WorldWideScience

Sample records for pseudoscalar meson photoproduction

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.)

  7. 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.

  8. 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)

  9. 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.

  10. 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.

  11. 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.

  12. 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).

  13. 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.

  14. 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.

  15. 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].

  16. 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).

  17. 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.

  18. 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.

  19. 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.

  20. Page 1 Weak decay constants of pseudoscalar mesons model with ...

    Indian Academy of Sciences (India)

    required energy conservation at the quark-boson vertex; since the sum total of the kinetic energy of the constituent quark and antiquark in the process in not equal to the mass–energy of the decaying pseudoscalar meson considered in its rest frame. This is a common feature with all the phenomenological models based on ...

  1. 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.

  2. 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 ...

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Exclusive central diffractive production of scalar, pseudoscalar and vector mesons

    Directory of Open Access Journals (Sweden)

    Lebiedowicz P.

    2014-01-01

    Full Text Available We discuss exclusive central diffractive production of scalar (ƒ0(980, ƒ0(1370, ƒ0(1500, pseudoscalar (η, η′(958, and vector (ρ0 mesons in proton-proton collisions. The amplitudes are formulated in terms of effective vertices required to respect standard rules of Quantum Field Theory and propagators for the exchanged pomeron and reggeons. Different pomeron-pomeron-meson tensorial (vectorial coupling structures are possible in general. In most cases two lowest orbital angular momentum - spin couplings are necessary to describe experimental differential distributions. For the ƒ0(980 and η production the reggeon-pomeron, pomeron-reggeon, and reggeon-reggeon exchanges are included in addition, which seems to be necessary at relatively low energies. The theoretical results are compared with the WA102 experimental data, in order to determine the model parameters. For the ρ0 production the photon-pomeron and pomeron-photon exchanges are considered. The coupling parameters of tensor pomeron and/or reggeon are fixed from the H1 and ZEUS experimental data of the γp → ρ0 p reaction. We present first predictions of this mechanism for pp → ppπ+π− reaction being studied at COMPASS, RHIC, Tevatron, and LHC. Correlation in azimuthal angle between outgoing protons and distribution in pion rapidities at √s = 7 TeV are presented. We show that high-energy central production of mesons could provide crucial information on the spin structure of the soft pomeron.

  8. The charge form factor of pseudoscalar mesons in a relativistic constituent quark model

    Energy Technology Data Exchange (ETDEWEB)

    Cardarelli, F.; Pace, E. [Univ. of Rome, Roma (Italy); Grach, I.L. [Inst. of Theoretical and Experimental Physics, Moscow (Russian Federation)] [and others

    1994-04-01

    The charge form factor of pseudoscalar mesons has been investigated in the light-cone formalism, up to Q{sup 2} relevant to CEBAF energies. The consequences of adopting the meson wave functions generated through the Godfrey-Isgur q{bar q} potential, which reproduces the mass spectra, are discussed.

  9. 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.

  10. {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.

  11. 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.

  12. 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.

  13. 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.

  14. 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}

  15. 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

  16. 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.

  17. 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

  18. Pseudoscalar glueball and $\\eta'$-meson in low-energy QCD expansion

    OpenAIRE

    Nekrasov, M L

    1995-01-01

    An effective chiral lagrangian of order $p^2$, describing the interaction of light pseudoscalar (PS) mesons with $\\eta'$-meson and PS-glueball, has been determined taking into consideration the renorm-group requirements imposed by QCD renormalization. It is shown that the interpolating fields for the lowest singlet quarkic and gluonic states, $\\eta^0$ and $\\eta^G$, may be involved into the effective theory to be renorm-invariant objects not mixing due to QCD renormalization. It is established...

  19. Excited scalar and pseudoscalar mesons in the extended linear sigma model

    Energy Technology Data Exchange (ETDEWEB)

    Parganlija, Denis [Technische Universitaet Wien, Institut fuer Theoretische Physik, Vienna (Austria); Giacosa, Francesco [Jan Kochanowski University, Institute of Physics, Kielce (Poland); Johann Wolfgang Goethe-Universitaet, Institut fuer Theoretische Physik, Frankfurt am Main (Germany)

    2017-07-15

    We present an in-depth study of masses and decays of excited scalar and pseudoscalar anti qq states in the Extended Linear Sigma Model (eLSM). The model also contains ground-state scalar, pseudoscalar, vector and axial-vector mesons. The main objective is to study the consequences of the hypothesis that the f{sub 0}(1790) resonance, observed a decade ago by the BES Collaboration and recently by LHCb, represents an excited scalar quarkonium. In addition we also analyse the possibility that the new a{sub 0}(1950) resonance, observed recently by BABAR, may also be an excited scalar state. Both hypotheses receive justification in our approach although there appears to be some tension between the simultaneous interpretation of f{sub 0}(1790)/a{sub 0}(1950) and pseudoscalar mesons η(1295), π(1300), η(1440) and K(1460) as excited anti qq states. (orig.)

  20. Masses of S and P wave mesons and pseudoscalar decay constants ...

    Indian Academy of Sciences (India)

    In the framework of relativistic harmonic confinement model for quarks and antiquarks, the masses of - and -wave mesons and pseudoscalar decay constants from light flavour to heavy flavour sectors are computed. The residual two-body Coulomb interaction and the spin-dependent interaction of the confined one gluon ...

  1. 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.

  2. 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.

  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. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Flavour breaking effects in the pseudoscalar meson decay constants

    Energy Technology Data Exchange (ETDEWEB)

    Bornyakov, V.G. [Institute for High Energy Physics, Protvino (Russian Federation); Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Far Eastern Federal Univ., Vladivostok (Russian Federation). School of Biomedicine; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Hyogo (Japan); Perlt, H.; Schiller, A. [Leipzig Univ. (Germany). Inst. fuer Theoretische Physik; Pleiter, D. [Forschungszentrum Juelich (Germany). Juelich Supercomputing Centre; Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division; Schierholz, G. [DESY Hamburg (Germany); Stueben, H. [Hamburg Univ. (Germany). Regionales Rechenzentrum; Zanotti, J.M. [Adelaide Univ. (Australia). CSSM, Dept. of Physics; Collaboration: QCDSF-UKQCD Collaborations

    2016-12-14

    The SU(3) flavour symmetry breaking expansion in up, down and strange quark masses is extended from hadron masses to meson decay constants. This allows a determination of the ratio of kaon to pion decay constants in QCD. Furthermore when using partially quenched valence quarks the expansion is such that SU(2) isospin breaking effects can also be determined. It is found that the lowest order SU(3) flavour symmetry breaking expansion (or Gell-Mann-Okubo expansion) works very well. Simulations are performed for 2+1 flavours of clover fermions at four lattice spacings.

  9. 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.

  10. 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...

  11. 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.

  12. 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.

  13. Charmed and strange pseudoscalar meson decay constants from HISQ simulations

    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; Kim, J; Komijani, J; Kronfeld, A S; Laiho, J; Levkova, L; Mackenzie, P B; Neil, E T; Simone, J N; Sugar, R L; Toussaint, D; Van de Water, R S; Zhou, R

    2013-01-01

    We update our determinations of $f_{D^+}$, $f_{D_s}$, $f_K$, and quark mass ratios from simulations with four flavors of HISQ dynamical quarks. The availability of ensembles with light quarks near their physical mass means that we can extract physical results with only small corrections for valence- and sea-quark mass mistunings instead of a chiral extrapolation. The adjusted valence-quark masses and lattice spacings may be determined from an ensemble-by-ensemble analysis, and the results for the quark mass ratios then extrapolated to the continuum limit. Our central values of the charmed meson decay constants, however, come from an alternative analysis, which uses staggered chiral perturbation theory for the heavy-light mesons, and allows us to incorporate data at unphysical quark masses where statistical errors are often smaller. A jackknife analysis propagated through all of these steps takes account of the correlations among all the quantities used in the analysis. Systematic errors from the finite spatia...

  14. 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

  15. Hard exclusive pseudoscalar meson electroproduction and spin structure of the nucleon

    Science.gov (United States)

    Frankfurt, L. L.; Pobylitsa, P. V.; Polyakov, M. V.; Strikman, M.

    1999-07-01

    The amplitude for hard exclusive pseudoscalar meson electroproduction off nucleon (nuclear) targets is computed in QCD within the leading αslnQ2/Λ2QCD approximation. We show that the distribution of recoil nucleons depends strongly on the angle between the momentum of the recoil nucleon and the polarization vector of the target (or outgoing nucleon). This dependence is especially sensitive to the spin flip skewed parton distribution (SPD) E~. We argue also that the scaling for this spin asymmetry sets in at lower Q2 than that for the absolute cross section. Based on the chiral quark-soliton model of the nucleon we estimate quantitatively the spin asymmetry. In the case of π+ production this asymmetry is dominated at small t by the contribution of the pion pole in the isovector SPD E~ as required by PCAC. In the case of K0 production off a proton we find a large enhancement of the cross section as compared to the case of π0 production. For the forward production of neutral pseudoscalar mesons off a deuteron target we find the cross section should be zero for the zero deuteron helicity (along the γ*D direction). We consider also cross sections of quasielastic processes off nuclei including the feasibility to implant K+,ρ mesons into nuclear volume.

  16. Deep Exclusive Pseudoscalar Meson Production at Jefferson Lab Hall C

    Energy Technology Data Exchange (ETDEWEB)

    Basnet, Samip [Univ. of Regina, SK (Canada)

    2017-09-01

    Measurements of exclusive meson production are a useful tool in the study of hadronic structure. In particular, one can discern the relevant degrees of freedom at different distance scales through these studies. In the transition region between low momentum transfer (where a description of hadronic degrees of freedom in terms of effective hadronic Lagrangians is valid) and high momentum transfer (where the degrees of freedom are quarks and gluons), the predictive power of Quantum Chromodynamics (QCD), the theory of the strong interaction, is limited due to the absence of a complete solution. Thus, one has to rely upon experimental data from the non-perturbative intermediate-energy regime to thoroughly understand the onset of perturbative QCD (pQCD) as the momentum transfer is increased. This work involves two deep exclusive meson electroproduction experiments at Jefferson Lab (JLab). The p(e,e'pi+)n reaction is studied at fixed Q^2 and W of 2.5 GeV2 and 2.0 GeV, respectively, while varying the four momentum transfer to the nucleon -t from 0.2 to 2.1 GeV2 . As -t is increased, the hadronic interaction scale is reduced independently of the observation scale of the virtual photon, providing valuable information about the hard- scattering process in general. The data was taken at JLab Hall C in 2003, as a part of the experiment E01-004, Fpi-2, using the High Momentum Spectrometer (HMS) and Short Orbit Spectrometer (SOS), and in this work, the results of the differential cross section analysis are presented and compared to prior data, as well as two theoretical models. Using these results over a wide -t range, the transition from hard to soft QCD is also studied. In addition, the p(e,e'K+)Lambda(Sigma0) reactions are also studied. Despite their importance in elucidating the reaction mechanism underlying strangeness production, we still do not have complete understanding of these reactions above the resonance region. The experiment, E12- 09-011, intends to

  17. In-medium pseudoscalar D/B mesons and charmonium decay width

    Energy Technology Data Exchange (ETDEWEB)

    Chhabra, Rahul; Kumar, Arvind [Dr. B.R. Ambedkar National Institute of Technology Jalandhar, Department of Physics, Jalandhar, Punjab (India)

    2017-05-15

    Using QCD sum rules and the chiral SU(3) model, we investigate the effect of temperature, density, strangeness fraction and isospin asymmetric parameter on the shift in masses and decay constants of the pseudoscalar D and B meson in the hadronic medium, which consist of nucleons and hyperons. The in-medium properties of D and B mesons within the QCD sum rule approach depend upon the quark and gluon condensates. In the chiral SU(3) model, quark and gluon condensates are introduced through the explicit symmetry breaking term and the trace anomaly property of the QCD, respectively and are written in terms of the scalar fields σ, ζ, δ and χ. Hence, through medium modification of σ, ζ, δ and χ fields, we obtain the medium-modified masses and decay constants of D and B mesons. As an application, using {sup 3}P{sub 0} model, we calculate the in-medium decay width of the higher charmonium states ψ(3686), ψ(3770) and χ(3556) to the D anti D pairs, considering the in-medium mass of D mesons. These results may be important to understand the possible outcomes of the high-energy physics experiments, e.g., CBM and PANDA at GSI, Germany. (orig.)

