopy at COMPASS

    Directory of Open Access Journals (Sweden)

    Grube Boris

    2016-01-01

    Full Text Available The goal of the COMPASS experiment at CERN is to study the structure and dynamics of hadrons. The two-stage spectrometer used by the experiment has large acceptance and covers a wide kinematic range for charged as well as neutral particles and can therefore measure a wide range of reactions. The spectroscopy of light mesons is performed with negative (mostly π− and positive (p, π+ hadron beams with a momentum of 190 GeV/c. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer t to the target between 0.1 and 1.0 (GeV=c2. The flagship channel is the π−π−π+ final state, for which COMPASS has recorded the currently world’s largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to observe new states. Among these is a new axial-vector signal, the a1(1420, with unusual properties. Novel analysis techniques have been developed to extract also the amplitude of the π−π+ subsystem as a function of 3π mass from the data. The findings are confirmed by the analysis of the π−π0π0 final state.

  2. Meson Spectroscopy at COMPASS

    CERN Document Server

    Grube, Boris

    2016-11-29

    The goal of the COMPASS experiment at CERN is to study the structure and dynamics of hadrons. The two-stage spectrometer used by the experiment has large acceptance and covers a wide kinematic range for charged as well as neutral particles and can therefore measure a wide range of reactions. The spectroscopy of light mesons is performed with negative (mostly $\\pi^-$) and positive ($p$, $\\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer $t$ to the target between 0.1 and 1.0 $(\\text{GeV}/c)^2$. The flagship channel is the $\\pi^-\\pi^-\\pi^+$ final state, for which COMPASS has recorded the currently world's largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to observe new states. Among these is a new axial-vector signal, the $a_1(1420)$, with unusual properties. Novel analysis techniques have been...

  3. Analysis of strong decays of charmed mesons D2*(2460 ) , D0(2560 ), D2(2740 ), D1(3000 ), D2*(3000 ), and their spin partners D1*(2680 ), D3*(2760 ), and D0*(3000 )

    Science.gov (United States)

    Gupta, Pallavi; Upadhyay, A.

    2018-01-01

    Using the effective Lagrangian approach, we examine the recently observed charm states DJ*(2460 ), DJ(2560 ), DJ(2740 ), DJ(3000 ), and their spin partners DJ*(2680 ), DJ*(2760 ), and DJ*(3000 ) with JP states 1 P3/22+, 2 S1/20-, 1 D5/22-, 2 P1/21+, and 2 S1/21-, 1 D5/23-, 2 P1/20+ respectively. We study their two body strong decays, coupling constants and branching ratios with the emission of light pseudo-scalar mesons (π ,η ,K ). We also analyze the newly observed charm state D2*(3000 ) and suggest it to be either 1 F (2+) or 2 P (2+) state and justify one of them to be the most favorable assignment for D2*(3000 ). We study the partial and the total decay width of unobserved states D (1 1F3) , Ds(1 1F3) and Ds(1 1F2) as the spin and the strange partners of the D2*(3000 ) charmed meson. The branching ratios and the coupling constants gT H, g˜H H, gY H, g˜S H, and gZ H calculated in this work can be confronted with the future experimental data.

  4. Investigation of in-medium ω photoproduction

    Indian Academy of Sciences (India)

    ω-meson mass at normal nuclear matter density ρ0, for example, vary within the range of 640 to 765 MeV [1–4] .... Eγ = Ee − Ee was determined event-by-event from the incident electron beam energy Ee and the energy Ee of the scattered ... shapes are reproduced by Monte Carlo simulations. This is demonstrated in figure.

  5. Antibaryon Photoproduction using CLAS at Jefferson Lab

    Science.gov (United States)

    Phelps, William; CLAS Collaboration

    2017-09-01

    There is little known about the baryon-antibaryon photoproduction mechanism. Three reactions, γp -> pp p , γp -> pp n π- , and γp -> pn p π+ have been investigated for the photon energy range of 3.95-5.45 GeV. The data were from the g12 experiment taken with the CLAS detector using a liquid hydrogen target in Hall B at Thomas Jefferson National Accelerator Facility. This experiment had high statistics, with an integrated luminosity of 68 pb-1. General features of the data and preliminary cross sections for the p p system will be discussed.

  6. Polarization Observables from two-pion and ρ meson photoproduction on polarized HD target at JLab

    Energy Technology Data Exchange (ETDEWEB)

    Zonta, Irene [Univ. of Rome, Tor Vergata (Italy)

    2015-05-01

    The preliminary results discussed in this theses have been carried out with the Nuclear Physics group of the Department of Physics at the University of Rome Tor Vergata, under the supervision of Prof. A. D’Angelo.On March 2012 I joined the CLAS collaboration at the Thomas Jefferson National Laboratory, in Virginia, USA, and became a term member after a probation period of 9 months. As a member I could participate to the g14 data taking, started on November 18th 2011 and finished on May 18th 2012. In that period I was in charge of the timing calibration of the CLAS forward electromagnetic spectrometer. For the duration of the experiment, I was also responsible of the Raman laboratory located at the University of Rome Tor Vergata, where the Raman measurements were performed. The Raman measurements were crucial for determining the relative concentrations of H2 and D2 in the Hydrogen-Deuteride gas which was used for the target of the g14 experiment.

  7. Light tetraquarks and mesons in a DSE/BSE approach

    Energy Technology Data Exchange (ETDEWEB)

    Heupel, Walter

    2015-07-01

    quark propagator and it's dressing functions. This enables one to derive closed expressions for the interaction kernel beyond the rainbow-ladder approximation. This technique is very general, and in principle applicable to any vertex that is given in terms of quark dressing functions. As an improvement over previous approaches this technique allows one to determine not only the masses of the bound-states but also their Bethe-Salpeter wave functions. As examples, this technique was applied to two type of vertices, the Ball-Chiu vertex and the Munczek vertex that both respect the constraints due to the vector Ward-Takahashi identity but contain additional structures related to spin-orbit forces. Upon solving the BSE for pseudo-scalar, scalar, vector and axial-vector mesons it was found that these structures alone are not sufficient to generate a physical spectrum of light mesons while keeping the pion properties intact.

  8. Diffractive $\\rho^0$ photoproduction at HERA

    CERN Document Server

    Weber, Ronald M

    2006-01-01

    From a sample of over 989'000 events taken at the experiment H1 using the new Fast Track Trigger (Ftt), a new measurement of the differential cross section for diffractive p" photoproduction is performed in the kinematic range 20 < W-m < 90 GeV and |r| < 3 GcV2. The large data sample allows for a measurement of the cross section double differentially in W1[, and t and thus the energy dependence of this process for eight / values in a single experiment. From this data, the pomeron trajectory in elastic p° photoproduction is determined to be aF (f) = 1.097 ± 0.004 (ataf)tU öos (*W*) + (0.133 ± 0.027 (stat) 1 o o^o («tf*)) GeV-2 • t. In 2002 the first complete readout chip (PS143) for the pixel detector at the Compact Muon Solenoid (CMS) became available at the Paul Scherrer Institut (PSI), Villigen. After extensive tests of the single readout chip, the first prototype modules were assembled and tested electrically. The experience obtained from these modules was used to optimize the next generati...

  9. J/ψ photoproduction in Pb–Pb and p–Pb ultra-peripheral collisions with ALICE at LHC

    Energy Technology Data Exchange (ETDEWEB)

    De Gruttola, D., E-mail: daniele.de.gruttola@cern.ch

    2014-06-15

    The photoproduction of vector mesons in Ultra-Peripheral Collisions (UPC) is a powerful tool to probe the nuclear gluon distribution, for which there is considerable uncertainty in the low-x region. We present the first measurements in Pb–Pb collisions at √(s{sub NN})=2.76 TeV, performed with the ALICE detector. The J/ψ is identified via its dimuon decay in the forward rapidity region and via dimuon and dielectron decay at midrapidity. The results are compared to theoretical models for coherent J/ψ production and found to be in good agreement with models which include nuclear gluon shadowing. The cross section measurement for incoherent J/ψ and γγ→e{sup +}e{sup −} at mid-rapidity is reported. Finally we present the first results on p–Pb UPC at √(s{sub NN})=5.02 TeV.

  10. Photoproduction of $J/\\psi$ in ultra-peripheral p-Pb and Pb-Pb collisions with the ALICE detector at the LHC

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00360890

    The physics of ultra-peripheral collisions is introduced in the first part along with the fundamental concepts of several theoretical models. The measurement of photoproduction of vector mesons off proton and lead nucleus allows to study the QCD structure of these targets at energies that have never been measured before. The next parts of the text describe the measurements, the results, and present the physics discussion of the results. The aim of the thesis is to present the analysis of coherent $J/\\psi$ photoproduction in the forward rapidity in ultra-peripheral Pb-Pb collisions and the analysis of exclusive $J/\\psi$ photoproduction in ultra-peripheral p-Pb collisions in the forward, semi-forward and central rapidity. The personal contribution of the author in the Pb-Pb analysis consists in the determination of the efficiency of coherent, incoherent and two-photon processes and computations of the feed-down correction. In the case of the p-Pb analyses, the author has prepared and managed the official and au...

  11. A Search for the LHCb Charmed 'Pentaquark' using Photo-Production of $J/{\\psi}$ at Threshold in Hall C at Jefferson Lab

    CERN Document Server

    Meziani, Z -E; Paolone, M; Chudakov, E; Jones, M; Adhikari, K; Aniol, K; Armstrong, W; Arrington, J; Asaturyan, A; Atac, H; Bae, S; Bhatt, H; Bhetuwal, D; Chen, J -P; Chen, X; Choi, H; Choi, S; Diefenthaler, M; Dunne, J; Dupré, R; Duran, B; Dutta, D; El-Fassi, L; Fu, Q; Gao, H; Go, H; Gu, C; Ha, J; Hafidi, K; Hansen, O; Hattawy, M; Higinbotham, D; Huber, G M; Markowitz, P; Meekins, D; Mkrtchyan, H; Li, W; Li, X; Liu, T; Peng, C; Pentchev, L; Pooser, E; Rehfuss, M; Sparveris, N; Tadevosyan, V; Wang, R; Wesselmann, F R; Wood, S; Xiong, W; Yan, X; Ye, L; Ye, Z; Zafar, A; Zhang, Y; Zhao, F; Zhao, Z; Zhamkochyana, S

    2016-01-01

    We propose to measure the photo-production cross section of $J/{\\psi}$ near threshold, in search of the recently observed LHCb hidden-charm resonances $P_c$(4380) and $P_c$(4450) consistent with 'pentaquarks'. The observation of these resonances in photo-production will provide strong evidence of the true resonance nature of the LHCb states, distinguishing them from kinematic enhancements. A bremsstrahlung photon beam produced with an 11 GeV electron beam at CEBAF covers the energy range of $J/{\\psi}$ production from the threshold photo-production energy of 8.2 GeV, to an energy beyond the presumed $P_c$(4450) resonance. The experiment will be carried out in Hall C at Jefferson Lab using a 50{\\mu}A electron beam incident on a 9% copper radiator. The resulting photon beam passes through a 15 cm liquid hydrogen target, producing $J/{\\psi}$ mesons through a diffractive process in the $t$-channel, or through a resonant process in the $s$- and $u$-channel. The decay $e^+e^-$ pair of the $J/{\\psi}$ will be detected...

  12. Exclusive Photoproduction of Charged Pions in Hydrogen and Deuterium from 1 to 6 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Lingyan [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2004-02-01

    The study of the transition region in the description of exclusive processes and hadron structure, from the nucleon-meson degrees of freedom in meson-exchange models at low energy to the quark-gluon degrees of freedom in pQCD at high energy, is essential for us to understand the strong interaction. The differential cross section measurements for exclusive reactions at fixed center-of-mass angles enable us to investigate the constituent counting rule, which explicitly connects the quark-gluon degrees of freedom to the energy dependence of differential cross sections. JLab Experiment E94-104 was carried out in Hall A with two high resolution spectrometers. It included the coincidence cross section measurement for the γn --> π-[p] process with a deuterium target and the singles measurement for the γp --> π+[n] process with a hydrogen target. The untagged real photons were generated by the electron beam impinging on a copper radiator. The photon energies ranged from 1.1 to 5.5 GeV, corresponding to the center-of-mass energies from 1.7 to 3.4 GeV. The pion center-of-mass angles were fixed at 50 deg, 70 deg, 90 deg, and also 100 deg, 110 deg at a few energies. The JLab E94-104 data presented in this thesis contain four interesting features. The data exhibit a global scaling behavior for both π- and π+ photoproduction at high energies and high transverse momenta, consistent with the constituent counting rule and the existing π+ photoproduction data. This implies that the quark-gluon degrees of freedom start to play a role at this energy scale. The data suggests possible substructure of the scaling behavior, which might be oscillations around the scaling value. There are several possible mechanisms that can cause oscillations, for example the one associated with the generalized constituent counting rule involving quark orbital angular momentum. The data show an enhancement in the scaled cross section at center

  13. Results and future prospects of exclusive vector meson production with pPb collisions at CMS

    CERN Document Server

    Chudasama, Ruchi

    2017-01-01

    Exclusive photoproduction of vector mesons (Upsilon and Rho0) is studied with the large photon flux available in ultra-peripheral pPb collisions at sqrt(sNN) =5.02 TeV with CMS experiment. It provides a clean probe of the gluon distribution at small values of parton fractional momenta $x$ at centralrapidities ($y < 2.5$). The cross sections are measured as a function of the photon-proton centre-of-mass energy, extending the energy range explored by H1 and ZEUS Experiments at HERA. In addition, the differential cross sections (dsigma/dt), where $\\abs{t} \\approx p^2_T$ is the squared transverse momentum of produced vector mesons, are measured and the slope parameters are obtained. The results are compared to previous measurements and to theoretical predictions. Finally, prospect for further measurements of vector meson production that can be performed using the 2016 pPb collision data at 8 TeV to be collected at the end of the year are presented.

  14. Prompt photons in photoproduction 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; Aldaya Martin, M. [DESY Hamburg (Germany); Alexa, C. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (RO)] (and others)

    2009-10-15

    The production of prompt photons is measured in the photoproduction regime of electronproton scattering at HERA. The analysis is based on a data sample corresponding to a total integrated luminosity of 340 pb{sup -1} collected by the H1 experiment. Cross sections are measured for photons with transverse momentum and pseudorapidity in the range 6< E{sub T}{sup {gamma}}<15 GeV and -1.0<{eta}{sup {gamma}}<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{sub {gamma}} and x{sub 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 kT factorisation approaches. (orig.)

  15. Putative Enzymes of UV Photoproduct Repair

    Directory of Open Access Journals (Sweden)

    Cynthia J. Sakofsky

    2011-01-01

    Full Text Available In order to determine the biological relevance of two S. acidocaldarius proteins to the repair of UV photoproducts, the corresponding genes (Saci_1227 and Saci_1096 were disrupted, and the phenotypes of the resulting mutants were examined by various genetic assays. The disruption used integration by homologous recombination of a functional but heterologous pyrE gene, promoted by short sequences attached to both ends via PCR. The phenotypic analyses of the disruptants confirmed that ORF Saci_1227 encodes a DNA photolyase which functions in vivo, but they could not implicate ORF Saci_1096 in repair of UV- or other externally induced DNA damage despite its similarity to genes encoding UV damage endonucleases. The success of the gene-disruption strategy, which used 5′ extensions of PCR primers to target cassette integration, suggests potential advantages for routine construction of Sulfolobus strains.

  16. Toxic photoproducts of phenanthrene in sunlight

    Energy Technology Data Exchange (ETDEWEB)

    McConkey, B.L.; Duxbury, C.L.; El-Alawi, Y.S.; Dixon, D.G.; Greenberg, B.M. [Univ. of Waterloo, Ontario (Canada). Dept. of Biology

    1995-12-31

    Phenanthrene, one of the most prevalent PAHs, undergoes a significant increase in toxicity on exposure to sunlight. Over a period of several days exposure to light, the toxicity of an aqueous phenanthrene solution increased dramatically. This increase in toxicity is largely due to the primary photoproduct, 9,10-phenanthrenequinone. This compound is more toxic than phenanthrene at equimolar concentrations, and is more water soluble than phenanthrene, increasing its bioavailability. Although many PAHs are potent photosensitizers, phenanthrene did not exhibit a significant increase in toxicity due to photosensitization. Photo-oxidation was the principal cause of photoinduced toxicity, with 9,10-phenanthrenequinone being formed via an unstable intermediate. In addition, mixtures of phenanthrene and 9,10-phenanthrenequinone exhibited potentially synergistic effects, as shown by joint toxicity testing using Photobacterium phosphoreum. Thus, mixtures of oxidized PAHs produced by photoaction in the environment create a significant risk to the biosphere.

  17. 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.

  18. Photoproduction of the Λ c charmed baryon

    Science.gov (United States)

    Alvarez, M. P.; Barate, R.; Bloch, D.; Bonamy, P.; Borgeaud, P.; Burchell, M.; Burmeister, H.; Brunet, J. M.; Calvino, F.; Cattaneo, M.; Crespo, J. M.; d'Almagne, B.; David, M.; DiCiaccio, L.; Dixon, J.; Druet, P.; Duane, A.; Engel, J. P.; Ferrer, A.; Filippas, T. A.; Fokitis, E.; Forty, R. W.; Foucault, P.; Gazis, E. N.; Gerber, J. P.; Giomataris, Y.; Hofmokl, T.; Katsoufis, E. C.; Koratzinos, M.; Krafft, C.; Lefievre, B.; Lemoigne, Y.; Lopez, A.; Lui, W. K.; Magneville, C.; Maltezos, A.; McEwen, J. G.; Papadopoulou, Th.; Pattison, B.; Poutot, D.; Primout, M.; Rahmani, H.; Roudeau, P.; Seez, C.; Six, J.; Strub, R.; Treille, D.; Triscos, P.; Tristram, G.; Villet, G.; Volte, A.; Wayne, M.; Websdale, D. M.; Wormser, G.; Zolnierowski, Y.; NA14/2 Collaboration

    1990-08-01

    In a photoproduction experiment using a mean photon energy of 100 GeV we have observed 29±8 Λ c( overlineΛ c) charmed-baryon and antibaryon decays in the pK-π + ( overlinepK +π -) final state. Quasi two-body final states do not contribite significantly to this channel. The mass of the Λ c was measured to be 2281.7±2.7±2.6 MeV/ c2 and its lifetime 0.18±0.03±0.03 ps. The ratio of {Λ c}/{D} production, measured in this experiment, is significantly greater than that predicted by photon-gluon fusion and using a Lund model to describe the hadronization. This excess cannot be completely accounted for in this model, even using a Λ c branching fraction in pK π as high as 5%.

  19. Photoproduction at high energy and high intensity

    CERN Multimedia

    2002-01-01

    The photon beam used for this programme is tagged and provides a large flux up to very high energies (150-200 GeV). It is also hadron-free, since it is obtained by a two-step conversion method. A spectrometer is designed to exploit this beam and to perform a programme of photoproduction with a high level of sensitivity (5-50 events/picobarn).\\\\ \\\\ Priority will be given to the study of processes exhibiting the point-like behaviour of the photon, especially deep inelastic Compton scattering. The spectrometer has two magnets. Charged tracks are measured by MWPC's located only in field-free regions. Three calorimeters provide a large coverage for identifying and measuring electrons and photons. An iron filter downstream identifies muons. Most of the equipment is existing and recuperated from previous experiments.

  20. Microbial degradation of thidiazuron and its photoproduct.

    Science.gov (United States)

    Benezet, H J; Knowles, C O

    1982-01-01

    Degradation of the cotton defoliant thidiazuron and its photoproduct photothidiazuron by soil and thirteen species of microorganisms was examined. Aspergillus versicolor, Torula rosea, and Flavobacter sp. were most active in degrading thidiazuron. Unknown water-soluble metabolites and phenylurea were the major products. A. versicolor and Penicillium cyclopium were most active in degrading photothidiazuron. 4-Hydroxyphenylphotothidiazuron was the major organosoluble product formed by A. versicolor; phenylurea and an unidentified metabolite constituted the major organosoluble products from P. cyclopium. Both microbes also formed appreciable water-soluble metabolites. Radioactive carbon dioxide was formed from thidiazuron-aniline-14C by Oscillatoria sp. but not by Chlorella sp., suggesting that the former algal species utilized the defoliant as an energy source.

  1. Meson-meson scattering from U(3) chiral perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Guo Zhihui, E-mail: zhguo@ugr.e [CAFPE and Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, Campus de Fuente Nueva, E-18002 Granada (Spain); Prades, Joaquim [CAFPE and Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, Campus de Fuente Nueva, E-18002 Granada (Spain); Oller, Jose Antonio, E-mail: oller@um.e [Departamento de Fisica, Universidad de Murcia, E-30071 Murcia (Spain)

    2010-10-15

    A complete one loop calculation of all the meson-meson scattering amplitudes in the framework of U(3) chiral perturbation theory with explicit resonance states is presented in this article. By performing the unitarization of the perturbative scattering amplitudes using a variant of the N/D method, we show that the approach can describe well the various scattering data. In the end, we use the parameters from the fit to determine the masses, widths and the corresponding residue of the relevant resonances.

  2. Meson Correlators in Finite Temperature Lattice QCD

    CERN Document Server

    De Forcrand, Philippe; Hashimoto, T; Hioki, S; Matsufuru, H; Miyamura, O; Nakamura, A; Takaishi, T; Umeda, T; Stamatescu, I O; CERN. Geneva; Forcrand, Ph. de

    2001-01-01

    We analyze temporal and spatial meson correlators in quenched lattice QCD at T>0. Below T_c we observe little change in the meson properties as compared with T=0. Above T_c we observe new features: chiral symmetry restoration and signals of plasma formation, but also indication of persisting mesonic (metastable) states and different temporal and spatial masses in the mesonic channels. This suggests a complex picture of QGP in the region 1 - 1.5 T_c.

  3. Heavy meson production in hot dense matter

    NARCIS (Netherlands)

    Tolos, Laura; Gamermann, Daniel; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Nieves, JM; Oset, E; Vacas, MJV

    2010-01-01

    The properties of charmed mesons in dense matter are studied using a unitary coupled-channel approach in the nuclear medium which takes into account Pauli-blocking effects and meson self-energies in a self-consistent manner. We obtain the open-charm meson spectral functions in this dense nuclear

  4. meson properties and its leptonic radiative decays

    Indian Academy of Sciences (India)

    Whereas it was realized first in 1992 that such fragmentation functions of the double heavy mesons, being different from that of a light meson or a heavy meson, can be further factorized out a perturbative part, which can be reliably calculated by pQCD [2]. As an important consequence of the 'further' factorization, the ...

  5. Measurement of D{sup *{+-}} meson produciton in e{sup {+-}}p scattering at low Q{sup 2}

    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 D{sup *{+-}}(2010) mesons in e{sup {+-}}p scattering in the range of exchanged photon virtuality 0.05mesons and the ZEUS beampipe calorimeter was used to identify the scattered electron. Differential D{sup *} cross sections as functions of Q{sup 2}, inelasticity, y, transverse momentum of the D{sup *} meson, p{sub T}(D{sup *}), and pseudorapidity of the D{sup *} meson, {eta}(D{sup *}), have been measured in the kinematic region 0.02photoproduction and DIS regimes. (orig.)

  6. Electroproduction of pseudoscalar mesons above the resonance region

    Energy Technology Data Exchange (ETDEWEB)

    Niczyporuk, B.B. [Continuous Electron beam Accelerator Facility, Newport News, VA (United States)

    1994-04-01

    In this paper, the author has revisited twenty year old data considering the progress achieved in related fields. To make further progress in our understanding of strong interactions, one needs much better quality of exclusive electroproduction data. A measurement of the differential cross section {sigma}(t, W, Q{sup 2}) for the reactions e{sup {minus}} + p {r_arrow} e{sup {minus}} + {pi}{sup +}(K{sup +}) + n({Lambda}{degrees}) at a beam energy of {ge} 4 GeV is proposed. Data will be collected simultaneously for both reactions using the CLAS detector at CEBAF in the following kinematical region: Q{sup 2} > 1 GeV{sup 2} and W > 2 GeV. One of the most interesting aspects of electroproduction is that it can be used to measure photoproduction amplitudes as functions of the photon mass squared Q{sup 2} and momentum transfer t. Emphasis is given to measuring the differential cross sections for t {approximately} m{sup 2}{sub {pi},{kappa}}. Above the resonance region (W > 2 GeV), the cross section is dominated by the amplitudes for scalar photons. Measured angular distributions of produced mesons will be used to estimate the contribution of various amplitudes to the cross sections. High statistics and good quality data collected simultaneously using a large acceptance detector will improve our understanding of nucleon structure as well as the hadronic properties of the photon.

  7. DETERMINATION OF APPARENT QUANTUM YIELD SPECTRA FOR THE FORMATION OF BIOLOGICALLY LABILE PHOTOPRODUCTS

    Science.gov (United States)

    Quantum yield spectra for the photochemical formation of biologically labile photoproducts from dissolved organic matter (DOM) have not been available previously, although they would greatly facilitate attempts to model photoproduct formation rates across latitudinal, seasonal, a...

  8. Detection of Ultraviolet Photoproducts in Mouse Skin Exposed to Natural Sunlight

    National Research Council Canada - National Science Library

    Qin, Xiusheng; Zhang, Shaomin; Zarkovic, Mirjana; Nakatsuru, Yoko; Shimizu, Seiichiro; Yamazaki, Yukari; Oda, Hideaki; Nikaido, Osamu; Ishikawa, Takatoshi

    1996-01-01

    ...) photoproducts, cyclobutane pyrimidine dimers (CPDs), pyrimidine‐pyrimidone (6–4) photoproducts (64PPs) and Dewar isomers, in vivo in shaved and depilated C3H/HeN mouse skin exposed to natural sunlight...

  9. Diffractive open charm production in deep-inelastic scattering and photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aktas, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Andreev, V. [Lebedev Physical Institute, Moscow (Russian Federation); Anthonis, T. [Inter-Univ. Institute for High Energies ULB-VUB, Brussels (Belgium)]|[Antwerp Univ. (BE)] (and others)

    2006-10-15

    Measurements are presented of diffractive open charm production at HERA. The event topology is given by ep{yields}eXY where the system X contains at least one charmed hadron and is well separated by a large rapidity gap from a leading low-mass proton remnant system Y. Two analysis techniques are used for the cross section measurements. In the first, the charm quark is tagged by the reconstruction of a D{sup *{+-}}(2010) meson. This technique is used in deep-inelastic scattering (DIS) and photoproduction ({gamma}p). In the second, a method based on the displacement of tracks from the primary vertex is used to measure the open charm contribution to the inclusive diffractive cross section in DIS. The measurements are compared with next-to-leading order QCD predictions based on diffractive parton density functions previously obtained from a QCD analysis of the inclusive diffractive cross section at H1. A good agreement is observed in the full kinematic regime, which supports the validity of QCD factorization for open charm production in diffractive DIS and {gamma}p. (orig.)

  10. Search for Resonances in the Photoproduction of Proton-Antiproton Pairs

    Energy Technology Data Exchange (ETDEWEB)

    Stokes, Burnham [Florida State Univ., Tallahassee, FL (United States)

    2006-01-01

    Results are reported on the reaction γp → p$\\bar{p}$p with beam energy in the range 4.8-5.5 GeV. The data were collected at the Thomas Jefferson National Accelerator Facility in CLAS experiment E01-017(G6C). The focus of this study is an understanding of the mechanisms of photoproduction of proton-antiproton pairs, and to search for intermediate resonances, both narrow and broad, which decay to p$\\bar{p}$. The total measured cross section in the photon energy range 4.8-5.5 GeV is σ = 33 ± 2 nb. Measurement of the cross section as a function of energy is provided. An upper limit on the production of a narrow resonance state previously observed with a mass of 2.02 GeV/c2 is placed at 0.35 nb. No intermediate resonance states were observed. Meson exchange production appears to dominate the production of the proton-antiproton pairs.

  11. A narrow structure in the excitation function of eta-photoproduction off the neutron

    CERN Document Server

    Werthmueller, D; Keshelashvili, I; Aguar-Bartolome, P; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Beck, R; Bekrenev, V; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Demissie, B; Dieterle, M; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Glazier, D I; Hamilton, D; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jaegle, I; Jahn, O; Jude, T C; Kaeser, A; Kashevarov, V L; Kondratiev, R; Korolija, M; Kruglov, S P; Krusche, B; Kulbardis, A; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; Martinez, M; McGeorge, J C; McNicoll, E F; Metag, V; Middleton, D G; Mushkarenkov, A; Nefkens, B M K; Nikolaev, A; Novotny, R; Oberle, M; Ostrick, M; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S N; Robinson, J; Rosner, G; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D; Starostin, A; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P

    2013-01-01

    The photoproduction of $\\eta$-mesons off nucleons bound in $^2$H and $^3$He has been measured in coincidence with recoil protons and recoil neutrons for incident photon energies from threshold up to 1.4 GeV. The experiments were performed at the Mainz MAMI accelerator, using the Glasgow tagged photon facility. Decay photons from the $\\eta\\rightarrow 2\\gamma$ and $\\eta\\rightarrow 3\\pi^0$ decays and the recoil nucleons were detected with an almost $4\\pi$ electromagnetic calorimeter combining the Crystal Ball and TAPS detectors. The data from both targets are of excellent statistical quality and show a narrow structure in the excitation function of $\\gamma n\\rightarrow n\\eta$. The results from the two measurements are consistent taking into account the expected effects from nuclear Fermi motion. The best estimates for position and intrinsic width of the structure are $W$ = (1670$\\pm$5) MeV and $\\Gamma$ =(30$\\pm$15) MeV. For the first time precise results for the angular dependence of this structure have been ext...

  12. Inclusive Photoproduction of Neutral Pions in the Photon Hemisphere 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.; Bertrand-Coremans, G.; 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.; Donovan, K.T.; Dowell, J.D.; Droutskoi, A.; Duprel, C.; Ebert, J.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferrarotto, F.; 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.; Ghazaryan, Samvel; Glazov, A.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haustein, V.; 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.; Hilton, C.D.; 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.; Kolanoski, H.; 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.; Lemaitre, V.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; Lobo, G.; 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, A.; 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, D.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Negri, I.; 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.; Passaggio, S.; 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.; Schleif, S.; Schleper, P.; Schmidt, D.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; Smith, M.; 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.; Sutton, J.P.; 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.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.; zur Nedden, M.

    2001-01-01

    The inclusive cross section for the photoproduction of neutral pions has been measured as a function of the transverse momentum, rapidity, and Feynman x of the pizero mesons at an average photon--proton centre-of-mass energy of 208 GeV and for photon virtualities below Q^2=0.01 GeV^2. The pizero measurement extends the range covered by previous charged particle measurements at HERA by two units of rapidity in the photon direction down to a value of -5.5 in the gamma p centre-of-mass frame. The pizero transverse momentum distribution is well described over the whole measured range by a power law ansatz, while an exponential fit falls below the data at transverse momentum values above 1.5 GeV/c. Good agreement with the predictions of the Monte Carlo models PYTHIA and PHOJET is found. In the context of the PYTHIA model the data are inconsistent with large intrinsic transverse momentum values in the photon.

  13. The GlueX Start Counter and Beam Asymmetry$\\Sigma$ in Single $\\pi^{0}$ Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Pooser, Eric [Florida Intl Univ., Miami, FL (United States)

    2016-03-26

    The GlueX experiment aims to study meson photoproduction while utilizing the coherent bremsstrahlung technique to produce a 9 GeV linearly polarized photon beam incident on a liquid H2 target. A Start Counter detector was fabricated to properly identify the accelerator electron beam buckets and to provide accurate timing information. The Start Counter detector was designed to operate at photon intensities of up to 108 γ/s in the coherent peak and provides a timing resolution ~300 ps so as to provide successful identification of the electron beam buckets to within 99% accuracy. Furthermore, the Start Counter detector provides excellent solid angle coverage, ~ 90% of 4π hermeticity, and a high degree of segmentation for background rejection. It consists of a cylindrical array of 30 scintillators with pointed ends that bend towards the beam at the downstream end. Magnetic field insensitive silicon photomultiplier detectors were selected as the readout system. An initial measurement of the beam asymmetry Sigma in the exclusive reaction γ$\\vec{p}$→ π0p, where π0 → γ has been carried out utilizing the GlueX spectrometer during the Spring 2015 commissioning run. The tagged photon energies ranged from 2.5≤ Eγ ≤ 3.0 GeV in the coherent peak. These measurements were then compared to the world data set and show remarkable agreement with only two hours of physics production running.

  14. Orbitally excited charm - strange mesons

    Energy Technology Data Exchange (ETDEWEB)

    Kasper, Penelope A. [Illinois Inst. of Technology, Chicago, IL (United States)

    1996-05-01

    This thesis describes an attempt to measure the properties of mesons containing a charm quark and a strange quark in a state of orbital angular momentum L > 0, and compare these with the predictions of theoretical models based on heavy quark effective theory.

  15. Existence of mesons after deconfinement

    NARCIS (Netherlands)

    F. Brau (Fabian); F. Buisseret

    2007-01-01

    textabstractWe investigate the possibility for a quark-antiquark pair to form a bound state at temperatures higher than the critical one ($T>T_c$), thus after deconfinement. Our main goal is to find analytical criteria constraining the existence of such mesons. Our formalism relies on a Schrödinger

  16. Exclusive meson production at COMPASS

    CERN Document Server

    Pochodzalla, Josef; Moinester, Murray; Piller, Gunther; Sandacz, Andrzej; Vanderhaeghen, Marc; Pochodzalla, Josef; Mankiewicz, Lech; Moinester, Murray; Piller, Gunther; Sandacz, Andrzej; Vanderhaeghen, Marc

    1999-01-01

    We explore the feasibility to study exclusive meson production (EMP) in hard muon-proton scattering at the COMPASS experiment. These measurements constrain the off-forward parton distributions (OFPD's) of the proton, which are related to the quark orbital contribution to the proton spin.

  17. Theoretical overview: The New mesons

    Energy Technology Data Exchange (ETDEWEB)

    Quigg, Chris; /Fermilab

    2004-11-01

    After commenting on the state of contemporary hadronic physics and spectroscopy, I highlight four areas where the action is: searching for the relevant degrees of freedom, mesons with beauty and charm, chiral symmetry and the D{sub sJ} levels, and X(3872) and the lost tribes of charmonium.

  18. Momentum dependence of hadronic production of the {phi}-meson and its width in nuclear matter

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Michael, E-mail: m.hartmann@fz-juelich.de [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics (Germany); Kaempfer, Burkhard [Institut fuer Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf (Germany); Kiselev, Yury T. [Institute for Theoretical and Experimental Physics (Russian Federation); Magas, Vacas K. [Universitat de Barcelona, Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos (Spain); Paryev, Eduard Ya. [Russian Academy of Science, Institute for Nuclear Research (Russian Federation); Polyanskiy, Andrey [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Centre for Hadron Physics (Germany); Roca, Luis [Universidad de Murcia, Departamento de Fisica (Spain); Schade, Henry [Institut fuer Strahlenphysik, Helmholtz-Zentrum Dresden-Rossendorf (Germany); Wilkin, Colin [UCL, Physics and Astronomy Department (United Kingdom)

    2012-05-15

    Information on the properties of the {phi} meson in the nuclear environment has been derived from its production in proton collisions with C, Cu, Al, and Au nuclear targets. The experiment was carried out with 2.83 GeV protons at the Cooler Synchrotron COSY, with the {phi} being detected via its K{sup + }K{sup }- decay using the ANKE magnetic spectrometer. The measured dependence of the production cross section on the nuclear mass number has been compared with calculations within three different nuclear models. These suggest a significant broadening of the width of the {phi} in medium relative to its vacuum value. The ANKE results obtained in the momentum range 0.6 < p{sub {phi}} < 1.6 GeV/c are compared with data from photoproduction experiments at slightly higher momenta.