  18. In-medium pseudoscalar D/B mesons and charmonium decay width

    Science.gov (United States)

    Chhabra, Rahul; Kumar, Arvind

    2017-05-01

    Using QCD sum rules and the chiral SU(3) model, we investigate the effect of temperature, density, strangeness fraction and isospin asymmetric parameter on the shift in masses and decay constants of the pseudoscalar D and B meson in the hadronic medium, which consist of nucleons and hyperons. The in-medium properties of D and B mesons within the QCD sum rule approach depend upon the quark and gluon condensates. In the chiral SU(3) model, quark and gluon condensates are introduced through the explicit symmetry breaking term and the trace anomaly property of the QCD, respectively and are written in terms of the scalar fields σ, ζ, δ and χ. Hence, through medium modification of σ, ζ, δ and χ fields, we obtain the medium-modified masses and decay constants of D and B mesons. As an application, using {}3P0 model, we calculate the in-medium decay width of the higher charmonium states ψ(3686), ψ(3770) and χ(3556) to the D\\bar{D} pairs, considering the in-medium mass of D mesons. These results may be important to understand the possible outcomes of the high-energy physics experiments, e.g., CBM and PANDA at GSI, Germany.

  19. In-medium properties of pseudoscalar D_s and B_s mesons

    Science.gov (United States)

    Chhabra, Rahul; Kumar, Arvind

    2017-11-01

    We calculate the shift in the masses and decay constants of D_s(1968) and B_s(5370) mesons in hot and dense asymmetric strange hadronic matter using QCD sum rules and chiral SU(3) model. In-medium strange quark condensates _{ρ _B}, and gluon condensates _{ρ _B}, to be used in the QCD sum rules for pseudoscalar D_s and B_s mesons, are calculated using a chiral SU(3) model. As an application of our present work, we calculate the in-medium decay widths of the excited (c\\bar{s}) states D_s^*(2715) and D_s^*(2860) decaying to (D_s(1968),η ) mesons. The medium effects in their decay widths are incorporated through the mass modification of the D_s(1968) and η mesons. The results of the present investigation may be helpful in understanding the possible outcomes of the future experiments like CBM and PANDA under the FAIR facility.

  20. 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.

  1. Pseudoscalar D and B mesons in the hot dense and nonstrange symmetric medium

    Science.gov (United States)

    Chhabra, Rahul; Kumar, Arvind

    2017-01-01

    We investigate the effect of temperature and density on the shift in the masses and decay constants of the pseudoscalar D and B mesons in the nonstrange symmetric medium. We use chiral SU(3) model to calculate the medium modified scalar and isoscalar fields σ, ζ, δ and χ. We use these modified fields to calculate the in-medium quark and gluon condensates by solving the coupled equations of motions in the chiral SU(3) model. We obtain the medium modified mass and decay constant through these medium modified condensates using the QCD sum rules. Further we use the 3P0 model by taking the internal structure of the mesons to calculate the in-medium decay width of the higher charmonium states χ(3556) , ψ(3686) and ψ(3770) to the D D pairs, through the in-medium mass of D meson and neglecting the mass modification of higher charmonium states. We also compare the present data with the previous results. These results of present investigation may be important to explain the possible outcomes of the experiments like CBM, Panda at GSI.

  2. Properties of pseudoscalar flavour-singlet mesons from 2+1+1 twisted mass lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Cichy, Krzysztof [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Poznan Univ. (Poland). Faculty of Physics; Drach, Vincent; Garcia Ramos, Elena; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Michael, Chris [Liverpool Univ. (United Kingdom). Dept. of Mathematical Sciences; Ottnad, Konstantin; Urbach, Carsten; Zimmermann, Falk [Bonn Univ. (Germany). Inst. fuer Strahlen- und Kernphysik

    2012-11-15

    We study properties of pseudoscalar flavour-singlet mesons from Wilson twisted mass lattice QCD with N{sub f}=2+1+1 dynamical quark flavors. Results for masses are presented at three values of the lattice spacing and light quark masses corresponding to values of the pion mass from 230 MeV to 500 MeV. We briefly discuss scaling effects and the light and strange quark mass dependence of M{sub {eta}}. In addition we present an exploratory study using Osterwalder-Seiler type strange and charm valence quarks. This approach avoids some of the complications of the twisted mass heavy doublet. We present first results for matching valence and unitary actions and a comparison of statistical uncertainties.

  3. Pseudoscalar-Meson Octet-Baryon Coupling Constants from two-flavor Lattice QCD

    CERN Document Server

    Takahashi, Toru T; Oka, Makoto

    2009-01-01

    We evaluate the pseudoscalar-meson octet-baryon coupling constants and the corresponding axial charges in eight channels ($\\pi N\\N$, $\\pi\\Sigma\\Sigma$, $\\pi\\Lambda\\Sigma$, $K\\Lambda N$, $K \\Sigma N $, $\\pi\\Xi\\Xi$, $K\\Lambda\\Xi$ and $K\\Sigma\\Xi$) in lattice QCD with two flavors of dynamical quarks. The parameter $\\alpha\\equiv F/(F+D)$ representing the SU(3)-flavor symmetry is computed at each u,d-quark hopping parameter and at the flavor-SU(3) symmetric point where the three quark flavors are degenerate at the physical $s$-quark mass. In particular, we obtain $\\alpha=0.395(6)$ at the SU(3) symmetric limit. The quark-mass dependences of the coupling constants are obtained by changing the $u$- and the $d$-quark masses and we find that the SU(3)-flavor symmetry is broken by only a few percent at each quark-mass we employ.

  4. Deeply Virtual Pseudoscalar Meson Production at Jefferson Lab and Transversity GPDs

    CERN Document Server

    Kubarovsky, Valery

    2016-01-01

    The cross section of the exclusive $\\pi^0$ and $\\eta$ electroproduction reaction $ep\\to e^\\prime p^\\prime \\pi^0/\\eta$ was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections $d^4\\sigma/dtdQ^2dx_Bd\\phi$ and structure functions $\\sigma_T+\\epsilon\\sigma_L, \\sigma_{TT}$ and $\\sigma_{LT}$ as functions of $t$ were obtained over a wide range of $Q^2$ and $x_B$. The data are compared with the GPD based theoretical models. Analyses find that a large dominance of transverse processes is necessary to explain the experimental results. Generalized form factors of the transversity GPDs $H_T^{\\pi,\\eta}$ and $\\bar E_T^{\\pi,\\eta}$ were directly extracted from the experimental observables for the first time. It was found that GPD $\\bar E_T$ dominates in pseudoscalar meson production. The combined $\\pi^0$ and $\\eta$ data opens the way for the flavor decomposition of the transversity GPDs. The first ever evaluation of this decomposition was demonstrated.

  5. 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.

  6. Inclusive Photoproduction of rho^0, K^{*0} and phi Mesons at HERA

    CERN Document Server

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

    2009-01-01

    Inclusive non-diffractive photoproduction of rho(770)^0, K^*(892)^0 and phi(1020) mesons is investigated with the H1 detector in ep collisions at HERA. The corresponding average \\gamma p centre-of-mass energy is 210 GeV. The mesons are measured in the transverse momentum range 0.5

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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...

  14. 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.

  15. The time-like electromagnetic form factors of the charged pseudoscalar mesons from 144 to 90 GeV/sup 2/

    CERN Document Server

    Bernardini, M; Brunini, P L; Fiorentino, E; Massam, Thomas; Monari, L; Palmonari, F; Rimondi, F; Zichichi, A

    1973-01-01

    The study of 620 hadron pairs produced in the s-range (1.44-9.0) GeV /sup 2/, has yielded 110 collinear hadronic events. Their identification in terms of pi and K mesons allows the determination of the time-like electromagnetic from factors of these pseudoscalar mesons in the above time-like range. The total number of (e/sup +or-/e /sup -/) events observed in the same experimental conditions is 18048. (10 refs).

  16. {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.)

  17. 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.)

  18. 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...

  19. 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.)

  20. 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.)

  1. 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.)

  2. 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

  3. 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.

  4. 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.)

  5. 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...

  6. Central Production of Two-Pseudoscalar Meson Systems at the COMPASS Experiment at CERN

    CERN Document Server

    Austregesilo, Alexander; Mallot, Gerhard

    The question of the existence of glueballs is one of the unsolved problems in modern particle physics and can be regarded as a stringent test for quantum chromodynamics. Especially the supernumerous states in the light scalar meson spectrum are candidates for the observation of mixing effects between $q\\bar q$ mesons and pure gluonic bound states. On the other hand, the existence and the properties of many resonances in this sector are disputed. The COMPASS experiment was proposed to make significant contributions to this field. COMPASS is a fixed-target experiment at the CERN SPS which focused on light-quark hadron spectroscopy during the data taking periods in 2008 and 2009. A world-leading data set was collected with a $190\\,\\mathrm{GeV}/c$ hadron beam impinging on a liquid hydrogen target in order to study, inter alia, the central production of glueball candidates in the light meson sector. Especially the double-Pomeron exchange mechanism is well suited for the production of mesons without valenc...

  7. 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.

  8. 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.

  9. 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.

  10. Electromagnetic effects on the light pseudoscalar mesons and determination of $m_u/m_d$

    CERN Document Server

    Basak, S; Bernard, C; DeTar, C; Freeland, E; Foley, J; Gottlieb, Steven; Heller, U M; Komijani, J; Laiho, J; Levkova, L; Osborn, J; Sugar, R L; Torok, A; Toussaint, D; Van de Water, R S; Zhou, R

    2016-01-01

    The MILC Collaboration has completed production running of electromagnetic effects on light mesons using asqtad improved staggered quarks. In these calculations, we use quenched photons in the noncompact formalism. We study four lattice spacings from $\\approx\\!0.12\\:$fm to $\\approx\\!0.045\\:$fm. To study finite-volume effects, we used six spatial lattice sizes $L/a=12$, 16, 20, 28, 40, and 48, at $a\\!\\approx\\!0.12\\:$fm. We update our preliminary values for the correction to Dashen's theorem ($\\epsilon$) and the quark-mass ratio $m_u/m_d$.

  11. 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.)

  12. 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...

  13. 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...

  14. 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.)

  15. 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.

  16. 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

  17. 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.

  18. 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.)

  19. Application of the light-front holographic wavefunction for heavy-light pseudoscalar meson in Bd,s → Dd,sP decays

    Science.gov (United States)

    Chang, Qin; Xu, Shuai; Chen, Lingxin

    2017-08-01

    In this paper we extend our analyses of the decay constant and distribution amplitude with an improved holographic wavefunction to the heavy-light pseudoscalar mesons. In the evaluations, the helicity-dependence of the holographic wavefunction is considered; and an independent mass scale parameter is employed to moderate the strong suppression induced by the heavy quark. Under the constraints from decay constants and masses of pseudoscalar mesons, the χ2-analyses for the holographic parameters exhibit a rough consistence with the results obtained by fitting the Regge trajectory. With the fitted parameters, the results for the decay constants and distribution amplitudes are presented. We then show their application in evaluating the Bd,s →Dd,s P decays, in which the power-suppressed spectator scattering and weak annihilation corrections are first estimated. Numerically, the spectator scattering and weak annihilation corrections present a negative shift of about 0.7% on the branching fractions; while, the predictions are still larger than the experimental data. Such small negative shift confirms the estimation based on the power counting rules.