  19. Photoproduction with a Leading Proton at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; 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.; 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.; 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.; 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.; 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.; 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.; 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.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kermiche, S.; Kiesling, Christian M.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Koutouev, R.; Koutov, A.; Krasny, M.W.; 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.; 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.; 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.; 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.; Risler, C.; 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.; Schmitt, S.; 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.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; Solochenko, V.; Soloviev, 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.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vichnevski, A.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; 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.; Zur Nedden, M.

    2001-01-01

    The total cross section for the photoproduction process with a leading proton in the final state has been measured at gamma p centre-of-mass energies W of 91, 181 and 231 GeV. The measured cross sections apply to the kinematic range with the transverse momentum of the scattered proton restricted to p_Tproton Xp'}(W,z)/dz is observed to be independent of W and z within the measurement errors and amounts to (8.05 +- 0.06 stat +- 0.89 syst) mub on average. The data are well described by a Triple Regge model in which the process is mediated by a mixture of exchanges with an effective Regge trajectory of intercept alpha_i(0)=0.33 +- 0.04 stat +- 0.04 syst. The total cross section for the interaction of the photon with this mixture (gamma alpha_i -> X) can be described by an effective trajectory of intercept alpha_k(0)=0.99 +- 0.01 stat +- 0.05 syst. The measured cross sections are compared with deep inelastic scattering leading proton data in the same region of z and p_Tproton for photon virtuality Q^2 > 2.5 GeV^...

  20. Kaon photoproduction on the deuteron at Sendai

    Directory of Open Access Journals (Sweden)

    Shirotori K.

    2012-02-01

    Full Text Available The photoproduction of K0 and Λ on the deuteron was measured in order to investigate the γn → K0Λ reaction process near the threshold (Eγ = 0.8-1.1 GeV. K0 and Λ events were clearly seen in the π+π− and the pπ− invariant mass spectra, respectively. The momentum spectra of the γd → K0X and the γd → ΛX reactions were derived. Additionally, the energy dependence of the integral cross section for the Λ production was also obtained. The K0 momentum spectra were in agreement with the previous results within statistical errors. The angular distribution of the γn → K0Λ reaction in the center of mass system was extracted and it had the backward distribution. The total cross section of the γn → K0Λ reaction, which was estimated by subtracting the contribution of K+Λ process from the Λ production on the deuteron, was almost the same as that of the γp → K+Λ.

  1. Exclusive meson production at COMPASS

    CERN Document Server

    Sznajder, Paweł

    2014-01-01

    In this paper we summarize recent measurements of exclusive meson production performed by the COMPASS Collaboration. In particular, recent results on the transverse target spin asymmetries for exclusive r 0 production are presented. Some of these asymmetries are sensitive to the GPDs E , which are related to the orbital angular momentum of quarks. Other asymmetries are sensitive to the chiral-odd, transverse GPDs H T . Measurements of exclusive processes, which are a part of the COMPASS-II proposal, are also discussed

  2. Measurement of heavy-quark jet photoproduction 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.; Bolilyi, O.; 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.; 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.; Dolgoshein, B. A.; Dolinska, G.; Doyle, A. T.; Drugakov, V.; Durkin, L. S.; Dusini, S.; Eisenberg, Y.; Ermolov, P. F.; Eskreys, A.; Fazio, S.; Ferrando, J.; Ferrero, M. I.; Figiel, J.; Forrest, M.; Foster, B.; Fourletov, S.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gialas, I.; Gladilin, L. K.; Gladkov, D.; Glasman, C.; Gogota, O.; Golubkov, Yu A.; Goettlicher, P.; Grabowska-Bold, I.; Grebenyuk, J.; Gregor, I.; Grigorescu, G.; Grzelak, G.; Gueta, O.; Gwenlan, C.; Haas, T.; Hain, W.; Hamatsu, R.; Hart, J. C.; Hartmann, H.; Hartner, G.; Hilger, E.; Hochman, D.; Hori, R.; Horton, K.; Huettmann, A.; Ibrahim, Z. A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jakob, H. -P.; Januschek, F.; Jimenez, M.; Jones, T. W.; Juengst, M.; Kadenko, I.; Kahle, B.; Kamaluddin, 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.; Kooijman, P.; Korol, I.; Korzhavina, I. A.; Kotanski, A.; Koetz, U.; Kowalski, H.; Kulinski, P.; Kuprash, O.; Kuze, M.; Lee, A.; Levchenko, B. B.; Libov, V.; Limentani, S.; Ling, T. Y.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Loehr, B.; Lohrmann, E.; Long, K. R.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu; Luzniak, P.; Maeda, J.; Magill, S.; Makarenko, I.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Mastroberardino, A.; Mattingly, M. C. K.; Melzer-Pellmann, I. -A.; Mergelmeyer, S.; Miglioranzi, S.; Idris, F. Mohamad; Monaco, V.; Montanari, A.; Mujkic, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Nicholass, D.; Nigro, A.; Ning, Y.; Nobe, T.; Noor, U.; Notz, D.; Nowak, R. J.; Nuncio-Quiroz, A. E.; Oh, B. Y.; Okazaki, N.; Oliver, K.; Olkiewicz, K.; Onishchuk, Yu; Papageorgiu, K.; Parenti, A.; 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.; Ron, E.; Rubinsky, I.; Ruspa, M.; Sacchi, R.; Salii, A.; Samson, U.; Sartorelli, G.; Savin, A. A.; Saxon, D. H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W. B.; Schneekloth, U.; Schoenberg, V.; Schoerner-Sadenius, T.; Schwartz, J.; Sciulli, F.; Shcheglova, L. M.; Shehzadi, R.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Smith, W. H.; Sola, V.; Solano, A.; Son, D.; Sosnovtsev, V.; Spiridonov, A.; Stadie, H.; Stanco, L.; 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.; Tomalak, O.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Tymieniecka, T.; Uribe-Estrada, C.; Vazquez, M.; Verbytskyi, A.; Viazlo, O.; Vlasov, N. N.; Volynets, O.; Walczak, R.; Abdullah, W. A. T. Wan; Whitmore, J. J.; Whyte, J.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Yaguees-Molina, A. G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhautykov, B. O.; Zhmak, N.; Zichichi, A.; Zolko, M.; Zotkin, D. S.; Zulkapli, Z.

    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

  3. Enhanced hydrogen photoproduction by non-heterocystous cyanobacterium Plectonema boryanum

    Energy Technology Data Exchange (ETDEWEB)

    Kashyap, A.K.; Pandey, K.D.; Sarkar, S. [Banaras Hindu Univ., Varanasi (India). Centre of Advanced Study in Botany

    1996-02-01

    Nitrogenase activity was depressed in Plectonema boryanum following 18-24 h of microaerobic incubation. The cyanobacterium evolved hydrogen at a slow rate. Addition of reducing substances (sulfide, sulfite or dithionite) to the diazotrophic cultures resulted in an increase in nitrogenase activity or photoproduction of hydrogen. The reducing substances also restored phycocyanin degradation. (author)

  4. Coherent $\\rho^0$ photoproduction in ultra-peripheral Pb-Pb collisions at $\\mathbf{\\sqrt{\\textit{s}_{\\rm NN}}} = 2.76$ TeV

    CERN Document Server

    Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahn, Sang Un; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Barth, Klaus; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Iii, Ronald John; Belmont Moreno, Ernesto; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biswas, Rathijit; Biswas, Saikat; Bjelogrlic, Sandro; Blanco, Fernando; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Buxton, Jesse Thomas; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Zhang, Chunhui; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Deisting, Alexander; Deloff, Andrzej; Denes, Ervin Sandor; D'Erasmo, Ginevra; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Engel, Heiko; Erazmus, Barbara Ewa; Erhardt, Filip; Eschweiler, Dominic; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Fleck, Martin Gabriel; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Gasik, Piotr Jan; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Ramirez, Andres; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harris, John William; Hartmann, Helvi; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hilden, Timo Eero; Hillemanns, Hartmut; Hippolyte, Boris; Hristov, Peter Zahariev; Huang, Meidana; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Ionita, Costin; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacobs, Peter Martin; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Kamal; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Do Won; Kim, Dong Jo; Kim, Hyeonjoong; Kim, Jinsook; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobayashi, Taiyo; Kobdaj, Chinorat; Kofarago, Monika; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kravcakova, Adela; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kulakov, Igor; Kumar, Jitendra; Lokesh, Kumar; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lea, Ramona; Leardini, Lucia; Lee, Graham Richard; Lee, Seongjoo; Legrand, Iosif; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loggins, Vera Renee; Loginov, Vitaly; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Ferreira Natal Da Luz, Pedro Hugo; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martin, Nicole Alice; Martin Blanco, Javier; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martinez Pedreira, Miguel; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Masui, Hiroshi; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzoni, Alessandra Maria; Mcdonald, Daniel; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mieskolainen, Matti Mikael; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Minervini, Lazzaro Manlio; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Nattrass, Christine; Nayak, Kishora; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pagano, Paola; Paic, Guy; Pajares Vales, Carlos; Pal, Susanta Kumar; Pan, Jinjin; Pandey, Ashutosh Kumar; Pant, Divyash; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Patra, Rajendra Nath; Paul, Biswarup; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Poljak, Nikola; Poonsawat, Wanchaloem; Pop, Amalia; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Jan; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puccio, Maximiliano; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rajput, Sonia; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reidt, Felix; Ren, Xiaowen; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Ristea, Catalin-Lucian; Rivetti, Angelo; Rocco, Elena; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Pragati; Sahoo, Raghunath; Sahoo, Sarita; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Saleh, Mohammad Ahmad; Salgado Lopez, Carlos Alberto; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Seeder, Karin Soraya; Seger, Janet Elizabeth; Sekiguchi, Yuko; Selyuzhenkov, Ilya; Senosi, Kgotlaesele; Seo, Jeewon; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabanov, Arseniy; Shabetai, Alexandre; Shadura, Oksana; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Ankita; Sharma, Natasha; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Sielewicz, Krzysztof Marek; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Snellman, Tomas Wilhelm; Soegaard, Carsten; Soltz, Ron Ariel; Song, Jihye; Song, Myunggeun; Song, Zixuan; Soramel, Francesca; Sorensen, Soren Pontoppidan; Spacek, Michal; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew Donald; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Sultanov, Rishat; Sumbera, Michal; Symons, Timothy; Szabo, Alexander; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Takahashi, Jun; Tanaka, Naoto; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tariq, Mohammad; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terasaki, Kohei; Terrevoli, Cristina; Teyssier, Boris; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Trogolo, Stefano; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Utrobicic, Antonija; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Vanat, Tomas; Vande Vyvre, Pierre; Varga, Dezso; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vauthier, Astrid; Vechernin, Vladimir; Veen, Annelies Marianne; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Vislavicius, Vytautas; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Jan; Wang, Hongkai; Wang, Mengliang; Wang, Yifei; Watanabe, Daisuke; Weber, Michael; Weber, Steffen Georg; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Ping; Yano, Satoshi; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yurchenko, Volodymyr; Yushmanov, Igor; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym

    2015-09-15

    We report the first measurement at the LHC of coherent photoproduction of $\\rho^0$ mesons in ultra-peripheral Pb-Pb collisions. The invariant mass and transverse momentum distributions for $\\rho^0$ production are studied in the $\\pi^+ \\pi^-$ decay channel at mid-rapidity. The production cross section in the rapidity range $|y|<0.5$ is found to be $\\mathrm{d}\\sigma/\\mathrm{d}y = 425 \\pm 10 \\, (\\mathrm{stat.})$ $^{+42}_{-50} \\, (\\mathrm{sys.})$ mb. Coherent $\\rho^0$ production is studied with and without requirement of nuclear breakup, and the fractional yields for various breakup scenarios are presented. The results are compared with those from lower energies and with model predictions based on the Glauber model and the color dipole model. The measured cross section is found to be inconsistent with a scaling of the $\\gamma$-nucleon cross section using the Glauber model.

  5. Meson-nucleus potentials and the search for meson-nucleus bound states

    Science.gov (United States)

    Metag, V.; Nanova, M.; Paryev, E. Ya.

    2017-11-01

    Recent experiments studying the meson-nucleus interaction to extract meson-nucleus potentials are reviewed. The real part of the potentials quantifies whether the interaction is attractive or repulsive while the imaginary part describes the meson absorption in nuclei. The review is focused on mesons which are sufficiently long-lived to potentially form meson-nucleus quasi-bound states. The presentation is confined to meson production off nuclei in photon-, pion-, proton-, and light-ion induced reactions and heavy-ion collisions at energies near the production threshold. Tools to extract the potential parameters are presented. In most cases, the real part of the potential is determined by comparing measured meson momentum distributions or excitation functions with collision model or transport model calculations. The imaginary part is extracted from transparency ratio measurements. Results on K+ ,K0 ,K- , η ,η‧ , ω, and ϕ mesons are presented and compared with theoretical predictions. The interaction of K+ and K0 mesons with nuclei is found to be weakly repulsive, while the K- , η ,η‧ , ω and ϕ meson-nucleus potentials are attractive, however, with widely different strengths. Because of meson absorption in the nuclear medium the imaginary parts of the meson-nucleus potentials are all negative, again with a large spread. An outlook on planned experiments in the charm sector is given. In view of the determined potential parameters, the criteria and chances for experimentally observing meson-nucleus quasi-bound states are discussed. The most promising candidates appear to be the η and η‧ mesons.

  6. Experimental evidence for hadroproduction of exotic mesons

    Energy Technology Data Exchange (ETDEWEB)

    G. S. Adams; T. Adams; Z. Bar-Yam; J. M. Bishop; V. A. Bodyagin; B. B. Brabson; D. S. Brown; N. M. Cason; S. U. Chung; R. R. Crittenden; J. P. Cummings; K. Danyo; S. Denisov; V. Dorofeev; J. P. Dowd; A. R. Dzierba; P. Eugenio; J. Gunter; R. W. Hackenburg; M. Hayek; E. I. Ivanov; I. Kachaev; W. Kern; E. King; O. L. Kodolova; V. L. Korotkikh; M. A. Kostin; J. Kuhn; R. Lindenbusch; V. Lipaev; J. M. LoSecco; J. J. Manak; J. Napolitano; M. Nozar; C. Olchanski; A. I. Ostrovidov; T. K. Pedlar; A. Popov; D. R. Rust; D. Ryabchikov; A. H. Sanjari; L. I. Sarycheva; E. Scott; K. K. Seth; N. Shenhav; W. D. Shephard; N. B. Sinev; J. A. Smith; P. T. Smith; D. L. Stienike; T. Sulanke; S. A. Taegar; S. Teige; D. R. Thompson; I. N. Vardanyan; D. P. Weygand; D. White; H. J. Willutzki; J. Wise; M. Witkowski; A. A. Yershov; D. Zhao

    2001-01-01

    New measurements of peripheral meson production are presented. The data confirm the existence of exotic mesons at 1.4 and 1.6 GeV/c2. The latter state dominates the eta'pi- decay spectrum. The data on eta pi+pi-pi- decay show large strength in several exotic (Jpc = 1- +) waves as well.

  7. Meson-photon transition form factors

    Energy Technology Data Exchange (ETDEWEB)

    Balakireva, Irina; Lucha, Wolfgang; Melikhov, Dmitri [SINP, Moscow State University, 119991 Moscow (Russian Federation); Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria) and Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria)

    2012-10-23

    We present the results of our recent analysis of the meson-photon transition form factors F{sub P{gamma}}(Q{sup 2}) for the pseudoscalar mesons P {pi}{sup 0},{eta},{eta} Prime ,{eta}{sub c}, using the local-duality version of QCD sum rules.

  8. Narrow mesons and colour symmetry

    CERN Document Server

    Volkovitsky, P E; Kaidalov, A B; Okun, Lev Borisovich

    1975-01-01

    The consequences of the hypothesis that the recently discovered narrow resonances psi (3105) and psi '(3695) are hadrons i.e. that they possess strong interactions and belong to the 'coloured' particle family are examined. The properties of psi bosons are examined within the framework of the coloured model in which the hadrons are made up of nine quarks p/sub i/, n/sub i/, lambda /sub i/ (i=1,2,3) and the ordinary hadrons are assumed to be singlets from the SU(3)' group and the properties of the decays of psi and psi ' mesons are discussed. (10 refs).

  9. Branching ratios and properties of D-meson decays

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, M.P.; Calvino, F.; Crespo, J.M. (Universidad Autonoma de Barcelona (Spain)); Barate, R.; Burmeister, H.; Di Ciaccio, L.; Ferrer, A.; Giomataris, Y.; Pattison, B.; Treille, D.; Zolnierowski, Y. (European Organization for Nuclear Research, Geneva (Switzerland)); Bloch, D.; Engel, J.P.; Foucault, P.; Gerber, J.P.; Strub, R. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires); Bonamy, P.; Borgeaud, P.; David, M.; Lemoigne, Y.; Magneville, C.; Primout, M.; Villet, G. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Physique des Particules Elementaires); Burchell, M.; Cattaneo, M.; Dixon, J.; Duane, A.; Forty, R.W.; Seez, C.; Websdale, D.M. (Imperial Coll. of Science and Technology, London (UK). Blackett Lab.); Brunet, J.M.; Lefievre, B.; Poutot, D.; Triscos, P.; Tristram, G.; Volte, A. (College de France, 75 - Paris (France)); Almagne, B. d' ; Druet, P.; Krafft, C.; Roudeau, P.; Six, J.; Wayne, M.; Wormser, G. (Institut National; NA14/2 Collaboration

    1991-04-01

    Properties of D mesons produced in the photoproduction experiment NA14/2 at CERN are reported. The following ratios of branching fractions were measured: Br(D{sup 0}{yields}K{sup +}K{sup -})/Br(D{sup 0}{yields}K{sup -}{pi}{sup +})=0.16{plus minus}0.05, Br(D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup 0})/Br(D{sup 0}{yields}K{sup -}{pi}{sup +})=4.0{plus minus}0.9{plus minus}1.0, Br(D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -})/Br(D{sup 0}{yields}K{sup -}{pi}{sup +})=1.9{plus minus}0.25{plus minus}0.20. The D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} decay was analysed and the contribution of resonant subprocesses found consistent with 1{rho}{sup 0} and 0.23 anti K{sup *0} per event. The angular distributions of D{sup 0}{yields}anti K{sup *0}{rho}{sup 0} showed parity violation and destructive interference between S- and D-waves. From a Dalitz-plot analysis of the decay D{sup +}{yields}K{sup -}{pi}{sup +}{pi}{sup +} the contribution from the quasi two-body decay D{sup +}{yields}anti K{sup *0}{pi}{sup +} was measured to be 0.14{plus minus}0.04{plus minus}0.04. (orig.).

  10. Discrete symmetries with neutral mesons

    Science.gov (United States)

    Bernabéu, José

    2018-01-01

    Symmetries, and Symmetry Breakings, in the Laws of Physics play a crucial role in Fundamental Science. Parity and Charge Conjugation Violations prompted the consideration of Chiral Fields in the construction of the Standard Model, whereas CP-Violation needed at least three families of Quarks leading to Flavour Physics. In this Lecture I discuss the Conceptual Basis and the present experimental results for a Direct Evidence of Separate Reversal-in-Time T, CP and CPT Genuine Asymmetries in Decaying Particles like Neutral Meson Transitions, using Quantum Entanglement and the Decay as a Filtering Measurement. The eight transitions associated to the Flavour-CP eigenstate decay products of entangled neutral mesons have demonstrated with impressive significance a separate evidence of TRV and CPV in Bd-physics, whereas a CPTV asymmetry shows a 2σ effect interpreted as an upper limit. Novel CPTV observables are discussed for K physics at KLOE-2, including the difference between the semileptonic asymmetries from KL and KS, the ratios of double decay rate Intensities to Flavour-CP eigenstate decay products and the ω-effect. Their observation would lead to a change of paradigm beyond Quantum Field Theory, however there is nothing in Quantum Mechanics forbidding CPTV.

  11. Exclusive φ meson production in HERMES

    Energy Technology Data Exchange (ETDEWEB)

    Golembiovskaya, Mayya

    2014-03-15

    In the present work exclusive φ meson leptoproduction at HERMES experiment in DESY was studied using the data collected at HERA accelerator in the period from 1998 till 2000 and from 2006 till 2007 years. In the analysis unpolarized and longitudinally polarized hydrogen and deuteron targets were used, the beam consisted of longitudinally polarized leptons. Via measurement of the angular and momentum distribution of the φ meson decay products 23 spin density matrix elements (SDMEs) for the φ meson were obtained. The number of SDMEs was defined by the experiment conditions, e.g. by the beam and target polarization directions. For the mentioned time period φ meson SDMEs were defined at HERMES for the first time. The quantities U{sub 1}, U{sub 2} and U{sub 3} which can be used to check presence of unnatural parity exchange (UPE) mechanism in phi meson production were calculated from SDMEs. All the results were obtained in 3 kinematic bins of Q{sup 2}, 4 kinematic bins of t' and for the integrated kinematics. No statistically significant difference between the results for hydrogen and deuteron targets was observed. The UPE quantities were found to be zero within 2 σ for the integrated kinematics, indicating negligible contribution of UPE for the φ meson production which is in agreement with theory predictions. The test of s-channel helicity conservation hypothesis via comparison of corresponding SDME values showed helicity conservation for the φ meson production.

  12. Meson Form Factors and Deep Exclusive Meson Production Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Horn, Tanja [The Catholic Univ. of America, Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2017-05-01

    Pion and kaon electroproduction data play a unique role in Nature and our understanding of them is essential for explaining hadron structure. Precision longitudinaltransverse separated pion and kaon cross sections are of particular interest. They allow for the extraction of meson form factors and validation of understanding of hard exclusive and semi-inclusive reactions (π+, K+, π0, γ) towards 3D hadron imaging and potential future flavor decomposition. We review recent data and present prospects for deep exclusive pion and kaon electroproduction at the 12 GeV Jefferson Lab including the prospects to use projected charged- and neutral pion data to further determine the spin, charge-parity and flavor of GPDs, including the helicity-flip GPDs.

  13. Meson-production and the structure of scalar mesons

    Energy Technology Data Exchange (ETDEWEB)

    Speth, J.; Sassen, F.P.; Krewald, S

    2003-06-30

    We used a revised version of the Juelich meson-exchange model for {pi}{pi} interaction including the {pi}{alpha}{sub 1}-channel to describe the results obtained by the BNL E852 collaboration for S-wave production amplitudes in the ultrarelativistic {pi}N reaction {pi}{sup -}p {yields} {pi}{sup 0}{pi}{sup 0}n with pion beam momentum of 18.3 GeV[2]. The strong dependence of these data on the momentum transfer t to the nucleon in the region of the f{sub 0}(980) resonance is explained by means of two competing production mechanisms, the {pi} and the {alpha}{sub 1}, which differ by their interference pattern between resonant-production and non-resonant background.

  14. Meson-production and the structure of scalar mesons

    Science.gov (United States)

    Speth, J.; Sassen, F. P.; Krewald, S.

    2003-06-01

    We used a revised version of the Jülich meson-exchange model for ππ interaction[1] including the πα1-channel to describe the results obtained by the BNL E852 collaboration for S-wave production amplitudes in the ultrarelativistic π N reaction π-p → π0π0n with pion beam momentum of 18.3 GeV[2]. The strong dependence of these data on the momentum transfer t to the nucleon in the region of the f0(980) resonance is explained by means of two competing production mechanisms, the π and the α1, which differ by their interference pattern between resonant-production and non-resonant background.

  15. Discovery of omega meson, first neutral vector meson. [Personal account by researcher

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    A personal account of the discovery of the ..omega.. meson is given by researcher B. Maglich. His account includes such topics as early and unsuccessful searches for a neutral vector meson (by himself and others), eventual discovery of the rho meson, the Goldhaber effect, and the observation and characterization of the ..omega.. meson. Explanatory physics notes on electromagnetic structure experiments and the determination of the quantum numbers of the ..omega.. meson are provided for nonspecialists. Also included are an outline of the relation between vector mesons and nuclear forces, a reprint of the Physical Review Letter on Evidence for a T = 0 three-pion resonance, and a scientific autobiography of the researcher. 14 figures, 1 table. (RWR)

  16. Photoproduction of events with rapidity gaps between jets 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 photoproduction of dijet events, where the two jets with the highest transverse energy are separated by a large gap in pseudorapidity, have been studied with the ZEUS detector using an integrated luminosity of 39 pb{sup -1}. Rapidity-gap events are defined in terms of the energy flow between the jets, such that the total summed transverse energy in this region is less than some value E{sub T}{sup C}UT. The data show a clear excess over the predictions of standard photoproduction models. This is interpreted as evidence for a strongly interacting exchange of a color-singlet object. Monte Carlo models which include such a color-singlet exchange are able to describe the data. (orig.)

  17. Pion photoproduction cross section at large momentum transfer

    Energy Technology Data Exchange (ETDEWEB)

    Sjoegren, Johan [Univ. of Glasgow, Scotland, United Kingdom

    2015-02-27

    The Real Compton Scattering experiment was performed in Hall A at the Thomas Jefferson National Accelerator Facility. It was designed to measure, for Compton scattering and π0-photoproduction, the differential cross section over a range of kinematic points and the polarisation transfer to the proton at a single kinematic point. The full range of the experiment in Mandelstam variables t and s was 1.6-6.46 GeV2 and 4.82-10.92 GeV2 respectively with beam energies of 2-6 GeV. The motivation for the experiment is to test the cross section and polarisation transfer predictions of perturbative QCD versus that of predictions from Generalised Parton Distribution models. This thesis will give an overview of the pertinent theory, experimental setup in Hall A and the extracting of the π0-photoproduction cross section.

  18. Hyperon resonances with spin-5/2 in kaon photoproduction

    Science.gov (United States)

    Nurussalam, A. I.; Mart, T.

    2017-07-01

    The effects of spin-5/2 hyperon resonances have been investigated in the photoproduction of kaon γp → K+Λ. To this end, we used the previously constructed isobar model and included a number of hyperon resonances in the u-channel of the background terms to investigated the effect of spin-5/2 hyperon resonances. To construct the vertex we followed the prescription of Pascalutsa, whereas to model the high-spin propagator we have adopted the recipe of Vrancx. We regularized the u-channel in order to avoid the singularity, since numerically the value of Mandelstam variable u could be zero. By minimizing the value of χ2 we have improved the consistency of the model to the experimental data, especially in the case of the cross-section and polarization observables. We have found that the spin-5/2 hyperon resonances contribute significantly to the kaon photoproduction process, especially in the backward directions.

  19. Measurement of the Photoproduction of Vector and Scalar Bosons

    CERN Document Server

    2002-01-01

    The original programme of the experiment consisted of a detailed study of projectile fragmentation on nucleons and nuclei with particular attention to diffractive excitation. This programme of research was then specified as the measurement of coherent photoproduction on nuclei up to $\\simeq$180 GeV with the following aims: \\item a) photoproduction of charmed particle pairs and measurement of charmed particle lifetimes by means of an active target; \\item b) study of the spectroscopy of the new massive particles with particular attention to the hadronic decay channels, containing charged particles and photons, and to radiative decays. \\end{enumerate}\\\\ \\\\ The apparatus consists of a forward spectrometer for charged particles and photons and of a large angle detector which provides the topology of individual events. The spectrometer subtends a solid angle of $\\simeq$ 40 msr and consists of four bending magnets interspaced by sets of drift chambers, counter hodoscopes and photon detectors. The momentum resolution...

  20. Photoproduction of events with rapidity gaps between jets at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Miglioranzi, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, M; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Rinaldi, L; Sartorelli, G; Zichichi, A; Aghuzumtsyan, G; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Paul, E; Rautenberg, J; Renner, R; Samson, U; Schonberg, V; Wang, M; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Namsoo, T; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; 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 B; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Bonato, A; Borras, K; Coppola, N; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Gregor, I; Haas, T; Hain, W; Horn, C; Kahle, B; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Montanari, A; Notz, D; Nuncio-Quiroz, A E; Santamarta, R; Schneekloth, U; Spiridonov, A A; Stadie, H; Stösslein, U; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, 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; Ferrando, J; Saxon, D H; Skillicorn, I O; Gialas, I; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Dossanov, A; Pokrovskiy, N S; Zhautykov, B O; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Rubinsky, I; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Katkov, I I; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H G; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Cottrell, A; Devenish, R C E; Foster, B; Korcsak-Gorzo, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-Estrada, C; Walczak, R; Bellan, P M; Bertolin, A; Brugnera, R; Carlin, R; Ciesielski, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; 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; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Targett-Adams, C; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

    2006-01-01

    The photoproduction of dijet events, where the two jets with the highest transverse energy are separated by a large gap in pseudorapidity, have been studied with the ZEUS detector using an integrated luminosity of 39 pb$^{-1}$. Rapidity-gap events are defined in terms of the energy flow between the jets, such that the total summed transverse energy in this region is less than some value $E_{\\rm T}^{\\rm CUT}$. The data show a clear excess over the predictions of standard photoproduction models. This is interpreted as evidence for a strongly interacting exchange of a color-singlet object. Monte Carlo models which include such a color-singlet exchange are able to describe the data.

  1. Effective Meson Field Theory from QCD

    OpenAIRE

    Hsieh, Ron-Chou

    2003-01-01

    We give a simple and straightforward procedure of how to construct an effective meson Lagrangian from QCD Lagrangian. We integrate the methods of Gasser, Leutwyler, Alkofer and Reinhardt and use the derivative expansion scheme to derive the low energy effective Lagrangian for meson fields to $O(p^4)$. In this paper, why the meson particle can be treated as the goldstone mode is very clear. In our calculation the result in $O(p^2)$ is the same as in the chiral perturbation theory, but the resu...

  2. Eta Meson Production in NN Collisions

    Science.gov (United States)

    Haidenbauer, J.; Baru, V.; Gasparyan, A. M.; Hanhart, C.; Speth, J.

    A model calculation for near-threshold h meson production in nucleon-nucleon collisions is presented. The h meson production is described by elementary rescattering processes via MN ® hN, with M = p, r, h and s. Corresponding amplitudes are taken from a multi-channel meson-exchange model of the pN system developed by the Jgroup. Effects of the NN interaction in the final as well as in the initial state are taken into account microscopically.

  3. Exclusive ϒ photoproduction in hadronic collisions at CERN LHC energies

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, V.P., E-mail: barros@ufpel.edu.br [High and Medium Energy Group, Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-900, Pelotas, RS (Brazil); Moreira, B.D.; Navarra, F.S. [Instituto de Física, Universidade de São Paulo, C.P. 66318, 05315-970 São Paulo, SP (Brazil)

    2015-03-06

    The exclusive ϒ photoproduction in proton–proton and proton–nucleus collisions at LHC energies is investigated using the color dipole formalism and considering different models for the ϒ wave function and forward dipole–target scattering amplitude. Our goal is to update the color dipole predictions and estimate the theoretical uncertainty present in these predictions. We present predictions for the kinematical ranges probed by the ALICE, CMS and LHCb Collaborations.

  4. Beauty in photoproduction at HERA II with the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Boutle, Sarah

    2010-02-15

    The production of beauty quarks in ep collisions should be accurately calculable in perturbative Quantum Chromodynamics (QCD) since the large mass of the b quark provides a hard scale. Therefore it is interesting to compare such predictions to results using photoproduction events where a low-virtuality photon, emitted by the incoming lepton, collides with a parton from the incoming proton. A measurement of beauty in photoproduction has been made 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 were measured and compared to QCD predictions and to previous measurements. The data were found to be well described by the predictions from next-to-leading-order QCD. The dijet sample of beauty photoproduction events was also used to study higher-order QCD topologies. At leading order, the two jets in the event are produced back-to-back in azimuthal angle, such that {delta}{phi}{sup jj}={phi}{sup j1}-{phi}{sup j2}={pi}. Additional soft radiation causes small azimuthal decorrelations, whilst {delta}{phi}{sup jj} significantly lower than {pi} is evidence of additional hard radiation. In this thesis, the cross section versus {delta}{phi}{sup jj} for beauty photoproduction and the comparison to NLO QCD predictions and Monte Carlo models are presented. (orig.)