  20. Electromagnetic structure and weak decay of pseudoscalar mesons in a theory inspired in the QCD; Estrutura eletromagnetica e decaimento fraco de mesons pseudoescalares em uma teoria inspirada na QCD

    Energy Technology Data Exchange (ETDEWEB)

    Salcedo, Luiz Alberto de Moraes

    2004-07-01

    The electroweak properties of the ground state of the pseudoscalar mesons, {pi}, K, D, D{sub s}, B e B{sub c} were investigated within a relativistic constituent quark model on the light-front, inspired by Quantum Chromodynamics (QCD). The dynamics of the original model is given in terms of a mass square operator which contains a Coulomb-like and a singular hyperfine short-range interaction, which was treated using an Hamiltonian renormalization method. In this dissertation, the singular hyperfine interaction was regulated by a separable operator. The regularized model was parameterized to fit the pion mass and weak decay constant. In this way, the experimental values of the mass splitting between the ground states of the pseudoscalar and vector mesons were reasonably reproduced by the model. The results for the weak decay constants of the K, D, Ds, B and B{sub c} were consistent with experimental values and calculations from lattice QCD. The experimental data for the {pi} and K electromagnetic form factors were reproduced as well. (author)

  1. 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.)

  2. 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.

  3. 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.

  4. 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

  5. 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.)

  6. Phase Difference Between the Electromagnetic and Strong Amplitudes for psi(2S) and J/psi Decays into Pairs of Pseudoscalar Mesons

    CERN Document Server

    Metreveli, Z; Tomaradze, A; Xiao, T; Seth, Kamal K; Yelton, J; Asner, D M; Tatishvili, G; Bonvicini, G

    2012-01-01

    Using the data for 24.5x10^6 psi(2S) produced in e^+e^- annihilations at sqrt{s}=3686 MeV at the CESR-c e^+e^- collider and 8.6x10^6 J/psi produced in the decay psi(2S)->pi^+pi^-J/psi, the branching fractions for psi(2S) and J/psi decays to pairs of pseudoscalar mesons, pi^+pi^-, K^+K^-, and K_S K_L, have been measured using the CLEO-c detector. We obtain branching fractions Br(psi(2S)->pi^+pi^-)=(7.6+-2.5+-0.6)x10^-6, Br(psi(2S)->K^+K^-)=(74.8+-2.3+-3.9)x10^-6, Br(psi(2S)->K_S K_L)=(52.8+-2.5+-3.4)x10^-6, and Br(J/psi->pi^+pi^-)=(1.47+-0.13+-0.13)x10^-4, Br(J/psi->K^+K^-)=(2.86+-0.09+-0.19)x10^-4, Br(J/psi+-K_S K_L)=(2.62+-0.15+-0.14)x10^-4, where the first errors are statistical and the second errors are systematic. The phase differences between the amplitudes for electromagnetic and strong decays of psi(2S) and J/psi to 0^{-+} pseudoscalar pairs are determined by a Monte Carlo method to be \\delta(psi(2S)_{PP}=(110.5^{+16.0}_{-9.5})^o and \\delta(J/psi)_{PP}=(73.5^{+5.0}_{-4.5})^o. The difference between the...

  7. 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.

  8. 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.)

  9. 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.

  10. 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

  11. 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.

  12. 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 $|t|$.

  13. 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.

  14. 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.)

  15. 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.

  16. 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.

  17. 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.)

  18. 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.

  19. Decay modes of the excited pseudoscalar glueball

    Science.gov (United States)

    Eshraim, Walaa I.; Schramm, Stefan

    2017-01-01

    We study three different chiral Lagrangians that describe the two- and three-body decays of an excited pseudoscalar glueball, JP C=0*-+ , into light mesons and charmonium states as well as into a scalar and pseudoscalar glueball. We compute the decay channels for an excited pseudoscalar glueball with a mass of 3.7 GeV and consider a ground-state pseudoscalar glueball of mass 2.6 GeV, following predictions from lattice QCD simulations. These states and channels are in reach of the ongoing BESIII experiment and the PANDA experiments at the upcoming FAIR facility experiment. We present the resulting decay branching ratios with a parameter-free prediction.

  20. 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.

  1. 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.)

  2. 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.

  3. 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 ...

  4. 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 ...

  5. 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.)

  6. 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.

  7. 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.

  8. 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.

  9. 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 ...

  10. 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.

  11. 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.

  12. 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.)

  13. 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.

  14. 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’.

  15. Exact formula of the spectrum of the pseudoscalar octet

    Directory of Open Access Journals (Sweden)

    R. Ling

    2015-01-01

    Full Text Available Non-perturbative proof is presented of a generalized version of Goldstone theorem, where the Lagrangian conserves an approximate SU(3 chiral symmetry, that both quark masses and electromagnetism make contributions to the masses of spinless particles of pseudoscalar octet. We show that apart from what comes in the form of some projections of a two-body Bethe–Salpeter amplitude for which the photon lines like the gluon ones are all internal in the case of neutral pseudo-Goldstone bosons, the charged pseudoscalar mesons receive additional contributions that may be expressed in terms of the axial–vectorial projection of a three-body Bethe–Salpeter amplitude with an extra external photon line.

  16. 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...

  17. 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 ...

  18. Stellar matter with pseudoscalar condensates

    Energy Technology Data Exchange (ETDEWEB)

    Andrianov, A.A. [Saint-Petersburg State University, St. Petersburg (Russian Federation); Universitat de Barcelona, Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos (ICCUB), Barcelona, Catalonia (Spain); Andrianov, V.A.; Kolevatov, S.S. [Saint-Petersburg State University, St. Petersburg (Russian Federation); Espriu, D. [Universitat de Barcelona, Departament d' Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos (ICCUB), Barcelona, Catalonia (Spain)

    2016-03-15

    In this work we consider how the appearance of gradients of pseudoscalar condensates in dense systems may possibly influence the transport properties of photons in such a medium as well as other thermodynamic characteristics. We adopt the hypothesis that in regions where the pseudoscalar density gradient is large the properties of photons and fermions are governed by the usual lagrangian extended with a Chern-Simons interaction for photons and a constant axial field for fermions. We find that these new pieces in the lagrangian produce non-trivial reflection coefficients both for photons and fermions when entering or leaving a region where the pseudoscalar has a non-zero gradient. A varying pseudoscalar density may also lead to instability of some fermion and boson modes and modify some properties of the Fermi sea. We speculate that some of these modifications could influence the cooling rate of stellar matter (for instance in compact stars) and have other observable consequences. While quantitative results may depend on the precise astrophysical details most of the consequences are quite universal and consideration should be given to this possibility. (orig.)

  19. 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.

  20. 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.

  1. Deeply Pseudoscalar Meson Electroproduction with CLAS and Generalized Parton Distributions

    Energy Technology Data Exchange (ETDEWEB)

    Guidal, Michel [Institut de Physique Nucleaire, Orsay (France); Kubarovsky, Valery P. [Jefferson Lab., Newport News, VA (United States)

    2015-06-01

    We discuss the recent data of exclusive $\\pi^0$ (and $\\pi^+$) electroproduction on the proton obtained by the CLAS collaboration at Jefferson Lab. It is observed that the cross sections, which have been decomposed in $\\sigma_T+\\epsilon\\sigma_L$, $\\sigma_{TT}$ and $\\sigma_{LT}$ structure functions, are dominated by transverse amplitude contributions. The data can be interpreted in the Generalized Parton Distribution formalism provided that one includes helicity-flip transversity GPDs.

  2. Charmed and light pseudoscalar meson decay constants from HISQ simulations

    CERN Document Server

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

    2014-01-01

    We compute the leptonic decay constants $f_{D^+}$, $f_{D_s}$, and $f_{K^+}$, and the quark-mass ratios $m_c/m_s$ and $m_s/m_l$ in unquenched lattice QCD. We use the MILC highly improved staggered quark (HISQ) ensembles with four dynamical quark flavors. Our primary results are $f_{D^+} = 212.6(0.4)({}^{+1.0}_{-1.2})\\ \\mathrm{MeV}$, $f_{D_s} = 249.0(0.3)({}^{+1.1}_{-1.5})\\ \\mathrm{MeV}$, and $f_{D_s}/f_{D^+} = 1.1712(10)({}^{+29}_{-32})$, where the errors are statistical and total systematic, respectively. We also obtain $f_{K^+}/f_{\\pi^+} = 1.1956(10)({}^{+26}_{-18})$, updating our previous result, and determine the quark-mass ratios $m_s/m_l = 27.35(5)({}^{+10}_{-7})$ and $m_c/m_s = 11.747(19)({}^{+59}_{-43})$. When combined with experimental measurements of the decay rates, our results lead to precise determinations of the CKM matrix elements $|V_{us}| = 0.22487(51) (29)(20)(5)$, $|V_{cd}|=0.217(1) (5)(1)$ and $|V_{cs}|= 1.010(5)(18)(6)$, where the errors are from this calculation of the decay constants, th...

  3. Charmed and light pseudoscalar meson decay constants from HISQ simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bazavov, Alexei; et al.

    2014-11-16

    We compute the leptonic decay constants $f_{D^+}$, $f_{D_s}$, and $f_{K^+}$, and the quark-mass ratios $m_c/m_s$ and $m_s/m_l$ in unquenched lattice QCD. We use the MILC highly improved staggered quark (HISQ) ensembles with four dynamical quark flavors. Our primary results are $f_{D^+} = 212.6(0.4)({}^{+1.0}_{-1.2})\\ \\mathrm{MeV}$, $f_{D_s} = 249.0(0.3)({}^{+1.1}_{-1.5})\\ \\mathrm{MeV}$, and $f_{D_s}/f_{D^+} = 1.1712(10)({}^{+29}_{-32})$, where the errors are statistical and total systematic, respectively. We also obtain $f_{K^+}/f_{\\pi^+} = 1.1956(10)({}^{+26}_{-18})$, updating our previous result, and determine the quark-mass ratios $m_s/m_l = 27.35(5)({}^{+10}_{-7})$ and $m_c/m_s = 11.747(19)({}^{+59}_{-43})$. When combined with experimental measurements of the decay rates, our results lead to precise determinations of the CKM matrix elements $|V_{us}| = 0.22487(51) (29)(20)(5)$, $|V_{cd}|=0.217(1) (5)(1)$ and $|V_{cs}|= 1.010(5)(18)(6)$, where the errors are from this calculation of the decay constants, the uncertainty in the experimental decay rates, structure-dependent electromagnetic corrections, and, in the case of $|V_{us}|$, the uncertainty in $|V_{ud}|$, respectively.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Meson loops in the f{sub 0}(980) and a{sub 0}(980) radiative decays into {rho},{omega}

    Energy Technology Data Exchange (ETDEWEB)

    Nagahiro, H. [Ibaraki, Research Center for Nuclear Physics (RCNP), Osaka (Japan); Roca, L. [Universidad de Murcia, Departamento de Fisica, Murcia (Spain); Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); Oset, E. [Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Departamento de Fisica Teorica and IFIC, Valencia (Spain)

    2008-04-15

    We calculate the radiative decay widths of the a{sub 0}(980) and f{sub 0}(980) scalar mesons into {rho}{gamma} and {omega}{gamma} considering the dynamically generated nature of these scalar resonances within the realm of the chiral unitary approach. The main ingredient in the evaluation of the radiative width of the scalar mesons are the loops coming from the decay into their constituent pseudoscalar-pseudoscalar components and the subsequent radiation of the photon. The dominant diagrams with only pseudoscalar mesons in the loops are found to be convergent while the divergence of those with a vector meson in the loop are written in terms of the two-meson loop function easily regularizable. We provide results for all the possible charge channels and obtain results, with uncertainties, which differ significantly from quark loops models and some version of vector meson dominance. (orig.)

  10. 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...

  11. {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.