  5. Inclusive parton cross sections in photoproduction and photon structure

    CERN Document Server

    Ahmed, T; Andrieu, B; Appuhn, R D; Arpagaus, M; Aïd, S; Babaev, A; Ban, Y; Baranov, P S; Barrelet, E; Bartel, Wulfrin; Barth, Monique; Bassler, U; Beck, H P; Behrend, H J; Belousov, A; Berger, C; Bergstein, H; Bernardi, G; Bernet, R; Bertrand-Coremans, G H; Besançon, M; Beyer, R; Biddulph, P; Bispham, P; Bizot, J C; Blobel, Volker; Borras, K; Botterweck, F; Boudry, V; Braemer, A; Brasse, F W; Braunschweig, W; Brisson, V; Bruncko, Dusan; Brune, C R; Buchholz, R; Buniatian, A Yu; Burke, S; Burton, M; Buschhorn, G W; Bán, J; Bähr, J; Büngener, L; Bürger, J; Büsser, F W; Campbell, A J; Carli, T; Charles, F; Charlet, M; Chernyshov, V; Clarke, D; Clegg, A B; Clerbaux, B; Colombo, M G; Contreras, J G; Cormack, C; Coughlan, J A; Courau, A; Coutures, C; Cozzika, G; Criegee, L; Cussans, D G; Cvach, J; Dagoret, S; Dainton, J B; Dau, W D; Daum, K; David, M; De Wolf, E A; Del Buono, L; Delcourt, B; Di Nezza, P; Dollfus, C; Dowell, John D; Dreis, H B; Droutskoi, A; Duboc, J; Duhm, H; Düllmann, D; Dünger, O; Ebert, J; Ebert, T R; Eckerlin, G; Efremenko, V; Egli, S; Eichenberger, S; Eichler, R; Eisele, Franz; Eisenhandler, Eric F; Ellison, R J; Elsen, E E; Erdmann, M; Erdmann, W; Erlichmann, H; Evrard, E; Favart, L; Fedotov, A; Feeken, D; Felst, R; Feltesse, Joel; Ferencei, J; Ferrarotto, F; Flamm, K; Fleischer, M; Flieser, M; Flügge, G; Fomenko, A; Fominykh, B A; Forbush, M; Formánek, J; Foster, J M; Franke, G; Fretwurst, E; Gabathuler, Erwin; Gabathuler, K; Gamerdinger, K; Garvey, J; Gayler, J; Gebauer, M; Gellrich, A; Genzel, H; Gerhards, R; Goerlach, U; Gogitidze, N; Goldberg, M; Goldner, D; González-Pineiro, B; Gorelov, I V; Goritchev, P A; Grab, C; Greenshaw, T J; Grindhammer, G; Gruber, A; Gruber, C; Grässler, Herbert; Grässler, R; Görlich, L; Haack, J; Haidt, Dieter; Hajduk, L; Hamon, O; Hampel, M; Hanlon, E M; Hapke, M; Haynes, W J; Heatherington, J; Heinzelmann, G; Henderson, R C W; Henschel, H; Herynek, I; Hess, M F; Hildesheim, W; Hill, P; Hiller, K H; Hilton, C D; Hladky, J; Hoeger, K C; Horisberger, R P; Hudgson, V L; Huet, Patrick; Hufnagel, H; Höppner, M; Hütte, M; Ibbotson, M; Itterbeck, H; Jabiol, M A; Jacholkowska, A; Jacobsson, C; Jaffré, M; Janoth, J; Jansen, T; Johnson, D P; Johnson, L; Jung, H; Jönsson, L B; Kalmus, Peter I P; Kant, D; Kaschowitz, R; Kasselmann, P; Kathage, U; Katzy, J M; Kaufmann, H H; Kazarian, S; Kenyon, Ian Richard; Kermiche, S; Keuker, C; Kiesling, C; Klein, M; Kleinwort, C; Knies, G; Ko, W; Kolanoski, H; Kole, F; Kolya, S D; Korbel, V; Korn, M; Kostka, P; Kotelnikov, S K; Krasny, M W; Krehbiel, H; Krämerkämper, T; Krücker, D; Krüger, U P; Krüner-Marquis, U; Kubenka, J P; Kuhlen, M; Kurca, T; Kurzhöfer, J; Kuznik, B; Köhler, T; Köhne, J H; Küster, H; Lacour, D; Lamarche, F; Lander, R; Landon, M P J; Lange, W; Lanius, P; Laporte, J F; Lebedev, A; Leverenz, C; Levonian, S; Ley, C; Lindner, A; Lindström, G; Link, J; Linsel, F; Lipinski, J; List, B; Lobo, G; Loch, P; Lohmander, H; Lomas, J W; Lubimov, V; López, G C; Lüke, D; Magnussen, N; Malinovskii, E I; Mani, S; Maracek, R; Marage, P; Marks, J; Marshall, R; Martens, J; Martin, R D; Martyn, H U; Martyniak, J; Masson, S; Mavroidis, A; Maxfield, S J; McMahon, S J; Mehta, A; Meier, K; Mercer, D; Merz, T; Meyer, C A; Meyer, H; Meyer, J; Migliori, A; Mikocki, S; Milstead, D; Moreau, F; Morris, J V; Mroczko, E; Murín, P; Müller, G; Müller, K; Nagovitsin, V; Nahnhauer, R; Naroska, Beate; Naumann, T; Newman, P R; Newton, D; Neyret, D; Nguyen, H K; Nicholls, T C; Niebergall, F; Niebuhr, C B; Niedzballa, C; Nisius, R; Nowak, G; Noyes, G W; Nyberg-Werther, M; Oakden, M N; Oberlack, H; Obrock, U; Olsson, J E; Ozerov, D; Panaro, E; Panitch, A; Pascaud, C; Patel, G D; Peppel, E; Phillips, J P; Pichler, C; Pieuchot, A; Pitzl, D; Pope, G; Prell, S; Prosi, R; Pérez, E; Rabbertz, K; Raupach, F; Reimer, P; Reinshagen, S; Ribarics, P; Rick, Hartmut; Riech, V; Riedlberger, J; Riess, S; Rietz, M; Rizvi, E; Robertson, S M; Robmann, P; Roloff, H E; Roosen, R; Rosenbauer, K; Rostovtsev, A A; Rouse, F; Royon, C; Rusakov, S V; Rybicki, K; Rylko, R; Rädel, G; Rüter, K; Sahlmann, N; Salesch, S G; Sankey, D P C; Schacht, P; Schiek, S; Schleper, P; Schmidt, C; Schmidt, D; Schmidt, G; Schröder, V; Schuhmann, E; Schwab, B; Schwind, A; Schöning, A; Sefkow, F; Seidel, M; Sell, R; Semenov, A A; Shekelian, V I; Shevyakov, I; Shooshtari, H; Shtarkov, L N; Siegmon, G; Siewert, U; Sirois, Y; Skillicorn, Ian O; Smirnov, P; Smith, J R; Solochenko, V; Soloviev, Yu V; Spiekermann, J; Spielman, S; Spitzer, H; Starosta, R; Steenbock, M; Steffen, P; Steinberg, R; Stella, B; Stephens, K; Stier, J; Stiewe, J; Stolze, K; Strachota, J; Straumann, U; Struczinski, W; Stösslein, U; Sutton, J P; Sánchez, E; Tapprogge, Stefan; Thiebaux, C; Thompson, G; Truöl, P; Turnau, J; Tutas, J; Uelkes, P; Usik, A; Valkár, S; Valkárová, A; Vallée, C; Van Esch, P; Van Mechelen, P; Vartapetian, A H; Vazdik, Ya A; Verrecchia, P; Villet, G; Wacker, K; Wagener, A; Wagener, M; Walker, I W; Walther, A; Weber, G; Weber, M; Wegener, D; Wegner, A; Wellisch, H P; West, L R; Willard, S; Winde, M; Winter, G G; Wittek, C; Wright, A E; Wulff, N; Wünsch, E; Yiou, T P; Zarbock, D; Zhang, Z; Zhokin, A S; Zimmer, M; Zimmermann, W; Zomer, F; Zuber, K; Zácek, J; de Roeck, A; von Schlippe, W

    1995-01-01

    Photoproduction of 2-jet events is studied with the H1 detector at HERA. Parton cross sections are extracted from the data by an unfolding method using leading order parton-jet correlations of a QCD generator. The gluon distribution in the photon is derived in the fractional momentum range 0.04\\le x_\\gamma \\le 1 at the average factorization scale 75 GeV^2.

  6. Diffractive photoproduction of dijets in ep collisions at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, M; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, 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; Adler, V; Behrens, U; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Drugakov, V; Fang, S; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Miglioranzi, S; Montanari, A; Namsoo, T; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; 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; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Holm, U; Klanner, R; Lohrmann, E; Schleper, P; Schörner-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; Borodin, M; Kozulia, A; Lisovyi, M; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, 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; Fos-ter, B; Korcsak-Gorzo, K; Oliver, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-Estrada, C; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; 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; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Smith, O; Stern, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Costa, M; Ruspa, M; Fourletov, S; Martin, J F; Stewart, T P; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

    2005-01-01

    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 7.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5 < eta^jet < 1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton.

  7. Exclusive Photoproduction of ϒ:. from Hera to Tevatron

    Science.gov (United States)

    Rybarska, Anna; Schäfer, Wolfgang; Szczurek, Antoni

    The amplitude for photoproduction γp → ϒp is calculated in a pQCD k⊥-factorization approach. The total cross section for diffractive ϒs is compared to recent HERA data. The amplitude is used to predict the cross section for exclusive pbar p-> pΥ (1S, 2S)bar p proces in hadronic reactions at Tevatron energies. We also included absorption effects.

  8. Studies of the diffractive photoproduction of isolated photons at HERA

    Science.gov (United States)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Antonelli, S.; Aushev, V.; Aushev, Y.; Behnke, O.; Behrens, U.; Bertolin, A.; Bloch, I.; Brock, I.; Brook, N. H.; Brugnera, R.; Bruni, A.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Dementiev, R. K.; Devenish, R. C. E.; Dusini, S.; Foster, B.; Gach, G.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Golubkov, Yu. A.; Grzelak, G.; Guzik, M.; Gwenlan, C.; Hlushchenko, O.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Jomhari, N. Z.; Kadenko, I.; Kananov, S.; Karshon, U.; Kaur, P.; Kisielewska, D.; Klanner, R.; Klein, U.; Korzhavina, I. A.; Kotański, A.; Kovalchuk, N.; Kowalski, H.; Krupa, B.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Lisovyi, M.; Lobodzinska, E.; Löhr, B.; Lohrmann, E.; Longhin, A.; Lukina, O. Yu.; Malka, J.; Mastroberardino, A.; Mohamad Idris, F.; Mohammad Nasir, N.; Myronenko, V.; Nagano, K.; Onishchuk, Yu.; Paul, E.; Perlański, W.; Pokrovskiy, N. S.; Polini, A.; Przybycień, M.; Ruspa, M.; Saxon, D. H.; Schioppa, M.; Schneekloth, U.; Schörner-Sadenius, T.; Shcheglova, L. M.; Shkola, O.; Shyrma, Yu.; Skillicorn, I. O.; Słomiński, W.; Solano, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stopa, P.; Sztuk-Dambietz, J.; Tassi, E.; Tokushuku, K.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Wan Abdullah, W. A. T.; Wichmann, K.; Wing, M.; Yamada, S.; Yamazaki, Y.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.; ZEUS Collaboration

    2017-08-01

    The photoproduction of isolated photons has been measured in diffractive events recorded by the ZEUS detector at HERA. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 5 0.9 , where zPmeas is the fraction of the longitudinal momentum of the colorless "Pomeron" exchange that is transferred to the photon-jet final state, giving evidence for direct Pomeron interactions.

  9. Charm and bottom photoproduction at HERA with MC@NLO

    CERN Document Server

    Toll, Tobias

    2011-01-01

    We apply the MC@NLO formalism to the production of heavy-quark pairs in pointlike photon-hadron collisions. By combining this result with its analogue relevant to hadron-hadron collisions, we obtain NLO predictions matched to parton showers for the photoproduction of QQ^{-} pairs. We compare MC@NLO results to the measurements of c- and b-flavoured hadron observables performed by the H1 and ZEUS collaborations at HERA.

  10. Phototransformation of amlodipine: degradation kinetics and identification of its photoproducts.

    Directory of Open Access Journals (Sweden)

    Anna Jakimska

    Full Text Available Nowadays, monitoring focuses on the primary compounds and does not include degradation products formed during various biological and chemical processes. Transformation products may have the same effects to human health and the environment or sometimes they can be more toxic than the parent compound. Unfortunately, knowledge about the formation of degradation products is still limited, however, can be very important for the environmental risk assessment. Firstly, the photodegradation kinetic of amlodipine was investigated in two experimental conditions: during the exposure to solar radiation and during the exposure to the light emitted by the xenon lamp. In all cases degradation of amlodipine followed a pseudo-first-order kinetics. In the next step, identification of transformation products of amlodipine formed during the exposure to xenon lamp irradiation was performed using ultra high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS. As a result sixteen photoproducts were identified, their structures were elucidated and ultimately the transformation pathway was proposed. Fifteen compounds (out of 16 photoproducts were newly identified and reported here for the first time; some of those compounds were formed from the first photoproduct, amlodipine pyridine derivative. Several analytes were formed only in acidic or basic conditions. Furthermore, the occurrence of amlodipine and its identified degradation products was investigated in environmental waters. Only one out of 16 compounds was found in wastewater effluent. The possibility of the sorption of examined analytes to sewage sludge particles was discussed based on QSAR.

  11. Meson's correlation functions in a nuclear medium

    Directory of Open Access Journals (Sweden)

    Chanyong Park

    2016-09-01

    Full Text Available We investigate meson's spectrum, decay constant and form factor in a nuclear medium through holographic two- and three-point correlation functions. To describe a nuclear medium composed of protons and neutrons, we consider a hard wall model on the thermal charged AdS geometry and show that due to the isospin interaction with a nuclear medium, there exist splittings of the meson's spectrum, decay constant and form factor relying on the isospin charge. In addition, we show that the ρ-meson's form factor describing an interaction with pseudoscalar fluctuation decreases when the nuclear density increases, while the interaction with a longitudinal part of an axial vector meson increases.

  12. The light scalar mesons as tetraquarks

    Directory of Open Access Journals (Sweden)

    Gernot Eichmann

    2016-02-01

    Full Text Available We present a numerical solution of the four-quark Bethe–Salpeter equation for ground-state scalar tetraquarks with JPC=0++. We find that the four-body equation dynamically generates pseudoscalar-meson poles in the Bethe–Salpeter amplitude. The resulting tetraquarks are genuine four-quark states that are dominated by pseudoscalar meson–meson correlations. Diquark–antidiquark contributions are subleading because of their larger mass scale. In the light quark sector, the sensitivity of the tetraquark wave function to the pion poles leads to an isoscalar tetraquark mass Mσ∼350 MeV which is comparable to that of the σ/f0(500. The masses of its multiplet partners κ and a0/f0 follow a similar pattern. This provides support for a tetraquark interpretation of the light scalar meson nonet in terms of ‘meson molecules’.

  13. Bs mesons: semileptonic and nonleptonic decays

    Directory of Open Access Journals (Sweden)

    Albertus C.

    2014-01-01

    Full Text Available In this contribution we compute some nonleptonic and semileptonic decay widths of Bs mesons, working in the context of constituent quark models [1, 2]. For the case of semileptonic decays we consider reactions leading to kaons or different Jπ Ds mesons. The study of nonleptonic decays has been done in the factorisation approximation and includes the final states enclosed in Table 2.

  14. Oscillations of neutral B mesons systems

    CERN Document Server

    Boucrot, J

    1999-01-01

    The oscillation phenomenon in the neutral B mesons systems is now well established. The motivations and principles of the measurements are given; then the most recent results from the LEP experiments, the CDF collaboration at Fermilab and the SLD collaboration at SLAC are reviewed. The present world average of the $\\bd$ meson oscillation frequency is $\\dmd = 0.471 \\pm 0.016 \\ps$ and the lower limit on the $\\bs$ oscillation frequency is

  15. Recent results on eta and eta-prime photoproduction on the proton

    Energy Technology Data Exchange (ETDEWEB)

    Barry Ritchie

    2004-06-01

    The experimental situation on eta and eta' photoproduction on the proton is reviewed, emphasizing progress made since 2001. New preliminary results for eta' photoproduction on the proton from Jefferson Lab are presented. Experimental results are compared with several theoretical approaches, with an emphasis on consequences for understanding baryon spectroscopy.

  16. Photoproduction of {pi}{sup 0}{pi}{sup 0} - and {pi}{sup 0}{pi}{sup +} -pairs off the proton from threshold to the second resonance region

    Energy Technology Data Exchange (ETDEWEB)

    Zehr, F.; Krusche, B.; Boillat, B.; Jaegle, I.; Kotulla, M.; Maghrbi, Y.; Pheron, F. [University of Basel, Department of Physics, Basel (Switzerland); Aguar, P.; Ahrens, J.; Arends, H.J.; Heid, E.; Jahn, O.; Krambrich, D.; Martinez, M.; Ostrick, M.; Rost, M.; Thomas, A.; Walcher, T. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Annand, J.R.M.; Codling, R.F.B.; Downie, E.J.; Livingston, K.; MacGregor, I.J.D.; McGeorge, J.C.; Rosner, G. [University of Glasgow, SUPA, School of Physics and Astronomy, Glasgow (United Kingdom); Beck, R.; Lang, M.; Nikolaev, A.; Schumann, S.; Unverzagt, M. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Bekrenev, V.; Kulbardis, A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Braghieri, A.; Pedroni, P.; Rostomyan, T. [Sezione di Pavia, INFN, Pavia (Italy); Branford, D.; Glazier, D.I.; Tarbert, C.M.; Watts, D.P. [University of Edinburgh, School of Physics, Edinburgh (United Kingdom); Briscoe, W.J. [The George Washington University, Center for Nuclear Studies, Washington (United States); Brudvik, J.; Nefkens, B.M.K.; Prakhov, S.; Price, J.W.; Starostin, A. [University of California Los Angeles, Los Angeles, California (United States); Cherepnya, S.; Fil' kov, L.V. [Lebedev Physical Institute, Moscow (Russian Federation); Drexler, P.; Gregor, R.; Lugert, S.; Metag, V. [University of Giessen, II. Physikalisches Institut, Giessen (Germany); Fix, A. [Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation); Hornidge, D. [Mount Allison University, New Brunswick (Canada); Kashevarov, V.L. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Lebedev Physical Institute, Moscow (Russian Federation); Knezevic, A.; Korolija, M.; Mekterovic, D.; Supek, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Kondratiev, R.; Lisin, V.; Polonski, A. [Institute for Nuclear Research, Moscow (Russian Federation); Manley, D.M. [Kent State University, Kent, Ohio (United States); Sober, D. [Catholic University of America, Washington (United States)

    2012-07-15

    Precise total cross-sections and invariant-mass distributions have been measured for photoproduction of pion pairs off the proton producing p{pi}{sup 0}{pi}{sup 0} and n{pi}{sup +}{pi}{sup 0} final states from the threshold region up to 800MeV incident photon energy. Additionally, beam helicity asymmetries have been measured in the second resonance region (550MeV-820MeV). The experiment was performed at the tagged photon beam of the Mainz MAMI accelerator with the Crystal Ball and TAPS detectors combined to give an almost 4{pi} solid-angle electromagnetic calorimeter. The results are much more precise than any previous measurements and confirm the chiral perturbation theory predictions for the threshold behavior of these reactions. In the second resonance region, the invariant-mass distributions of meson-meson and meson-nucleon pairs are in reasonable agreement with model predictions, but none of the models reproduce the asymmetries for the mixed-charge channel. (orig.)

  17. Search for eV (pseudo)scalar penetrating particles in the SPS neutrino beam

    CERN Document Server

    Astier, Pierre; Baldisseri, Alberto; Baldo-Ceolin, Massimilla; Ballocchi, G; Banner, M; Bassompierre, Gabriel; Benslama, K; Besson, N; Bird, I G; Blumenfeld, B; Bobisut, F; Bouchez, J; Boyd, S; Bueno, A G; Bunyatov, S A; Camilleri, L L; Cardini, A; Cattaneo, Paolo Walter; Cavasinni, V; Cervera-Villanueva, A; Collazuol, G; Conforto, G; Conta, C; Contalbrigo, M; Cousins, R D; Daniels, D C; Degaudenzi, H M; Del Prete, T; De Santo, A; Dignan, T; Di Lella, L; do Couto e Silva, E; Dumarchez, J; Ellis, M; Feldman, G J; Ferrari, R; Ferrère, D; Flaminio, Vincenzo; Fraternali, M; Gaillard, Jean-Marc; Gangler, E; Geiser, A; Geppert, D; Gibin, D; Gninenko, S N; Godley, A; Gómez-Cadenas, J J; Gosset, J; Gössling, C; Gouanère, M; Grant, A; Graziani, G; Guglielmi, A M; Hagner, C; Hernando, J; Hubbard, D B; Hurst, P; Hyett, N; Iacopini, E; Joseph, C L; Juget, F R; Kirsanov, M M; Klimov, O L; Kokkonen, J; Kovzelev, A; Krasnikov, N V; Krasnoperov, A V; Kuznetsov, V E; Lacaprara, S; Lachaud, C; Lakic, B; Lanza, A; La Rotonda, L; Laveder, M; Letessier-Selvon, A A; Lévy, J M; Linssen, Lucie; Ljubicic, A; Long, J; Lupi, A; Marchionni, A; Martelli, F; Méchain, X; Mendiburu, J P; Meyer, J P; Mezzetto, Mauro; Mishra, S R; Moorhead, G F; Mossuz, L; Nédélec, P; Nefedov, Yu A; Nguyen-Mau, C; Orestano, D; Pastore, F; Peak, L S; Pennacchio, E; Pessard, H; Petti, R; Placci, Alfredo; Polesello, G; Pollmann, D; Polyarush, A Yu; Popov, B; Poulsen, C; Rico, J; Roda, C; Rubbia, André; Salvatore, F; Schahmaneche, K; Schmidt, B; Schmidt, T; Sevior, M E; Sillou, D; Soler, F J P; Sozzi, G; Steele, D; Steininger, M; Stiegler, U; Stipcevic, M; Stolarczyk, T; Tareb-Reyes, M; Taylor, G N; Tereshchenko, V V; Toropin, A N; Touchard, A M; Tovey, Stuart N; Tran, M T; Tsesmelis, E; Ulrichs, J; Vacavant, L; Valdata-Nappi, M; Valuev, V Yu; Vannucci, François; Varvell, K E; Veltri, M; Vercesi, V; Verkindt, D; Vieira, J M; Vinogradova, T G; Volkov, S A; Weber, F V; Weisse, T; Wilson, F F; Winton, L J; Yabsley, B D; Zaccone, Henri; Zioutas, Konstantin; Zuber, K; Zuccon, P

    2000-01-01

    We carried out a model-independent search for light scalar or pseudoscalar particles $a$'s (an example of which is the axion) that couple to two photons by using a photon-regeneration method at high energies allowing a substantial increase in the sensitivity to $eV$ masses.\\ The experimental set-up is based on elements of the CERN West Area Neutrino Facility (WANF) beam line and theNOMAD neutrino detector.\\ The new particles, if they exist, could be produced through the Primakoff effect in interactions of high energy photons, generated by the 450 $GeV$ protons in the CERN SPS neutrino target, with virtual photons from the WANF horn magnetic field.\\ The particles would penetrate the downstream shieldingand would be observed in the NOMAD neutrino detector through their re-conversion into real high energy photons byinteracting with the virtual photons from the magnetic field of the NOMAD dipole magnet.\\ From the analysis of the data collected during the 1996 run with $1.08\\times10^{19}$ protons on target, 312 ca...

  18. Improved constraints on monopole–dipole interaction mediated by pseudo-scalar bosons

    Directory of Open Access Journals (Sweden)

    N. Crescini

    2017-10-01

    Full Text Available We present a more stringent upper limit on long-range axion-mediated forces obtained by the QUAX-gpgs experiment, located at the INFN – Laboratori Nazionali di Legnaro. By measuring variations of a paramagnetic GSO crystal magnetization with a dc-SQUID magnetometer we investigate the possible coupling between electron spins and unpolarized nucleons in lead disks. The induced magnetization can be interpreted as the effect of a long-range spin dependent interaction mediated by axions or Axion Like Particles (ALPs. The corresponding coupling strength is proportional to the CP violating term gpegsN, i.e. the product of the pseudoscalar and scalar coupling constants of electron and nucleon, respectively. Our upper limit is more constraining than previous ones in the interaction range 0.01 m<λa<0.2 m, with a best result on gpegsN/(ħc of 4.3×10−30 at 95% confidence level in the interval 0.1 m<λa<0.2 m. We eventually discuss our plans to improve the QUAX-gpgs sensitivity by a few orders of magnitude, which will allow us to investigate the ϑ≃10−10 range of CP-violating parameter and test some QCD axion models.

  19. Ultraviolet-induced mutations in Cockayne syndrome cells are primarily caused by cyclobutane dimer photoproducts while repair of other photoproducts is normal

    Energy Technology Data Exchange (ETDEWEB)

    Parris, C.N.; Kraemer, K.H. (National Cancer Institute, Bethesda, MD (United States))

    1993-08-01

    The authors compared the contribution to mutagenesis on Cockayne syndrome (CS) cells of the major class of UV photoproducts, the cyclobutane pyrimidine dimer, to that of other DNA photoproducts by using the mutagenesis shuttle vector pZ189. Lymphoblastoid cell lines from the DNA repair-deficient disorders CS and xeroderma pigmentosum (XP) and a normal line were transfected with UV-treated pZ189. Cyclobutane dimers were selectively removed before transfection by photoreactivation (PR), leaving nondimer photoproducts intact. After UV exposure and replication in CS and XP cells, plasmid survival was abnormally elevated. After PR, plasmid survival increased and mutation frequency in CS cells decreased to normal levels but remained abnormal in XP cells. Sequence analysis of >200 mutant plasmids showed that with CS cells a major mutational hot spot was caused by unrepaired cyclobutane dimers. These data indicate that with both CS and XP cyclobutane dimers are major photoproducts generating reduced plasmid survival and increased mutation frequency. However, unlike XP, CS cells are proficient in repair of nondimer photoproducts. Since XP but not CS patients have a high frequency of UV-induced skin cancers, the data suggest that prevention of UV-induced skin cancers is associated with proficient repair of nondimer photoproducts. 38 refs., 3 figs., 2 tabs.

  20. Oscillazioni del mesone D^0

    CERN Document Server

    Schiraldi, Vito; Morello, Michael Joseph

    In fisica delle particelle, con il termine di "oscillazione" si indica la trasformazione di una particella neutra nella sua antiparticella e viceversa, fenomeno dovuto al fatto che gli autostati di flavor non sono autostati della matrice di massa. Il Modello Standard delle interazioni fondamentali predice che l'oscillazione del mesone D^0 avvenga su tempi molto maggiori di una vita media, e appaia perciò come un effetto piccolo, inferiore al percento, in contrasto con il caso dei mesoni B^0 e B^0_s che oscillano con molta maggiore rapidità. Sperimentalmente, l'oscillazione dei mesoni D^0 è rimasta inosservata fino a tempi recenti: la prima evidenza sperimentale dell'esistenza di un effetto di oscillazione è stata ottenuta soltanto nella primavera del 2007 dagli esperimenti BaBar (SLAC, USA) e Belle (KEKB, Japan). Nell'agosto 2007 anche l’esperimento CDF (Fermilab, USA) ha presentato una evidenza simile, basata sull'analisi di una parte del campione di dati disponibile. La tesi descrive gli aspetti speri...

  1. Hard Photoproduction by Colour Singlet Exchange at HERA

    OpenAIRE

    Sinclair, L.E.

    1995-01-01

    A search for photoproduction events which contain a rapidity gap between the two highest transverse energy jets has been conducted at HERA using the ZEUS detector. The jets have transverse energies greater than 6~GeV, and are separated by pseudorapidity intervals of up to four units. The fraction of events containing a gap is measured as a function of the gap-width. It is expected that this gap-fraction will fall exponentially with the gap-width, until the dominant gap-production mechanism be...

  2. 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.)

  3. Measurement of heavy-quark jet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H.; Gueta, O.; Ingbir, R.; Kananov, S.; Levy, A.; Stern, A. [Tel Aviv University, Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics, Tel Aviv (Israel); Abt, I.; Caldwell, A.; Reisert, B.; Schmidke, W.B. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Adamczyk, L.; Bold, T.; Gach, G.; Grabowska-Bold, I.; Kisielewska, D.; Przybycien, M.; Suszycki, L. [AGH-University of Science and Technology, Faculty of Physics and Applied Computer Science, Cracow (Poland); Adamus, M.; Plucinski, P.; Tymieniecka, T. [Institute for Nuclear Studies, Warsaw (Poland); Aggarwal, R.; Kaur, M.; Kaur, P.; Singh, I. [Panjab University, Department of Physics, Chandigarh (India); Antonelli, S.; Basile, M.; Bindi, M.; Cifarelli, L.; Contin, A.; De Pasquale, S.; Sartorelli, G.; Zichichi, A. [University Bologna (Italy); INFN Bologna, Bologna (Italy); Antonioli, P.; Bari, G.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cindolo, F.; Corradi, M.; Margotti, A.; Nania, R.; Polini, A. [INFN Bologna, Bologna (Italy); Antonov, A.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S. [Moscow Engineering Physics Institute, Moscow (Russian Federation); Arneodo, M.; Ruspa, M. [Universita del Piemonte Orientale, Novara (Italy); INFN, Torino (Italy); Aushev, V.; Dolinska, G.; Gogota, O.; Korol, I. [National Academy of Sciences, Institute for Nuclear Research, Kyiv (Ukraine); National Taras Shevchenko Univ. of Kyiv, Dept. of Nuclear Physics, Kyiv (Ukraine); Aushev, Y.; Bartosik, N.; Bolilyi, O.; Bondarenko, K.; Kadenko, I.; Kuprash, O.; Lontkovskyi, D.; Makarenko, I.; Onishchuk, Yu.; Salii, A.; Tomalak, O.; Volynets, O.; Zenaiev, O.; Zolko, M. [National Taras Shevchenko Univ. of Kyiv, Dept. of Nuclear Physics, Kyiv (Ukraine); Bachynska, O.; Behnke, O.; Behr, J.; Behrens, U.; Blohm, C.; Borras, K.; Bot, D.; Ciesielski, R.; Coppola, N.; Fang, S.; Geiser, A.; Goettlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T. [and others

    2011-05-15

    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{sub T}{sup jet}, 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.)

  4. Doubly-polarised pion photoproduction on the nucleon at MAMI

    Directory of Open Access Journals (Sweden)

    Costanza Susanna

    2017-01-01

    These new, high-quality doubly-polarised pion-photoproduction data sets provide a valuable input to the study of the nucleon structure and excitation spectrum by significantly constraining the electromagnetic multipole evaluation performed by the different available partial wave analysis models. Furthermore, the helicity dependent observables provide the main ingredient for the verification of the well-known Gerasimov-Drell-Hearn (GDH sum rule, which relates the helicity-dependent photoasborption process to the main static nucleon properties (mass, charge, spin.

  5. Quasifree photoproduction of eta-pion pairs off the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Kaeser, Alexander [Departement of Physics, University of Basel, CH-4056 Basel, Switzerland (Switzerland); Collaboration: Crystal Ball/TAPS Collaboration

    2013-07-01

    The photoproduction of ηπ{sup 0} and ηπ{sup ±} pairs off the deuteron was investigated at the Mainz Microtron accelerator facility MAMI for photon energies up to 1.5 GeV. The detector setup consisted of the combined Crystal Ball and TAPS electromagnetic calorimeters. Invariant mass distributions for the neutral and charged channels as well as angular distributions for Φ and cos(Θ) were extracted from the data. In addition, total cross-sections for both channels have been extracted. The results are discussed in the context of the contributions of different resonances to the respective reactions.

  6. 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.)

  7. Hard photoproduction of a diphoton with a large invariant mass

    Science.gov (United States)

    Pedrak, A.; Pire, B.; Szymanowski, L.; Wagner, J.

    2017-10-01

    The electromagnetic probe has proven to be a very efficient way to access the three-dimensional structure of the nucleon, particularly thanks to the exclusive Compton processes. We explore the hard photoproduction of a large invariant mass diphoton in the kinematical regime where the diphoton is nearly forward and its invariant mass is the hard scale enabling to factorize the scattering amplitude in terms of generalized parton distributions. We calculate unpolarized cross sections and the angular asymmetry triggered by a linearly polarized photon beam.

  8. Pion photoproduction on 27Al: The effect of Vopt

    Science.gov (United States)

    Freed, N.; Ostrander, P.

    1981-07-01

    Total cross sections for pion photoproduction to bound states in 27Mg are calculated in the distorted wave impulse approximation and compared to experiment. Particular attention is paid to the form of the optical potential used to incorporate final state effects. Substantial differences are found between results using an earlier potential and present results using potentials having different analytic forms. The latter lead to good agreement with experiment. [NUCLEAR REACTIONS 27Al(γ,π+). Calculated total cross sections; effects of pion optical potential.

  9. Review of meson spectroscopy: quark states and glueballs

    Energy Technology Data Exchange (ETDEWEB)

    Chanowitz, M.S.

    1981-11-01

    A group of three lectures on hadron spectroscopy are presented. Topics covered include: light L = 0 mesons, light L = 1 mesons, antiquark antiquark quark quark exotics, a catalogue of higher quark antiquark excitations, heavy quarkonium, and glueballs. (GHT)

  10. Rare meson decays into very light neutralinos

    Energy Technology Data Exchange (ETDEWEB)

    Dreiner, H.K.; Grab, S. [Bonn Univ. (Germany). Bethe Center for Theoretical Physics und Physikalisches Inst.; Koschade, D. [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Physik; London Univ. (United Kingdom). Centre for Reserach in String Theory; Kraemer, M.; O' Leary, B. [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Physik; Langenfeld, U. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2009-05-15

    We investigate the bounds on the mass of the lightest neutralino from rare meson decays within the MSSM with and without minimal flavor violation. We present explicit formulae for the two-body decays of mesons into light neutralinos and perform the first complete calculation of the loop-induced decays of kaons to pions and light neutralinos and B mesons to kaons and light neutralinos. We find that the supersymmetric branching ratios are strongly suppressed within the MSSM with minimal flavor violation, and that no bounds on the neutralino mass can be inferred from experimental data, i.e. a massless neutralino is allowed. The branching ratios for kaon and B meson decays into light neutralinos may, however, be enhanced when one allows for non-minimal flavor violation. We find new constraints on the MSSM parameter space for such scenarios and discuss prospects for future kaon and B meson experiments. Finally, we comment on the search for light neutralinos in monojet signatures at the Tevatron and at the LHC. (orig.)

  11. Mixing among light scalar mesons and L=1 qq-bar scalar mesons

    Energy Technology Data Exchange (ETDEWEB)

    Teshima, T. [Department of Applied Physics, Chubu University, Kasugai (Japan)]. E-mail: teshima@isc.chubu.ac.jp; Kitamura, I.; Morisita, N. [Department of Applied Physics, Chubu University, Kasugai (Japan)

    2002-06-01

    Following the re-establishment of the {sigma}(500) and the {kappa}(900), the light scalar mesons a{sub 0}(980) and f{sub 0}(980) together with the {sigma}(500) and the {kappa}(900) are considered as the chiral scalar partner of pseudoscalar nonet in SU(3) chiral symmetry, and the high mass scalar mesons a{sub 0}(1450), K*{sub 0}(1430), f{sub 0}(1370) and f{sub 0}(1710) turned out to be considered as the L=1 qq-bar scalar mesons. We assume that the high mass of the L=1 qq-bar scalar mesons is caused by the mixing with the light scalar mesons. For the structure of the light scalar mesons, we adopted the qqq-barq-bar model in order to explain the 'scalar meson puzzle'. The inter-mixing between the light scalar nonet and the high mass L=1 qq-bar nonet and the intra-mixing among each nonet are analysed by including the glueball into the high mass scalar nonet. (author)

  12. Strong decays of light vector mesons

    Science.gov (United States)

    Jarecke, Dennis; Maris, Pieter; Tandy, Peter C.

    2003-03-01

    The vector meson strong decays ρ→ππ, φ→KK, and K⋆→πK are studied within a covariant approach based on the ladder-rainbow truncation of the QCD Dyson-Schwinger equation for the quark propagator and the Bethe-Salpeter equation for the mesons. The model preserves the one-loop behavior of QCD in the ultraviolet regime, has two infrared parameters, and implements quark confinement and dynamical chiral symmetry breaking. The three-point decay amplitudes are described in impulse approximation. The Bethe-Salpeter study motivates a method for estimating the masses of heavier mesons within this model without continuing the propagators into the complex plane. We test the accuracy via the ρ, φ, and K⋆ masses and then produce estimates of the model results for ma1 and mb1, as well as the proposed exotic vector π1(1400).

  13. Charm photoproduction using electron taggers with the zeus detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aghuzumtsyan, G.

    2006-07-15

    Charm production has been studied at a centre-of-mass energy of {radical}(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{sup *}(2010) meson via the decay chain D{sup *+}{yields}K{sup -}{pi}{sup +}{pi}{sup +} (+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{sub T}(D{sup *}), {eta}(D{sup *}) and W were measured in the restricted phase space: -1.0<{eta}D({sup *})<1.5, p{sub T}(D{sup *})>1.5 GeV, 80 GeV2.0 GeV, 200 GeV

  14. Antibacterial activity of oxytetracycline photoproducts in marine aquaculture's water.

    Science.gov (United States)

    Leal, J F; Henriques, I S; Correia, A; Santos, E B H; Esteves, V I

    2017-01-01

    Oxytetracycline (OTC) is one of the most used antibiotics in aquaculture. The main concern related to its use is the bacterial resistance, when ineffective treatments are applied for its removal or inactivation. OTC photo-degradation has been suggested as an efficient complementary process to conventional methods used in intensive fish production (e.g.: ozonation). Despite this, and knowing that the complete mineralization of OTC is difficult, few studies have examined the antibacterial activity of OTC photoproducts. Thus, the main aim of this work is to assess whether the OTC photoproducts retain the antibacterial activity of its parent compound (OTC) after its irradiation, using simulated sunlight. For that, three Gram-negative bacteria (Escherichia coli, Vibrio sp. and Aeromonas sp.) and different synthetic and natural aqueous matrices (phosphate buffered solutions at different salinities, 0 and 21‰, and three different samples from marine aquaculture industries) were tested. The microbiological assays were made using the well-diffusion method before and after OTC has been exposed to sunlight. The results revealed a clear effect of simulated sunlight, resulting on the decrease or elimination of the antibacterial activity for all strains and in all aqueous matrices due to OTC photo-degradation. For E. coli, it was also observed that the antibacterial activity of OTC is lower in the presence of sea-salts, as demonstrated by comparison of halos in aqueous matrices containing or not sea-salts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. MC rate at NLO for heavy flavour photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Toll, Tobias

    2010-02-15

    A Monte Carlo at next-to-leading order (MC rate at NLO) has been constructed for the production of heavy quark flavours in photoproduction. As such, it is the rst Monte Carlo event generator with next-to-leading order (NLO) accuracy for a process in lepton hadron scattering. In order to construct such an MC rate at NLO, the matrix element for the process has to be calculated at NLO and then be matched with a parton shower. When doing this, it is important that none of the parton configurations produced are doubly counted. In this thesis, the concept of a Monte Carlo event generator will be explained, with emphasis on the HERWIG parton shower. Also, different techniques of calculating matrix elements at NLO accuracy will be explained. It will then be shown how the NLO calculation can be matched with the HERWIG parton shower in an MC rate at NLO without double counting, producing unweighted events at NLO-accuracy. Many comparisons are made between the MC rate at NLO here constructed, the HERWIG Monte Carlo and the FMNR NLO calculation. Also many comparisons are made to HERA data from the H1 and ZEUS experiments. It is shown that all HERA data with heavy quarks produced in photoproduction can be described by the MC rate at NLO program constructed in this thesis. (orig.)