  12. Dirac particle in a pseudoscalar potential

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, M. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Ap. Postal 20-364, 01000 (Mexico), D.F.; Zentella-Dehesa, A. [Departamento de Fisicoquimica, Intituto de Quimica, UNAM Ap. Postal 70-213, 04510 (Mexico), D.F.

    1996-02-01

    We study the problem of a Dirac particle with a pseudoscalar interaction in the potential approximation. It is shown how nonperturbative relativistic solutions arise. The case of the central pseudoscalar potential is explicitly worked out also in a closed form. The angular functions are worked out in general for this central case. Finally for the special case of the spherical well the radial solutions are shown to behave like Bessel-type functions. {copyright} {ital 1996 American Institute of Physics.}

  13. 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.

  14. 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.

  15. 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)

  16. 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.

  17. 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.

  18. 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)

  19. 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.

  20. Lattice results for low moments of light meson distribution amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, R.; Boyle, P.A. [Edinburgh Univ. (United Kingdom). SUPA, School of Physics; Broemmel, D.; Flynn, J.M.; Rae, T.D.; Sachrajda, C.T.C. [Southampton Univ. (United Kingdom). School of Physics and Astronomy; Donnellan, M.A. [NIC/DESY Zeuthen (Germany); Juettner, A. [CERN, Geneva (Switzerland). Physics Dept.

    2010-12-15

    As part of the UKQCD and RBC collaborations' N{sub f} = 2+1 domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons {pi} and K and the (longitudinally-polarised) vector mesons {rho}, K{sup *} and {phi}. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavour breaking effects. An important ingredient of the calculation is the nonperturbative renormalisation of lattice operators using the RI{sup '}/MOM technique. (orig.)

  1. 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.

  2. A lattice QCD determination of potentials between pairs of static-light mesons

    Energy Technology Data Exchange (ETDEWEB)

    Hetzenegger, Martin

    2011-07-04

    Potentials between pairs of static-light mesons are interesting in a sense that they give insights in the nature of strong interactions from first principles for multiquark systems. For large heavy quark masses, e.g., the spectra of heavy-light mesons are determined by excitations of the light quark and gluonic degrees of freedom. In particular, the vector-pseudoscalar splitting vanishes and a static-light meson can be interpreted as either a B, a B{sup *}, a D or a D{sup *} heavy-light meson. Calculating potentials between two static-light mesons also enables investigations of possible bound tetraquark states or for particles that are close to the meson-antimeson threshold, such as the X(3872) or the Z{sup +}(4430).

  3. Observation of Pseudoscalar and Axial Vector Resonances in pi- p -> K+ K- pi0 n at 18 GeV

    Energy Technology Data Exchange (ETDEWEB)

    G.S. Adams; T. Adams; Z. Bar-Yam; J.M. Bishop; V.A. Bodyagin; D.S. Brown; N.M. Cason; S.U. Chung; J.P. Cummings; K. Danyo; A.I. Demianov; S. Denisov; V. Dorofeev; J.P. Dowd; P. Eugenio; X.L. Fan; A.M. Gribushin; R.W. Hackenburg; M. Hayek; J. Hu; E.I. Ivanov; D. Joffe; I. Kachaev; W. Kern; E. King; O.L. Kodolova; V.L. Korotkikh; M.A. Kostin; Joachim Kuhn; V. Lipaev; J.M. Losecco; M. Lu; J.J. Manak; J. Napolitano; M. Nozar; C. Olchanski; A.I. Ostrovidov; T.K. Pedlar; A. Popov; D. Ryabchikov; A.H. Sanjari; L.I. Sarycheva; K.K. Seth; N. Shenhav; X. Shen; W.D. Shephard; N.B. Sinev; D.L. Stienike; S.A. Taegar; D.R. Thompson; A. Tomaradze; I.N. Vardanyan; D.P. Weygand; D. White; H.J. Willutzki; A.A. Yershov

    2001-09-01

    The number of pseudoscalar mesons in the mass range from 1400 to 1500 MeV/c{sup 2} has been a subject of considerable interest for many years, with several experiments having presented evidence for two closely spaced states. A new measurement of the reaction {pi}{sup -} p {yields} K{sup +} K{sup -} {pi}{sup 0}n has been made at a beam energy of 18 GeV. A partial wave analysis of the K{sup +} K{sup -} {pi}{sup 0} system shows evidence for three pseudoscalar resonances, {eta}(1295), {eta}(1416), and {eta}(1485), as well as two axial vectors, f{sub 1}(1285), and f{sub 1}(1420). Their observed masses, widths and decay properties are reported. No signal was observed for C(1480), an I{sub G} J{sup PC} = 1{sup +} 1{sup --} state previously reported in {phi}{pi}{sup 0} decay.

  4. 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...

  5. Generalized SU(3) Nambu-Jona-Lasinio model. Pt. 1; Mesonic modes

    Energy Technology Data Exchange (ETDEWEB)

    Klimt, S.; Lutz, M.; Vogl, U.; Weise, W. (Regensburg Univ. (Germany, F.R.). Inst. fuer Physik 1 - Theoretische Physik)

    1990-10-08

    We present calculations of mesonic (quark-antiquark) modes in a generalized Nambu-Jona-Lasinio model with three quark flavours. The effective interaction between quarks is symmetric under chiral SU(3){sub L}xSU(3){sub R} and incorporates a U(1){sub A}-breaking six-point interaction as suggested by 't Hooft. We coencentrate on the evaluation of masses and decay constants of pseudoscalar mesons, with special emphasis on the underlying symmetry breaking patterns. Scalar, vector and axial vector mesonic modes are also discussed. (orig.).

  6. Electromagnetic corrections to pseudoscalar decay constants

    Energy Technology Data Exchange (ETDEWEB)

    Glaessle, Benjamin Simon

    2017-03-06

    First principles Lattice quantum chromodynamics (LQCD) calculations enable the determination of low energy hadronic amplitudes. Precision LQCD calculations with relative errors smaller than approximately 1% require the inclusion of electromagnetic effects. We demonstrate that including (quenched) quantum electrodynamics effects in the LQCD calculation effects the values obtained for pseudoscalar decay constants in the per mille range. The importance of systematic effects, including finite volume effects and the charge dependence of renormalization and improvement coefficients, is highlighted.

  7. 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.

  8. 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.

  9. Decay angular distributions of K* and D* vector mesons in pion-nucleon scattering

    Science.gov (United States)

    Kim, Sang-Ho; Oh, Yongseok; Titov, Alexander I.

    2017-05-01

    The production mechanisms of open strangeness (K*) and open charm (D*) vector mesons in π-p scattering, namely, π-+p →K*0+Λ and π-+p →D*-+Λc+ , are investigated within the modified quark-gluon string model. To identify the major reaction mechanisms, we consider the subsequent decays of the produced vector mesons into two pseudoscalar mesons, i.e., K*→K +π and D*→D +π . We found that the decay distributions and density matrix elements are sensitive to the production mechanisms and can be used to disentangle the vector trajectory and pseudoscalar trajectory exchange models. Our results for K* production are compared with the currently available experimental data and the predictions for D* production process are presented as well. Our predictions can be tested at the present or planned experimental facilities.

  10. On the efficiency of stochastic volume sources for the determination of light meson masses

    CERN Document Server

    Endress, E; Wittig, H

    2011-01-01

    We investigate the efficiency of single timeslice stochastic sources for the calculation of light meson masses on the lattice as one varies the quark mass. Simulations are carried out with Nf = 2 flavours of non-perturbatively O(a) improved Wilson fermions for pion masses in the range of 450 - 760 MeV. Results for pseudoscalar and vector meson two-point correlation functions computed using stochastic as well as point sources are presented and compared. At fixed computational cost the stochastic approach reduces the variance considerably in the pseudoscalar channel for all simulated quark masses. The vector channel is more affected by the intrinsic stochastic noise. In order to obtain stable estimates of the statistical errors and a more pronounced plateau for the effective vector meson mass, a relatively large number of stochastic sources must be used.

  11. Self-energies of octet and decuplet baryons due to the coupling to the baryon-meson continuum

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Tecocoatzi, H. [INFN, Sezione di Genova, Genova (Italy); Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico (Mexico); Bijker, R. [Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico (Mexico); Ferretti, J. [Chinese Academy of Sciences, Institute of Theoretical Physics, Beijing (China); Dipartimento di Fisica, Universita di Roma Sapienza, Roma (Italy); INFN, Roma (Italy); Santopinto, E. [INFN, Sezione di Genova, Genova (Italy)

    2017-06-15

    We present an unquenched quark model calculation of the mass shifts of ground-state octet and decuplet baryons due to the coupling to the meson-baryon continuum. All ground-state baryons and pseudoscalar mesons are included in our calculation as intermediate states. The q anti q pair creation effects are taken explicitly into account through a microscopic, QCD-inspired, quark-antiquark pair creation mechanism. (orig.)

  12. The role of meson exchanges in light-by-light scattering

    Science.gov (United States)

    Lebiedowicz, Piotr; Szczurek, Antoni

    2017-09-01

    We discuss the role of meson exchange mechanisms in γγ → γγ scattering. Several pseudoscalar (π0, η, η‧ (958), ηc (1 S), ηc (2 S)), scalar (f0 (500), f0 (980), a0 (980), f0 (1370), χc0 (1 P)) and tensor (f2 (1270), a2 (1320), f2‧ (1525), f2 (1565), a2 (1700)) mesons are taken into account. We consider not only s-channel but also for the first time t- and u-channel meson exchange amplitudes corrected for off-shell effects including vertex form factors. We find that, depending on not well known vertex form factors, the meson exchange amplitudes interfere among themselves and could interfere with fermion-box amplitudes and modify the resulting cross sections. The meson contributions are shown as a function of collision energy as well as angular distributions are presented. Interesting interference effects separately for light pseudoscalar, scalar and tensor meson groups are discussed. The meson exchange contributions may be potentially important in the context of a measurement performed recently in ultraperipheral collisions of heavy ions by the ATLAS collaboration. The light-by-light interactions could be studied in future in electron-positron collisions by the Belle II at SuperKEKB accelerator.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.)

  18. 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.

  19. 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.

  20. 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.

  1. Exotic meson decays in the environment with chiral imbalance

    Directory of Open Access Journals (Sweden)

    Andrianov A. A.

    2017-01-01

    Full Text Available 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.

  2. Mass spectrum and decay constants of radially excited vector mesons

    Science.gov (United States)

    Mojica, Fredy F.; Vera, Carlos E.; Rojas, Eduardo; El-Bennich, Bruno

    2017-07-01

    We calculate the masses and weak decay constants of flavorless and flavored ground and radially excited JP=1- mesons within a Poincaré covariant continuum framework based on the Bethe-Salpeter equation. We use in both the quark's gap equation and the meson bound-state equation an infrared massive and finite interaction in the leading symmetry-preserving truncation. While our numerical results are in rather good agreement with experimental values where they are available, no single parametrization of the QCD inspired interaction reproduces simultaneously the ground and excited mass spectrum, which confirms earlier work on pseudoscalar mesons. This feature being a consequence of the lowest truncation, we pin down the range and strength of the interaction in both cases to identify common qualitative features that may help to tune future interaction models beyond the rainbow-ladder approximation.

  3. Strong couplings and form factors of charmed mesons in holographic QCD

    Science.gov (United States)

    Ballon-Bayona, Alfonso; Krein, Gastão; Miller, Carlisson

    2017-07-01

    We extend the two-flavor hard-wall holographic model of Erlich, Katz, Son, and Stephanov [Phys. Rev. Lett. 95, 261602 (2005), 10.1103/PhysRevLett.95.261602] to four flavors to incorporate strange and charm quarks. The model incorporates chiral and flavor symmetry breaking and provides a reasonable description of masses and weak decay constants of a variety of scalar, pseudoscalar, vector, and axial-vector strange and charmed mesons. In particular, we examine flavor symmetry breaking in the strong couplings of the ρ meson to the charmed D and D* mesons. We also compute electromagnetic form factors of the π , ρ , K , K*, D and D* mesons. We compare our results for the D and D* mesons with lattice QCD data and other nonperturbative approaches.