  16. Pseudoscalar meson physics with four dynamical quarks

    CERN Document Server

    Bazavov, A; Bouchard, C; DeTar, C; Du, D; El-Khadra, A X; Foley, J; Freeland, E D; Gamiz, E; Gottlieb, Steven; Heller, U M; Hetrick, J E; Kim, J; Kronfeld, A S; Laiho, J; Levkova, L; Lightman, M; Mackenzie, P B; Neil, E T; Oktay, M; Simone, J N; Sugar, R L; Toussaint, D; Van de Water, R S; Zhou, R

    2012-01-01

    We present preliminary results for light, strange and charmed pseudoscalar meson physics from simulations using four flavors of dynamical quarks with the highly improved staggered quark (HISQ) action. These simulations include lattice spacings ranging from 0.15 to 0.06 fm, and sea-quark masses both above and at their physical value. The major results are charm meson decay constants f_D, f_{D_s} and f_{D_s}/f_D and ratios of quark masses. This talk will focus on our procedures for finding the decay constants on each ensemble, the continuum extrapolation, and estimates of systematic error.

  17. Turbulent meson condensation in quark deconfinement

    Directory of Open Access Journals (Sweden)

    Koji Hashimoto

    2015-06-01

    Full Text Available In a QCD-like strongly coupled gauge theory at large Nc, using the AdS/CFT correspondence, we find that heavy quark deconfinement is accompanied by a coherent condensation of higher meson resonances. This is revealed in non-equilibrium deconfinement transitions triggered by static, as well as quenched electric fields even below the Schwinger limit. There, we observe a “turbulent” energy flow to higher meson modes, which finally results in the quark deconfinement. Our observation is consistent with seeing deconfinement as a condensation of long QCD strings.

  18. Meson exchange-current effects in heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Dehesa, J.S.; Lallena, A. (Granada Univ. (Spain). Dept. de Fisica Nuclear); Krewald, S. (Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.). Inst. fuer Kernphysik); Donnelly, T.W. (Massachusetts Inst. of Tech., Cambridge (USA). Lab. for Nuclear Science; Massachusetts Inst. of Tech., Cambridge (USA). Dept. of Physics)

    1985-04-15

    Meson exchange-current effects in the electroexcitation of magnetic states are evaluated in /sup 16/O and /sup 208/Pb. A new method is suggested which properly includes the influence of the nuclear mean field on meson exchange-current effects. In addition, an effective meson exchange-current operator is developed which considerably simplifies the evaluation of meson exchange-current effects. Over a wide range of momentum transfers, the magnetic cross sections for the electroexcitation of high-spin, stretched 1 plh states are found to be smoothly enhanced by meson exchange currents.

  19. Issues in light meson spectroscopy: The case for meson spectroscopy at CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Godfrey, S. [Carleton Univ., Ottawa (Canada)

    1994-04-01

    The author reviews some outstanding issues in meson spectroscopy. The most important qualitative issue is whether hadrons with explicit gluonic degrees of freedom exist. To answer this question requires a much better understanding of conventional q{bar q} mesons. The author therefore begins by examining the status of conventional meson spectroscopy and how the situation can be improved. The expected properties of gluonic excitations are discussed with particular emphasis on hybrids to give guidance to experimental searches. Multiquark systems are commented upon as they are likely to be important in the mass region under study and will have to be understood better. In the final section the author discusses the opportunities that CEBAF can offer for the study of meson spectroscopy.

  20. Quarkonium Contribution to Meson Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Cincioglu, E.; Yilmazer, A.U. [Ankara University, Department of Physics Engineering, Ankara (Turkey); Nieves, J. [Instituto de Fisica Corpuscular (IFIC) Centro Mixto CSIC-Universidad de Valencia, Institutos de Investigacion de Paterna, Valencia (Spain); Ozpineci, A. [Middle East Technical University, Department of Physics, Ankara (Turkey)

    2016-10-15

    Starting from a molecular picture for the X(3872) resonance, this state and its J{sup PC} = 2{sup ++} heavy-quark spin symmetry partner [X{sub 2}(4012)] are analyzed within a model which incorporates possible mixings with 2P charmonium (c anti c) states. Since it is reasonable to expect the bare χ{sub c1}(2P) to be located above the D anti D{sup *} threshold, but relatively close to it, the presence of the charmonium state provides an effective attraction that will contribute to binding the X(3872), but it will not appear in the 2{sup ++} sector. Indeed in the latter sector, the χ{sub c2}(2P) should provide an effective small repulsion, because it is placed well below the D{sup *} anti D{sup *} threshold. We show how the 1{sup ++} and 2{sup ++} bare charmonium poles are modified due to the D{sup (*)} anti D{sup (*)} loop effects, and the first one is moved to the complex plane. The meson loops produce, besides some shifts in the masses of the charmonia, a finite width for the 1{sup ++} dressed charmonium state. On the other hand, X(3872) and X{sub 2}(4012) start developing some charmonium content, which is estimated by means of the compositeness Weinberg sum rule. It turns out that in the heavy-quark limit, there is only one coupling between the 2P charmonia and the D{sup (*)} anti D{sup (*)} pairs. We also show that, for reasonable values of this coupling, leading to X(3872) molecular probabilities of around 70-90 %, the X{sub 2} resonance destabilizes and disappears from the spectrum, becoming either a virtual state or one being located deep into the complex plane, with decreasing influence in the D{sup *} anti D{sup *} scattering line. Moreover, we also discuss how around 10-30 % charmonium probability in the X(3872) might explain the ratio of radiative decays of this resonance into ψ(2S)γ and J/ψγ. Finally, we qualitatively discuss within this scheme, the hidden bottom flavor sector, paying a special attention to the implications for the X{sub b} and X

  1. Relative rates of B meson decays into psi(2S) and J/psi mesons

    NARCIS (Netherlands)

    Abazov, V.M.; et al., [Unknown; Anastasoaie, M.; Ancu, L.S.; de Jong, S.J.; Filthaut, F.; Galea, C.F.; Hegeman, J.G.; Houben, P.; Naumann, N.A.; van den Berg, P.J.; van Leeuwen, W.M.

    2009-01-01

    We report on a study of the relative rates of B meson decays into psi(2S) and J/psi mesons using 1.3 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe the channels B-s(0) -> psi(2S)phi, B-s(0) -> J/psi phi,

  2. Model of mesons with constituent gluons

    Energy Technology Data Exchange (ETDEWEB)

    Horn, D.; Mandula, J.

    1978-02-01

    A model of mesons composed of a quark, an antiquark, and a gluon is proposed. The binding of the constituents is provided by a confining linear potential between the gluon and the quarks. The lowest states of the model are described, and their relative masses evaluated, for the case of heavy (charmed) quarks, i.e., ccg states.

  3. Charmonium meson and hybrid radiative transitions

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Peng [Indiana U., JLAB; Yépez-Martínez, Tochtli [Indiana U.; Szczepaniak, Adam P. [Indiana U., JLAB

    2014-06-01

    We consider the non-relativistic limit of the QCD Hamiltonian in the Coulomb gauge, to describe radiative transitions between conventional charmonium states and from the lowest multiplet of cc¯ hybrids to charmonium mesons. The results are compared to potential quark models and lattices calculations.

  4. QED effects in the pseudoscalar meson sector

    Energy Technology Data Exchange (ETDEWEB)

    Horsley, R. [School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD (United Kingdom); Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo, 650-0047 (Japan); Perlt, H. [Institut für Theoretische Physik, Universität Leipzig, Brüderstrasse 16, Leipzig, 04109 (Germany); Pleiter, D. [Jülich Supercomputer Centre, Forschungszentrum Jülich, Jülich, 52425 (Germany); Institut für Theoretische Physik, Universität Regensburg, Regensburg, 93040 (Germany); Rakow, P.E.L. [Theoretical Physics Division, Department of Mathematical Sciences, University of Liverpool, Peach Street , Liverpool, L69 3BX (United Kingdom); Schierholz, G. [Deutsches Elektronen-Synchrotron DESY, Hamburg, 22603 (Germany); Schiller, A. [Institut für Theoretische Physik, Universität Leipzig, Brüderstrasse 16, Leipzig, 04109 (Germany); Stokes, R. [CSSM, Department of Physics, University of Adelaide, Adelaide, SA, 5005 (Australia); Stüben, H. [Regionales Rechenzentrum, Universität Hamburg, Hamburg, 20146 (Germany); Young, R.D.; Zanotti, J.M. [CSSM, Department of Physics, University of Adelaide, Adelaide, SA, 5005 (Australia); Collaboration: the QCDSF and UKQCD collaboration

    2016-04-15

    In this paper we present results on the pseudoscalar meson masses from a fully dynamical simulation of QCD+QED, concentrating particularly on violations of isospin symmetry. We calculate the π{sup +}–π{sup 0} splitting and also look at other isospin violating mass differences. We have presented results for these isospin splittings in http://arxiv.org/abs/1508.06401. In this paper we give more details of the techniques employed, discussing in particular the question of how much of the symmetry violation is due to QCD, arising from the different masses of the u and d quarks, and how much is due to QED, arising from the different charges of the quarks. This decomposition is not unique, it depends on the renormalisation scheme and scale. We suggest a renormalisation scheme in which Dashen’s theorem for neutral mesons holds, so that the electromagnetic self-energies of the neutral mesons are zero, and discuss how the self-energies change when we transform to a scheme such as (MS)-bar , in which Dashen’s theorem for neutral mesons is violated.

  5. Extracting excited mesons from the finite volume

    Energy Technology Data Exchange (ETDEWEB)

    Doring, Michael [George Washington Univ., Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2014-12-01

    As quark masses come closer to their physical values in lattice simulations, finite volume effects dominate the level spectrum. Methods to extract excited mesons from the finite volume are discussed, like moving frames in the presence of coupled channels. Effective field theory can be used to stabilize the determination of the resonance spectrum.

  6. Vector mesons in strongly interacting matter

    Indian Academy of Sciences (India)

    higher statistics and inrceased acceptance in particular for low-momentum vector mesons. Keywords. Hadrons ... the mass splittings to decrease due to mass shifts or that the mass distributions of hadrons become softer in .... mass distribution for the most central collisions is compared in figure 3 with the spectral function of a ...

  7. New physics effects from meson decays

    Indian Academy of Sciences (India)

    Abstract. In this talk, we point out some of the present and future possible signatures of physics beyond the Standard Model from -meson decays, taking -parity conserving and violating supersymmetry as illustrative examples. An expanded version is available on hep-ph archive.

  8. Mesonic spectroscopy of Minimal Walking Technicolor

    DEFF Research Database (Denmark)

    Del Debbio, Luigi; Lucini, Biagio; Patella, Agostino

    2010-01-01

    We investigate the structure and the novel emerging features of the mesonic non-singlet spectrum of the Minimal Walking Technicolor (MWT) theory. Precision measurements in the nonsinglet pseudoscalar and vector channels are compared to the expectations for an IR-conformal field theory and a QCD-l...

  9. Vector mesons in strongly interacting matter

    Indian Academy of Sciences (India)

    ... used to extract experimental information on in-medium properties of hadrons. Results on the light vector mesons ρ, , and , are summarized and compared. Almost all experiments report a softening of the spectral functions with increases in width depending on the density and temperature of the hadronic environment.

  10. What have we learned on mesons?

    CERN Document Server

    Moebes, J P

    1972-01-01

    The author discusses pp annihilation processes involving resonances. These include omega /sup 0/; KK-threshold effects; pi /sub N/(1016), S*(1070); 'diffractive' mesons: A/sub 1/, B, C; KK pi -effects: D/sub 1/E/sub 1/F/sub 1/. (14 refs).

  11. JPC = ODD-- Radial Trajectories for Light Mesons

    Science.gov (United States)

    Dumanoglu, I.; Peaslee, D. C.

    2003-01-01

    Versification of the Veneziano model for light meson radial trajectories has found surprising constancy of slope for several different sequences of resonant states with JPC = even++. Efforts to extend this result to JPC = odd-- trajectories have been hampered by a comparative scarcity of data, but we present an early survey to seek similarities and differences with even++ resonances.

  12. Summary of the [eta]-meson sessions

    Energy Technology Data Exchange (ETDEWEB)

    Chrien, R.E.

    1993-01-01

    This summary describes the contents of the nineteen talks related to research on the [eta] meson and presented at the Workshop of Future Directions. The subjects of this area include threshold [eta] production, [eta]-nuclear spectroscopy, baryon spectroscopy, [eta] decays, facilities, and instrumentation.

  13. Summary of the {eta}-meson sessions

    Energy Technology Data Exchange (ETDEWEB)

    Chrien, R.E.

    1993-06-01

    This summary describes the contents of the nineteen talks related to research on the {eta} meson and presented at the Workshop of Future Directions. The subjects of this area include threshold {eta} production, {eta}-nuclear spectroscopy, baryon spectroscopy, {eta} decays, facilities, and instrumentation.

  14. Inclusive D{sup *}-meson production in ep scattering at low Q{sup 2} in the GM-VFN scheme at NLO

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, G. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Spiesberger, H. [Johannes Gutenberg Univ., Mainz (Germany). Inst. fuer Physik

    2009-05-15

    We have calculated the next-to-leading order cross sections for the inclusive production of D{sup *}-mesons in ep collisions at HERA for finite, although very small Q{sup 2}. In this Q{sup 2}-range, the same approximations as for photoproduction can be used. Our calculation is performed in the general-mass variable-flavour-number scheme. In this approach, large logarithms of the charm transverse momentum are resummed and finite terms depending on m{sup 2}/p{sub T}{sup 2} are kept in the hard scattering cross sections. The theoretical results are compared with recent data from the ZEUS collaboration at HERA. On average, we find good agreement. (orig.)

  15. The isospin structure of photoproduction of πη pairs from the nucleon in the threshold region

    Directory of Open Access Journals (Sweden)

    A. Käser

    2015-09-01

    Full Text Available Photoproduction of πη-pairs from nucleons has been investigated from threshold up to incident photon energies of ≈ 1.4 GeV. The quasi-free reactions γp→pπ0η, γn→nπ0η, γp→nπ+η, and γn→pπ−η were for the first time measured from nucleons bound in the deuteron. The corresponding reactions from a free-proton target were also studied to investigate final-state interaction effects (for neutral pions the free-proton results could be compared to previous measurements; the γp→nπ+η reaction was measured for the first time. For the π0η final state coherent production via the γd→dπ0η reaction was also investigated. The experiments were performed at the tagged photon beam of the Mainz MAMI accelerator using an almost 4π coverage electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. The total cross sections for the four different final states obey the relation σ(pπ0η≈σ(nπ0η≈2σ(pπ−η≈2σ(nπ+η as expected for a dominant contribution from a Δ⋆→ηΔ(1232→πηN reaction chain, which is also supported by the shapes of the invariant-mass distributions of nucleon–meson and π–η pairs. The experimental results are compared to the predictions from an isobar reaction model.

  16. Quarkonium Photoproduction at Next-to-leading Order

    CERN Document Server

    Maltoni, Fabio; Petrelli, Andrea

    1998-01-01

    We present the calculation of O(as^2 aem) corrections to heavy-quarkonium total photoproduction cross-sections. Results are given for the colour-octet component of S and P waves. The calculation is performed using covariant projectors in dimensional regularization. A phenomenological study of the results, including a discussion of the high-energy behaviour of the cross sections, is presented. For gamma-p energies up to few hundred GeV the NLO corrections significantly reduce the scale dependence of the production rates relative to the Born-level results. Large small-x corrections arise at higher energies, making the predictions strongly dependent on the shape of the gluon density and on the choice of factorization scale.

  17. High-E_T dijet photoproduction at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, USAM; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, V; Shehzadi, R; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Wills, H H; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; 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; Adler, V; Behrens, U; Bloch, I; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Dossanov, A; Drugakov, V; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Horn, C; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Miglioranzi, S; Montanari, A; Namsoo, T; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Stadie, H; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; 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; Ferrando, J; Forrest, M; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Perrey, H; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Aushev, V; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Cottrell, A; Devenish, R C E; Foster, B; Korcsak-Gorzo, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-, C; Estrada; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; 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; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Targett-Adams, C; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

    2007-01-01

    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 photon, Q^2, of less than 1 GeV^2 and a photon-proton centre-of-mass energy in the range 142 20 GeV and E_T(jet2) > 15 GeV and pseudorapidity requirements of -1 < eta(jet1,2) < 3, with at least one of the jets satisfying -1 < eta(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.

  18. 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.)

  19. Photoproduction of top and higgs particles at the LHC

    CERN Document Server

    Ovyn, Séverine

    Thanks to its high energy and luminosity, the Large Hadron Collider (LHC) at CERN can also be exploited as an high energy photon collider. In particular photoproduction offers interesting possibilities for the study of the electroweak sector up to TeV scale. After a brief presentation of cross sections for many photon-induced processes, prospects are discussed for the Higgs boson search as well as for the top quark physics. Although the studied final states possess striking characteristics, the separation of photon-induced processes from the overwhelming background of partonic interactions requires the use of advanced techniques. In this context, several tagging strategies are proposed, depending on the LHC luminosity. In order to realistically perform a simulation of the response of a multipurpose detector, a dedicated framework called DELPHES was designed. Using this fast simulation of a LHC-like detector, expected sensitivity on the tWb coupling measurement using several topologies resulting from the W ass...

  20. 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

  1. Measurement of Prompt Photon Cross Sections in Photoproduction 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.; 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-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.; 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.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2004-01-01

    Results are presented on the photoproduction of isolated prompt photons, inclusively and associated with jets, in the gamma p center of mass energy range 142 4.5 GeV. They are measured differentially as a function of E_T^gamma, E_T^jet, the pseudorapidities eta^gamma and eta^jet and estimators of the momentum fractions x_gamma and x_p of the incident photon and proton carried by the constituents participating in the hard process. In order to further investigate the underlying dynamics, the angular correlation between the prompt photon and the jet in the transverse plane is studied. Predictions by perturbative QCD calculations in next to leading order are about 30% below the inclusive prompt photon data after corrections for hadronisation and multiple interactions, but are in reasonable agreement with the results for prompt photons associated with jets. Comparisons with the predictions of the event generators PYTHIA and HERWIG are also presented.

  2. Spin O decay angular distribution for interfering mesons in electroproduction

    Energy Technology Data Exchange (ETDEWEB)

    Funsten, H.; Gilfoyle, G.

    1994-04-01

    Self analyzing meson electroproduction experiments are currently being planned for the CEBAF CLAS detector. These experiments deduce the spin polarization of outgoing unstable spin s (?)0 mesons from their decay angular distribution, W({theta},{psi}). The large angular acceptance of the CLAS detector permits kinematic tracking of a sufficient number of these events to accurately determine electroproduction amplitudes from the deduced polarization. Maximum polarization information is obtained from W({theta},{psi}) for decay into spin 0 daughters. The helicity of the decaying meson is transferred to the daughter`s relative orbital angular momentum m-projection; none is {open_quotes}absorbed{close_quotes} into daughter helicities. The decaying meson`s helicity maximally appears in W({theta},{psi}). W({theta},{psi}) for spin 0 daughters has been derived for (1) vector meson electroproduction and (2) general interfering mesons produced by incident pions. This paper derives W({theta},{psi}) for electroproduction of two interfering mesons that decay into spin 0 daughters. An application is made to the case of interfering scalar and vector mesons. The derivation is an extension of work by Schil using the general decay formalism of Martin. The expressions can be easily extended to the case of N interfering mesons since interference occurs pairwise in the observable W ({theta},{psi}), a quadratic function of the meson amplitudes. The derivation uses the virtual photon density matrix of Schil which is transformed by a meson electroproduction transition operator, T. The resulting density matrix for the interfering mesons is then converted into a corresponding statistical tensor and contracted into the efficiency tensor for spin 0 daughters.

  3. Spore photoproduct within DNA is a surprisingly poor substrate for its designated repair enzyme-The spore photoproduct lyase.

    Science.gov (United States)

    Yang, Linlin; Jian, Yajun; Setlow, Peter; Li, Lei

    2017-05-01

    DNA repair enzymes typically recognize their substrate lesions with high affinity to ensure efficient lesion repair. In UV irradiated endospores, a special thymine dimer, 5-thyminyl-5,6-dihydrothymine, termed the spore photoproduct (SP), is the dominant DNA photolesion, which is rapidly repaired during spore outgrowth mainly by spore photoproduct lyase (SPL) using an unprecedented protein-harbored radical transfer process. Surprisingly, our in vitro studies using SP-containing short oligonucleotides, pUC 18 plasmid DNA, and E. coli genomic DNA found that they are all poor substrates for SPL in general, exhibiting turnover numbers of 0.01-0.2min(-1). The faster turnover numbers are reached under single turnover conditions, and SPL activity is low with oligonucleotide substrates at higher concentrations. Moreover, SP-containing oligonucleotides do not go past one turnover. In contrast, the dinucleotide SP TpT exhibits a turnover number of 0.3-0.4min(-1), and the reaction may reach up to 10 turnovers. These observations distinguish SPL from other specialized DNA repair enzymes. To the best of our knowledge, SPL represents an unprecedented example of a major DNA repair enzyme that cannot effectively repair its substrate lesion within the normal DNA conformation adopted in growing cells. Factors such as other DNA binding proteins, helicases or an altered DNA conformation may cooperate with SPL to enable efficient SP repair in germinating spores. Therefore, both SP formation and SP repair are likely to be tightly controlled by the unique cellular environment in dormant and outgrowing spore-forming bacteria, and thus SP repair may be extremely slow in non-spore-forming organisms. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. The lightest hybrid meson supermultiplet in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Dudek, Jozef J

    2011-10-01

    We interpret the spectrum of meson states recently obtained in non-perturbative lattice QCD calculations in terms of constituent quark-antiquark bound states and states, called 'hybrids', in which the q{bar q} pair is supplemented by an excitation of the gluonic field. We identify a lightest supermultiplet of hybrid mesons with J{sup PC} = (0,1,2){sup {-+}}, 1{sup -} built from a gluonic excitation of chromomagnetic character coupled to q{bar q} in an S-wave. The next lightest hybrids are suggested to be quark orbital excitations with the same gluonic excitation, while the next distinct gluonic excitation is significantly heavier. Existing models of gluonic excitations are compared to these findings and possible phenomenological consequences explored.

  5. LHCb: LHCb results on $B$ meson mixing

    CERN Multimedia

    Eitschberger, U

    2013-01-01

    On the poster three LHCb results on B meson mixing using a datasample of 1 fb$^{-1}$ of $pp$ collisions at $\\sqrt{s} =$ 7 TeV are presented. The B meson oscillation frequencies are measured as $\\Delta m_d = 0.5156 \\pm 0.0051 (\\text{stat}) \\pm 0.0033 (\\text{syst}) \\text{ps}^{-1}$ and $\\Delta m_s = 17.768 \\pm 0.023 (\\text{stat}) \\pm 0.006 (\\text{syst}) \\text{ps}^{-1}$. The CP violation observables in the decay channel $B^0 \\rightarrow J/\\psi K^0_S$ are determined as $S_{J/\\psi K^0_S} = 0.73 \\pm 0.07 (\\text{stat})\\pm 0.04 (\\text{syst})$ and $C_{J/\\psi K^0_S} = 0.03 \\pm 0.09 (\\text{stat})\\pm 0.01 (\\text{syst})$.

  6. Meson Spectroscopy from QCD - Project Results

    Energy Technology Data Exchange (ETDEWEB)

    Dudek, Jozef [Old Dominion Univ., Norfolk, VA (United States)

    2017-04-17

    Highlights of the research include: the determination of the form of the lowest energy gluonic excitation within QCD and the spectrum of hybrid hadrons which follows; the first calculation of the spectrum of hybrid baryons within a first-principles approach to QCD; a detailed mapping out of the phase-shift of elastic ππ scattering featuring the ρ resonance at two values of the light quark mass within lattice QCD; the first (and to date, only) determinations of coupled-channel meson-meson scattering within first-principles QCD; the first (and to date, only) determinations of the radiative coupling of a resonant state, the ρ appearing in πγ→ππ; the first (and to date, only) determination of the properties of the broad σ resonance in elastic ππ scattering within QCD without unjustified approximations.

  7. Exclusive electroproduction of $\\phi$ mesons at HERA

    CERN Document Server

    Chekanov, S; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Allfrey, P D; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P M; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Büttner, C; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cassel, D G; Catterall, C D; Abramowicz, H; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danilov, P; De Pasquale, S; Dementiev, R K; Derrick, M; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Everett, A; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Graciani-Díaz, R; Grigorescu, G; Grijpink, S; Groys, M; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Hilger, E; Hochman, D; Holm, U; Horn, C; Iacobucci, G; Iga, Y; Irrgang, P; Jakob, H P; Jiménez, M; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karshon, U; Karstens, F; Kasemann, M; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowalski, H; Kramberger, G; Kreisel, A; Krumnack, N; Kulinski, P; Kuze, M; Kuzmin, V A; Labarga, L; Lammers, S; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Limentani, S; Ling, T Y; Liu, C; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Ma, K J; Maddox, E; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Martínez, M; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Olkiewicz, K; Ota, O; Padhi, S; Palmonari, F; Patel, S; Paul, E; Pavel, Usan; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plamondon, M; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Robins, S; Rosin, M; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Santamarta, R; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Tyszkiewicz, A; Ukleja, A; Ukleja, J; Vázquez, M; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Whitmore, J J; Whyte, J; Wichmann, K; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wlasenko, M; Wolf, G; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Ziegler, A; Zotkin, D S; Zotkin, S A; De Favereau, J; De Wolf, E; Del Peso, J

    2005-01-01

    Exclusive electroproduction of $\\phi$ mesons has been studied in $e^\\pm p$ collisions at $\\sqrt{s}=318 \\gev$ with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb$^{-1}$. The $\\gamma^*p$ cross section is presented in the kinematic range $2mesons. The ratios $R$ of the cross sections for longitudinally and transversely polarized virtual photons are presented as functions of $Q^2$ and $W$. The data are also compared to predictions from theoretical models.

  8. Helicity operators for mesons in flight on the lattice

    CERN Document Server

    Thomas, Christopher E; Dudek, Jozef J

    2011-01-01

    Motivated by the desire to construct meson-meson operators of definite relative momentum in order to study resonances in lattice QCD, we present a set of single-meson interpolating fields at non-zero momentum that respect the reduced symmetry of a cubic lattice in a finite cubic volume. These operators follow from the subduction of operators of definite helicity into irreducible representations of the appropriate little groups. We show their effectiveness in explicit computations where we find that the spectrum of states interpolated by these operators is close to diagonal in helicity, admitting a description in terms of single-meson states of identified J^{PC}. The variationally determined optimal superpositions of the operators for each state give rapid relaxation in Euclidean time to that state, ideal for the construction of meson-meson operators and for the evaluation of matrix elements at finite momentum.

  9. B decays to excited charm mesons

    Energy Technology Data Exchange (ETDEWEB)

    Colangelo, P.; De Fazio, F.; Paver, N

    1999-04-01

    We review several aspects of the phenomenology of P-wave q-barQ mesons: mass splittings, effective strong couplings and leptonic constants. We also describe a QCD sum rule determination to order {alpha}{sub s} of the form factor {tau}{sub 1/}2(y) governing the semileptonic B decays to the charm doublet with J{sup P} = (0{sup +}{sub 1/2}), 1{sup +}{sub 1/2}))00.

  10. Remarks on the exotic U-meson

    Energy Technology Data Exchange (ETDEWEB)

    Chan Hongmo [Rutherford Appleton Lab., Chilton (United Kingdom); Tsou Sheungtsun [Oxford Univ. (United Kingdom). Mathematical Inst.

    1991-12-01

    In expectation of imminent results from the new hyperon beam experiment at CERN concerning the exotic U-meson at 3.1 GeV, we propose a detailed program of experimental tests to check the suggestion that U is a qqq-barq-bar ``M-diquonium`` state. Apart from some very characteristic decay modes, the U is expected to occur together with several analogous states with various quantum numbers to which it is intimately related. (author).

  11. LAMPF: the meson factory. A LASL monograph

    Energy Technology Data Exchange (ETDEWEB)

    Allred, J.C.

    1977-08-01

    A general and simplified introduction to the entire concept of LAMPF is given in terms of its experimental capabilities. Parts of the current experimental program are used as illustrative examples. Topics discussed include: (1) the evolution of the meson factory; (2) accelerator construction; (3) strong focusing; (4) accelerator innovations at LAMPF; (5) photons and pions; (6) muons as nuclear probes; (7) nuclear chemistry; (8) radiobiology and medical applications; (9) radioisotope production; (10) materials testing; and (11) LAMPF management and users group. (PMA)

  12. Holographic picture of heavy vector meson melting

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Nelson R.F.; Diles, Saulo [Universidade Federal do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro, RJ (Brazil); Martin Contreras, Miguel Angel [Universidad de los Andes, High Energy Group, Department of Physics, Bogota (Colombia)

    2016-11-15

    The fraction of heavy vector mesons produced in a heavy ion collision, as compared to a proton-proton collision, serves as an important indication of the formation of a thermal medium, the quark-gluon plasma. This sort of analysis strongly depends on understanding the thermal effects of a medium like the plasma on the states of heavy mesons. In particular, it is crucial to know the temperature ranges where they undergo a thermal dissociation, or melting. AdS/QCD models are know to provide an important tool for the calculation of hadronic masses, but in general are not consistent with the observation that decay constants of heavy vector mesons decrease with excitation level. It has recently been shown that this problem can be overcome using a soft wall background and introducing an extra energy parameter, through the calculation of correlation functions at a finite position of anti-de Sitter space. This approach leads to the evaluation of masses and decay constants of S wave quarkonium states with just one flavor dependent and one flavor independent parameter. Here we extend this more realistic model to finite temperatures and analyze the thermal behavior of the states 1S, 2S and 3S of bottomonium and charmonium. The corresponding spectral function exhibits a consistent picture for the melting of the states where, for each flavor, the higher excitations melt at lower temperatures. We estimate for these six states the energy ranges in which the heavy vector mesons undergo a transition from a well-defined peak in the spectral function to complete melting in the thermal medium. A very clear distinction between the heavy flavors emerges, with the bottomonium state Υ(1S) surviving a deconfinement transition at temperatures much larger than the critical deconfinement temperature of the medium. (orig.)

  13. Exclusive ω meson production at COMPASS

    Directory of Open Access Journals (Sweden)

    Nowak Wolf-Dieter

    2016-01-01

    Full Text Available Exclusive ω meson production is studied by the COMPASS Collaboration using the CERN 160 GeV/c muon beam and a transversely polarised proton target. Single-spin and double-spin asymmetries are measured, some of which are sensitive to the Generalised Parton Distributions E that are related to quark orbital angular momenta. The results, which are sensitive also to the pion-pole contribution to the production mechanism, are compared to the predictions of a phenomenological model.

  14. Understanding the baryon and meson spectra

    Energy Technology Data Exchange (ETDEWEB)

    Pennington, Michael R. [JLAB

    2013-10-01

    A brief overview is given of what we know of the baryon and meson spectra, with a focus on what are the key internal degrees of freedom and how these relate to strong coupling QCD. The challenges, experimental, theoretical and phenomenological, for the future are outlined, with particular reference to a program at Jefferson Lab to extract hadronic states in which glue unambiguously contributes to their quantum numbers.

  15. Spin self-analysis of photoproduced meson and baryon resonances

    Energy Technology Data Exchange (ETDEWEB)

    Kloet, W.M. (Department of Physics and Astronomy, Rutgers University, New Jersey (United States)); Wen-Tai Chiang; Tabakin, F. (Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh (United States))

    1998-11-01

    Spin-1 mesons are self analyzing with respect to their tensor polarization, and spin-2 mesons are self-analyzing with respect to their rank-2 and their rank-4 polarization. Also spin-3/2 baryons are self-analyzing with respect to their rank-2 polarization. These properties make, for example, spin-correlations involving the vector-meson's vector polarization inaccessible directly with present experimental techniques. (author)

  16. Spin Self-Analysis of Photoproduced Meson and Baryon Resonances

    Science.gov (United States)

    Kloet, W. M.; Chiang, Wen-Tai; Tabakin, Frank

    1998-11-01

    Spin-1 mesons are self-analyzing with respect to their tensor polarization, and spin-2 mesons are self-analyzing with respect to their rank-2 and their rank-4 polarization. Also spin-3/2 baryons are self-analyzing with respect to their rank-2 polarization. These properties make, for example, spin-correlations involving the vector-meson's vector polarization inaccessible directly with present experimental techniques.

  17. Experiments Needed in Meson and Baryon Spectroscopy

    Directory of Open Access Journals (Sweden)

    D. V. Bugg

    2008-03-01

    Full Text Available Three (or four straightforward experiments would contribute greatly to completing the spectroscopy of baryons and light mesons. In the baryon sector, data are needed on inelastic reactions from a polarised target with π± and K± beams up to ∼ 3 GeV/c. Similar data are needed in the light meson sector for p¯p interactions in the momentum range 0.3–2 GeV/c. In both cases, valuable information is to be obtained from longitudinal (L and sideways (S target polarisations as well as the conventional normal (N polarisation. Thirdly, 3S1 and 3D1 mesons in the mass range 1–2.4 GeV could probably be separated either by diffractive dissociation of transversely polarised photons or by e+e− radiative return experiments using transversely and longitudinally polarised electrons.

  18. Antiproton-proton annihilation into light neutral meson pairs within an effective meson theory

    Science.gov (United States)

    Wang, Ying; Bystritskiy, Yury M.; Ahmadov, Azad I.; Tomasi-Gustafsson, Egle

    2017-08-01

    Antiproton-proton annihilation into light neutral mesons in the few GeV energy domain is investigated in view of a global description of the existing data and predictions for future work at the Antiproton Annihilation at Darmstadt (PANDA) experiment at the Facility for Antiproton and Ion Research (FAIR). An effective meson model earlier developed, with mesonic and baryonic degrees of freedom in s , t , and u channels, is applied here to π0π0 production. Form factors with logarithmic s and t (u ) dependencies are applied. A fair agreement with the existing angular distributions is obtained. Applying SU(3) symmetry, it is straightforward to recover the angular distributions for π0η and η η production in the same energy range. A good agreement is generally obtained with all existing data.

  19. Photoproduction of γ p →K+Λ*(1520 ) and decay of Λ*(1520 ) →K-p in the Reggeized framework

    Science.gov (United States)

    Yu, Byung-Geel; Kong, Kook-Jin

    2017-08-01

    Photoproduction of Λ*(1520 ) resonance of spin-parity 3/2- off the proton target is investigated within the Regge framework where the reggeization of the t -channel meson exchange is applied for the K (494 ) +K*(892 ) +K2*(1430 ) exchanges in the Born amplitude. The present model is based on two basic ingredients; one is the minimal gauge prescription for the convergence of the reaction and the other is the role of K2* crucial to be consistent with high energy data. Cross sections for total, differential, and photon polarization asymmetry are reproduced without fit parameters and compared with existing data. The LAMP2 and LEPS measurements of the angular distribution of K- in the Λ*(1520 ) →K-p decay are investigated and found to be dominated by the decay of Λ* with helicity ±3 /2 based on the analysis of the density matrix elements. Detailed discussion on the density matrix elements is given to clarify the analysis of the observable. The reaction mechanism is featured by the dominance of the contact term with K and K2* exchanges following in the low energy region. The K* exchange appears in a minor role. At high energies beyond Eγ≈5 GeV the role of K2* exchange leads over other exchanges in the reaction process.

  20. Measurement of the beam-helicity asymmetry $I^{\\odot}$ in the photoproduction of $\\pi^0$-pairs off the proton and off the neutron

    CERN Document Server

    Oberle, M; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Bartolome, P A; Beck, R; Bekrenev, V; Berghaeuser, H; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Demissie, B; Dieterle, M; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Glazier, D I; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jahn, O; Jaegle, I; Jude, T C; Kaeser, A; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Kruglov, S P; Kulbardis, A; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; Martinez, M; McGeorge, J C; McNicoll, E; Mekterovic, D; Metag, V; Micanovic, S; Middleton, D G; Mushkarenkov, A; Nefkens, B M K; Nikolaev, A; Novotny, R; Ostrick, M; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S N; Robinson, J; Rosner, G; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D I; Starostin, A; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P; Werthmueller, D; Witthauer, L; Zehr, F

    2013-01-01

    Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz for the photoproduction of neutral pion pairs in the reactions $\\vec{\\gamma}p\\rightarrow p\\pi^0\\pi^0$ and $\\vec{\\gamma}d\\rightarrow (n)p\\pi^0\\pi^0$, $\\vec{\\gamma}d\\rightarrow (p)n\\pi^0\\pi^0$ off free protons and off quasi-free nucleons bound in the deuteron for incident photon energies up to 1.4 GeV. Circularly polarized photons were produced from bremsstrahlung of longitudinally polarized electrons and tagged with the Glasgow magnetic spectrometer. Decay photons from the $\\pi^0$ mesons, recoil protons, and recoil neutrons were detected in the 4$\\pi$ covering electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. After kinematic reconstruction of the final state, excellent agreement was found between the results for free and quasi-free protons. This demonstrates that the free-nucleon behavior of such observables can be extracted from measurements with quasi-free nucleons, which is the only possibility for the n...

  1. Measurement of the beam-helicity asymmetry $I^{\\odot}$ in the photoproduction of $\\pi^0\\pi^{\\pm}$-pairs off protons and off neutrons

    CERN Document Server

    Oberle, M; Annand, J R M; Arends, H J; Bantawa, K; Bartolome, P A; Beck, R; Bekrenev, V; Berghaeuser, H; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Demissie, B; Dieterle, M; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Glazier, D I; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jahn, O; Jaegle, I; Jude, T C; Kaeser, A; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Kruglov, S P; Krusche, B; Kulbardis, A; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; Martinez, M; McGeorge, J C; McNicoll, E; Mekterovic, D; Metag, V; Micanovic, S; Middleton, D G; Mushkarenkov, A; Nefkens, B M K; Nikolaev, A; Novotny, R; Ostrick, M; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S N; Robinson, J; Rosner, G; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D I; Starostin, A; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P; Werthmueller, D; Witthauer, L; Zehr, F

    2014-01-01

    Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz for the photoproduction of mixed-charge pion pairs in the reactions $\\boldsymbol{\\gamma}p\\rightarrow n\\pi^0\\pi^+$ off free protons and $\\boldsymbol{\\gamma}d\\rightarrow (p)p\\pi^0\\pi^-$ and $\\boldsymbol{\\gamma}d\\rightarrow (n)n\\pi^0\\pi^+$ off quasi-free nucleons bound in the deuteron for incident photon energies up to 1.4 GeV. Circularly polarized photons were produced from bremsstrahlung of longitudinally polarized electrons and tagged with the Glasgow-Mainz magnetic spectrometer. The charged pions, recoil protons, recoil neutrons, and decay photons from $\\pi^0$ mesons were detected in the 4$\\pi$ electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. Using a complete kinematic reconstruction of the final state, excellent agreement was found between the results for free and quasi-free protons, suggesting that the quasi-free neutron results are also a close approximation of the free-neutron asymmetries. A comparis...

  2. The Meson Spectroscopy Program at the Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Filippi, Alessandro [Istituto Nazionale di Fisica Nucleare (INFN), Torino (Italy). et al.

    2015-06-01

    The experimental techniques that will be applied by the next generation meson spectroscopy experiments at JLab are described. For the first time, these experiments will be able to exploit the features of a photon beam of unprecedented intensity and momentum resolution, that will allow to perform precision studies of meson states with masses below 3 GeV/c2. Photon induced reactions will enhance the production of spin-1 mesons, that are of particular interest according to the most recent Lattice QCD calculations of the lightest exotic hybrid meson.

  3. Effects of isovector scalar meson on hyperon star

    OpenAIRE

    Biswal, S. K.; Kumar, Bharat; Patra, S. K.

    2016-01-01

    We study the effects of isovector-scalar ($\\delta$)-meson on neutron star. Influence of $\\delta$-meson on both static and rotating neutron star is discussed. Inclusion of $\\delta$-meson in a neutron star system consisting of proton, neutron and electron, make the equation of state stiffer in higher density and consequently increases the maximum mass of the star. But induction of $\\delta$-meson in the hyperon star decreases the maximum mass of the hyperon star. This is due to the early evoluti...

  4. The hybrid mesons quest: the MesonEx experiment at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, Alessandro [Univ. of Rome Tor Vergata (Italy)

    2016-03-01

    The meson spectroscopy plays nowadays a central role in the investigation of hadron structure thanks to the possible existence of exotic hybrid mesons, quark-antiquark-gluon bound states. Their explicit gluonic degrees of freedom which should clearly emerge from a Partial Wave Analysis (PWA) of the corresponding Dalitz plot of the exotic particle decay, may result in final JPC configurations not allowed in the constituent quark model. Besides this clear signature, hybrid mesons are also expected to have a large particle multiplicity decays, requiring for their search an experimental apparatus with high performances in terms of rate capability, resolution and almost a full acceptance to apply PWA methods. New-generation experiments are planned at Thomas Jefferson National Laboratory (VA, USA) for which an unprecedented statistics of large multiplicity decay events with fully reconstructed kinematics will be available. In particular for the MesonEx (CLAS12) experiment in Hall B, a wide scientific program that will start in 2016 has been deployed to study the meson spectrum at energies up to 11 GeV. A key role in such program is played by the Forward Tagger apparatus of the experiment, which will allow to extend the study of meson electro-production to very low Q2 values, in a quasi-real photo production kinematical region, where the production of hybrid mesons is expected to be favorite. Currently a new analysis framework for the search of the hybrid mesons is being set up by the HASPECT network, an international structure which gather people involved into theoretical and experimental hadronic physics all over the world. The goals of the network is to develop new analysis models and statistical techniques to unfold the signal and background distributions in high-statistics datasets. In this work are briefly presented the first preliminary results from the application of a statistical technique, namely the sPlot, to the data already acquired by the CLAS experiment for

  5. Photoproducts in DNA irradiated In vitro and In vivo under extreme environmental conditions

    Science.gov (United States)

    Riklis, Emanuel

    UV-irradiated DNA forms different photoproducts in accordance with its state of hydration, and the environment in which the irradiation takes place. Photoproducts in addition to the well-known thymine dimer are produced, some of which probably not recognized due to being heat or acid labile, and milder methods for DNA hydrolysis are needed. The isolation, structure and properties of photoproducts which are formed in UV-irradiated frozen thymine solutions are described. Urea, n-propylurea and dihydrothymine are obtained as photolytic products by high radiation doses in low concentrations of thymine. The cyclobutane cis-anti thymine dimer is obtained at high concentrations of thymine, following several cycles of freezing, thawing and irradiations. A trimer is obtained with 290 nm UV light filtered through Pyrex. It reverts back to thymine dimer and thymine when reirradiated in solution. The cis-syn dimer is obtained at all concentrations of frozen thymine and in a dose dependent form. The adduct 5-hydroxy-6-4' (5'- methylpyrimid 2'-1) dihydrothymine is also obtained. In vacuum-dried thymine or DNA, other photoproducts are formed, including the spore-product, TDHT. Several solvent systems were used to develop chromatograms that allow seperation of photoproducts.

  6. Melanin offers protection against induction of cyclobutane pyrimidine dimers and 6-4 photoproducts by UVB in cultured human melanocytes

    NARCIS (Netherlands)

    Smit, N.P.M.; Vink, A.A.; Kolb, R.M.; Steenwinkel, M.J.S.T.; Berg, P.T.M. van den; Nieuwpoort, F. van; Roza, L.; Pavel, S.

    2001-01-01

    The goal of this investigation was to correlate the melanin content in human pigmentary cells with the generation of UVB-induced photoproducts and to examine the relationship between the melanin content and the removal of the photoproducts. Cultured melanocytes from light-skinned individuals

  7. Measurement of D sup * meson cross sections at HERA and determination of the gluon density in the proton using NLO QCD

    CERN Document Server

    Adloff, C; Andreev, V; Andrieu, B; Arkadov, V; Arndt, C; Ayyaz, I; Babaev, A; Bähr, J; Baranov, P; Barrelet, E; Bartel, Wulfrin; Bassler, U; Bate, P; Beck, M; Beglarian, A; Behnke, O; Behrend, H J; Beier, C; Belousov, A; Berger, C; Bernardi, G; Bertrand-Coremans, G; Biddulph, P; Bizot, J C; Boudry, V; Braunschweig, W; Brisson, V; Brown, D P; Brückner, W; Bruel, P; Bruncko, Dusan; Bürger, J; Büsser, 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, John D; Droutskoi, A; Ebert, J; Eckerlin, G; Eckstein, D; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Eisenhandler, E F; Elsen, E; Enzensberger, H M; Erdmann, M; Fahr, A B; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Ferrarotto, F; Fleischer, M; Flügge, G; Fomenko, A; Formánek, J; Foster, J M; Franke, G; Gabathuler, Erwin; Gabathuler, K; Gaede, F; Garvey, J; Gassner, J; Gayler, J; Gerhards, R; Ghazaryan, S; Glazov, A; Görlich, L; Gogitidze, N; Goldberg, M; Gorelov, I; Grab, C; Grässler, Herbert; Greenshaw, T; Griffiths, R K; Grindhammer, G; Hadig, T; Haidt, Dieter; 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 P; Hurling, S; Ibbotson, M; Issever, C; Jacquet, M; Jaffré, M; Jansen, D M; Jönsson, L B; 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; Köhne, J H; Kolanoski, H; Kolya, S D; Korbel, V; Kostka, P; Kotelnikov, S K; Kraemerkaemper, T; Krasny, M W; Krehbiel, H; Krücker, D; Krüger, K; Küpper, A; Küster, H; Kuhlen, M; Kurca, T; Lahmann, R; Landon, M P J; Lange, W; Langenegger, U; Lebedev, A; Lehner, F; Lemaître, V; Lendermann, V; Levonian, S; Lindstrøm, M; List, B; Lobo, G; Lobodzinska, E; Lubimov, V; Lüders, S; Lüke, D; Lytkin, L; Magnussen, N; Mahlke-Krüger, H; Malinovskii, E I; 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 F; Mohrdieck, S; Moreau, F; Morris, J V; Müller, D; Müller, K; Murín, P; Nagovizin, V; Naroska, Beate; Naumann, T; Negri, I; Newman, P R; Nguyen, H K; Nicholls, T C; Niebergall, F; Niebuhr, C B; Niedzballa, C; Niggli, H; Nikitin, D K; 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; Pérez, E; Phillips, J P; Pieuchot, A; Pitzl, D; Pöschl, 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 A; Rouse, F; Royon, C; Rusakov, S V; Rybicki, K; Sankey, D P C; Schacht, P; Scheins, J; Schilling, F P; Schleif, S; Schleper, P; Schmidt, D; Schmidt, D; Schoeffel, L; Schröder, V; Schultz-Coulon, H C; Schwab, B; Sefkow, F; Semenov, A; Shekelyan, V; Shevyakov, I; Shtarkov, L N; Siegmon, G; Sirois, Y; Sloan, T; Smirnov, P; Smith, M; Solochenko, V; Soloviev, Yu V; 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, Stefan; Tasevsky, M; Tchernov, V V; Chechelnitskii, S; Theissen, J; Thompson, G; Thompson, P D; Tobien, N; Todenhagen, R; Truöl, P; Tsipolitis, G; Turnau, J; Tzamariudaki, E; Udluft, S; Usik, A; Valkár, S; Valkárová, A; Vallée, C; Van Esch, P; Van Haecke, A; Van Mechelen, P; Vazdik, Ya A; 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; Wünsch, E; Zácek, J; Zaleisak, 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 sup * meson production cross sections have been measured in deep inelastic scattering with four-momentum transfers Q sup 2 > 3 GeV sup 2 and in photoproduction at energies around W subgamma sub p approx 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 sub g g(x sub g), has been extracted in the momentum fraction range 7.5 x 10 sup - sup 4 < x sub g < 4 x 10 sup - sup 2 at average scales mu sup 2 = 25 to 50 GeV sup 2. The gluon momentum fraction x sub g has been obtained from the measured kinematics of the scattered electron and the D sup * 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 sub 2.

  8. Diffractive dijet photoproduction in ep collisions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering (NIPNE), 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. (Armenia); Barrelet, E. [CNRS/IN2P3, LPNHE, Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris 7, Paris (France); 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.; 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.; Marti, Ll.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nikiforov, A.; 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. [CNRS/IN2P3, LAL, Univ. Paris-Sud, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [CNRS/IN2P3, LLR, Ecole Polytechnique, 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 (United Kingdom). School of Physics and Astronomy] (and others)

    2010-11-15

    Measurements are presented of single and double-differential dijet cross sections in diffractive photoproduction based on a data sample with an integrated luminosity of 47 pb{sup -1}. The events are of the type ep{yields}eXY, where the hadronic system X contains at least two jets and is separated by a large rapidity gap from the system Y, which consists of a leading proton or low-mass proton excitation. The dijet cross sections are compared with QCD calculations at next-to-leading order and with a Monte Carlo model based on leading order matrix elements with parton showers. The measured cross sections are smaller than those obtained from the next-to-leading order calculations by a factor of about 0.6. This suppression factor has no significant dependence on the fraction x{sub {gamma}} of the photon four-momentum entering the hard subprocess. Ratios of the diffractive to the inclusive dijet cross sections are measured for the first time and are compared with Monte Carlo models. (orig.)

  9. Diffractive Dijet Photoproduction in ep Collisions 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.; Bruncko, D.; Bunyatyan, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; 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.; 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.; 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.; Marti, Ll.; 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.; Raicevic, N.; Raspiareza, A.; 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.; Shaw-West, R.N.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; 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.

    2010-01-01

    Measurements are presented of single and double-differential dijet cross sections in diffractive photoproduction based on a data sample with an integrated luminosity of 47 pb^-1. The events are of the type ep -> eXY, where the hadronic system X contains at least two jets and is separated by a large rapidity gap from the system Y, which consists of a leading proton or low-mass proton excitation. The dijet cross sections are compared with QCD calculations at next-to-leading order and with a Monte Carlo model based on leading order matrix elements with parton showers. The measured cross sections are smaller than those obtained from the next-to-leading order calculations by a factor of about 0.6. This suppression factor has no significant dependence on the fraction x_gamma of the photon four-momentum entering the hard subprocess. Ratios of the diffractive to the inclusive dijet cross sections are measured for the first time and are compared with Monte Carlo models.

  10. Diffractive photoproduction of dijets in ep collisions at HERA

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-09-15

    Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb{sup -1}. The measurements were made in the kinematic range Q{sup 2}<1 GeV{sup 2}, 0.207.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5<{eta}{sup jet}<1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton. (orig.)

  11. 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.)

  12. Diffractive dijet photoproduction in ep collisions 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)

    2010-03-15

    Measurements are presented of single and double-differential dijet cross sections in diffractive photoproduction based on a data sample with an integrated luminosity of 47 pb{sup -1}. The events are of the type ep{yields}eXY, where the hadronic system X contains at least two jets and is separated by a large rapidity gap from the system Y, which consists of a leading proton or low-mass proton excitation. The dijet cross sections are compared with QCD calculations at next-to-leading order and with a Monte Carlo model based on leading order matrix elements with parton showers. The measured cross sections are smaller than those obtained from the next-to-leading order calculations by a factor of about 0.6. This suppression factor has no significant dependence on the fraction x{sub {gamma}} of the photon four-momentum entering the hard subprocess. Ratios of the diffractive to the inclusive dijet cross sections are measured for the first time and are compared with Monte Carlo models. (orig.)

  13. Dijets in diffractive photoproduction measured with the ZEUS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Renner, R.

    2006-10-15

    The diffractive photoproduction of dijets in electron-proton scattering has been studied using 77.1 pb{sup -1} of data taken with the ZEUS detector at HERA. The measurements have been made at a centre-of- mass energy {radical}s=318 GeV in the kinematic range 0.27.5 and 6.5 GeV, respectively, and to be in the pseudorapidity range -1.5<{eta}<1.5. Differential cross sections have been measured and been confronted with the predictions from leading order Monte Carlo simulations and next-to-leading order QCD calculations. (orig.)

  14. Photoproduction of the. Lambda. sub c charmed baryon

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, M.P.; Calvino, F.; Crespo, J.M. (Universidad Autonoma de Barcelona (Spain)); Barate, R.; DiCiaccio, L.; Ferrer, A.; Giomataris, Y.; Pattison, B.; Treille, D.; Zolnierowski, Y. (European Organization for Nuclear Research, Geneva (Switzerland)); Bloch, D.; Engel, J.P.; Foucault, P.; Gerber, J.P.; Strub, R. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires Strasbourg-1 Univ., 67 (France)); Bonamy, P.; Borgeaud, P.; David, M.; Lemoigne, Y.; Magneville, C.; Primout, M.; Villet, G. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Physique des Particules Elementaires); Burchell, M.; Burmeister, H.; Cattaneo, M.; Dixon, J.; Duane, A.; Forty, R.W.; Seez, C.; Websdale, D.M. (Imperial Coll. of Science and Technology, London (UK). Blackett Lab.); Brunet, J.M.; Poutot, D.; Triscos, P.; Tristram, G.; Volte, A. (College de France, 75 - Paris (France)); Almagne, B. d' ; Druet, P.; Krafft, C.; Lefievre, B.; Roudeau, P.; Six, J.; Wayne, M.; NA14/2 Collaboration

    1990-08-23

    In a photoproduction experiment using a mean photon energy of 100 GeV we have observed 29{plus minus}8 {Lambda}{sub c} (anti {Lambda}{sub c}) charmed-baryon and antibaryon decays in the pK{sup -}{pi}{sup +} (anti pK{sup +}{pi}{sup -}) final state. Quasi two-body final states do not contribute significantly to this channel. The mass of the {Lambda}{sub c} was measured to be 2281.7{plus minus}2.7{plus minus}2.6 MeV/c{sup 2} and its lifetime 0.18{plus minus}0.03{plus minus}0.03 ps. The ratio of {Lambda}{sub c}/D production, measured in this experiment, is significantly greater than that predicted by photon-gluon fusion and using a Lund model to describe the hadronization. This excess cannot be completely accounted for in this model, even using a {Lambda}{sub c} branching fraction in pK{pi} as high as 5%. (orig.).

  15. Photoproduction of $\\pi^0$-pairs off protons and off neutrons

    CERN Document Server

    Dieterle, M; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Bartolome, P A; Beck, R; Bekrenev, V; Berghäuser, H; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Costanza, S; Demissie, B; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Garni, S; Glazier, D I; Hamilton, D; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jahn, O; Jude, T C; Käser, A; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; McGeorge, J C; McNicoll, E; Mekterovic, D; Metag, V; Micanovic, S; Middleton, D G; Mushkarenkov, A; Nikolaev, A; Novotny, R; Ostrick, M; Otte, P; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S; Robinson, J; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D I; Starostin, A; Strub, Th; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Walford, N K; Watts, D P; Werthmüller, D; Witthauer, L

    2015-01-01

    Total cross sections, angular distributions, and invariant-mass distributions have been measured for the photoproduction of $\\pi^0\\pi^0$ pairs off free protons and off nucleons bound in the deuteron. The experiments were performed at the MAMI accelerator facility in Mainz using the Glasgow photon tagging spectrometer and the Crystal Ball/TAPS detector. The accelerator delivered electron beams of 1508 and 1557~MeV, which produced bremsstrahlung in thin radiator foils. The tagged photon beam covered energies up to 1400~MeV. The data from the free proton target are in good agreement with previous measurements and were only used to test the analysis procedures. The results for differential cross sections (angular distributions and invariant-mass distributions) for free and quasi-free protons are almost identical in shape, but differ in absolute magnitude up to 15\\%. Thus, moderate final-state interaction effects are present. The data for quasi-free neutrons are similar to the proton data in the second resonance r...

  16. Near-Threshold Incoherent φ Photoproduction on the Deuteron

    Science.gov (United States)

    Kiswandhi, Alvin; Yang, Shin Nan; Dong, Yu Bing

    We study the near-threshold incoherent φ photoproduction on the deuteron based on a model of γ N to φ N, consisting of Pomeron, (π ,η ) exchanges, and a JP = 3/2- resonance, which describes the low energy γ p to φ p LEPS data well. The calculation is done up to double rescatterings, by including the spin dependence of the elementary γ N to φ N amplitude, Fermi motion, and final-state interactions (FSI). The couplings of the resonance to γ n and φ n channels are estimated with the help of a constituent quark model. The LEPS and CLAS data are described reasonably well except at very low energies and low momentum transfer regions. It is found that the contributions of Fermi motion, pn FSI, and resonance are all indispensable. The off-shell rescattering is found to be important as well. No peak is found as it gets smeared out by the Fermi motion and the FSI between the outgoing nucleons. The problem at very low energy region hints at the possible contributions from other mechanisms and should be studied with the use of the recent γ p to φ p data from CLAS.

  17. Neutron Skin of Pb208 from Coherent Pion Photoproduction

    Science.gov (United States)

    Tarbert, C. M.; Watts, D. P.; Glazier, D. I.; Aguar, P.; Ahrens, J.; Annand, J. R. M.; Arends, H. J.; Beck, R.; Bekrenev, V.; Boillat, B.; Braghieri, A.; Branford, D.; Briscoe, W. J.; Brudvik, J.; Cherepnya, S.; Codling, R.; Downie, E. J.; Foehl, K.; Grabmayr, P.; Gregor, R.; Heid, E.; Hornidge, D.; Jahn, O.; Kashevarov, V. L.; Knezevic, A.; Kondratiev, R.; Korolija, M.; Kotulla, M.; Krambrich, D.; Krusche, B.; Lang, M.; Lisin, V.; Livingston, K.; Lugert, S.; MacGregor, I. J. D.; Manley, D. M.; Martinez, M.; McGeorge, J. C.; Mekterovic, D.; Metag, V.; Nefkens, B. M. K.; Nikolaev, A.; Novotny, R.; Owens, R. O.; Pedroni, P.; Polonski, A.; Prakhov, S. N.; Price, J. W.; Rosner, G.; Rost, M.; Rostomyan, T.; Schadmand, S.; Schumann, S.; Sober, D.; Starostin, A.; Supek, I.; Thomas, A.; Unverzagt, M.; Walcher, Th.; Zana, L.; Zehr, F.; Crystal Ball at MAMI; A2 Collaboration

    2014-06-01

    Information on the size and shape of the neutron skin on Pb208 is extracted from coherent pion photoproduction cross sections measured using the Crystal Ball detector together with the Glasgow tagger at the MAMI electron beam facility. On exploitation of an interpolated fit of a theoretical model to the measured cross sections, the half-height radius and diffuseness of the neutron distribution are found to be cn=6.70±0.03(stat.) fm and an=0.55±0.01(stat.)-0.03+0.02(sys.) fm, respectively, corresponding to a neutron skin thickness Δrnp=0.15±0.03(stat.)-0.03+0.01(sys.) fm. The results give the first successful extraction of a neutron skin thickness with an electromagnetic probe and indicate that the skin of Pb208 has a halo character. The measurement provides valuable new constraints on both the structure of nuclei and the equation of state for neutron-rich matter.

  18. Unusually large deuterium discrimination during spore photoproduct formation.

    Science.gov (United States)

    Ames, David M; Lin, Gengjie; Jian, Yajun; Cadet, Jean; Li, Lei

    2014-06-06

    The deuterium-labeling strategy has been widely used and proved highly effective in mechanistic investigation of chemical and biochemical reactions. However, it is often hampered by the incomplete label transfer, which subsequently obscures the mechanistic conclusion. During the study of photoinduced generation of 5-thyminyl-5,6-dihydrothymine, which is commonly called the spore photoproduct (SP), the Cadet laboratory found an incomplete (~67%) deuterium transfer in SP formation, which contrasts to the exclusive transfer observed by the Li laboratory. Here, we investigated this discrepancy by re-examining the SP formation using d3-thymidine. We spiked the d3-thymidine with varying amounts of unlabeled thymidine before the SP photochemistry is performed. Strikingly, our data show that the reaction is highly sensitive to the trace protiated thymidine in the starting material. As many as 17-fold enrichment is detected in the formed SP, which may explain the previously observed one-third protium incorporation. Although commercially available deuterated reagents are generally satisfactory as mechanistic probes, our results argue that attention is still needed to the possible interference from the trace protiated impurity, especially when the reaction yield is low and large isotopic discrimination is involved.

  19. Hydrogen photoproduction by use of photosynthetic organisms and biomimetic systems.

    Science.gov (United States)

    Allakhverdiev, Suleyman I; Kreslavski, Vladimir D; Thavasi, Velmurugan; Zharmukhamedov, Sergei K; Klimov, Vyacheslav V; Nagata, Toshi; Nishihara, Hiroshi; Ramakrishna, Seeram

    2009-02-01

    Hydrogen can be important clean fuel for future. Among different technologies for hydrogen production, oxygenic natural and artificial photosyntheses using direct photochemistry in synthetic complexes have a great potential to produce hydrogen, since both use clean and cheap sources: water and solar energy. Artificial photosynthesis is one way to produce hydrogen from water using sunlight by employing biomimetic complexes. However, splitting of water into protons and oxygen is energetically demanding and chemically difficult. In oxygenic photosynthetic microorganisms such as algae and cyanobacteria, water is split into electrons and protons, which during primary photosynthetic process are redirected by photosynthetic electron transport chain, and ferredoxin, to the hydrogen-producing enzymes hydrogenase or nitrogenase. By these enzymes, e- and H+ recombine and form gaseous hydrogen. Biohydrogen activity of hydrogenase can be very high but it is extremely sensitive to photosynthetic O2. In contrast, nitrogenase is insensitive to O2, but has lower activity. At the moment, the efficiency of biohydrogen production is low. However, theoretical expectations suggest that the rates of photon conversion efficiency for H2 bioproduction can be high enough (>10%). Our review examines the main pathways of H2 photoproduction by using of photosynthetic organisms and biomimetic photosynthetic systems.

  20. High-E{sub T} dijet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-06-15

    The cross section for high-E{sub T} dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb{sup -1}. The events were required to have a virtuality of the incoming pho- ton, Q{sup 2}, of less than 1 GeV{sup 2} and a photon-proton centre-of-mass energy in the range 14220 GeV and E{sub T}{sup jet2}>15 GeV and pseudorapidity requirements of -1<{eta}{sup jet1,2}<3, with at least one of the jets satisfying -1<{eta}{sup 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.)

  1. 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.

  2. Unusually Large Deuterium Discrimination during Spore Photoproduct Formation

    Science.gov (United States)

    2015-01-01

    The deuterium-labeling strategy has been widely used and proved highly effective in mechanistic investigation of chemical and biochemical reactions. However, it is often hampered by the incomplete label transfer, which subsequently obscures the mechanistic conclusion. During the study of photoinduced generation of 5-thyminyl-5,6-dihydrothymine, which is commonly called the spore photoproduct (SP), the Cadet laboratory found an incomplete (∼67%) deuterium transfer in SP formation, which contrasts to the exclusive transfer observed by the Li laboratory. Here, we investigated this discrepancy by re-examining the SP formation using d3-thymidine. We spiked the d3-thymidine with varying amounts of unlabeled thymidine before the SP photochemistry is performed. Strikingly, our data show that the reaction is highly sensitive to the trace protiated thymidine in the starting material. As many as 17-fold enrichment is detected in the formed SP, which may explain the previously observed one-third protium incorporation. Although commercially available deuterated reagents are generally satisfactory as mechanistic probes, our results argue that attention is still needed to the possible interference from the trace protiated impurity, especially when the reaction yield is low and large isotopic discrimination is involved. PMID:24820206

  3. In-medium QCD sum rules for {omega} meson, nucleon and D meson

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Ronny

    2008-07-01

    The modifications of hadronic properties caused by an ambient nuclear medium are investigated within the scope of QCD sum rules. This is exemplified for the cases of the {omega} meson, the nucleon and the D meson. By virtue of the sum rules, integrated spectral densities of these hadrons are linked to properties of the QCD ground state, quantified in condensates. For the cases of the {omega} meson and the nucleon it is discussed how the sum rules allow a restriction of the parameter range of poorly known four-quark condensates by a comparison of experimental and theoretical knowledge. The catalog of independent four-quark condensates is covered and relations among these condensates are revealed. The behavior of four-quark condensates under the chiral symmetry group and the relation to order parameters of spontaneous chiral symmetry breaking are outlined. In this respect, also the QCD condensates appearing in differences of sum rules of chiral partners are investigated. Finally, the effects of an ambient nuclear medium on the D meson are discussed and relevant condensates are identified. (orig.)

  4. Phototransformation of Amlodipine in Aqueous Solution: Toxicity of the Drug and Its Photoproduct on Aquatic Organisms

    Directory of Open Access Journals (Sweden)

    Marina DellaGreca

    2007-01-01

    Full Text Available The phototransformation of amlodipine in water was investigated under various conditions. A quantum yield ΦS2.2×10−4 and a half-life time t1/2 0.419 days were calculated when the drug in water (10−4 M was exposed to sunlight. The only photoproduct found was its pyridine derivative. Formation of this product was explained on the basis of a radical cation intermediate. The acute and chronic toxicity of the drug and its photoproduct were evaluated on different organisms of the freshwater chain (Brachionus calyciflorus, Thamnocephalus platyurus, Daphnia magna, Ceriodaphnia dubia. The photoproduct exhibited a stronger toxic potential than the parent drug on the long time for C. dubia.

  5. Non-Strange Meson Production with Hadronic Probes

    OpenAIRE

    Hanhart, C.

    2008-01-01

    Recent progress in the field of meson production in hadron collisions is presented. Special emphasis is put new developments in the application of effective field theory methods to pion production, but also theoretical concepts for two-pion, eta, and vector-meson production will be presented.

  6. Widths of narrow mesons made from heavy quarks

    CERN Document Server

    Farrar, Glennys R S; Okun, Lev Borisovich; Shifman, M A; Voloshin, M B; Zakharov, V I

    1977-01-01

    Presents predictions for the electronic widths of neutral vector mesons made from heavy quarks. Relying principally on dispersion relations and asymptotic freedom of QCD, these results are quite model-independent. Photonic and total hadronic widths of C-even mesons are also discussed. (6 refs).

  7. Beauty vector meson decay constants from QCD sum rules

    Energy Technology Data Exchange (ETDEWEB)

    Lucha, Wolfgang [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Melikhov, Dmitri [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); D. V. Skobeltsyn Institute of Nuclear Physics, M. V. Lomonosov Moscow State University, 119991, Moscow (Russian Federation); Simula, Silvano [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146, Roma (Italy)

    2016-01-22

    We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.

  8. Mass shift of σ-meson in nuclear matter

    Indian Academy of Sciences (India)

    2Facultad de Ingeniería y Arquitectura, Universidad Regiomontana, 15 de Mayo 567, Monterrey,. N.L., 64000, México. ∗ ... controversy is not about its existence but about its structure [9]. The composition of σ- meson as a ... Additionally it can be proved, from the quark structure, that the σ-meson is the chiral partner of the ...

  9. Properties of flavour-singlet pseudoscalar mesons from lattice QCD

    Directory of Open Access Journals (Sweden)

    Urbach Carsten

    2017-01-01

    Full Text Available We report on the status of the determination of properties of flavour-singlet pseudoscalar mesons using Wilson twisted mass lattice QCD at maximal twist. As part of project C7, a large number of phenomenologically relevant quantities could be extracted from first principle, from η and η′ masses to decay widths of pseudoscalar mesons to two photons.

  10. A precise measurement of the B-0 meson oscillation frequency

    NARCIS (Netherlands)

    Aaij, R.; Beteta, C. Abelian; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Cartelle, P. Alvarez; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Gutierrez, O. Aquines; Archilli, F.; d' Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Radalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Bellee, V.; Belloli, N.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M-O; van Beuzekom, M.; Bien, A.; Bifani, S.; Billoir, P.; Bird, T.; Birnkraut, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Buchanan, E.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Perez, D. Campora; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Garcia, L. Castillo; Cattaneo, M.; Cauet, Ch; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Cheung, S-F; Chiapolini, N.; Chrzaszcz, M.; Vidal, X. Cid; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Simone, P.; Dean, C-T; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Deleage, N.; Demmer, M.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suarez, A.; Dossett, D.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Farber, C.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fohl, K.; Fol, P.; Fontana, M.; Fontanelli, F.; Forshaw, D. C.; Forty, R.; Frei, C.; Frosini, M.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Garcia Pardinas, J.; Tico, J. Gana; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Giani, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gligorov, V. V.; Gobel, C.; Golubkov, D.; Golutvin, A.; Gotti, C.; Gandara, M. Grabalosa; Graciani Diaz, R.; Cardoso, L. A. Granado; Grauges, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Grunberg, O.; Gui, B.; Gushchin, E.; Guz, Yu; Gys, T.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Hess, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jalocha, J.; Jans, E.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koppenburg, P.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J-P; Lefevre, R.; Leflat, A.; Lefrancois, J.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusardi, N.; Lusiani, A.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Marks, J.; Martellotti, G.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; Mcnab, A.; McNulty, R.; Meadows, B.; Meier, F.; Melnychuk, D.; Merk, M.; Michielin, E.; Milanes, D. A.; Minard, M-N; Mitzel, D. S.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Morda, A.; Morello, M. J.; Moron, J.; Morriss, A. B.; Mountain, R.; Muheim, F.; Mulller, D.; Mueller, J.; Mueller, V.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen-Mau, C.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Palano, A.; Palombo, F.; Palutan, M.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Pappenheimer, C.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Altarelli, M. Pepe; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilar, T.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Navarro, A. Puig; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Perez, P. Rodriguez; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M-H; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Siddi, B. G.; Coutinho, R. Silva; Silva de Oliveira, L.; Simi, G.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smiih, E.; Smith, I. T.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefkova, S.; Steinkamp, O.; Stenyakin, O.; Stevenson, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Teklishyn, M.; Tellarini, G.; Teubert, F.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Todd, J.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Gomez, R. Vazquez; Vazquez Regueiro, P.; Vazquez Sierra, C.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voss, C.; Waldi, R.; Wallace, C.; Wallace, R.; Wandernoth, S.; Ward, D. R.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wilkinson, G.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wyllie, K.; Xie, Y.; Yang, Z.; Yu, J.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhelezov, A.; Zhokhov, A.; Zhong, L.; Zhukov, V.; Zucchelli, S.