  4. 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.

  5. The dynamical mixing of light and pseudoscalar fields

    Indian Academy of Sciences (India)

    pseudoscalar fields coupled by axion-type interactions Lint = gφφ ϵµναβFµν Fαβ . The problem depends on several dimensionful scales, including the magnitude and ... [15], although this effect might be limited by observations of radio galaxies [16]. It has also been pointed out that pseudoscalar field can generate magnetic ...

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. Covariant Spectator Theory of heavy–light and heavy mesons and the predictive power of covariant interaction kernels

    Energy Technology Data Exchange (ETDEWEB)

    Leitão, Sofia, E-mail: sofia.leitao@tecnico.ulisboa.pt [CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Stadler, Alfred, E-mail: stadler@uevora.pt [Departamento de Física, Universidade de Évora, 7000-671 Évora (Portugal); CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Peña, M.T., E-mail: teresa.pena@tecnico.ulisboa.pt [Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Biernat, Elmar P., E-mail: elmar.biernat@tecnico.ulisboa.pt [CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

    2017-01-10

    The Covariant Spectator Theory (CST) is used to calculate the mass spectrum and vertex functions of heavy–light and heavy mesons in Minkowski space. The covariant kernel contains Lorentz scalar, pseudoscalar, and vector contributions. The numerical calculations are performed in momentum space, where special care is taken to treat the strong singularities present in the confining kernel. The observed meson spectrum is very well reproduced after fitting a small number of model parameters. Remarkably, a fit to a few pseudoscalar meson states only, which are insensitive to spin–orbit and tensor forces and do not allow to separate the spin–spin from the central interaction, leads to essentially the same model parameters as a more general fit. This demonstrates that the covariance of the chosen interaction kernel is responsible for the very accurate prediction of the spin-dependent quark–antiquark interactions.

  12. Phenomenology of pseudotensor mesons and the pseudotensor glueball

    Energy Technology Data Exchange (ETDEWEB)

    Koenigstein, Adrian [Johann Wolfgang Goethe University, Institute for Theoretical Physics, Frankfurt am Main (Germany); Frankfurt Institute for Advanced Studies, Frankfurt am Main (Germany); Giacosa, Francesco [Jan Kochanowski University, Institute of Physics, Kielce (Poland); Johann Wolfgang Goethe University, Institute for Theoretical Physics, Frankfurt am Main (Germany)

    2016-12-15

    We study the decays of the pseudotensor mesons (π{sub 2}(1670), K{sub 2}(1770), η{sub 2}(1645), η{sub 2}(1870)) interpreted as the ground-state nonet of 1{sup 1}D{sub 2} anti qq states using interaction Lagrangians which couple them to pseudoscalar, vector, and tensor mesons. While the decays of π{sub 2}(1670) and K{sub 2}(1770) can be well described, the decays of the isoscalar states η{sub 2}(1645) and η{sub 2}(1870) can be brought in agreement with the present experimental data only if the mixing angle between nonstrange and strange states is surprisingly large (about -42 {sup circle}, similar to the mixing in the pseudoscalar sector, in which the chiral anomaly is active). Such a large mixing angle is however at odd with all other conventional quark-antiquark nonets: if confirmed, a deeper study of its origin will be needed in the future. Moreover, the anti qq assignment of pseudotensor states predicts that the ratio [η{sub 2}(1870) → a{sub 2}(1320) π]/[η{sub 2}(1870) → f{sub 2}(1270) η] is about 23.5. This value is in agreement with Barberis et al., (20.4 ± 6.6), but disagrees with the recent reanalysis of Anisovich et al., (1.7 ± 0.4). Future experimental studies are necessary to understand this puzzle. If Anisovich's value is confirmed, a simple nonet of pseudoscalar mesons cannot be able to describe data (different assignments and/or additional states, such as an hybrid state, will be needed). In the end, we also evaluate the decays of a pseudoscalar glueball into the aforementioned conventional anti qq states: a sizable decay into K{sub 2}{sup *}(1430) K and a{sub 2}(1230) π together with a vanishing decay into pseudoscalar-vector pairs (such as ρ(770) π and K*(892) K) are expected. This information can be helpful in future studies of glueballs at the ongoing BESIII and at the future PANDA experiments. (orig.)

  13. Quarkonia and heavy-light mesons in a covariant quark model

    Directory of Open Access Journals (Sweden)

    Leitão Sofia

    2016-01-01

    Full Text Available Preliminary calculations using the Covariant Spectator Theory (CST employed a scalar linear confining interaction and an additional constant vector potential to compute the mesonic mass spectra. In this work we generalize the confining interaction to include more general structures, in particular a vector and also a pseudoscalar part, as suggested by a recent study [1]. A one-gluon-exchange kernel is also implemented to describe the short-range part of the interaction. We solve the simplest CST approximation to the complete Bethe-Salpeter equation, the one-channel spectator equation, using a numerical technique that eliminates all singularities from the kernel. The parameters of the model are determined through a fit to the experimental pseudoscalar meson spectra, with a good agreement for both quarkonia and heavy-light states.

  14. Measurement of the pseudoscalar mixing angle and $\\eta^{\\prime}$ gluonium content with KLOE detector

    CERN Document Server

    Ambrosino, F; Antonelli, M; Bacci, C; Beltrame, P; Bencivenni, G; Bertolucci, S; Bini, C; Bloise, C; Bocchetta, S; Bocci, V; Bossi, F; Bowring, D; Branchini, P; Caloi, R; Campana, P; Capon, G; Capussela, T; Ceradini, F; Chi, S; Chiefari, G; Ciambrone, P; Conetti, S; De Lucia, E; De Santis, A; De Simone, P; De Zorzi, G; Dell'Agnello, S; Denig, A; Di Domenico, A; Di Donato, C; Di Falco, S; Di Micco, B; Doria, A; Dreucci, M; Felici, G; Ferrari, A; Ferrer, M L; Finocchiaro, G; Fiore, S; Forti, C; Franzini, P; Gatti, C; Gauzzi, P; Giovannella, S; Gorini, E; Graziani, E; Incagli, M; Kluge, W; Kulikov, V; Lacava, F; Lanfranchi, G; Lee-Franzini, J; Leone, D; Martini, M; Massarotti, P; Mei, W; Meola, S; Miscetti, S; Moulson, M; Murtas, F; Müller, S; Napolitano, M; Nguyen, F; Palutan, M; Pasqualucci, E; Passeri, A; Patera, V; Perfetto, F; Pontecorvo, L; Primavera, M; Santangelo, P; Santovetti, E; Saracino, G; Sciascia, B; Sciubba, A; Scuri, F; Sfiligoi, I; Spadaro, T; Testa, M; Tortora, L; Valente, P; Valeriani, B; Venanzoni, G; Veneziano, S; Ventura, A; Versaci, R; Xu, G; al, et

    2007-01-01

    We have measured the ratio $R_{\\phi}=BR(\\phi \\to \\eta^{\\prime} \\gamma)/BR(\\phi \\to \\eta \\gamma)$ by looking for the radiative decays $\\phi \\to \\eta^{\\prime} \\gamma$ and $\\phi \\to \\eta \\gamma$ in the final states $\\pi^+\\pi^-$ 7 $\\gamma$'s and 7 $\\gamma$'s respectively, in a sample of $\\sim 1.3\\cdot 10^{9}$ $\\phi$ mesons produced at the Frascati $\\phi$-factory. We obtain $R_{\\phi}=(4.77\\pm0.09_{stat}\\pm0.19_{sys})\\cdot 10^{-3}$ from which we derive $BR(\\phi \\to \\eta^{\\prime} \\gamma)=(6.20\\pm0.11_{stat}\\pm0.25_{sys})\\cdot 10^{-5}$. In the hypothesis of no gluonium content we extract the pseudoscalar mixing angle in the quark-flavor basis $\\phi_P=(41.4\\pm0.3_{stat}\\pm0.7_{sys}\\pm0.6_{th})^{\\circ}$. Combining the value of $R_{\\phi}$ with other constraints, we estimate the gluonium fractional content of $\\eta^{\\prime}$ meson as $Z^2 = 0.14\\pm0.04$ and the mixing angle $\\phi_P = (39.7\\pm0.7)^{\\circ}$.

  15. Role of the a1(1260) resonance in multipion decays of light vector mesons

    Science.gov (United States)

    Achasov, N. N.; Kozhevnikov, A. A.

    2005-02-01

    The contribution of the a1(1260) meson to the amplitudes of the decays ρ(770)→4π, ω(782)→5π, and ϕ(1020)→5π is analyzed in the chiral model of pseudoscalar, vector, and axial vector mesons based on the generalized hidden local symmetry added with the anomalous terms. The analysis shows that inclusion of a1 meson in the intermediate states results in enhancement of the branching ratios of the above decays by the factor ranging from 1.3 to 1.9 depending on the mass of a1 meson ranging from 1.23 GeV to ma1=mρ√(2)=1.09 GeV, the greater factor standing in case of lower mass of the a1.

  16. 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.

  17. Decays of open charmed mesons in the extended Linear Sigma Model

    Directory of Open Access Journals (Sweden)

    Eshraim Walaa I.

    2014-01-01

    Full Text Available We enlarge the so-called extended linear Sigma model (eLSM by including the charm quark according to the global U(4r × U(4l chiral symmetry. In the eLSM, besides scalar and pseudoscalar mesons, also vector and axial-vector mesons are present. Almost all the parameters of the model were fixed in a previous study of mesons below 2 GeV. In the extension to the four-flavor case, only three additional parameters (all of them related to the bare mass of the charm quark appear.We compute the (OZI dominant strong decays of open charmed mesons. The results are compatible with the experimental data, although the theoretical uncertainties are still large.

  18. SU(3) implications of the observation of the A/sub 1/ and C mesons

    CERN Document Server

    Mazzucato, M; Dionisi, C; Foster, B; Gavillet, P; Gurtu, A; Kluyver, J C; McDowell, W L; Pennington, Michael R; Van de Walle, R T; Vergeest, J S M; Wells, J; Wolters, G F; Zralek, M

    1979-01-01

    A new determination of the Q/sub A/-Q/sub B/ mixing angle and of the antisymmetric coupling for the vector-pseudoscalar decay of the axial vector mesons is presented. This uses information from the decay rates of the A/sub 1/ and C mesons found in the study of baryon exchange processes in K/sup -/p interactions at 4.2 GeV/c combined with the decay rate B to omega pi . The consistency between the results obtained from backward produced A/sub 1/ and C and diffractively produced Q/sub 1/ and Q/sub 2/ is discussed. (22 refs).

  19. 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.

  20. 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.

  1. Charmed mesons with a symmetry-preserving contact interaction

    Science.gov (United States)

    Serna, Fernando E.; El-Bennich, Bruno; Krein, Gastão

    2017-07-01

    A symmetry-preserving treatment of a vector-vector contact interaction is used to study charmed heavy-light mesons. The contact interaction is a representation of nonperturbative kernels used in Dyson-Schwinger and Bethe-Salpeter equations of QCD. The Dyson-Schwinger equation is solved for the u , d , s and c quark propagators and the bound-state Bethe-Salpeter amplitudes respecting spacetime-translation invariance and the Ward-Green-Takahashi identities associated with global symmetries of QCD are obtained to calculate masses and electroweak decay constants of the pseudoscalar π , K , D and Ds and vector ρ , K*, D*, and Ds* mesons. The predictions of the model are in good agreement with available experimental and lattice QCD data.

  2. 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.)

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.)

  10. 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.

  11. Collider constraints on light pseudoscalars arXiv

    CERN Document Server

    Haisch, Ulrich; Malinauskas, Augustinas; Spira, Michael

    We investigate the bounds on light pseudoscalars that arise from a variety of collider searches. Special attention is thereby devoted to the mass regions $[3, 5] \\, {\\rm GeV}$ and $[9,11] \\, {\\rm GeV}$, in which a meaningful theoretical description has to include estimates of non-perturbative effects such as the mixing of the pseudoscalar with QCD bound states. A compendium of formulas that allows to deal with the relevant corrections is provided. It should prove useful for the interpretation of future LHC searches for light CP-odd spin-0 states.

  12. 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.

  13. 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.

  14. Masses of S and P wave mesons and pseudoscalar decay constants ...

    Indian Academy of Sciences (India)

    J. C3, 1 (1998). [5] S Godfrey and J Napolitano, Rev. Mod. Phys. 71, 1411 (1999). [6] F Iachello, N C Mukhopadhyay and L Zhang, Phys. Rev. D44, 898 (1991). [7] C Quigg and J Rosner, Phys. Rep. 56, 167, 222 (1979). [8] Buchmüller and Tye, Phys. Rev. D24, 132 (1981). [9] N Isgur and G Karl, Phys. Rev. D18, 4187 (1997).

  15. Regge description of two pseudoscalar meson production in antiproton-proton annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Wiele, J. van de [Universite de Paris-Sud, Institut de Physique Nucleaire, IN2P3-CNRS, Orsay Cedex (France); Ong, S. [Universite de Paris-Sud, Institut de Physique Nucleaire, IN2P3-CNRS, Orsay Cedex (France); Universite de Picardie Jules Verne, Amiens (France)

    2010-11-15

    A Regge-inspired model is used to discuss the hard exclusive two-body hadronic reactions (anti pp{yields}{pi}{sup -}{pi}{sup +}, {pi}{sup 0}{pi}{sup 0}, K{sup -}K{sup +}, anti K{sup 0}K{sup 0}) for the FAIR facility project at GSI with the PANDA detector. The comparison between the differential cross-sections predictions and the available data is shown to determine the values of the few parameters of the model. (orig.)

  16. Elastic and transition form factors of light pseudoscalar mesons from QCD sum rules

    Energy Technology Data Exchange (ETDEWEB)

    Balakireva, I. A., E-mail: iraxff@mail.ru [Moscow State University, SINP (Russian Federation); Lucha, W., E-mail: Wolfgang.Lucha@oeaw.ac.at [Austrian Academy of Sciences, Institute for High Energy Physics (Austria); Melikhov, D. I., E-mail: dmitri_melikhov@gmx.de [Moscow State University, SINP (Russian Federation)

    2013-03-15

    We revisit F{sub {pi}}(Q{sup 2}) and F{sub P{gamma}}(Q{sup 2}), P = {pi}, {eta}, {eta} Prime , making use of the local-duality (LD) version of QCD sum rules. We give arguments that the LD sum rule provides reliable predictions for these form factors at Q{sup 2} {>=} 5-6 GeV{sup 2}, the accuracy of the method increasing with Q{sup 2} in this region. For the pion elastic form factor, the well-measured data at small Q{sup 2} give a hint that the LD limit may be reached already at relatively low values of momentum transfers, Q{sup 2} Almost-Equal-To 4-8 GeV{sup 2}; we therefore conclude that large deviations from LD in the region Q{sup 2} = 20-50 GeV{sup 2} seem very unlikely. The data on the ({eta}, {eta} Prime ) {yields} {gamma}{gamma}* form factors meet the expectations from the LD model. However, the BaBar results for the {pi}{sup 0} {yields} {gamma}{gamma}* form factor imply a violation of LD growing with Q{sup 2} even at Q{sup 2} Almost-Equal-To 40 GeV{sup 2}, at odds with the {eta}, {eta} Prime case and with the general properties expected for the LD sum rule.

  17. 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

  18. Searches for Light Scalars, Pseudoscalars, and Gauge Bosons

    CERN Document Server

    Soffer, Abner

    2015-01-01

    In the past few years there has been a great deal of theoretical and experimental activity related to the search for low-mass scalars, pseudoscalars, and vectors in various scenarios of physics beyond the standard model. I review the current status of this topic, focusing on results obtained since FPCP 2014.

  19. The Matter and the Pseudoscalar Densities in Lattice QCD

    CERN Document Server

    Alexandrou, C; Tsapalis, A; Forcrand, Ph. de

    2003-01-01

    The matter and the pseudoscalar densities inside a hadron are calculated via gauge-invariant equal-time correlation functions. A comparison is made between the charge charge and the matter density distributions for the pion, the rho, the nucleon and the $Delta^+$ within the quenched theory, and with two flavours of dynamical quarks.

  20. On the observability of pseudoscalar toponium at future hadron colliders

    CERN Document Server

    Cakir, O; Recepoglu, E; Sultansoy, S

    2004-01-01

    Possible existence of extra SM families and/or isosinglet E/sub 6/ quarks may sufficiently decrease ¿V/sub tb/¿ of CKM matrix so that toponia can be formed. Production of pseudoscalar toponium at the LHC and VLHC has been considered. The observability of eta /sub t/ to gamma gamma signal is discussed.

  1. 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.)

  2. 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.

  3. 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.).

  4. Leading-twist distribution amplitudes of scalar and vector mesons

    Energy Technology Data Exchange (ETDEWEB)

    Li, B. -L.; Chang, L.; Ding, M.; Roberts, C. D.; Zong, H. -S.

    2016-11-01

    A symmetry-preserving truncation of the two-body light-quark bound-state problem in relativistic quantum field theory is used to calculate the leading-twist parton distribution amplitudes (PDAs) of scalar systems, both ground-state and radial excitations, and the radial excitations of vector mesons. Owing to the fact that the scale-independent leptonic decay constant of a scalar meson constituted from equal-mass valence-constituents vanishes, it is found that the PDA of a given scalar system possesses one more zero than that of an analogous vector meson. Consequently, whereas the mean light-front relative momentum of the valence-constituents within a vector meson is zero, that within a scalar meson is large, an outcome which hints at a greater role for light-front angular momentum in systems classified as P-wave in quantum mechanical models. Values for the scale-dependent decay constants of ground-state scalar and vector systems are a by-product of this analysis, and they turn out to be roughly equal, viz. ≃ 0.2 GeV at an hadronic scale. In addition, it is confirmed that the dilation characterising ground-state PDAs is manifest in the PDAs of radial excitations too. The impact of SU(3)-flavour symmetry breaking is also considered. When compared with pseudoscalar states, it is a little stronger in scalar systems, but the size is nevertheless determined by the flavour-dependence of dynamical chiral symmetry breaking and the PDAs are still skewed toward the heavier valence-quark in asymmetric systems.

  5. Recent Results on Meson Decays from A2

    Science.gov (United States)

    Adlarson, Patrik

    2018-01-01

    Light meson decays are used to investigate topics related to fundamental aspects of particle physics. Precision measurements of meson Dalitz decays give input to theoretical evaluations of the Hadronic Light-by-Light contribution (HLbL) to the anomalous magnetic moment of the muon. The pseudoscalar η' decays allow for studies of topics like ππ scattering lengths, effective field theories and fundamental symmetries. The A2 collaboration, using the Crystal Ball/TAPS setup at MAMI, has recently published several high precision results on transition form factors which are related to HLbL. The value obtained for the slope parameter of the π0 electromagnetic (e/m) transition form factor (TFF) is απ = 0.030 ± 0.010tot. The slope parameters for the e/m TFFs of ηγ and ωπ0 are and , respectively. In 2014 the collaboration had a dedicated experimental campaign for the production of η' mesons. One of the main goals was to measure the dynamics of η' → ηπ0π0 with high precision. An overview of the physics cases, the experimental setup and the results are given.

  6. Light Scalar Mesons in Central Production at COMPASS

    CERN Document Server

    Austregesilo, A.

    2016-01-01

    COMPASS is a fixed-target experiment at the CERN SPS that studies the spectrum of light-quark hadrons. In 2009, it collected a large dataset using a $190\\,$GeV$/c$ positive hadron beam impinging on a liquid-hydrogen target in order to measure the central exclusive production of light scalar mesons. One of the goals is the search for so-called glueballs, which are hypothetical meson-like objects without valence-quark content. We study the decay of neutral resonances by selecting centrally produced pion pairs from the COMPASS dataset. The angular distributions of the two pseudoscalar mesons are decomposed in terms of partial waves, where particular attention is paid to the inherent mathematical ambiguities. The large dataset allows us to perform a detailed analysis in bins of the two squared four-momentum transfers carried by the exchange particles in the reaction. Possible parameterisations of the mass dependence of the partial-wave amplitudes in terms of resonances are also discussed.

  7. 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.

  8. 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.)

  9. Investigating light NMSSM pseudoscalar states with boosted ditau tagging

    Energy Technology Data Exchange (ETDEWEB)

    Conte, Eric [Groupe de Recherche de Physique des Hautes Énergies (GRPHE),Université de Haute-Alsace, IUT Colmar,34 rue du Grillenbreit BP 50568, 68008 Colmar Cedex (France); Fuks, Benjamin [Sorbonne Universités, UPMC University Paris 06,UMR 7589, LPTHE, F-75005, Paris (France); CNRS, UMR 7589, LPTHE, F-75005, Paris (France); Guo, Jun [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics,Chinese Academy of Sciences,Beijing 100190 (China); Institut Pluridisciplinaire Hubert Curien/Département Recherches Subatomiques,Université de Strasbourg/CNRS-IN2P3,23 rue du Loess, F-67037 Strasbourg (France); Li, Jinmian; Williams, Anthony G. [ARC Centre of Excellence for Particle Physics at the Terascale and CSSM,Department of Physics, University of Adelaide,Adelaide, SA 5005 (Australia)

    2016-05-17

    We study a class of realizations of the Next-to-Minimal Supersymmetric Standard Model that is motivated by dark matter and Higgs data, and in which the lightest pseudoscalar Higgs boson mass is smaller than twice the bottom quark mass and greater than twice the tau lepton mass. In such scenarios, the lightest pseudoscalar Higgs boson can be copiously produced at the LHC from the decay of heavier superpartners and will dominantly further decay into a pair of tau leptons that is generally boosted. We make use of a boosted object tagging technique designed to tag such a ditau jet, and estimate the sensitivity of the LHC to the considered supersymmetric scenarios with 20 to 50 fb{sup −1} of proton-proton collisions at a center-of-mass energy of 13 TeV.

  10. A pseudoscalar at the LHC: Technicolor vs a fourth family

    Energy Technology Data Exchange (ETDEWEB)

    Holdom, B., E-mail: bob.holdom@utoronto.ca [Department of Physics, University of Toronto, Toronto, ON, M5S1A7 (Canada)

    2012-03-23

    Condensates of colored fermions driving electroweak symmetry breaking could give rise to a light pseudoscalar that would show up in the Higgs search at the LHC. The branching ratios of its decay will distinguish it from the Higgs and illuminate its origin. In particular the colored fermions may be the techniquarks of a one family technicolor theory or the quarks of a strongly interacting fourth family. The former has more difficulties in this context.

  11. 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

  12. 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

  13. 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...

  14. 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.

  15. Excited meson radiative transitions from lattice QCD using variationally optimized operators

    Energy Technology Data Exchange (ETDEWEB)

    Shultz, Christian J. [Old Dominion Univ., Norfolk, VA (United States); Dudek, Jozef J. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2015-06-02

    We explore the use of 'optimized' operators, designed to interpolate only a single meson eigenstate, in three-point correlation functions with a vector-current insertion. These operators are constructed as linear combinations in a large basis of meson interpolating fields using a variational analysis of matrices of two-point correlation functions. After performing such a determination at both zero and non-zero momentum, we compute three-point functions and are able to study radiative transition matrix elements featuring excited state mesons. The required two- and three-point correlation functions are efficiently computed using the distillation framework in which there is a factorization between quark propagation and operator construction, allowing for a large number of meson operators of definite momentum to be considered. We illustrate the method with a calculation using anisotopic lattices having three flavors of dynamical quark all tuned to the physical strange quark mass, considering form-factors and transitions of pseudoscalar and vector meson excitations. In conclusion, the dependence on photon virtuality for a number of form-factors and transitions is extracted and some discussion of excited-state phenomenology is presented.