    2016-01-01

    The oscillation frequency, Delta m(d), of B-0 mesons is measured using semileptonic decays with a D- or D*(-) meson in the final state. The data sample corresponds to 3.0 fb(-1) of pp collisions, collected by the LHCb experiment at centre-of-mass energies root s = 7 and 8 TeV. A combination of the

  11. Meson Spectra: Power Law Potential Model in the Dirac Equation ...

    African Journals Online (AJOL)

    A single mass-spectra potential model has been used to predict the spectra of both light and heavy mesons (including leptonic decay-widths) in the Dirac equation. In fact a power law potential has been proposed with effective power where is the mass of the constituent quarks (in GeV) of the mesons considered.

  12. Mesonic and isobar modes in matter

    Energy Technology Data Exchange (ETDEWEB)

    Riek, Felix C.

    2007-07-01

    Experiments with heavy ion collisions, like the ones performed at the GSI, are a tool to gain insight in the structure of matter. One key point needed to understand the experimental data is the theoretical description of the in medium properties of mesons and baryons. In this thesis we first developed a self-consistent description for the light vector mesons, {rho} and {omega}, and the pion at finite temperature and in a baryon free environment. A generalisation of these calculations towards finite densities mandatorily needs a reliable description for the pion and the {delta}(1232) resonance. Here we extended the approaches discussed in literature by the inclusion of vertex corrections and a selfconsistent and completely relativistic description. Within these models we were able to show that even at high temperatures the {rho}-meson properties are not changed dramatically when temperature effects are considered only. In contrast to this the behaviour of the pion and the {delta}-isobar is dramatically changed a finite density. The isobar mass-shift is given by an appropriate choice of the mean-fields. Therefore we can not draw a final conclusion about such shifts within our model. In order to do so more calculations, especially of the photo absorption on the nucleus, have to be performed. A further aspect of the calculations presented is that due to a consistent consideration of vertex corrections we were able to achieve a description of the {delta}-resonance without the usually used soft formfactor. This is especially important for the in-medium calculations because only in this way we can guarantee that soft modes of the spectrum are treated consistently. The techniques developed within this thesis allow for a straight forward generalisation of the presented models with respect to the consideration of more resonances or couplings. Doing so the here obtained description of the in-medium properties of the considered particles can be refined. (orig.)

  13. Leptonic Decays of Charged Pseudoscalar Mesons - 2015

    Energy Technology Data Exchange (ETDEWEB)

    Rosner, Jonathan L. [Chicago U., EFI; Stone, Sheldon [Syracuse U.; Van de Water, Ruth S. [Fermilab

    2015-09-07

    We review the physics of purely leptonic decays of $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of the constituent quarks and a strong interaction parameter related to the overlap of the quark and antiquark wave-functions in the meson, called the decay constant $f_P$. The leptonic decay constants for $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ mesons can be obtained with controlled theoretical uncertainties and high precision from {\\it ab initio} lattice-QCD simulations. The combination of experimental leptonic decay-rate measurements and theoretical decay-constant calculations enables the determination of several elements of the CKM matrix within the standard model. These determinations are competitive with those obtained from semileptonic decays, and also complementary because they are sensitive to different quark flavor-changing currents. They can also be used to test the unitarity of the first and second rows of the CKM matrix. Conversely, taking the CKM elements predicted by unitarity, one can infer "experimental" values for $f_P$ that can be compared with theory. These provide tests of lattice-QCD methods, provided new-physics contributions to leptonic decays are negligible at the current level of precision. This review is the basis of the article in the Particle Data Group's 2016 edition, updating the versions in Refs. [1-3].

  14. Voriconazole N-oxide and its UVB photoproduct sensitize keratinocytes to UVA

    Science.gov (United States)

    Ona-Vu, K.; Oh, D.H.

    2015-01-01

    Background The antifungal agent, voriconazole, is associated with phototoxicity and photocarcinogenicity. Prior work has indicated that voriconazole and its hepatic N-oxide metabolite do not sensitize keratinocytes to ultraviolet B (UVB). Clinical observations have suggested ultraviolet A (UVA) may be involved. Objectives To determine the photochemistry and photobiology of voriconazole and its major hepatic metabolite, voriconazole N-oxide. Methods Voriconazole and voriconazole N-oxide were spectrophotometrically monitored following various doses of UVB. Cultured human keratinocytes were treated with parental drugs or with their UVB photoproducts, and survival following UVA irradiation was measured by thiazolyl blue metabolism. Reactive oxygen species and 8-oxoguanine were monitored by fluorescence microscopy. Results Voriconazole and voriconazole N-oxide have varying ultraviolet B (UVB) absorption but do not acutely sensitize cultured human keratinocytes following UVB exposure. However, sustained UVB exposures produced notable dose- and solvent-dependent changes in the absorption spectra of voriconazole N-oxide which in aqueous solution acquires a prominent ultraviolet A (UVA) absorption band, suggesting formation of a discrete photoproduct. Neither the parental drugs nor their photoproducts sensitized cells to UVB though all but voriconazole N-oxide were moderately toxic to cells in the dark. Notably, both voriconazole N-oxide and its UVB photoproduct, but not voriconazole or its photoproduct, additionally sensitized cells to UVA by >3-fold relative to controls in association with UVA-induced reactive oxygen species and 8-oxoguanine levels. Conclusions Voriconazole N-oxide and its UVB-photoproduct act as UVA-sensitizers that generate reactive oxygen species and that produce oxidative DNA damage. These results suggest a mechanism for the phototoxicity and photocarcinogenicity observed with voriconazole treatment. PMID:25919127

  15. Holographic corrections to meson scattering amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Armoni, Adi; Ireson, Edwin, E-mail: 746616@swansea.ac.uk

    2017-06-15

    We compute meson scattering amplitudes using the holographic duality between confining gauge theories and string theory, in order to consider holographic corrections to the Veneziano amplitude and associated higher-point functions. The generic nature of such computations is explained, thanks to the well-understood nature of confining string backgrounds, and two different examples of the calculation in given backgrounds are used to illustrate the details. The effect we discover, whilst only qualitative, is re-obtainable in many such examples, in four-point but also higher point amplitudes.

  16. Spectroscopic properties of the B meson

    Directory of Open Access Journals (Sweden)

    Devlani Nayneshkumar

    2015-01-01

    Full Text Available Investigation of the B(bq̄; q = u, d meson properties is carried out using variational method within phenomenological quark antiquark potential(coulomb plus power model using the Gaussian wave function. O(1/m correction to the potential energy term and relativistic corrections to the kinetic energy term of the hamiltonian are incorporated. Spin-orbit, spin-spin and tensor interactions are employed to obtain the mass spectra. Various other properties such as the decay constants, e1 and m1 transitions are also obtained

  17. Theoretical aspects of light meson spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, T. [Oak Ridge National Lab., TN (United States). Computational and Theoretical Physics Group]|[Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy

    1995-12-31

    In this pedagogical review the authors discuss the theoretical understanding of light hadron spectroscopy in terms of QCD and the quark model. They begin with a summary of the known and surmised properties of QCD and confinement. Following this they review the nonrelativistic quark potential model for q{anti q} mesons and discuss the quarkonium spectrum and methods for identifying q{anti q} states. Finally, they review theoretical expectations for non-q{anti q} states (glueballs, hybrids and multiquark systems) and the status of experimental candidates for these states.

  18. Isoscalar meson spectroscopy from lattice QCD

    CERN Document Server

    Dudek, Jozef J; Joo, Balint; Peardon, Michael J; Richards, David G; Thomas, Christopher E

    2011-01-01

    We extract to high statistical precision an excited spectrum of single-particle isoscalar mesons using lattice QCD, including states of high spin and, for the first time, light exotic JPC isoscalars. The use of a novel quark field construction has enabled us to overcome the long-standing challenge of efficiently including quark-annihilation contributions. Hidden-flavor mixing angles are extracted and while most states are found to be close to ideally flavor mixed, there are examples of large mixing in the pseudoscalar and axial sectors in line with experiment. The exotic JPC isoscalar states appear at a mass scale comparable to the exotic isovector states.

  19. 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.

  20. Couplings between the ρ and D and D* mesons

    Science.gov (United States)

    El-Bennich, Bruno; Paracha, M. Ali; Roberts, Craig D.; Rojas, Eduardo

    2017-02-01

    We compute couplings between the ρ -meson and D and D* mesons—D(*)ρ D(*)—that are relevant to phenomenological meson-exchange models used to analyze nucleon-D -meson scattering and explore the possibility of exotic charmed nuclei. Our framework is built from elements constrained by Dyson-Schwinger equation studies in QCD, and therefore expresses a simultaneous description of light- and heavy-quarks and the states they constitute. We find that all interactions, including the three independent D*ρ D* couplings, differ markedly amongst themselves in strength and also in range, as measured by their evolution with ρ -meson virtuality. As a consequence, it appears that one should be cautious in using a single coupling strength or parametrization for the study of interactions between D(*) mesons and matter.

  1. Photoproduction of events with rapidity gaps between jets with ZEUS at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, P.D.

    2006-11-15

    Cross sections for the photoproduction of dijet events, where the two jets with the highest transverse energy are separated by a large gap in pseudorapidity, have been studied with the ZEUS detector using an integrated luminosity of 38.6 pb{sup -1}. Rapidity-gap events are defined in terms of the energy flow between the jets, such that the total summed transverse energy in this region is less than some value E{sup CUT}{sub T}. The data show a clear excess above the predictions of standard photoproduction models. Models which include color-singlet exchange are able to describe the data. (orig.)

  2. Crossing symmetry and phenomenological widths in effective Lagrangian models of the pion photoproduction process

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Ramirez, C. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain)], E-mail: cesar@nuc2.fis.ucm.es; Moya de Guerra, E. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain); Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain); Udias, J.M. [Grupo de Fisica Nuclear, Departamento de Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain)

    2008-02-21

    We investigate the importance of crossing symmetry in effective field models and the effects of phenomenological nucleon resonance widths on the paradigmatic case of pion photoproduction. We use reaction models containing four star resonances up to 1.8 GeV ({delta}(1232), N(1440), N(1520), N(1535), {delta}(1620), N(1650), {delta}(1700), and N(1720)) with different prescriptions for crossed terms and widths, to fit the latest world database on pion photoproduction. We compare {chi}{sup 2} results from selected multipoles and fits. The {chi}{sup 2} is highly dependent on the fulfillment of crossing symmetry and the inclusion of u channels.

  3. Complete next-to-leading-order corrections to J/psi photoproduction in nonrelativistic quantum chromodynamics.

    Science.gov (United States)

    Butenschön, Mathias; Kniehl, Bernd A

    2010-02-19

    We calculate the cross section of inclusive direct J/psi photoproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics for the first time including the full relativistic corrections due to the intermediate {1}S{0}{[8]}, {3}S{1}{[8]}, and {3}P{J}{[8]} color-octet states. A comparison of our results to recent H1 data suggests that the color-octet mechanism is indeed realized in J/psi photoproduction, although the predictivity of our results still suffers from uncertainties in the color-octet long-distance matrix elements.

  4. Precision measurement of $D$ meson mass differences

    CERN Document Server

    INSPIRE-00258707; Abellan Beteta, C; Adeva, B; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves Jr, A A; Amato, S; Amerio, S; Amhis, Y; Anderlini, L; Anderson, J; Andreassen, R; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Baesso, C; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bauer, Th; Bay, A; Beddow, J; Bedeschi, F; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Benayoun, M; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bettler, M -O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bowen, E; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brook, N H; Brown, H; Burducea, I; Bursche, A; Busetto, G; Buytaert, J; Cadeddu, S; Callot, O; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Campora Perez, D; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carranza-Mejia, H; Carson, L; Carvalho Akiba, K; Casse, G; Cattaneo, M; Cauet, Ch; Charles, M; Charpentier, Ph; Chen, P; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coca, C; Coco, V; Cogan, J; Cogneras, E; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Couturier, B; Cowan, G A; Craik, D C; Cunliffe, S; Currie, R; D'Ambrosio, C; David, P; David, P N Y; Davis, A; De Bonis, I; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Silva, W; De Simone, P; Decamp, D; Deckenhoff, M; Del Buono, L; Derkach, D; Deschamps, O; Dettori, F; Di Canto, A; Dijkstra, H; Dogaru, M; Donleavy, S; Dordei, F; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dupertuis, F; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; 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Tisserand, V; Tobin, M; Tolk, S; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tresch, M; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ubeda Garcia, M; Ukleja, A; Urner, D; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vilasis-Cardona, X; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; Waldi, R; Wallace, R; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Webber, A D; Websdale, D; Whitehead, M; Wicht, J; Wiechczynski, J; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, F; Xing, Z; Yang, Z; Young, R; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhokhov, A; Zhong, L; Zvyagin, A

    2013-01-01

    Using three- and four-body decays of $D$ mesons produced in semileptonic $b$-hadron decays, precision measurements of $D$ meson mass differences are made together with a measurement of the $D^{0}$ mass. The measurements are based on a dataset corresponding to an integrated luminosity of 1.0 fb$^{-1}$ collected in $pp$ collisions at 7~TeV. Using the decay $D^0 \\rightarrow K^{+} K^{-} K^{-} \\pi^{+}$, the $D^0$ mass is measured to be \\begin{alignat*}{3} M(D^0) \\phantom{ghd} &=&~1864.75 \\pm 0.15 \\,({\\rm stat}) \\pm 0.11 \\,({\\rm syst}) \\, \\textrm{MeV}/c^2. \\end{alignat*} The mass differences \\begin{alignat*}{3} M(D^{+}) - M(D^{0}) &=& 4.76 \\pm 0.12 \\,({\\rm stat}) \\pm 0.07 \\,({\\rm syst}) \\, \\textrm{MeV}/c^2, \\\\ M(D^{+}_s) - M(D^{+}) &=& \\phantom{00}98.68 \\pm 0.03 \\,({\\rm stat}) \\pm 0.04 \\,({\\rm syst}) \\, \\textrm{MeV}/c^2 \\end{alignat*} are measured using the $D^0 \\rightarrow K^{+} K^{-} \\pi^{+} \\pi^{-}$ and $D^{+}_{(s)} \\rightarrow K^{+}K^{-} \\pi^{+}$ modes.

  5. Constraining New Physics with D meson decays

    Energy Technology Data Exchange (ETDEWEB)

    Barranco, J.; Delepine, D.; Gonzalez Macias, V. [Departamento de Física, División de Ciencias e Ingeniería, Universidad de Guanajuato, Campus León, León 37150 (Mexico); Lopez-Lozano, L. [Departamento de Física, División de Ciencias e Ingeniería, Universidad de Guanajuato, Campus León, León 37150 (Mexico); Área Académica de Matemáticas y Física, Universidad Autónoma del Estado de Hidalgo, Carr. Pachuca-Tulancingo Km. 4.5, C.P. 42184, Pachuca, HGO (Mexico)

    2014-04-04

    Latest Lattice results on D form factors evaluation from first principles show that the Standard Model (SM) branching ratios prediction for the leptonic D{sub s}→ℓν{sub ℓ} decays and the semileptonic SM branching ratios of the D{sup 0} and D{sup +} meson decays are in good agreement with the world average experimental measurements. It is possible to disprove New Physics hypothesis or find bounds over several models beyond the SM. Using the observed leptonic and semileptonic branching ratios for the D meson decays, we performed a combined analysis to constrain non-standard interactions which mediate the cs{sup ¯}→lν{sup ¯} transition. This is done either by a model-independent way through the corresponding Wilson coefficients or in a model-dependent way by finding the respective bounds over the relevant parameters for some models beyond the Standard Model. In particular, we obtain bounds for the Two Higgs Doublet Model Type-II and Type III, the Left–Right model, the Minimal Supersymmetric Standard Model with explicit R-parity violation and Leptoquarks. Finally, we estimate the transverse polarization of the lepton in the D{sup 0} decay and we found it can be as high as P{sub T}=0.23.

  6. Light-Meson Spectroscopy at COMPASS

    CERN Document Server

    Krinner, Fabian

    2017-01-01

    The goal of the COMPASS experiment at CERN is to study the structure and spectroscopy of hadrons. The two-stage spectrometer has large acceptance and covers a wide kinematic range for charged as well as neutral particles allowing to access a wide range of reactions. Light mesons are studied with negative (mostly $\\pi^-$) and positive ($p$, $\\pi^+$) hadron beams with a momentum of $190\\,\\text{GeV}/c$. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer $t$ to the target between $0.1$ and $1.0\\,(\\text{GeV}/c)^2$. The flagship channel is the $\\pi^-\\pi^+\\pi^-$ final state, for which COMPASS has recorded the currently world's largest data sample. These data not only allow us to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new axial-vector signal, the $a_1(1420)$, with unusual properties. The findings are confirmed by the analysis of the $\\pi^-\\pi^0\\pi^...

  7. Light-Meson Spectroscopy with COMPASS

    CERN Document Server

    Grube, Boris

    2010-01-01

    COMPASS is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron investigating the structure and spectrum of hadrons. One primary goal is the search for new hadronic states, in particular spin-exotic mesons and glueballs. After a short pilot run in 2004 with a 190 GeV/c $\\pi^-$ beam on a Pb target, which showed a significant spin-exotic $J^{PC} = 1^{-+}$ resonance consistent with the controversial $\\pi_1(1600)$, COMPASS collected large data samples with negative and positive hadron beams on H$_2$, Ni, W, and Pb targets in 2008 and 2009. We present results from a partial-wave analysis of diffractive dissociation of 190 GeV/c $\\pi^-$ into $\\pi^-\\pi^+\\pi^-$ final states on Pb and H$_2$ targets with squared four-momentum transfer in the range 0.1 < t' < 1 (GeV/c)^2. This reaction provides clean access to the light-quark meson spectrum up to masses of 2.5 GeV/c^2. A first comparison of the data from Pb and H$_2$ target shows a strong target dependence of the production strength of stat...

  8. The phi-meson and Chiral-mass-meson production in heavy-ion collisions as potential probes of quark-gluon-plasma and Chiral symmetry transitions

    Science.gov (United States)

    Takahashi, Y.; Eby, P. B.

    1985-01-01

    Possibilities of observing abundances of phi mesons and narrow hadronic pairs, as results of QGP and Chiral transitions, are considered for nucleus-nucleus interactions. Kinematical requirements in forming close pairs are satisfied in K+K decays of S(975) and delta (980) mesons with small phi, and phi (91020) mesons with large PT, and in pi-pi decays of familiar resonance mesons only in a partially restored chiral symmetry. Gluon-gluon dominance in QGP can enhance phi meson production. High hadronization rates of primordial resonance mesons which form narrow hadronic pairs are not implausible. Past cosmic ray evidences of anomalous phi production and narrow pair abundances are considered.

  9. Photoproduction of W Bosons at HERA Reweighting Method for implementing QCD Corrections in Monte Carlo Programs

    CERN Document Server

    Diener, K P O; Spira, Michael; Diener, Kai-Peer O.; Schwanenberger, Christian; Spira, Michael

    2003-01-01

    A procedure of implementing QCD corrections in Monte Carlo programs by a reweighting method is described for the photoproduction of W bosons at HERA. Tables for W boson production in LO and NLO are given in bins of the transverse momentum of the W boson and its rapidity.

  10. UV Resonance Raman Investigation of Pentaerythritol Tetranitrate Solution Photochemistry and Photoproduct Hydrolysis.

    Science.gov (United States)

    Gares, Katie L; Bykov, Sergei V; Asher, Sanford A

    2017-10-19

    Ultraviolet resonance Raman spectroscopy (UVRR) is being developed for standoff trace explosives detection. To accomplish this, it is important to develop a deep understanding of the accompanying UV excited photochemistry of explosives, as well as the impact of reactions on the resulting photoproducts. In the work here we used 229 nm excited UVRR spectroscopy to monitor the photochemistry of pentaerythritol tetranitrate (PETN) in acetonitrile. We find that solutions of PETN in CD3CN photodegrade with a quantum yield of 0.08 ± 0.02, as measured by high performance liquid chromatography (HPLC). The initial step in the 229 nm UV photolysis of PETN in CD3CN is cleavage of an O-NO2 bond to form NO2. The accompanying photoproduct is pentaerythritol trinitrate (PETriN), (CH2ONO2)3CCH2OH formed by photolysis of a single O-NO2. The resulting UVRR spectra show a dominant photoproduct band at ∼1308 cm-1, which derives from the symmetric stretch of dissolved NO2. This photoproduct NO2 is hydrolyzed by trace amounts of water, which downshifts this 1308 cm-1 NO2 Raman band due to the formation of molecular HNO3. The dissociation of HNO3 to NO3- in the presence of additional water results in an intense NO3- symmetric stretching UVRR band at 1044 cm-1.

  11. Measurement of prompt photons with associated jets in photoproduction at HERA

    NARCIS (Netherlands)

    Chekanov, S.; Kooijman, P.

    2007-01-01

    The photoproduction of prompt photons, together with an accompanying jet, has been studied in ep collisions at a centre-of-mass energy of 318 GeV with the ZEUS detector at HERA using an integrated luminosity of 77 pb-1. Cross sections were measured for the transverse energy of the photon and the jet

  12. Rho0 Photoproduction in Ultra-Peripheral Relativistic Heavy Ion Collisions with STAR

    Energy Technology Data Exchange (ETDEWEB)

    STAR Coll

    2007-12-20

    Photoproduction reactions occur when the electromagnetic field of a relativistic heavy ion interacts with another heavy ion. The STAR collaboration presents a measurement of {rho}{sup 0} and direct {pi}{sup +}{pi}{sup -} photoproduction in ultra-peripheral relativistic heavy ion collisions at {radical}s{sub NN} = 200 GeV. We observe both exclusive photoproduction and photoproduction accompanied by mutual Coulomb excitation. We find a coherent cross-section of {sigma}(AuAu {yields} Au*Au* {rho}{sup 0}) = 530 {+-} 19 (stat.) {+-} 57 (syst.) mb, in accord with theoretical calculations based on a Glauber approach, but considerably below the predictions of a color dipole model. The {rho}{sup 0} transverse momentum spectrum (p{sub T}{sup 2}) is fit by a double exponential curve including both coherent and incoherent coupling to the target nucleus; we find {sigma}{sub inc}/{sigma}{sub coh} = 0.29 {+-} 0.03 (stat.) {+-} 0.08 (syst.). The ratio of direct {pi}{sup +}{pi}{sup -} production is comparable to that observed in {gamma}p collisions at HERA, and appears to be independent of photon energy. Finally, the measured {rho}{sup 0} spin helicity matrix elements agree within errors with the expected s-channel helicity conservation.

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

    NARCIS (Netherlands)

    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.; Samson, U.; Schoenberg, V.; Shehzadi, R.; Wlasenko, M.; Brook, N. H.; Heath, G. P.; Kaur, M.; Kaur, P.; Singh, I.; Capua, M.; Fazio, S.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Tassi, E.; Kim, J. Y.; Ibrahim, Z. A.; Idris, F. Mohamad; Kamaluddin, B.; Abdullah, W. A. T. Wan; Ning, Y.; Ren, Z.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Galas, A.; Olkiewicz, K.; Pawlik, B.; Stopa, P.; Zawiejski, L.; Adamczyk, L.; Bold, T.; Grabowska-Bold, I.; Kisielewska, D.; Lukasik, J.; Przybycien, M.; Suszycki, L.; Kotanski, A.; Slominski, W.; Behnke, O.; Behrens, U.; Blohm, C.; Bonato, A.; Borras, K.; Ciesielski, R.; Coppola, N.; 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.; Lisovyi, M.; 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.; Schneekloth, U.; Spiridonov, A.; Szuba, D.; Szuba, J.; Theedt, T.; Ukleja, J.; Wolf, G.; Wrona, K.; Molina, A. G. Yaguees; 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.; Perrey, H.; 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.; Lontkovskyi, D.; Makarenko, I.; Sorokin, Iu.; Verbytskyi, A.; Volynets, O.; Son, D.; de Favereau, J.; Piotrzkowski, K.; Barreiro, F.; Glasman, C.; Jimenez, M.; Labarga, L.; del Peso, J.; Ron, E.; Soares, M.; Terron, J.; Uribe-Estrada, C.; Corriveau, F.; Schwartz, J.; Walsh, R.; 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.; Kooijman, P.; Pellegrino, A.; Tiecke, H.; Vazquez, M.; 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.; Gwenlan, C.; Horton, K.; Oliver, K.; Robertson, A.; 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.; Whitmore, J. J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cole, J. E.; Hart, J. C.; Abramowicz, H.; Ingbir, R.; Kananov, S.; Stern, A.; Kuze, M.; Maeda, J.; Hori, R.; Kagawa, S.; Okazaki, N.; Tawara, T.; Hamatsu, R.; Kaji, H.; Kitamura, S.; Ota, O.; Ri, Y. D.; Costa, M.; Ferrero, M. I.; Monaco, V.; Sacchi, R.; Sola, V.; Solano, A.; Arneodo, M.; Ruspa, M.; Fourletov, S.; Stewart, T. P.; Boutle, S. K.; Butterworth, J. M.; Hall-Wilton, R.; Jones, T. W.; Loizides, J. H.; Wing, M.; Brzozowska, B.; Ciborowski, J.; Grzelak, G.; Kulinski, P.; Luzniak, P.; Malka, J.; Nowak, R. J.; Pawlak, J. M.; Perlanski, W.; Tymieniecka, T.; Zarnecki, A. F.; Adamus, M.; Plucinski, P.; Ukleja, A.; Eisenberg, Y.; Hochman, D.; Karshon, U.; Brownson, E.; Reeder, D. D.; Savin, A. A.; Smith, W. H.; Wolfe, H.; Bhadra, S.; Catterall, C. D.; Hartner, G.; Menary, S.; Noor, U.; Standage, J.; Whyte, J.

    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

  14. Helicity Asymmetry Measurement for π0 Photoproduction with FROST

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, Hideko [George Washington Univ., Washington, DC (United States)

    2011-08-15

    This thesis reports on the first helicity asymmetry measurement for single neutral pion photoproduction using the CLAS detector in Hall B at the Thomas Jefferson National Accelerator Facility (JLab). This measurement used longitudinally polarized protons and circularly polarized photons at energies between 350 MeV and 2400 MeV. The experimental results are compared to three available model calculations.

  15. Helicity Asymmetry Measurement for pi0 Photoproduction with FROST

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, Hideko [George Washington Univ., Washington, DC (United States)

    2011-08-15

    This thesis reports on the first helicity asymmetry measurement for single neutral pion photoproduction using the CLAS detector in Hall B at the Thomas Jefferson National Accelerator Facility (JLab). This measurement used longitudinally polarized protons and circularly polarized photons at energies between 350 MeV and 2400 MeV. The experimental results are compared to three available model calculations.

  16. Scaled momentum distributions of charged particles in dijet photoproduction at HERA

    NARCIS (Netherlands)

    Chekanov, S.; Kooijman, P.|info:eu-repo/dai/nl/068449542

    2009-01-01

    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

  17. 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.

  18. 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

    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.

  19. K meson leptonic decays progress in nuclear physics

    CERN Document Server

    Bailey, J; Jones, P B; Brink, D M; Mulvey, J H

    2013-01-01

    Progress in Nuclear Physics, Volume 12, Part 1: K Meson Leptonic Decay: The Anomalous Magnetic Moment of the Muon and Related Topics focuses on K Meson leptonic decay. The volume first discusses K Meson leptonic decay, including weak hadronic current, polarization of the muon, form of coupling, rate of partial decay, and density function of the Dalitz plot. The text then takes a look at the anomalous magnetic moment of the muon and other topics. The theory of the anomalous magnetic moment of electrons and muon and clock paradox, including muon and special relativity and lifetime of the muon in

  20. Absorption of the omega and phi Mesons in Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    M. H. Wood, R. Nasseripour, M. Paolone, C. Djalali, D. P. Weygand, the CLAS Collaboration

    2010-09-01

    Due to their long lifetimes, the $\\omega$ and $\\phi$ mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from $^{2}$H, C, Ti, Fe, and Pb targets. This paper reports the first measurement of the ratio of nuclear transparencies for the $e^{+}e^{-}$ channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels.

  1. Spectrally resolved efficiencies of carbon monoxide (CO photoproduction in the western Canadian Arctic: particles versus solutes

    Directory of Open Access Journals (Sweden)

    G. Song

    2013-06-01

    Full Text Available Spectrally resolved efficiency (i.e. apparent quantum yield, AQY of carbon monoxide (CO photoproduction is a useful indicator of substrate photoreactivity and a crucial parameter for modeling CO photoproduction rates in the water column. Recent evidence has suggested that CO photoproduction from particles in marine waters is significant compared to the well-known CO production from chromophoric dissolved organic matter (CDOM photodegradation. Although CDOM-based CO AQY spectra have been extensively determined, little is known of this information on the particulate phase. Using water samples collected from the Mackenzie estuary, shelf, and Canada Basin in the southeastern Beaufort Sea, the present study for the first time quantified the AQY spectra of particle-based CO photoproduction and compared them with the concomitantly determined CDOM-based CO AQY spectra. CO AQYs of both particles and CDOM decreased with wavelength but the spectral shape of the particulate AQY was flatter in the visible regime. This feature resulted in a disproportionally higher visible light-driven CO production by particles, thereby increasing the ratio of particle- to CDOM-based CO photoproduction with depth in the euphotic zone. In terms of depth-integrated production in the euphotic zone, CO formation from CDOM was dominated by the ultraviolet (UV, 290–400 nm radiation whereas UV and visible light played roughly equal roles in CO production from particles. Spatially, CO AQY of bulk particulate matter (i.e. the sum of organics and inorganics augmented from the estuary and shelf to the basin while CO AQY of CDOM trended inversely. Water from the deep chlorophyll maximum layer revealed higher CO AQYs than did surface water for both particles and CDOM. CO AQY of bulk particulate matter exceeded that of CDOM on the shelf and in the basin, but the sequence reversed in the estuary. Without consideration of the potential role of metal oxides (e.g. iron oxides in particle

  2. Antiproton-proton annihilation into charged light meson pairs within effective meson theory

    Science.gov (United States)

    Wang, Ying; Bystritskiy, Yury M.; Tomasi-Gustafsson, Egle

    2017-04-01

    We revisit antiproton-proton annihilation into light mesons in the energy domain relevant to the antiproton annihilation at Darmstadt (PANDA) experiment at the GSI Facility for Antiproton and Ion Research (FAIR) [2.25 (1.5 ) ≤√{s }(pL) ≤5.47 (15 ) GeV (GeV /c ) where √{s }(pL) is the total energy (the beam momentum in the laboratory frame)]. An effective meson model is developed, with mesonic and baryonic degrees of freedom. Form factors are added to take into account the composite nature of the interacting hadrons. A comparison is made with the existing data for charged pion pair production and predictions for angular distributions and energy dependence in the range 3.362 (5 ) ≤√{s }(pL) ≤4.559 (10.1 ) GeV (GeV /c ). The model is applied to π±p elastic scattering, using crossing symmetry, and to charged kaon pair production, on the basis of SU(3) symmetry. In all cases the results illustrate a nice agreement with the data.

  3. Dijets in photoproduction and soft multiparton interactions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Naumann, S.

    2007-07-15

    Dijet events in photoproduction at HERA have been studied using data collected with the ZEUS detector in the period 1998-2000 that correspond to an integrated luminosity of 81.7 pb{sup -1}. The events have been selected in a kinematic region defined by restricting the virtuality of the incoming photon, Q{sup 2}, to Q{sup 2}<1 GeV{sup 2} and its inelasticity, y, to 0.214 GeV and E{sub T,2}>11 GeV in each event. Cross sections measured for this inclusive dijet sample have been compared to results obtained in data from the 1996-1997 period. Another sample of dijet events has been obtained using the transverse-energy requirements E{sub T,1}>10 GeV and E{sub T,2}>8 GeV, demanding additionally that the two jets are roughly back-to-back in the azimuthal plane and have almost equal transverse energies and that no third hard jet is found in the event. All results have been compared to leading-order Monte Carlo predictions. The transverse energy in the region between the jets shows a large sensitivity to multiparton interactions, allowing parameters of the corresponding models to be tested. The measurement suggests that multiparton interactions are needed to describe the data. The analysis presented here contains the most comprehensive study of soft multiparton interactions at ZEUS to date. (orig.)

  4. Open charm meson production at LHC*

    Directory of Open Access Journals (Sweden)

    Luszczak Marta

    2012-12-01

    Full Text Available We discuss charm production at the LHC. The production of single cc¯$car c$ pairs is calculated in the kt-factorization approach. We use Kimber-Martin-Ryskin unintegrated gluon distributions in the proton. The hadronization is included with the help of Peterson fragmentation functions. Transverse momentum and pseudorapidity distributions of charmed mesons are presented and compared to recent results of the ALICE, LHCb and ATLAS collaborations. Furthermore we discuss production of two pairs of cc¯ $car c$ within a simple formalism of double-parton scattering (DPS. Surprisingly large cross sections, comparable to single-parton scattering (SPS, are predicted for LHC energies. We discuss perspectives how to identify the double scattering contribution. We predict much larger cross section for large rapidity distance between charm quarks from different hard parton scatterings compared to single scattering.

  5. Orientifold Planar Equivalence: The Quenched Meson Spectrum

    CERN Document Server

    Lucini, Biagio; Patella, Agostino; Rago, Antonio

    2010-01-01

    A numerical study of Orientifold Planar Equivalence is performed in SU(N) Yang-Mills theories for N=2,3,4,6. Quenched meson masses are extracted in the antisymmetric, symmetric and adjoint representations for the pseudoscalar and vector channels. An extrapolation of the vector mass as a function of the pseudoscalar mass to the large-N limit shows that the numerical results agree within errors for the three theories, as predicted by Orientifold Planar Equivalence. As a byproduct of the extrapolation, the size of the corrections up to O(1/N^3) are evaluated. A crucial prerequisite for the extrapolation is the determination of an analytical relationship between the corrections in the symmetric and in the antisymmetric representations, order by order in a 1/N expansion.

  6. Light-Meson Spectroscopy at Compass

    Directory of Open Access Journals (Sweden)

    Krinner Fabian

    2017-01-01

    The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer t to the target between 0.1 and 1.0 (GeV/c2. The flagship channel is the π−π+π− final state, for which Compass has recorded the currently world’s largest data sample. These data not only allow us to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new axial-vector signal, the a1(1420, with unusual properties. The findings are confirmed by the analysis of the π−π0π0 final state.

  7. Moscow Meson Factory DTL RF System Upgrade

    CERN Document Server

    Esin, S K; Kvasha, A I; Serov, V L

    2004-01-01

    The last paper devoted to description of the first part (DTL) RF system of Moscow Meson Factory upgrade was published in the Proceedings of PAC95 Conference in Dallas. Since then some new works directed at improvement of reliability and efficiency of the RF system were carried out. Among them there are a new powerful pulse triode “Katran” installed in the output RF power amplifiers (PA) of three channels, modifications of the anode modulator control circuit and crow-bar system, a new additional RF channel for RF supply of RFQ and some alterations in placing of the anode modulator equipment decreasing a level of interference’s at crow-bar circuits. Some new checked at MMF RF channels ideas concerning of PA tuning are of interest for people working in this sphere of activity.