  16. Generation of Pseudoscalar Bosons by Stimulated Raman Scattering of Light in Dielectric Media

    Directory of Open Access Journals (Sweden)

    Gorelik V.S.

    2015-01-01

    Full Text Available The conditions of pseudoscalar excitations of liquids and crystals vibration states in spontaneous and stimulated Raman spectra revealing are reported. The selection rules for pseudoscalar modes of molecules and crystals observation have been obtained. The experiments on observation of spontaneous and stimulated Raman scattering on pseudoscalar modes of molecules and crystals have been fulfilled. The excitation of stimulated Raman scattering was with using of solid state laser YAG:Nd3+, generating intense (up to 1 TW/cm2 ultrashort (60 ps laser pulses with energy 10 mJ and frequency repetition 10 Hz. The relationship between pseudoscalar bosons of dielectric media and axion of vacuum is analyzed.

  17. 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).

  18. 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.

  19. 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.)

  20. 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.)

  1. 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.

  2. 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

  3. 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

  4. Scalar-pseudoscalar interaction in the francium atom

    Science.gov (United States)

    Skripnikov, L. V.; Maison, D. E.; Mosyagin, N. S.

    2017-02-01

    Fr atom can be successively used to search for the atomic permanent electric dipole moment (EDM) [Hyperfine Interact. 236, 53 (2015), 10.1007/s10751-015-1193-1; J. Phys.: Conference Series 691, 012017 (2016), 10.1088/1742-6596/691/1/012017]. It can be induced by the permanent electron EDM predicted by modern extensions of the standard model to be nonzero at the level accessible by the new generation of EDM experiments. We consider another mechanism of the atomic EDM generation in Fr. This is caused by the scalar-pseudoscalar nucleus-electron neutral current interaction with the dimensionless strength constant kT ,P. Similar to the electron EDM this interaction violates both spatial parity and time-reversal symmetries and can also induce permanent atomic EDM. It was shown in [Phys. Rev. D 89, 056006 (2014), 10.1103/PhysRevD.89.056006] that the scalar-pseudoscalar contribution to the atomic EDM can dominate over the direct contribution from the electron EDM within the standard model. We report high-accuracy combined all-electron and two-step relativistic coupled cluster treatment of the effect from the scalar-pseudoscalar interaction in the Fr atom. Up to the quadruple cluster amplitudes within the coupled cluster method with single, double, triple, and noniterative quadruple amplitudes, CCSDT(Q), were included in correlation treatment. This calculation is required for the interpretation of the experimental data in terms of kT ,P. The resulted EDM of the Fr atom expressed in terms of kT ,P is dFr=kT ,P4.50 ×10-18e cm , where e is the (negative) charge of the electron. The value of the ionization potential of the 2S1 /2 ground state of Fr calculated within the same methods is in very good agreement with the experimental datum.

  5. Scalar meson f{sub 0}(980) in heavy-meson decays.

    Energy Technology Data Exchange (ETDEWEB)

    El-Bennich, B.; Leitner, O.; Dedonder, J.-P.; Loiseau, B.; Physics; Lab. de Physique Nucleaire et de Hautes Energies; Lab. Nazionali di Frascati

    2009-04-01

    A phenomenological analysis of the scalar meson f{sub 0}(980) is performed that relies on the quasi-two-body decays D and D{sub s} {yields} f{sub 0}(980)P, with P = {pi}, K. The two-body branching ratios are deduced from experimental data on D or D{sub s} {yields} {pi}{pi}{pi}, K{sup -} K{pi} and from the f{sub 0}(980) {yields} {pi}{sup +}{pi}{sup -} and f{sub 0}(980) {yields} K{sup +}K{sup -} branching fractions. Within a covariant quark model, the scalar form factors for the transitions D and D{sub s} {yields} f{sub 0}(980) are computed. The weak D decay amplitudes, in which these form factors enter, are obtained in the naive factorization approach assuming a q{bar q} state for the scalar and pseudoscalar mesons. They allow to extract information on the f{sub 0}(980) wave function in terms of u{bar u}, d{bar d}, and s{bar s} pairs as well as on the mixing angle between the strange and nonstrange components. The weak transition form factors are modeled by the one-loop triangular diagram using two different relativistic approaches: covariant light-front dynamics and dispersion relations. We use the information found on the f{sub 0}(980) structure to evaluate the scalar and vector form factors in the transitions D and D{sub s} {yields} f{sub 0}(980), as well as to make predictions for B and B{sub s} {yields} f{sub 0}(980), for the entire kinematically allowed momentum range of q{sup 2}.

  6. 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 ...

  7. 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 ...

  8. 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.)

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Detection prospects of light pseudoscalar Higgs boson at the LHC

    Science.gov (United States)

    Guchait, Monoranjan; Vijay, Aravind H.; Kumar, Jacky

    2017-08-01

    The discovery potential of light pseudo scalar Higgs boson for the mass range 10-60 GeV is explored. In the context of the next-to-minimal supersymmetric standard (NMSSM) model, the branching fraction of light pseudo scalar Higgs boson decaying to a pair of photon can be quite large. A pair of light pseudo scalar Higgs boson produced indirectly through the standard model Higgs boson decay yields multiple photons in the final state and the corresponding production rate is restricted by ATLAS data. Discussing the impact of this constraint in the NMSSM, the detection prospects of light pseudoscalar Higgs boson in the channel consisting of at least three photons, a lepton and missing transverse energy are reported. It is observed that the possibilities of finding the pseu-doscalar Higgs boson for the above mass range are promising for an integrated luminosity L= 100fb-1 with moderate significances, which can reach to more than 5 σ for higher luminosity options.

  15. Production and decay of charmed mesons at the Z resonance

    Science.gov (United States)

    Decamp, D.; Deschizeaux, B.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Alemany, R.; Crespo, J. M.; Delfino, M.; Fernandez, E.; Gaitan, V.; Garrido, Ll.; Mir, Ll. M.; Pacheco, A.; Catanesi, M. G.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Maggi, M.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Gao, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Lou, J.; Qiao, C.; Ruan, T.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhao, W.; Atwood, W. B.; Bauerdick, L. A. T.; Bird, F.; Blucher, E.; Bonvicini, G.; Bossi, F.; Boudreau, J.; Brown, D.; Burnett, T. H.; Drevermann, H.; Forty, R. W.; Grab, C.; Hagelberg, R.; Haywood, S.; Hilgart, J.; Jost, B.; Kasemann, M.; Knobloch, J.; Lacourt, A.; Lançon, E.; Lehraus, I.; Lohse, T.; Lusiani, A.; Marchioro, A.; Martinez, M.; Mato, P.; Menary, S.; Minten, A.; Miotto, A.; Miquel, R.; Moser, H.-G.; Nash, J.; Palazzi, P.; Ranjard, F.; Redlinger, G.; Roth, A.; Rothberg, J.; Rotscheidt, H.; Saich, M.; St. Denis, R.; Schlatter, D.; Takashima, M.; Talby, M.; Tejessy, W.; Wachsmuth, H.; Wasserbaech, S.; Wheeler, S.; Wiedenmann, W.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Bardadin-Otwinowska, M.; El Fellous, R.; Falvard, A.; Gay, P.; Harvey, J.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Proriol, J.; Prulhière, F.; Stimpfl, G.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Møllerud, R.; Nilsson, B. S.; Efthymiopoulos, I.; Simopoulou, E.; Vayaki, A.; Badier, J.; Blondel, A.; Bonneaud, G.; Bourotte, J.; Braems, F.; Brient, J. C.; Fouque, G.; Gamess, A.; Guirlet, R.; Orteu, S.; Rosowsky, A.; Rougé, A.; Rumpf, M.; Tanaka, R.; Videau, H.; Candlin, D. J.; Veitch, E.; Moneta, L.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Lannutti, J.; Levinthal, D.; Mermikides, M.; Sawyer, L.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; D'Ettorre-Piazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Nicoletti, G.; Passalacqua, L.; Pepe-Altarelli, M.; Picchi, P.; Zografou, P.; Altoon, B.; Boyle, O.; Halley, A. W.; Ten Have, I.; Hearns, J. L.; Lynch, J. G.; Morton, W. T.; Raine, C.; Scarr, J. M.; Smith, K.; Thompson, A. S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geiges, R.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Belk, A. T.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Dornan, P. J.; Dugeay, S.; Greene, A. M.; Hassard, J. F.; Lieske, N. M.; Patton, S. J.; Payne, D. G.; Phillips, M. J.; Sedgbeer, J. K.; Taylor, G.; Tomalin, I. R.; Wright, A. G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Keemer, N. R.; Nuttall, M.; Patel, A.; Rowlingson, B. S.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Barczewski, T.; Kleinknecht, K.; Raab, J.; Renk, B.; Roehn, S.; Sander, H.-G.; Schmelling, M.; Schmidt, H.; Steeg, F.; Walther, S. M.; Wolf, B.; Albanese, J.-P.; Aubert, J.-J.; Benchouk, C.; Bernard, V.; Bonissent, A.; Courvoisier, D.; Etienne, F.; Papalexiou, S.; Payre, P.; Pietrzyk, B.; Qian, Z.; Becker, H.; Blum, W.; Cattaneo, P.; Cowan, G.; Dehning, B.; Dietl, H.; Dydak, F.; Fernandez-Bosman, M.; Hansl-Kozanecka, T.; Jahn, A.; Kozanecki, W.; Lange, E.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Pan, Y.; Richter, R.; Schröder, J.; Schwarz, A. S.; Settles, R.; Stierlin, U.; Thomas, J.; Wolf, G.; Bertin, V.; Boucrot, J.; Callot, O.; Chen, X.; Cordier, A.; Davier, M.; Ganis, G.; Grivaz, J.-F.; Heusse, Ph.; Janot, P.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Veillet, J.-J.; Videau, I.; Zhang, Z.; Zomer, F.; Abbaneo, D.; Amendolia, S. R.; Bagliesi, G.; Batignani, G.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Carpinelli, M.; Ciocci, M. A.; dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Focardi, E.; Forti, F.; Gatto, C.; Giassi, A.; Giorgi, M. A.; Ligabue, F.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Sanguinetti, G.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Carter, J. M.; Green, M. G.; March, P. V.; Medcalf, T.; Quazi, I. S.; Strong, J. A.; Thomas, R. M.; West, L. R.; Wildish, T.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Edwards, M.; Fisher, S. M.; Jones, T. J.; Norton, P. R.; Salmon, D. P.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Klopfenstein, C.; Locci, E.; Loucatos, S.; Monnier, E.; Perez, P.; Perlas, J. A.; Perrier, F.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Vallage, B.; Ashman, J. G.; Booth, C. N.; Buttar, C.; Carney, R.; Cartwright, S.; Combley, F.; Dinsdale, M.; Dogru, M.; Hatfield, F.; Martin, J.; Parker, D.; Reeves, P.; Thompson, L. F.; Barberio, E.; Brandt, S.; Burkhardt, H.; Grupen, C.; Meinhard, H.; Mirabito, L.; Schäfer, U.; Seywerd, H.; Apollinari, G.; Giannini, G.; Gobbo, B.; Liello, F.; Ragusa, F.; Rolandi, L.; Stiegler, U.; Bellantoni, L.; Chen, X.; Cinabro, D.; Conway, J. S.; Cowen, D. F.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; Jacobsen, J. E.; Jared, R. C.; Johnson, R. P.; Leclaire, B. W.; Pan, Y. B.; Pater, J. R.; Saadi, Y.; Sharma, V.; Shi, Z. H.; Tang, Y. H.; Walsh, A. M.; Wear, J. A.; Weber, F. V.; Whitney, M. H.; Sau, Lan, Wu; Zobernig, G.