  8. Improved measurement of the B 0 and B + meson lifetimes

    Science.gov (United States)

    Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J. P.; Lucotte, A.; Minard, M. N.; Odier, P.; Pietrzyk, B.; Casado, M. P.; Chmeissani, M.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, L.; Juste, A.; Martinez, M.; Orteu, S.; Pacheco, A.; Padilla, C.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Alemany, R.; Bazarko, A. O.; Bonvicini, G.; Cattaneo, M.; Comas, P.; Coyle, P.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Martin, E. B.; Mato, P.; Minten, A.; Miquel, R.; Mir, Ll. M.; Moneta, L.; Oest, T.; Palla, F.; Pater, J. R.; Pusztaszeri, J. F.; Ranjard, F.; Rensing, P.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wagner, A.; Wildish, T.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rossignol, J. M.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Wäänänen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Thompson, A. S.; Thomson, F.; Thorn, S.; Turnbull, R. M.; Becker, U.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Rensch, B.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Abbaneo, D.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Moutoussi, A.; Nash, J.; Sedgbeer, J. K.; Stacey, A. M.; Williams, M. D.; Dissertori, G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A. P.; Bowdery, C. K.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Sloan, T.; Williams, M. I.; Galla, A.; Greene, A. M.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H. G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Abt, I.; Assmann, R.; Bauer, C.; Blum, W.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Jakobs, K.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H. G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; St. Denis, R.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J. F.; Heusse, Ph.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A. M.; Nikolic, I.; Park, H. J.; Park, I. C.; Schune, M. H.; Simion, S.; Veillet, J. J.; Videau, I.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Rizzo, G.; Sanguinetti, G.; Sciabà, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Verdini, P. G.; Walsh, J.; Blair, G. A.; Bryant, L. M.; Cerutti, F.; Chambers, J. T.; Gao, Y.; Green, M. G.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Maley, P.; Norton, P. R.; Thompson, J. C.; Wright, A. E.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J. F.; Roussarie, A.; Schuller, J. P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Boswell, R.; Brew, C. A. J.; Cartwright, S.; Combley, F.; Koksal, A.; Letho, M.; Newton, W. M.; Reeve, J.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Büscher, V.; Cowan, G.; Grupen, C.; Lutters, G.; Minguet-Rodriguez, J.; Rivera, F.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Bellantoni, L.; Elmer, P.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; González, S.; Grahl, J.; Greening, T. C.; Harton, J. L.; Hayes, O. J.; Hu, H.; McNamara, P. A.; Nachtman, J. M.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Scott, I. J.; Sharma, V.; Walsh, A. M.; Wu, Sau Lan; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.

    1996-03-01

    The lifetimes of the B 0 and B + mesons have been measured with the Aleph detector at LEP, using approximately 3 million hadronic Z decays collected in the period 1991 1994. In the first of three methods, semileptonic decays of B 0 and B + mesons were partially reconstructed by identifying events containing a lepton with an associated D*- orbar D^0 meson. The second method used fully reconstructed B 0 and B + mesons. The third method, used to measure the B 0 lifetime, employed a partial reconstruction technique to identify B 0→ D*- π + X decays. The combined results are begin{gathered} tau _0 = 1.55 ± 0.06 ± 0.03 ps, \\ tau _ + = 1.58 ± 0.09 ± 0.03 ps, \\ tfrac{{tau _ + }}{{tau _0 }} = 1.03 ± 0.08 ± 0.02. \\ .

  9. Measurement of the B0 and B- meson lifetimes

    Science.gov (United States)

    Barate, R.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Merle, E.; Minard, M.-N.; Pietrzyk, B.; Bravo, S.; Casado, M. P.; Chmeissani, M.; Crespo, J. M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, L.; Graugés, E.; Martinez, M.; Merino, G.; Miquel, R.; Mir, L. M.; Pacheco, A.; Ruiz, H.; Colaleo, A.; Creanza, D.; de Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Boix, G.; Buchmüller, O.; Cattaneo, M.; Cerutti, F.; Dissertori, G.; Drevermann, H.; Forty, R. W.; Frank, M.; Greening, T. C.; Hansen, J. B.; Harvey, J.; Janot, P.; Jost, B.; Lehraus, I.; Mato, P.; Minten, A.; Moutoussi, A.; Ranjard, F.; Rolandi, L.; Schlatter, D.; Schmitt, M.; Schneider, O.; Spagnolo, P.; Tejessy, W.; Teubert, F.; Tournefier, E.; Wright, A. E.; Ajaltouni, Z.; Badaud, F.; Chazelle, G.; Deschamps, O.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Wäänänen, A.; Daskalakis, G.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Blondel, A.; Bonneaud, G.; Brient, J.-C.; Rougé, A.; Rumpf, M.; Swynghedauw, M.; Verderi, M.; Videau, H.; Focardi, E.; Parrini, G.; Zachariadou, K.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Chiarella, V.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Halley, A. W.; Lynch, J. G.; Negus, P.; O'Shea, V.; Raine, C.; Teixeira-Dias, P.; Thompson, A. S.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Sommer, J.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Girone, M.; Marinelli, N.; Sedgbeer, J. K.; Thompson, J. C.; Thomson, E.; Ghete, V. M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Buck, P. G.; Finch, A. J.; Foster, F.; Hughes, G.; Jones, R. W. L.; Robertson, N. A.; Giehl, I.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.-G.; Wachsmuth, H.; Zeitnitz, C.; Bonissent, A.; Carr, J.; Coyle, P.; Leroy, O.; Payre, P.; Rousseau, D.; Talby, M.; Aleppo, M.; Ragusa, F.; Dietl, H.; Ganis, G.; Heister, A.; Hüttmann, K.; Lütjens, G.; Mannert, C.; Männer, W.; Moser, H.-G.; Schael, S.; Settles, R.; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Azzurri, P.; Boucrot, J.; Callot, O.; Chen, S.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, P.; Jacholkowska, A.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Yuan, C.; Zerwas, D.; Bagliesi, G.; Boccali, T.; Calderini, G.; Ciulli, V.; Foà, L.; Giassi, A.; Ligabue, F.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Sciabà, A.; Sguazzoni, G.; Tenchini, R.; Venturi, A.; Verdini, P. G.; Blair, G. A.; Cowan, G.; Green, M. G.; Medcalf, T.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Clifft, R. W.; Edgecock, T. R.; Norton, P. R.; Tomalin, I. R.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M.-C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Johnson, R. P.; Kim, H. Y.; Konstantinidis, N.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Cartwright, S.; Combley, F.; Lehto, M.; Thompson, L. F.; Affholderbach, K.; Böhrer, A.; Brandt, S.; Grupen, C.; Misiejuk, A.; Prange, G.; Sieler, U.; Giannini, G.; Gobbo, B.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Cranmer, K.; Elmer, P.; Ferguson, D. P. S.; Gao, Y.; González, S.; Hayes, O. J.; Hu, H.; Jin, S.; Kile, J.; McNamara, P. A., III; Nielsen, J.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Scott, I. J.; Walsh, J.; Wu, S.; Wu, X.; Zobernig, G.

    2000-01-01

    The lifetimes of the B0 and B- mesons are measured using a sample of about four million hadronic /Z decays collected from 1991 to 1995 with the Aleph detector at LEP. The data sample has been recently reprocessed, achieving a substantial improvement in the tracking performance. Semileptonic decays of B0 and B- mesons are partially reconstructed by identifying events containing a lepton with an associated D*+ or D0 meson. The proper time of the /B meson is estimated from the measured decay length and the momentum of the /D-lepton system. A fit to the proper time of 1880 D*+l- and 2856 D0l- candidates yields the following results: τB^0=1.518+/-0.053+/-0.034 ps, τB^-=1.648+/-0.049+/-0.035 ps, τB^-/τB^0=1.085+/- 0.059+/-0.018.

  10. Toward the excited isoscalar meson spectrum from lattice QCD

    CERN Document Server

    Dudek, Jozef J; Guo, Peng; Thomas, Christopher E

    2013-01-01

    We report on the extraction of an excited spectrum of isoscalar mesons using lattice QCD. Calculations on several lattice volumes are performed with a range of light quark masses corresponding to pion masses down to about 400 MeV. The distillation method enables us to evaluate the required disconnected contributions with high statistical precision for a large number of meson interpolating fields. We find relatively little mixing between light and strange in most JPC channels; one notable exception is the pseudoscalar sector where the approximate SU(3)F octet, singlet structure of the {\\eta}, {\\eta}' is reproduced. We extract exotic JPC states, identified as hybrid mesons in which an excited gluonic field is coupled to a color-octet qqbar pair, along with non-exotic hybrid mesons embedded in a qqbar-like spectrum.

  11. Exclusive Hard Diffraction at HERA (DVCS and Vector Mesons)

    CERN Document Server

    Marage, P

    2010-01-01

    Recent results obtained at HERA on deeply virtual Compton scattering and exclusive vector meson production are reviewed, with the emphasis on the transition from soft to hard diffraction and on spin dynamics.

  12. Scattering vector mesons in D4/D8 model

    Energy Technology Data Exchange (ETDEWEB)

    Ballon Bayona, C.A., E-mail: ballon@cbpf.b [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, Urca, 22290-180 Rio de Janeiro, RJ (Brazil); Boschi-Filho, Henrique, E-mail: boschi@if.ufrj.b [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Braga, Nelson R.F., E-mail: braga@if.ufrj.b [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Torres, Marcus A.C., E-mail: mtorres@if.ufrj.b [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ (Brazil)

    2010-02-15

    We review in this proceedings some recent results for vector meson form factors obtained using the holographic D4-D8 brane model. The D4-D8 brane model, proposed by Sakai and Sugimoto, is a holographic dual of a semi-realistic strongly coupled large N{sub c} QCD since it breaks supersymmetry and incorporates chiral symmetry breaking. We analyze the vector meson wave functions and Regge trajectories as well.

  13. Observation and Properties of the Orbitally Excited Bs2* Meson

    Science.gov (United States)

    Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T.; Aguilo, E.; Ahn, S. H.; Ahsan, M.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Anastasoaie, M.; Ancu, L. S.; Andeen, T.; Anderson, S.; Andrieu, B.; Anzelc, M. S.; Arnoud, Y.; Arov, M.; Arthaud, M.; Askew, A.; Åsman, B.; Assis Jesus, A. C. S.; Atramentov, O.; Autermann, C.; Avila, C.; Ay, C.; Badaud, F.; Baden, A.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Banerjee, P.; Barberis, E.; Barfuss, A.-F.; Bargassa, P.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bauer, D.; Beale, S.; Bean, A.; Begalli, M.; Begel, M.; Belanger-Champagne, C.; Bellantoni, L.; Bellavance, A.; Benitez, J. A.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Biscarat, C.; Blazey, G.; Blekman, F.; Blessing, S.; Bloch, D.; Bloom, K.; Boehnlein, A.; Boline, D.; Bolton, T. A.; Borissov, G.; Bose, T.; Brandt, A.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Buchanan, N. J.; Buchholz, D.; Buehler, M.; Buescher, V.; Bunichev, S.; Burdin, S.; Burke, S.; Burnett, T. H.; Buszello, C. P.; Butler, J. M.; Calfayan, P.; Calvet, S.; Cammin, J.; Carvalho, W.; Casey, B. C. K.; Cason, N. M.; Castilla-Valdez, H.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chan, K.; Chandra, A.; Charles, F.; Cheu, E.; Chevallier, F.; Cho, D. K.; Choi, S.; Choudhary, B.; Christofek, L.; Christoudias, T.; Cihangir, S.; Claes, D.; Coadou, Y.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Crépé-Renaudin, S.; Cutts, D.; Ćwiok, M.; da Motta, H.; Das, A.; Davies, G.; de, K.; de Jong, S. J.; de La Cruz-Burelo, E.; de Oliveira Martins, C.; Degenhardt, J. D.; Déliot, F.; Demarteau, M.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Diehl, H. T.; Diesburg, M.; Dominguez, A.; Dong, H.; Dudko, L. V.; Duflot, L.; Dugad, S. R.; Duggan, D.; Duperrin, A.; Dyer, J.; Dyshkant, A.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Eno, S.; Ermolov, P.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Ferapontov, A. V.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Ford, M.; Fortner, M.; Fox, H.; Fu, S.; Fuess, S.; Gadfort, T.; Galea, C. F.; Gallas, E.; Galyaev, E.; Garcia, C.; Garcia-Bellido, A.; Gavrilov, V.; Gay, P.; Geist, W.; Gelé, D.; Gerber, C. E.; Gershtein, Y.; Gillberg, D.; Ginther, G.; Gollub, N.; Gómez, B.; Goussiou, A.; Grannis, P. D.; Greenlee, H.; Greenwood, Z. D.; Gregores, E. M.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guo, J.; Guo, F.; Gutierrez, P.; Gutierrez, G.; Haas, A.; Hadley, N. J.; Haefner, P.; Hagopian, S.; Haley, J.; Hall, I.; Hall, R. E.; Han, L.; Hanagaki, K.; Hansson, P.; Harder, K.; Harel, A.; Harrington, R.; Hauptman, J. M.; Hauser, R.; Hays, J.; Hebbeker, T.; Hedin, D.; Hegeman, J. G.; Heinmiller, J. M.; Heinson, A. P.; Heintz, U.; Hensel, C.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hoeth, H.; Hohlfeld, M.; Hong, S. J.; Hossain, S.; Houben, P.; Hu, Y.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jain, S.; Jakobs, K.; Jarvis, C.; Jesik, R.; Johns, K.; Johnson, C.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Juste, A.; Käfer, D.; Kajfasz, E.; Kalinin, A. M.; Kalk, J. R.; Kalk, J. M.; Kappler, S.; Karmanov, D.; Kasper, P.; Katsanos, I.; Kau, D.; Kaur, R.; Kaushik, V.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. M.; Khatidze, D.; Kim, H.; Kim, T. J.; Kirby, M. H.; Kirsch, M.; Klima, B.; Kohli, J. M.; Konrath, J.-P.; Kopal, M.; Korablev, V. M.; Kozelov, A. V.; Krop, D.; Kuhl, T.; Kumar, A.; Kunori, S.; Kupco, A.; Kurča, T.; Kvita, J.; Lacroix, F.; Lam, D.; Lammers, S.; Landsberg, G.; Lebrun, P.; Lee, W. M.; Leflat, A.; Lehner, F.; Lellouch, J.; Leveque, J.; Lewis, P.; Li, J.; Li, Q. Z.; Li, L.; Lietti, S. M.; Lima, J. G. R.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, Y.; Liu, Z.; Lobo, L.; Lobodenko, A.; Lokajicek, M.; Love, P.; Lubatti, H. J.; Lyon, A. L.; Maciel, A. K. A.; Mackin, D.; Madaras, R. J.; Mättig, P.; Magass, C.; Magerkurth, A.; Mal, P. K.; Malbouisson, H. B.; Malik, S.; Malyshev, V. L.; Mao, H. S.; Maravin, Y.; Martin, B.; McCarthy, R.; Melnitchouk, A.; Mendes, A.; Mendoza, L.; Mercadante, P. G.; Merkin, M.; Merritt, K. W.; Meyer, J.; Meyer, A.; Millet, T.; Mitrevski, J.; Molina, J.; Mommsen, R. K.; Mondal, N. K.; Moore, R. W.; Moulik, T.; Muanza, G. S.; Mulders, M.; Mulhearn, M.; Mundal, O.; Mundim, L.; Nagy, E.; Naimuddin, M.; Narain, M.; Naumann, N. A.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nilsen, H.; Nogima, H.; Nomerotski, A.; Novaes, S. F.; Nunnemann, T.; O'Dell, V.; O'Neil, D. C.

    2008-02-01

    We report the direct observation of the excited L=1 state Bs2* in fully reconstructed decays to B+K-. The mass of the Bs2* meson is measured to be 5839.6±1.1(stat)±0.7(syst)MeV/c2, and its production rate relative to the B+ meson is measured to be [1.15±0.23(stat)±0.13(syst)]%.

  14. Quenched scalar-meson correlator with domain wall fermions

    Energy Technology Data Exchange (ETDEWEB)

    Prelovsek, S.; Orginos, K

    2003-05-01

    We study the q-barq singlet and non-singlet scalar-meson masses using domain wall fermions and the quenched approximation. The singlet mass is found to be smaller than the non-singlet mass and indicates that the lowest singlet meson state could be lighter than 1 GeV. The two-point functions for very small quark masses are compared with expectations from the small-volume chiral perturbation theory and the presence of fermionic zero modes.

  15. Insight into the scalar mesons from a lattice calculation

    Energy Technology Data Exchange (ETDEWEB)

    Alford, Mark E-mail: alford@mit.edu; Jaffe, R.L

    2000-07-03

    We study the possibility that the light scalar mesons are q-bar{sup 2}q{sup 2} states rather than q-barq . We perform a lattice QCD calculation of pseudoscalar meson scattering amplitudes, ignoring quark loops and quark annihilation, and find indications that for sufficiently heavy quarks there is a stable four-quark bound state with J{sup PC}=0{sup ++} and non-exotic flavor quantum numbers.

  16. Mesons in ultra-intense magnetic field: an evaded collapse

    Directory of Open Access Journals (Sweden)

    Kerbikov B.O.

    2017-01-01

    Full Text Available Spectra of qq̄ mesons are investigated in the framework of the Hamiltonian obtained from the relativistic path integral in external homogeneous magnetic field. The spectra of all 12 spin-isospin s-wave states generated by π- and ρ-mesons with different spin projections, are studied analytically as functions of the field strength. Three types of behavior with characteristic splittings are found. The results are in agreement with recent lattice calculations.

  17. Production of η mesons in nucleon-nucleon collisions

    Science.gov (United States)

    Baru, V.; Gasparyan, A. M.; Haidenbauer, J.; Hanhart, C.; Kudryavtsev, A. E.; Speth, J.

    2003-06-01

    A model calculation for the reaction NN → NNη near-threshold is presented. The η meson production is described by elementary rescattering processes via MN → νN, with M = π, ϱ, η and δ. Corresponding amplitudes are taken from a multi-channel meson-exchange model of the πN system developed by the Jülich group. Effects of the NN interaction in the final as well as in the initial state are taken into account microscopically.

  18. Production of {eta} mesons in nucleon-nucleon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Baru, V.; Gasparyan, A.M.; Haidenbauer, J.; Hanhart, C.; Kudryavtsev, A.E.; Speth, J

    2003-06-30

    A model calculation for the reaction NN {yields} NN{eta} near-threshold is presented. The {eta} meson production is described by elementary rescattering processes via MN {yields} {nu}N, with M = {pi}, {rho}, {eta} and {delta}. Corresponding amplitudes are taken from a multi-channel meson-exchange model of the {pi}N system developed by the Juelich group. Effects of the NN interaction in the final as well as in the initial state are taken into account microscopically.

  19. A meson exchange model for the YN interaction

    Energy Technology Data Exchange (ETDEWEB)

    J. Haidenbauer; W. Melnitchouk; J. Speth

    2001-09-01

    We present a new model for the hyperon-nucleon (Lambda N, Sigma N) interaction, derived within the meson exchange framework. The model incorporates the standard one boson exchange contributions of the lowest pseudoscalar and vector meson multiplets with coupling constants fixed by SU(6) symmetry relations. In addition - as the main feature of the new model - the exchange of two correlated pions or kaons, both in the scalar-isoscalar (sigma) and vector-isovector (rho) channels, is included.

  20. $\\phi$- meson Production at RHIC energies using the PHENIX Detector

    CERN Document Server

    Sharma, Deepali

    2009-01-01

    Light vector mesons are among the most informative probes to understand the strongly coupled Quark Gluon Plasma created at RHIC. The suppression of light mesons at high transverse momentum, compared to expectations from scaled $p+p$ results, reflects the properties of the strongly interacting matter formed. The $\\phi$-meson is one of the probes whose systematic measurement in $p+p$, $d+Au$ and $Au+Au$ collisions can provide useful information about initial and final state effects on particle production. The mass, width and branching ratio of the $\\phi$-meson decay in the di-kaon and di-electron decay channels could be modified in \\au collisions due to the restoration of chiral symmetry in the QGP. The PHENIX experiment at RHIC has measured $\\phi$-meson production in various systems ranging form $p+p$, $d+Au$ to $Au+Au$ collisions via both its di-electron and di-kaon decay modes. A summary of PHENIX results on invariant spectra, nuclear modification factor and elliptic flow of the $\\phi$-meson are presented he...

  1. Effects of scalar mesons in a Skyrme model with hidden local symmetry

    Science.gov (United States)

    He, Bing-Ran; Ma, Yong-Liang; Harada, Masayasu

    2015-10-01

    We study the effects of light scalar mesons on the Skyrmion properties by constructing and examining a mesonic model including pion, rho meson, and omega meson fields as well as two-quark and four-quark scalar meson fields. In our model, the physical scalar mesons are defined as mixing states of the two- and four-quark fields. We first omit the four-quark scalar meson field from the model and find that when there is no direct coupling between the two-quark scalar meson and the vector mesons, the soliton mass is smaller and the soliton size is larger for lighter scalar mesons; when direct coupling is switched on, as the coupling strength increases, the soliton becomes heavy, and the radius of the baryon number density becomes large as the repulsive force arising from the ω meson becomes strong. We then include the four-quark scalar meson field in the model and find that mixing between the two-quark and four-quark components of the scalar meson fields also affects the properties of the soliton. When the two-quark component of the lighter scalar meson is increased, the soliton mass decreases and the soliton size increases.

  2. Beam Spin Asymmetry Measurements for Two Pion Photoproduction at CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark D. [Univ. of Glasgow, Scotland (United Kingdom)

    2015-09-01

    The overarching goal of this analysis, and many like it, is to develop our understanding of the strong force interactions within the nucleon by examining the nature of their excitation spectra. As the resonances of these spectra have very short lifetimes (tau = 1x10-23 s) and often have very similar masses, it is often impossible to directly observe resonances in the excitation spectra of nucleons. Polarization observables allow us to study the resonances by looking at how they affect the spin state of final state particles. The beam asymmetry is a polarization observable that allows us to detect the sensitivity of these resonances, and other transition mechanisms, to the electric vector orientation of incident photons. Presented in this thesis are first measurements of the beam asymmetries in the resonant region for the reaction channel pgamma p --> p π+ π-focusing on the intermediate mesonic states rho^0 and f^0, and the final state pions. The analysis used data from the g8b experiment undertaken at the Thomas Jefferson National Accelerator Facility (JLab), the first experiment at JLab to use a linearly polarized photon beam. Using the coherent Bremsstrahlung facility and the CLAS detector of Hall B at JLab allowed for many multi-channel reactions to be detected and the first measurements of many polarization observables including those presented here. A brief overview of the theoretical framework used to undertake this analysis is given, followed by a description of the experimental details of the facilities used, then a description of the calibration of the Bremsstrahlung tagging facility which the author undertook, and finally the analysis is presented and the resulting measurements.

  3. Elastic and proton dissociative J/{psi} photoproduction at low W{sub {gamma}p} with the H1 detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Florian

    2013-02-15

    Elastic and proton dissociative photoproduction of J/{psi} mesons is measured with the H1 detector at the HERA electron proton collider in the photon virtuality phase space of Q{sup 2}

  4. On Decays of B Mesons to a Strange Meson and an Eta or Eta' Meson at Babar

    Energy Technology Data Exchange (ETDEWEB)

    Hirschauer, James Francis [Univ. of Colorado, Boulder, CO (United States)

    2009-01-01

    We describe studies of the decays of B mesons to final states ηK*(892), ηK*0(S-wave), ηK*2(1430), and η'K based on data collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collier at the Stanford Linear Accelerator Center. We measure branching fractions and charge asymmetries for the decays B → ηK*, where K* indicates a spin 0, 1, or 2 Kπ system, making first observations of decays to final states ηK0*0(S-wave), ηK+*0 (S-wave), and ηK0*2(1430). We measure the time-dependent CP-violation parameters S and C for the decays B0 → η'K0, observing CP violation in a charmless B decay with 5σ significance considering both statistical and systematic uncertainties.

  5. Study of light mesons with WASA-at-COSY

    Directory of Open Access Journals (Sweden)

    Prencipe Elisabetta

    2014-06-01

    Full Text Available The WASA detector, operating at the COSY facility in Jülich (Germany has been collecting data since 2007. The experiment allows to perform studies of light mesons, such as π0, η and ω rare decay processes, in order to perform precise measurements of branching ratios, determine Dalitz plot parameters, test symmetry and symmetry breaking, and evaluate transition form factors. In the experiments a proton or deuteron beam impinged on a pellet target of hydrogen or deuterium, which allows the reactions proton-proton (pp or proton-deuteron (pd. A high-statistics sample of η mesons has been collected: in the reaction pd →3He η, 3×107η mesons were tagged at a beam energy of 1.0 GeV, while 5×108η mesons were produced in the reaction pp → ppη at 1.4 GeV. This corresponds to the production of 10 η/s and 100 η/s, respectively, for the two reaction processes. In the pp dataset a higher background level is found compared to the pd data set. In both cases, we identify the η mesons by means of the missing mass derived from the recoil particles. A kinematic fit largely rejects the background in our analysis. The advantage in using the pp dataset is that the production of η mesons is almost a factor of 10 higher than in the pd fusion to 3He. As we plan to measure the branching ratios of very rare processes, high statistics is needed. A summary of the recent activity on the study of light mesons with WASA-at-COSY here is given.

  6. arXiv Exclusive Photoproduction of Upsilon in pPb collisions with the CMS

    CERN Document Server

    INSPIRE-00360169; Dutta, Dipanwita

    2016-06-24

    Results of exclusive photoproduction of Upsilon states in Ultraperipheral collisions (UPC) of protons and ions with the CMS experiment are presented, which provides a clean probe of the gluon distribution at small values of parton fractional momenta $x \\approx 10^{-2} 10^{4}$ at central rapidities (|y| $< 2.5$). The three Upsilon states (1S, 2S, 3S) are measured in the dimuon decay channel along with the photon-photon decaying to dimuon QED continuum at $\\sqrt{s_{NN}}=5.02$~TeV for integrated luminosity of $L_{int} = 35$ nb$^{-1}$. The total Upsilon photoproduction cross sections at different photon-proton center of mass energy $W_{\\gamma p}$ and t-differential distributions are presented and compared with other experimental results as well as theoretical predictions.

  7. Double-polarization observable G in neutral-pion photoproduction off the proton

    Energy Technology Data Exchange (ETDEWEB)

    Thiel, A.; Lang, M.; Afzal, F.; Beck, R.; Boese, S.; Funke, C.; Gottschall, M.; Gruener, M.; Hammann, C.; Hannappel, J.; Hartmann, J.; Hoffmeister, P.; Honisch, C.; Kaiser, D.; Kalinowsky, H.; Kalischewski, F.; Klassen, P.; Klempt, E.; Koop, K.; Kube, M.; Mahlberg, P.; Mueller, J.; Muellers, J.; Piontek, D.; Schmidt, C.; Seifen, T.; Sokhoyan, V.; Spieker, K.; Thoma, U.; Urban, M.; Pee, H. van; Walther, D.; Wendel, C.; Winnebeck, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Eberhardt, H.; Bantes, B.; Dutz, H.; Elsner, D.; Ewald, R.; Fornet-Ponse, K.; Frommberger, F.; Goertz, S.; Hammann, D.; Hillert, W.; Jude, T.; Kammer, S.; Kleber, V.; Klein, F.; Reeve, S.; Runkel, S.; Schmieden, H. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Anisovich, A.V.; Bayadilov, D.; Nikonov, V.; Sarantsev, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Bichow, M.; Meyer, W.; Reicherz, G. [Ruhr-Universitaet Bochum, Institut fuer Experimentalphysik I, Bochum (Germany); Brinkmann, K.T.; Gutz, E. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen und Kernphysik, Bonn (Germany); Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Crede, V. [Florida State University, Department of Physics, Tallahassee, FL (United States); Dieterle, M.; Keshelashvili, I.; Krusche, B.; Witthauer, L. [Universitaet Basel, Institut fuer Physik, Basel (Switzerland); Friedrich, S.; Makonyi, K.; Metag, V.; Nanova, M. [Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Gridnev, A.; Lopatin, I. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Wilson, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Florida State University, Department of Physics, Tallahassee, FL (United States); Collaboration: The CBELSA/TAPS Collaboration

    2017-01-15

    This paper reports on a measurement of the double-polarization observable G in π{sup 0} photoproduction off the proton using the CBELSA/TAPS experiment at the ELSA accelerator in Bonn. The observable G is determined from reactions of linearly polarized photons with longitudinally polarized protons. The polarized photons are produced by bremsstrahlung off a diamond radiator of well-defined orientation. A frozen spin butanol target provides the polarized protons. The data cover the photon energy range from 617 to 1325 MeV and a wide angular range. The experimental results for G are compared to predictions by the Bonn-Gatchina (BnGa), Juelich-Bonn (JueBo), MAID and SAID partial wave analyses. Implications of the new data for the pion photoproduction multipoles are discussed. (orig.)

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

    CERN Document Server

    Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, M; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, 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; Ma, K J; 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; Adler, V; Behrens, U; Bloch, I; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Dossanov, A; Drugakov, V; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Horn, C; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Miglioranzi, S; Montanari, A; Namsoo, T; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Stadie, H; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; 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; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Aushev, V; Borodin, M; Kozulia, A; Lisovyi, M; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, 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; Fos-ter, B; Korcsak-Gorzo, K; Oliver, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-Estrada, C; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Oh, B Y; Raval, A; Ukleja, J; Whitmore, J J; Iga, Y; D'Agostini, Distiller 3011 page IVG; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

    2007-01-01

    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_T^jet>6 GeV and pseudorapidity |eta^jet|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 order(alpha alpha_s^2) perturbative QCD calculation.

  9. Upper limits for the photoproduction cross section for the Phi--(1860) pentaquark state off the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Hovanes Egiyan

    2012-01-01

    We searched for the {Phi}{sup --}(1860) pentaquark in the photoproduction process off the deuteron in the {Xi}{sup -} {pi}{sup -} decay channel using CLAS. The invariant mass spectrum of the {Xi}{sup -} {pi}{sup -} system does not indicate any statistically significant enhancement near the reported mass M = 1.860 GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a 90% confidence level upper limit of 0.7 nb for the photoproduction cross section of {Phi}{sup --}(1860) with a consecutive decay into {Xi}{sup -} {pi}{sup -} in the photon energy range 4.5 GeV < E{sub {gamma}} < 5.5 GeV.

  10. Positive parity $D_s$ mesons

    CERN Document Server

    Leskovec, Luka; Mohler, Daniel; Prelovsek, Sasa; Woloshyn, R M

    2015-01-01

    We study the positive parity charmed strange mesons using lattice QCD, the only reliable ab initio method to study QCD at low energies. Especially the experimentally observed $D_{s0}^*(2317)$ and $D_{s1}(2460)$ have challenged theory for quite some time. The dynamical lattice QCD simulations are performed at two distinct pion masses, $m_{\\pi}$ = 266 MeV and 156 MeV, using both $\\bar{c}s$ as well as $DK$ and $D^*K$ scattering operators in the construction of the correlation matrix in order to take into the account threshold effects. While the $J^P = 0^+$ channel benefited most from the inclusion of scattering operators, it was also crucial for the case of the $D_{s1}(2460)$. Using the L\\"uscher method, which relates the finite volume spectrum to the infinite volume scattering matrix, we were able to determine the near threshold behavior of the scattering amplitude. From it we extracted the binding momenta and the masses of the below-threshold bound states $D_{s0}^*(2317)$ and $D_{s1}(2460)$ by determining the ...

  11. Positive Parity $D_s$ Mesons

    Energy Technology Data Exchange (ETDEWEB)

    Leskovec, Luka [Stefan Inst., Ljubljana; Lang, C. B. [Graz U.; Mohler, Daniel [Fermilab; Prelovsek, Sasa [Stefan Inst., Ljubljana; Woloshyn, R. M. [TRIUMF

    2015-11-12

    We study the positive parity charmed strange mesons using lattice QCD, the only reliable ab initio method to study QCD at low energies. Especially the experimentally observed $D_{s0}^*(2317)$ and $D_{s1}(2460)$ have challenged theory for quite some time. The dynamical lattice QCD simulations are performed at two distinct pion masses, $m_{\\pi}$ = 266 MeV and 156 MeV, using both $\\bar{c}s$ as well as $DK$ and $D^*K$ scattering operators in the construction of the correlation matrix in order to take into the account threshold effects. While the $J^P = 0^+$ channel benefited most from the inclusion of scattering operators, it was also crucial for the case of the $D_{s1}(2460)$. Using the L\\"uscher method, which relates the finite volume spectrum to the infinite volume scattering matrix, we were able to determine the near threshold behavior of the scattering amplitude. From it we extracted the binding momenta and the masses of the below-threshold bound states $D_{s0}^*(2317)$ and $D_{s1}(2460)$ by determining the pole positions of the scattering amplitudes. Our results compare well with experiment, resolving a long standing discrepancy between theory and experiment.

  12. Electromagnetic Studies of Mesons, Nucleons, and Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Oliver K.

    2013-08-20

    Professor Baker was a faculty member at Hampton University in Hampton, Virginia, and, jointly, a Staff Physicist at Jefferson Lab in nearby Newport News from September 1989 to July 2006. The Department of Energy (DOE) funded the grant DE-FG02-97ER41035 Electromagnetic Studies of Mesons, Nucleons, and Nuclei, while Baker was in this joint appointment. Baker sent a closeout report on these activities to Hampton University’s Sponsored Research Office some years ago, shortly after joining Yale University in 2006. In the period around 2001, the research grant with Baker as the Principal Investigator (PI) was put under the supervision of Professor Liguang Tang at Hampton University. Baker continued to pursue the research while in this join appointment, however the administrative responsibilities with the DOE and with Hampton University rested with Professor Tang after 2001, to my recollection. What is written in this document is from Baker’s memory of the research activities, which he has not pursued since joining the Yale University faculty.

  13. Radiative Decays of the B Meson

    CERN Document Server

    Tanaka, H

    2002-01-01

    The radiative decays of the B meson to the final states K *(892)gamma and rho(770)gamma proceed through virtual effective flavor-changing neutral current processes which are sensitive to contributions from high mass scales from within the Standard Model of particle interactions and from possible new physics. In the context of the Standard Model, these transitions are of interest in probing the weak interaction behavior of the top quark. In particular, the ratio of branching fractions for the two processes can be used to extract the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |V sub t sub d /V sub t sub s |. Potential new physics contributions in these virtual transitions may induce new sources of direct CP violation and enhancement or suppression of the rate of these processes. The B -> K*gamma is a manifestation of the b -> s gamma radiative transition. This process has been previously observed by the CLEO collaboration and its branching fraction measured. While the theoretical prediction for the incl...

  14. Precision for B-meson matrix elements

    Energy Technology Data Exchange (ETDEWEB)

    Guazzini, D.; Sommer, R. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Tantalo, N. [INFN sezione ' ' Tor Vergata' ' , Rome (Italy)]|[Centro E. Fermi, Rome (Italy)

    2007-10-15

    We demonstrate how HQET and the Step Scaling Method for B-physics, pioneered by the Tor Vergata group, can be combined to reach a further improved precision. The observables considered are the mass of the b-quark and the B{sub s}-meson decay constant. The demonstration is carried out in quenched lattice QCD. We start from a small volume, where one can use a standard O(a)-improved relativistic action for the b-quark, and compute two step scaling functions which relate the observables to the large volume ones. In all steps we extrapolate to the continuum limit, separately in HQET and in QCD for masses below m{sub b}. The physical point m{sub b} is then reached by an interpolation of the continuum results in 1/m. The essential, expected and verified, feature is that the step scaling functions have a weak mass-dependence resulting in an easy interpolation to the physical point. With r{sub 0}=0.5 fm and the experimental B{sub s} and K masses as input, we find F{sub B{sub s}}=191(6) MeV and the renormalization group invariant mass M{sub b}=6.88(10) GeV, translating into anti m{sub b}(anti m{sub b})=4.42(6) GeV in the MS scheme. This approach seems very promising for full QCD. (orig.)

  15. Analysis of orbitally excited B-mesons

    CERN Document Server

    Albrecht, Zoltan; Quast, Gunter

    2003-01-01

    This thesis reports on the study of orbitally excited B** mesons in DELPHI b-events taken in the years 1994 to 2000 with the DELPHI detector at the LEP collider. The analyses presented represent the result of applying much improved and extended techniques of spectroscopy since the first DELPHI publication in 1995. A major improvement has occurred in the area of particle identification, where a neural network approach has been implemented in the DELPHI software package. Developments in the area of neural networks have led to much improved enrichment of the excited B states. The Bˆ{**} neural networks identify, on a track-by-track basis, the decay pion/kaon originating from the Bˆ{**} decay, suppressing background and keeping signal events in an efficient way. To improve detector resolution, a further application of neural networks has been applied to reconstruct the underlying Q-value. The corresponding network gives a correction on existing measurements of the Q-value in the form of a probability density fu...

  16. Spectroscopy And Decays Of Charmed Strange Mesons

    CERN Document Server

    Li, S Z

    2004-01-01

    Using 13.4fb−1 of e +e− collision data taken with the CLEO-II detector at center- of-mass energies near 10.6 GeV, we present two analyses to study the spectroscopy and decays of charmed strange mesons. In the first analysis, we have obtained the first confirming evidence for the existence of the D*sJ (2317)+. We have also observed and established the existence of a second narrow resonance, denoted as the DsJ(2463) +. The two narrow resonances are observed in the D+s π0 and D*+s π0 final state, respectively. Accounting for the cross-feed backgrounds due to the addition or omission of photons, we have measured the mean mass differences 〈ΔM( Dsπ0)〉 = 350.0 ± 1.2 [stat.] ± 1.0 [syst.] MeV/c2 for the D*sJ (2317)+ state, and 〈ΔM( D*s π0)〉 = 351.2 ± 1.7 [stat.] ± 1.0 [syst.] MeV/c2 for the new DsJ(2463) + state. We have also searched, but find no evidence, for d...

  17. 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.)

  18. Transverse polarization of $\\Lambda$ hyperons from quasi-real photoproduction on nuclei

    CERN Document Server

    Airapetian, A; Akopov, Z; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetissian, A; Avetisyan, E; Belostotski, S; Bianchi, N; Blok, H P; Borissov, A; Bowles, J; Brodski, I; Bryzgalov, V; Burns, J; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; De Nardo, L; De Sanctis, E; Diefenthaler, M; Di Nezza, P; Düren, M; Ehrenfried, M; Elbakian, G; Ellinghaus, F; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Gabbert, D; Gapienko, G; Gapienko, V; Garibaldi, F; Gavrilov, G; Gharibyan, V; Giordano, F; Gliske, S; Golembiovskaya, M; Hadjidakis, C; Hartig, M; Hasch, D; Hillenbrand, A; Hoek, M; Holler, Y; Hristova, I; Imazu, Y; Ivanilov, A; Jackson, H E; Jo, H S; Joosten, S; Kaiser, R; Karyan, G; Keri, T; Kinney, E; Kisselev, A; Kobayashi, N; Korotkov, V; Kozlov, V; Kravchenko, P; Krivokhijine, V G; Lagamba, L; Lapikás, L; Lehmann, I; Lenisa, P; Ruiz, A López; Lorenzon, W; Lu, X -G; Ma, B -Q; Mahon, D; Makins, N C R; Manaenkov, S I; Mao, Y; Marianski, B; de la Ossa, A Martinez; Marukyan, H; Miller, C A; Miyachi, Y; Movsisyan, A; Muccifora, V; Murray, M; Mussgiller, A; Nappi, E; Naryshkin, Y; Nass, A; Negodaev, M; Nowak, W -D; Pappalardo, L L; Perez-Benito, R; Reimer, P E; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanftl, F; Schäfer, A; Schnell, G; Schüler, K P; Seitz, B; Shibata, T -A; Shutov, V; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stewart, J; Stinzing, F; Taroian, S; Terkulov, A; Truty, R; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van Haarlem, Y; Van Hulse, C; Veretennikov, D; Vikhrov, V; Vilardi, I; Wang, S; Yaschenko, S; Ye, Z; Yu, W; Zagrebelnyy, V; Zeiler, D; Zihlmann, B; Zupranski, P

    2014-01-01

    The transverse polarization of $\\Lambda$ hyperons was measured in inclusive quasi-real photoproduction for various target nuclei ranging from hydrogen to xenon. The data were obtained by the HERMES experiment at HERA using the 27.6 GeV lepton beam and nuclear gas targets internal to the lepton storage ring. The polarization observed is positive for light target nuclei and is compatible with zero for krypton and xenon.

  19. Extending Isobar Model for Kaon Photoproduction up to 16 GeV

    CERN Document Server

    Mart, T

    2003-01-01

    We extend the isobar model for kaon photoproduction to consider higher energy data by combining the model with a Regge approach. The extended model works nicely between threshold and 16 GeV. It is shown that model with crossing symmetric Born terms leads to a better description of experimental data. We use the model to calculate contributions of kaon channels to the Gerasimov-Drell-Hearn sum rule up to 16 GeV.

  20. Tests of the standard model in photoproduction at HERA and the LHC

    CERN Document Server

    de Favereau de Jeneret, Jérôme; Piotrzkowski, Krzysztof

    Photoproduction has been used at colliders for decades in order to study hadronic properties of matter. The energy and luminosity of recent and future colliders allow probing also the electroweak sector through photon-photon and photon-proton interactions. At the HERA electron-proton collider, studies of the W boson production provide a stringent test of the Standard Model. At the LHC, photoproduction has to be separated from the overwhelming background of partonic interactions. A powerful ‘tagging’ technique can be introduced by adding special detectors placed far from the interaction point to detect forward scattered protons, usually present in photon-mediated processes. The HECTOR software package was written in order to provide accurate simulation of forward protons trajectories in the LHC beam-lines. These tools have been used in order to study the photoproduction of top quarks via flavor-changing neutral currents. This process is practically absent in the Standard Model, while it appears in some of ...

  1. Photodegradation of aqueous argatroban investigated by LC/MSn: Photoproducts, transformation processes and potential implications.

    Science.gov (United States)

    Secrétan, Philippe-Henri; Karoui, Maher; Bernard, Mélisande; Ghermani, Noureddine; Safta, Fathi; Yagoubi, Najet; Do, Bernard

    2016-11-30

    Argatroban (ARGA), used as intravenous anticoagulant drug, has been reported to photodegrade under light exposure, requiring specific precautions at handling, storage and administration. Thus, for the first time, aqueous ARGA photodegradation under aerobic conditions has been described in terms of photoproducts, phototransformation processes and potential implications. ARGA significant photoproducts were successfully separated and characterized by gradient reversed-phase liquid chromatography coupled with high-resolution multistage mass spectrometry (LC/HR-MSn). Hitherto still not available in literature, ARGA in-depth fragmentation study was conducted so as to thoroughly sort out the main mechanisms specific to the molecule and therefore, to propose a fragmentation pattern relevant to the identification of ARGA related substances. Thereafter, in view of the structural characteristics of the photoproducts formed, ARGA photodegradation pathways could be worked out, showing that whether by direct photolysis or through photosensitization, the methyltetrahydroquinoline nitrogen and that of guanidine group would be mainly involved in photolysis initiation reactions, through one-electron oxidation along with proton loss. Desulfonation, cyclisation affording compounds of diazinane type, and/or rearrangements with transfer of the methyltetrahydroquinoline group toward the guanidine function were observed accordingly. Having a good insight into ARGA photodegradation pathways allows for consistent measures in view of mitigating or avoiding the drug decay and the related potential effects. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Relations between Heavy-light Meson and Quark Masses

    Energy Technology Data Exchange (ETDEWEB)

    Brambilla, N.; Komijani, J.; Kronfeld, A. S.; Vairo, A.

    2017-12-13

    The study of heavy-light meson masses should provide a way to determine renormalized quark masses and other properties of heavy-light mesons. In the context of lattice QCD, for example, it is possible to calculate hadronic quantities for arbitrary values of the quark masses. In this paper, we address two aspects relating heavy-light meson masses to the quark masses. First, we introduce a definition of the renormalized quark mass that is free of both scale dependence and renormalon ambiguities, and discuss its relation to more familiar definitions of the quark mass. We then show how this definition enters a merger of the descriptions of heavy-light masses in heavy-quark effective theory and in chiral perturbation theory ($\\chi$PT). For practical implementations of this merger, we extend the one-loop $\\chi$PT corrections to lattice gauge theory with heavy-light mesons composed of staggered fermions for both quarks. Putting everything together, we obtain a practical formula to describe all-staggered heavy-light meson masses in terms of quark masses as well as some lattice artifacts related to staggered fermions. In a companion paper, we use this function to analyze lattice-QCD data and extract quark masses and some matrix elements defined in heavy-quark effective theory.

  3. Molecular components in P-wave charmed-strange mesons

    CERN Document Server

    Ortega, Pablo G.

    2016-01-01

    Results obtained by various experiments show that the $D_{s0}^{\\ast}(2317)$ and $D_{s1}(2460)$ mesons are very narrow states located below the $DK$ and $D^{\\ast}K$ thresholds, respectively. This is markedly in contrast with the expectations of naive quark models and heavy quark symmetry. Motivated by a recent lattice study which addresses the mass shifts of the $c\\bar{s}$ ground states with quantum numbers $J^{P}=0^{+}$ ($D_{s0}^{\\ast}(2317)$) and $J^{P}=1^{+}$ ($D_{s1}(2460)$) due to their coupling with $S$-wave $D^{(\\ast)}K$ thresholds, we perform a similar analysis within a nonrelativistic constituent quark model in which quark-antiquark and meson-meson degrees of freedom are incorporated. The quark model has been applied to a wide range of hadronic observables and thus the model parameters are completely constrained. The coupling between quark-antiquark and meson-meson Fock components is done using a modified version of the $^{3}P_{0}$ decay model. We observe that the coupling of the $0^{+}$ $(1^{+})$ mes...

  4. Rapidity resummation for B-meson wave functions

    Directory of Open Access Journals (Sweden)

    Shen Yue-Long

    2014-01-01

    Full Text Available Transverse-momentum dependent (TMD hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity ζ of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for B-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic B-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of B-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive B-meson decays. The phenomenological consequence of rapidity-resummation improved B-meson wave functions is further discussed in the context of B → π transition form factors at large hadronic recoil.

  5. Novel T-Violation observable open to any pair of decay channels at meson factories

    OpenAIRE

    Bernabéu, José; Botella, Francisco J.; Nebot, Miguel

    2013-01-01

    Quantum entanglement between the two neutral mesons produced in meson factories has allowed the first indisputable direct observation of Time Reversal Violation in the time evolution of the neutral meson between the two decays. The exceptional meson transitions are directly connected to semileptonic and CP eigenstate decay channels. The possibility of extending the observable asymmetries to more decay channels confronts the problem of the “orthogonality condition”, which can be stated with th...

  6. Decay properties of charm and bottom mesons in a quantum isotonic nonlinear oscillator potential model

    Energy Technology Data Exchange (ETDEWEB)

    Rahmani, S.; Hassanabadi, H. [Shahrood University of Technology, Physics Department, Shahrood (Iran, Islamic Republic of)

    2017-09-15

    Employing generalized quantum isotonic oscillator potential we determine wave function for mesonic system in nonrelativistic formalism. Then we investigate branching ratios of leptonic decays for heavy-light mesons including a charm quark. Next, by applying the Isgur-Wise function we obtain branching ratios of semileptonic decays for mesons including a bottom quark. The weak decay of the B{sub c} meson is also analyzed to study the life time. Comparison with other available theoretical approaches is presented. (orig.)

  7. Measurement of the beam-helicity asymmetry I{sup s}un in the photoproduction of π{sup 0} π{sup ±} pairs off protons and off neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Oberle, M.; Dieterle, M.; Jaegle, I.; Kaeser, A.; Keshelashvili, I.; Krusche, B.; Maghrbi, Y.; Pheron, F.; Werthmueller, D.; Witthauer, L.; Zehr, F. [University of Basel, Department of Physics, Basel (Switzerland); Ahrens, J.; Arends, H.J.; Bartolome, P.A.; Heid, E.; Jahn, O.; Martinez, M.; Ostrick, M.; Schumann, S.; Thomas, A. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Annand, J.R.M.; Howdle, D.; Livingston, K.; MacGregor, I.J.D.; Mancell, J.; McGeorge, J.C.; McNicoll, E.; Robinson, J.; Rosner, G. [University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); Bantawa, K.; Manley, D.M. [Kent State University, Kent, Ohio (United States); Beck, R.; Nikolaev, A. [University of Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Bekrenev, V.; Kruglov, S.P.; Kulbardis, A. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Berghaeuser, H.; Drexler, P.; Metag, V.; Novotny, R.; Thiel, M. [University of Giessen, II. Physikalisches Institut, Giessen (Germany); Braghieri, A.; Mushkarenkov, A.; Pedroni, P. [INFN, Sezione di Pavia, Pavia (Italy); Branford, D.; Glazier, D.I.; Jude, T.C.; Sikora, M.H.; Watts, D.P. [University of Edinburgh, School of Physics, Edinburgh (United Kingdom); Briscoe, W.J.; Demissie, B.; Marinides, Z. [The George Washington University, Center for Nuclear Studies, Washington, DC (United States); Brudvik, J.; Nefkens, B.M.K.; Prakhov, S.N.; Starostin, A. [University of California Los Angeles, Los Angeles, California (United States); Cherepnya, S.; Fil' kov, L.V. [Lebedev Physical Institute, Moscow (Russian Federation); Downie, E.J. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Glasgow, School of Physics and Astronomy, Glasgow (United Kingdom); The George Washington University, Center for Nuclear Studies, Washington, DC (United States); Fix, A. [Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation); Hornidge, D.; Middleton, D.G. [Mount Allison University, New Brunswick (Canada); Huber, G.M. [University of Regina, Regina, SK (Canada); Kashevarov, V.L. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Lebedev Physical Institute, Moscow (Russian Federation); Kondratiev, R.; Lisin, V.; Polonski, A. [Institute for Nuclear Research, Moscow (Russian Federation); Korolija, M.; Mekterovic, D.; Micanovic, S.; Supek, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Oussena, B. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); The George Washington University, Center for Nuclear Studies, Washington, DC (United States); Rostomyan, T. [University of Basel, Department of Physics, Basel (Switzerland); INFN, Sezione di Pavia, Pavia (Italy); Sober, D.I. [The Catholic University of America, Washington, DC (United States); Unverzagt, M. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Collaboration: The Crystal Ball at MAMI, TAPS; A2 Collaboration

    2014-03-15

    Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz for the photoproduction of mixed-charge pion pairs in the reactions γp → nπ{sup 0}π{sup +} off free protons and γd → (p)pπ{sup 0}π{sup -} and γd → (n)nπ{sup 0}π{sup +} off quasi-free nucleons bound in the deuteron for incident photon energies up to 1.4 GeV. Circularly polarized photons were produced from bremsstrahlung of longitudinally polarized electrons and tagged with the Glasgow-Mainz magnetic spectrometer. The charged pions, recoil protons, recoil neutrons, and decay photons from π{sup 0} mesons were detected in the 4π electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. Using a complete kinematic reconstruction of the final state, excellent agreement was found between the results for free and quasi-free protons, suggesting that the quasi-free neutron results are also a close approximation of the free-neutron asymmetries. A comparison of the results to the predictions of the Two-Pion-MAID reaction model shows that the reaction mechanisms are still not well understood, in particular at low incident photon energies in the second nucleon-resonance region. (orig.)

  8. Diffractive S and D-wave vector mesons in deep inelastic scattering

    OpenAIRE

    Ivanov, I. P.; Nikolaev, N.N.

    1999-01-01

    We derive helicity amplitudes for diffractive leptoproduction of the S and D wave states of vector mesons. We predict a dramatically different spin dependence for production of the S and D wave vector mesons. We find very small $R=\\sigma_{L}/\\sigma_{T}$ and abnormally large higher twist effects in production of longitudinally polarized D-wave vector mesons.

  9. Composite-meson--quark interactions under the condition of dynamical breaking of chiral symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, M.

    1989-03-01

    Starting from the QCD-inspired model Hamiltonian which can lead to the dynamical breakdown of chiral symmetry, we describe a vacuum consisting of a condensate of q-barq pairs and furthermore meson states and composite-meson field operators within the new Tamm-Dancoff approximation. Using these fields operators and the Hamiltonian we construct composite-meson--quark interactions.

  10. Light meson gas in the QCD vacuum and oscillating universe

    Science.gov (United States)

    Prokhorov, George; Pasechnik, Roman

    2018-01-01

    We have developed a phenomenological effective quantum-field theoretical model describing the "hadron gas" of the lightest pseudoscalar mesons, scalar σ-meson and σ-vacuum, i.e. the expectation value of the σ-field, at finite temperatures. The corresponding thermodynamic approach was formulated in terms of the generating functional derived from the effective Lagrangian providing the basic thermodynamic information about the "meson plasma + QCD condensate" system. This formalism enables us to study the QCD transition from the hadron phase with direct implications for cosmological evolution. Using the hypothesis about a positively-definite QCD vacuum contribution stochastically produced in early universe, we show that the universe could undergo a series of oscillations during the QCD epoch before resuming unbounded expansion.

  11. Properties of L=1 B1 and B2* Mesons

    Science.gov (United States)

    Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T.; Aguilo, E.; Ahn, S. H.; Ahsan, M.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Anastasoaie, M.; Ancu, L. S.; Andeen, T.; Anderson, S.; Andrieu, B.; Anzelc, M. S.; Arnoud, Y.; Arov, M.; Arthaud, M.; Askew, A.; Åsman, B.; Assis Jesus, A. C. S.; Atramentov, O.; Autermann, C.; Avila, C.; Ay, C.; Badaud, F.; Baden, A.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Banerjee, P.; Barberis, E.; Barfuss, A.-F.; Bargassa, P.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bauer, D.; Beale, S.; Bean, A.; Begalli, M.; Begel, M.; Belanger-Champagne, C.; Bellantoni, L.; Bellavance, A.; Benitez, J. A.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Berntzon, L.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Biscarat, C.; Blazey, G.; Blekman, F.; Blessing, S.; Bloch, D.; Bloom, K.; Boehnlein, A.; Boline, D.; Bolton, T. A.; Borissov, G.; Bos, K.; Bose, T.; Brandt, A.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Buchanan, N. J.; Buchholz, D.; Buehler, M.; Buescher, V.; Burdin, S.; Burke, S.; Burnett, T. H.; Buszello, C. P.; Butler, J. M.; Calfayan, P.; Calvet, S.; Cammin, J.; Caron, S.; Carvalho, W.; Casey, B. C. K.; Cason, N. M.; Castilla-Valdez, H.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chan, K.; Chandra, A.; Charles, F.; Cheu, E.; Chevallier, F.; Cho, D. K.; Choi, S.; Choudhary, B.; Christofek, L.; Christoudias, T.; Cihangir, S.; Claes, D.; Clément, C.; Clément, B.; Coadou, Y.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Crépé-Renaudin, S.; Cutts, D.; Ćwiok, M.; da Motta, H.; Das, A.; Davies, G.; de, K.; de Jong, S. J.; de Jong, P.; de La Cruz-Burelo, E.; Martins, C. De Oliveira; Degenhardt, J. D.; Déliot, F.; Demarteau, M.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Diehl, H. T.; Diesburg, M.; Dominguez, A.; Dong, H.; Dudko, L. V.; Duflot, L.; Dugad, S. R.; Duggan, D.; Duperrin, A.; Dyer, J.; Dyshkant, A.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Eno, S.; Ermolov, P.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Ferapontov, A. V.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Ford, M.; Fortner, M.; Fox, H.; Fu, S.; Fuess, S.; Gadfort, T.; Galea, C. F.; Gallas, E.; Galyaev, E.; Garcia, C.; Garcia-Bellido, A.; Gavrilov, V.; Gay, P.; Geist, W.; Gelé, D.; Gerber, C. E.; Gershtein, Y.; Gillberg, D.; Ginther, G.; Gollub, N.; Gómez, B.; Goussiou, A.; Grannis, P. D.; Greenlee, H.; Greenwood, Z. D.; Gregores, E. M.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guo, J.; Guo, F.; Gutierrez, P.; Gutierrez, G.; Haas, A.; Hadley, N. J.; Haefner, P.; Hagopian, S.; Haley, J.; Hall, I.; Hall, R. E.; Han, L.; Hanagaki, K.; Hansson, P.; Harder, K.; Harel, A.; Harrington, R.; Hauptman, J. M.; Hauser, R.; Hays, J.; Hebbeker, T.; Hedin, D.; Hegeman, J. G.; Heinmiller, J. M.; Heinson, A. P.; Heintz, U.; Hensel, C.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hoeth, H.; Hohlfeld, M.; Hong, S. J.; Hooper, R.; Hossain, S.; Houben, P.; Hu, Y.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jain, S.; Jakobs, K.; Jarvis, C.; Jesik, R.; Johns, K.; Johnson, C.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Juste, A.; Käfer, D.; Kahn, S.; Kajfasz, E.; Kalinin, A. M.; Kalk, J. R.; Kalk, J. M.; Kappler, S.; Karmanov, D.; Kasper, J.; Kasper, P.; Katsanos, I.; Kau, D.; Kaur, R.; Kaushik, V.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. M.; Khatidze, D.; Kim, H.; Kim, T. J.; Kirby, M. H.; Kirsch, M.; Klima, B.; Kohli, J. M.; Konrath, J.-P.; Kopal, M.; Korablev, V. M.; Kothari, B.; Kozelov, A. V.; Krop, D.; Kryemadhi, A.; Kuhl, T.; Kumar, A.; Kunori, S.; Kupco, A.; Kurča, T.; Kvita, J.; Lacroix, F.; Lam, D.; Lammers, S.; Landsberg, G.; Lazoflores, J.; Lebrun, P.; Lee, W. M.; Leflat, A.; Lehner, F.; Lellouch, J.; Lesne, V.; Leveque, J.; Lewis, P.; Li, J.; Li, Q. Z.; Li, L.; Lietti, S. M.; Lima, J. G. R.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, Y.; Liu, Z.; Lobo, L.; Lobodenko, A.; Lokajicek, M.; Lounis, A.; Love, P.; Lubatti, H. J.; Lyon, A. L.; Maciel, A. K. A.; Mackin, D.; Madaras, R. J.; Mättig, P.; Magass, C.; Magerkurth, A.; Makovec, N.; Mal, P. K.; Malbouisson, H. B.; Malik, S.; Malyshev, V. L.; Mao, H. S.; Maravin, Y.; Martin, B.; McCarthy, R.; Melnitchouk, A.; Mendes, A.; Mendoza, L.; Mercadante, P. G.; Merkin, M.; Merritt, K. W.; Meyer, J.; Meyer, A.; Michaut, M.; Millet, T.; Mitrevski, J.; Molina, J.; Mommsen, R. K.; Mondal, N. K.; Moore, R. W.; Moulik, T.; Muanza, G. S.; Mulders, M.; Mulhearn, M.; Mundal, O.; Mundim, L.; Nagy, E.

    2007-10-01

    This Letter presents the first strong evidence for the resolution of the excited B mesons B1 and B2* as two separate states in fully reconstructed decays to B+(*)π-. The mass of B1 is measured to be 5720.6±2.4±1.4MeV/c2 and the mass difference ΔM between B2* and B1 is 26.2±3.1±0.9MeV/c2, giving the mass of the B2* as 5746.8±2.4±1.7MeV/c2. The production rate for B1 and B2* mesons is determined to be a fraction (13.9±1.9±3.2)% of the production rate of the B+ meson.

  12. Scalar mesons above and below 1 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Close, Frank E. [Department of Theoretical Physics, University of Oxford, Oxford (United Kingdom)]. E-mail: F.Close@physics.ox.ac.uk; Toernqvist, Nils A. [Department of Physical Sciences, University of Helsinki, Helsinki (Finland)]. E-mail: nils.tornqvist@helsinki.fi

    2002-10-01

    We show that two nonets and a glueball provide a consistent description of data on scalar mesons below 1.7 GeV. Above 1 GeV the states form a conventional qq-bar nonet mixed with the glueball of lattice QCD. Below 1 GeV the states also form a nonet, as implied by the attractive forces of QCD, but of a more complicated nature. Near the centre they are (qq)3-bar(q-barq-bar){sub 3} in S-wave, with some qq-bar in P-wave, but further out they rearrange as (qq-bar){sub 1}(qq-bar){sub 1} and finally as meson-meson states. A simple effective chiral model for such a system with two scalar nonets can be made involving two coupled linear sigma models. One of these could be looked upon as the Higgs sector of nonpertubative QCD. (author)

  13. Hard exclusive neutrino production of a light meson

    Science.gov (United States)

    Pire, B.; Szymanowski, L.; Wagner, J.

    2017-06-01

    We update the leading order in αs QCD amplitude for deep exclusive neutrino and antineutrino production of a light meson on an unpolarized nucleon. The factorization theorems of the collinear QCD approach allow us to write the amplitude as the convolution of generalized parton distributions and perturbatively calculable coefficient functions. We study both the pseudoscalar-meson and longitudinally polarized vector-meson cases. It turns out that, contrarily to the electroproduction case, the leading-twist scattering amplitudes for π and ρL productions are proportional to one another, which may serve as an interesting new test of the leading-twist dominance of exclusive processes at medium scale. The importance of the gluonic contribution to most cross sections is stressed.

  14. Properties of L=1 B(1) and B(2)* mesons.

    Science.gov (United States)

    Abazov, V M; Abbott, B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguilo, E; Ahn, S H; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Ancu, L S; Andeen, T; Anderson, S; Andrieu, B; Anzelc, M S; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; Asman, B; Assis Jesus, A C S; Atramentov, O; Autermann, C; Avila, C; Ay, C; Badaud, F; Baden, A; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Banerjee, P; Barberis, E; Barfuss, A-F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benitez, J A; Beri, S B; Bernardi, G; Bernhard, R; Berntzon, L; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Biscarat, C; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Borissov, G; Bos, K; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Buchanan, N J; Buchholz, D; Buehler, M; Buescher, V; Burdin, S; Burke, S; Burnett, T H; Buszello, C P; Butler, J M; Calfayan, P; Calvet, S; Cammin, J; Caron, S; Carvalho, W; Casey, B C K; Cason, N M; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chan, K; Chandra, A; Charles, F; Cheu, E; Chevallier, F; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Christoudias, T; Cihangir, S; Claes, D; Clément, C; Clément, B; Coadou, Y; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Crépé-Renaudin, S; Cutts, D; Cwiok, M; da Motta, H; Das, A; Davies, G; De, K; de Jong, S J; de Jong, P; De La Cruz-Burelo, E; Martins, C De Oliveira; Degenhardt, J D; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dong, H; Dudko, L V; Duflot, L; Dugad, S R; Duggan, D; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Ermolov, P; Evans, H; Evdokimov, A; Evdokimov, V N; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Ford, M; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Gallas, E; Galyaev, E; Garcia, C; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Gelé, D; Gerber, C E; Gershtein, Y; Gillberg, D; Ginther, G; Gollub, N; Gómez, B; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, J; Guo, F; Gutierrez, P; Gutierrez, G; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Hanagaki, K; Hansson, P; Harder, K; Harel, A; Harrington, R; Hauptman, J M; Hauser, R; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinmiller, J M; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hoeth, H; Hohlfeld, M; Hong, S J; Hooper, R; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jarvis, C; Jesik, R; Johns, K; Johnson, C; Johnson, M; Jonckheere, A; Jonsson, P; Juste, A; Käfer, D; Kahn, S; Kajfasz, E; Kalinin, A M; Kalk, J R; Kalk, J M; Kappler, S; Karmanov, D; Kasper, J; Kasper, P; Katsanos, I; Kau, D; Kaur, R; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y M; Khatidze, D; Kim, H; Kim, T J; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Konrath, J-P; Kopal, M; Korablev, V M; Kothari, B; Kozelov, A V; Krop, D; Kryemadhi, A; Kuhl, T; Kumar, A; Kunori, S; Kupco, A; Kurca, T; Kvita, J; Lacroix, F; Lam, D; Lammers, S; Landsberg, G; Lazoflores, J; Lebrun, P; Lee, W M; Leflat, A; Lehner, F; Lellouch, J; Lesne, V; Leveque, J; Lewis, P; Li, J; Li, Q Z; Li, L; Lietti, S M; Lima, J G R; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobo, L; Lobodenko, A; Lokajicek, M; Lounis, A; Love, P; Lubatti, H J; Lyon, A L; Maciel, A K A; Mackin, D; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Makovec, N; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Mao, H S; Maravin, Y; Martin, B; McCarthy, R; Melnitchouk, A; Mendes, A; Mendoza, L; Mercadante, P G; Merkin, M; Merritt, K W; Meyer, J; Meyer, A; Michaut, M; Millet, T; Mitrevski, J; Molina, J; Mommsen, R K; Mondal, N K; Moore, R W; Moulik, T; Muanza, G S; Mulders, M; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Nomerotski, A; Novaes, S F; Nunnemann, T; O'Dell, V; O'Neil, D C; Obrant, G; Ochando, C; Onoprienko, D; Oshima, N; Osta, J; Otec, R; Y Garzón, G J Otero; Owen, M; Padley, P; Pangilinan, M; Parashar, N; Park, S-J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Penning, B; Perea, P M; Peters, K; Peters, Y; Pétroff, P; Petteni, M; Piegaia, R; Piper, J; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M-E; Polozov, P; Pompos, A; Pope, B G; Popov, A V; Potter, C; da Silva, W L Prado; Prosper, H B; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rakitine, A; Rangel, M S; Rani, K J; Ranjan, K; Ratoff, P N; Renkel, P; Reucroft, S; Rich, P; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Robinson, S; Rodrigues, R F; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Santoro, A; Savage, G; Sawyer, L; Scanlon, T; Schaile, D; Schamberger, R D; Scheglov, Y; Schellman, H; Schieferdecker, P; Schliephake, T; Schmitt, C; Schwanenberger, C; Schwartzman, A; Schwienhorst, R; Sekaric, J; Sengupta, S; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shivpuri, R K; Shpakov, D; Siccardi, V; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Smith, R P; Snow, J; Snow, G R; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Souza, M; Spurlock, B; Stark, J; Steele, J; Stolin, V; Stone, A; Stoyanova, D A; Strandberg, J; Strandberg, S; Strang, M A; Strauss, M; Strauss, E; Ströhmer, R; Strom, D; Strovink, M; Stutte, L; Sumowidagdo, S; Svoisky, P; Sznajder, A; Talby, M; Tamburello, P; Tanasijczuk, A; Taylor, W; Telford, P; Temple, J; Tiller, B; Tissandier, F; Titov, M; Tokmenin, V V; Tomoto, M; Toole, T; Torchiani, I; Trefzger, T; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Unalan, R; Uvarov, S; Uvarov, L; Uzunyan, S; Vachon, B; van den Berg, P J; van Eijk, B; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vartapetian, A; Vasilyev, I A; Vaupel, M; Verdier, P; Vertogradov, L S; Verzocchi, M; Villeneuve-Seguier, F; Vint, P; Vokac, P; Von Toerne, E; Voutilainen, M; Vreeswijk, M; Wagner, R; Wahl, H D; Wang, L; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, M; Weber, G; Weerts, H; Wenger, A; Wermes, N; Wetstein, M; White, A; Wicke, D; Wilson, G W; Williams, M R J; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yacoob, S; Yamada, R; Yan, M; Yasuda, T; Yatsunenko, Y A; Yip, K; Yoo, H D; Youn, S W; Yu, J; Yu, C; Yurkewicz, A; Zatserklyaniy, A; Zeitnitz, C; Zhang, D; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zivkovic, L; Zutshi, V; Zverev, E G

    2007-10-26

    This Letter presents the first strong evidence for the resolution of the excited B mesons B(1) and B(2)* as two separate states in fully reconstructed decays to B(+)(*)pi(-). The mass of B(1) is measured to be 5720.6+/-2.4+/-1.4 MeV/c(2) and the mass difference DeltaM between B(2)* and B(1) is 26.2+/-3.1+/-0.9 MeV/c;{2}, giving the mass of the B(2)* as 5746.8+/-2.4+/-1.7 MeV/c(2). The production rate for B(1) and B(2)* mesons is determined to be a fraction (13.9+/-1.9+/-3.2)% of the production rate of the B+ meson.

  15. Exotic meson decays in the environment with chiral imbalance

    Science.gov (United States)

    Andrianov, A. A.; Andrianov, V. A.; Espriu, D.; Iakubovich, A. V.; Putilova, A. E.

    2017-10-01

    An emergence of Local Parity Breaking (LPB) in central heavy-ion collisions (HIC) at high energies is discussed. LPB in the fireball can be produced by a difference between the number densities of right- and left-handed chiral fermions (Chiral Imbalance) which is implemented by a chiral (axial) chemical potential. The effective meson lagrangian induced by QCD is extended to the medium with Chiral Imbalance and the properties of light scalar and pseudoscalar mesons (π, α0) are analyzed. It is shown that exotic decays of scalar mesons arise as a result of mixing of π and α0 vacuum states in the presence of chiral imbalance. The pion electromagnetic formfactor obtains an unusual parity-odd supplement which generates a photon polarization asymmetry in pion polarizability. We hope that the above pointed indications of LPB can be identified in experiments on LHC, RHIC, CBM FAIR and NICA accelerators.

  16. Current status of high energy nucleon-meson transport code

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Hiroshi; Sasa, Toshinobu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Current status of design code of accelerator (NMTC/JAERI code), outline of physical model and evaluation of accuracy of code were reported. To evaluate the nuclear performance of accelerator and strong spallation neutron origin, the nuclear reaction between high energy proton and target nuclide and behaviors of various produced particles are necessary. The nuclear design of spallation neutron system used a calculation code system connected the high energy nucleon{center_dot}meson transport code and the neutron{center_dot}photon transport code. NMTC/JAERI is described by the particle evaporation process under consideration of competition reaction of intranuclear cascade and fission process. Particle transport calculation was carried out for proton, neutron, {pi}- and {mu}-meson. To verify and improve accuracy of high energy nucleon-meson transport code, data of spallation and spallation neutron fragment by the integral experiment were collected. (S.Y.)

  17. Importance of Nonperturbative QCD Parameters for Bottom Mesons

    Directory of Open Access Journals (Sweden)

    A. Upadhyay

    2014-01-01

    Full Text Available The importance of nonperturbative quantum chromodynamics (QCD parameters is discussed in context to the predicting power for bottom meson masses and isospin splitting. In the framework of heavy quark effective theory, the work presented here focuses on the different allowed values of the two nonperturbative QCD parameters used in heavy quark effective theory formula, and using the best fitted parameter, masses of the excited bottom meson states in jp=1/2+ doublet in strange and nonstrange sectors are calculated here. The calculated masses are found to be matching well with experiments and other phenomenological models. The mass splitting and hyperfine splitting have also been analyzed for both strange and nonstrange heavy mesons with respect to spin and flavor symmetries.

  18. Reaction e+e-→D¯D and ψ' mesons

    Science.gov (United States)

    Limphirat, A.; Sreethawong, W.; Khosonthongkee, K.; Yan, Y.

    2014-03-01

    We study the reaction e+e-→D¯D near threshold in the P30 nonrelativistic quark mod