    1991-08-01

    In a sample of 190 000 hadronic Z decays, three signals of charm production are observed: two from the exclusive decays D° --> K-π+ and D*+ --> D°π+ --> K-π+π+ and one in the transverse-momentum distribution of soft hadrons relative to the nearest jet. The features of these signals are in good agreement with expectations based on the standard model and previous measurements of the branching fractions. The number of D*+/- --> K+/-π+/-π+/- per hadronic decay of the Z is measured to be (5.11+/-0.34) × 10-3, and the branching ratio B(D0 --> K-π+) is (3.62 +/- 0.34 +/- 0.44)%. Charm hadronization has been studied. The average fraction of the beam energy carried by the D* meson is found to be c = 0.504-0.017+0.013+/-0.008, and implications of the measurements on the pseudoscalar-to-vector production ratio of charmed mesons are discussed. Supported by the US Department of Energy, contract DE-AC02-76ER00881.

  16. Hadronic decays of the D/sub s/ meson

    Energy Technology Data Exchange (ETDEWEB)

    Wasserbaech, S.R.

    1989-06-01

    The D/sub s//sup +/ is the lowest-lying pseudoscalar meson containing charm and anti-strange quarks. Evidence for this state was first reported in 1977, although more recent observations disagree with some of the early results. Since 1983 the weakly decaying D/sub s//sup +/ has been observed in many experiments. Relative branching fractions have been measured for many non-leptonic decay modes, including D/sub s//sup +/ /yields/ /phi//pi//sup +/, /phi//pi//sup +//pi//sup +//pi//sup /minus//, /bar K/*/sup 0/K/sup +/, and f/sub 0/(975)/pi//sup +/. The absolute branching fractions are estimated in high energy e/sup +/e/sup /minus// annihilation from the observed numbers of reconstructed D/sub s//sup +/ decays and the expected D/sub s//sup +/ production cross section. The lowest-lying vector c/bar s/ meson, the D/sub s/*/sup +/, has also been seen in its decay to /gamma/D/sub s//sup +/. Weak decays of the heavy quark and lepton flavors are relevant to the development of the Standard Model of both the electroweak and the strong interactions. Measurements of charmed particle weak decay are useful for determining the parameter of the Standard Model and for testing phenomenological models which include strong effects. 83 refs., 56 figs., 12 tabs.

  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. 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)

  4. 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.)

  5. Light quark masses and pseudoscalar decay constants from $N_f = 2$ Lattice QCD with twisted mass fermions

    CERN Document Server

    Blossier, B; Dimopoulos, P; Farchioni, F; Frezzotti, R; Giménez, V; Herdoiza, G; Jansen, K; Lubicz, V; Michael, C; Palao, D; Papinutto, Mauro; Shindler, A; Simula, S; Tarantino, C; Urbach, C; Wenger, U

    2008-01-01

    We present the results of a lattice QCD calculation of the average up-down and strange quark masses and of the light meson pseudoscalar decay constants with Nf=2 dynamical fermions. The simulation is carried out at a single value of the lattice spacing with the twisted mass fermionic action at maximal twist, which guarantees automatic O(a)-improvement of the physical quantities. Quark masses are renormalized by implementing the non-perturbative RI-MOM renormalization procedure. Our results for the light quark masses are m_ud^{msbar}(2 GeV)= 3.85 +- 0.12 +- 0.40 MeV, m_s^{msbar}(2 GeV) = 105 +- 3 +- 9 MeV and m_s/m_ud = 27.3 +- 0.3 +- 1.2. We also obtain fK = 161.7 +- 1.2 +- 3.1 MeV and the ratio fK/fpi=1.227 +- 0.009 +- 0.024. From this ratio, by using the experimental determination of Gamma(K-> mu nu (gamma))/Gamma(pi -> mu nu (gamma)) and the average value of |Vud| from nuclear beta decays, we obtain |Vus|=0.2192(5)(45), in agreement with the determination from Kl3 decays and the unitarity constraint.

  6. 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).

  7. 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.

  8. 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}.

  9. 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)...

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Determination of the Production Rate of $D^{*0}$ Mesons and of the Ratio V/(V+P) in $Z^{0} \\to c\\overline{c}$ Decays

    CERN Document Server

    Ackerstaff, K; Allison, J; Altekamp, N; Anderson, K J; Anderson, S; Arcelli, S; Asai, S; Ashby, S F; Axen, D A; Azuelos, Georges; Ball, A H; Barberio, E; Barlow, R J; Bartoldus, R; Batley, J Richard; Baumann, S; Bechtluft, J; Behnke, T; Bell, K W; Bella, G; Bentvelsen, Stanislaus Cornelius Maria; Bethke, Siegfried; Betts, S; Biebel, O; Biguzzi, A; Bird, S D; Blobel, Volker; Bloodworth, Ian J; Bobinski, M; Bock, P; Bonacorsi, D; Boutemeur, M; Braibant, S; Brigliadori, L; Brown, R M; Burckhart, Helfried J; Burgard, C; Bürgin, R; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Clarke, P E L; Cohen, I; Conboy, J E; Cooke, O C; Couyoumtzelis, C; Coxe, R L; Cuffiani, M; Dado, S; Dallapiccola, C; Dallavalle, G M; Davis, R; De Jong, S; del Pozo, L A; de Roeck, A; Desch, Klaus; Dienes, B; Dixit, M S; Doucet, M; Duchovni, E; Duckeck, G; Duerdoth, I P; Eatough, D; Estabrooks, P G; Etzion, E; Evans, H G; Evans, M; Fabbri, Franco Luigi; Fanfani, A; Fanti, M; Faust, A A; Feld, L; Fiedler, F; Fierro, M; Fischer, H M; Fleck, I; Folman, R; Fong, D G; Foucher, M; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gascon, J; Gascon-Shotkin, S M; Geddes, N I; Geich-Gimbel, C; Geralis, T; Giacomelli, G; Giacomelli, P; Giacomelli, R; Gibson, V; Gibson, W R; Gingrich, D M; Glenzinski, D A; Goldberg, J; Goodrick, M J; Gorn, W; Grandi, C; Gross, E; Grunhaus, Jacob; Gruwé, M; Hajdu, C; Hanson, G G; Hansroul, M; Hapke, M; Hargrove, C K; Hart, P A; Hartmann, C; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herndon, M; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hillier, S J; Hobson, P R; Höcker, Andreas; Homer, R James; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Hutchcroft, D E; Igo-Kemenes, P; Imrie, D C; Ishii, K; Jawahery, A; Jeffreys, P W; Jeremie, H; Jimack, Martin Paul; Joly, A; Jones, C R; Jones, M; Jost, U; Jovanovic, P; Junk, T R; Kanzaki, J I; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Kirk, J; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Koetke, D S; Kokott, T P; Kolrep, M; Komamiya, S; Kowalewski, R V; Kress, T; Krieger, P; Von Krogh, J; Kyberd, P; Lafferty, G D; Lahmann, R; Lai, W P; Lanske, D; Lauber, J; Lautenschlager, S R; Lawson, I; Layter, J G; Lazic, D; Lee, A M; Lefebvre, E; Lellouch, Daniel; Letts, J; Levinson, L; List, B; Lloyd, S L; Loebinger, F K; Long, G D; Losty, Michael J; Ludwig, J; Liu, D; Macchiolo, A; MacPherson, A L; Mannelli, M; Marcellini, S; Markopoulos, C; Markus, C; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Menke, S; Merritt, F S; Mes, H; Meyer, J; Michelini, Aldo; Mihara, S; Mikenberg, G; Miller, D J; Mincer, A; Mir, R; Mohr, W; Montanari, A; Mori, T; Nagai, K; Nakamura, I; Neal, H A; Nellen, B; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Oh, A; Oldershaw, N J; Oreglia, M J; Orito, S; Pálinkás, J; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, J L; Plane, D E; Poffenberger, P R; Poli, B; Posthaus, A; Rembser, C; Robertson, S; Robins, S A; Rodning, N L; Roney, J M; Rooke, A M; Rossi, A M; Routenburg, P; Rozen, Y; Runge, K; Runólfsson, O; Ruppel, U; Rust, D R; Sachs, K; Saeki, T; Sahr, O; Sang, W M; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharf, F; Scharff-Hansen, P; Schieck, J; Schleper, P; Schmitt, B; Schmitt, S; Schöning, A; Schröder, M; Schumacher, M; Schwick, C; Scott, W G; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Siroli, G P; Sittler, A; Skillman, A; Skuja, A; Smith, A M; Snow, G A; Sobie, Randall J; Söldner-Rembold, S; Springer, R W; Sproston, M; Stephens, K; Steuerer, J; Stockhausen, B; Stoll, K; Strom, D; Ströhmer, R; Szymanski, P; Tafirout, R; Talbot, S D; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomson, M A; Von Törne, E; Torrence, E; Towers, S; Trigger, I; Trócsányi, Z L; Tsur, E; Turcot, A S; Turner-Watson, M F; Ueda, I; Utzat, P; Van Kooten, R; Vannerem, P; Verzocchi, M; Vikas, P; Vokurka, E H; Voss, H; Wäckerle, F; Wagner, A; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wermes, N; White, J S; Wilson, G W; Wilson, J A; Wyatt, T R; Yamashita, S; Yekutieli, G; Zacek, V; Zer-Zion, D

    1998-01-01

    In e^+e^- collisions at centre-of-mass energies around 91 GeV, D^*0 mesons have been reconstructed using data collected with the OPAL detector at LEP. The hadronisation fraction has been measured to be f(c -> D^*0) = 0.218 +/- 0.054 +/- 0.045 +/- 0.007, where the errors correspond to the statistical and systematic errors specific to this analysis, and to systematic uncertainties from externally measured branching fractions, respectively. Together with previous OPAL measurements of the hadron isation fractions of other charmed mesons, this value is used to investigate the relative production of observed vector and pseudoscalar charmed mesons in Z^0 -> cc(bar) decays. The production ratio production rate in hadronic Z^0 decays is presented.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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...

  3. 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.

  4. 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.

  5. 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...

  6. Charmed and light pseudoscalar meson decay constants from four-flavor lattice QCD with physical light quarks

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-10-30

    We compute the leptonic decay constants fD+, fDs, and fK+ and the quark-mass ratios mc/ms and ms/ml in unquenched lattice QCD using the experimentally determined value of fπ+ for normalization. We use the MILC highly improved staggered quark ensembles with four dynamical quark flavors—up, down, strange, and charm—and with both physical and unphysical values of the light sea-quark masses. The use of physical pions removes the need for a chiral extrapolation, thereby eliminating a significant source of uncertainty in previous calculations. Four different lattice spacings ranging from a0.06 to 0.15 fm are included in the analysis to control the extrapolation to the continuum limit. Our primary results are fD+=212.6(0.4)(+1.0-1.2) MeV, fDs=249.0(0.3)(+1.1-1.5) MeV, and fDs/fD+=1.1712(10)(+29-32), where the errors are statistical and total systematic, respectively. The errors on our results for the charm decay constants and their ratio are approximately 2–4 times smaller than those of the most precise previous lattice calculations. We also obtain fK+/fπ

  7. 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.)

  8. 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.

  9. 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.

  10. New Methods for B Meson Decay Constants and Form Factors from Lattice NRQCD

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, C. [Fermilab; Davies, C. T.H. [SUPA, UK; Monahan, C. J. [Washington U., Seattle

    2017-11-27

    We determine the normalisation of scalar and pseudoscalar current operators made from non-relativistic $b$ quarks and Highly Improved Staggered light quarks in lattice Quantum Chromodynamics (QCD) through $\\mathcal{O}(\\alpha_s)$ and $\\Lambda_{\\text{QCD}}/m_b$. We use matrix elements of these operators to extract $B$ meson decay constants and form factors, then compare to those obtained using the standard vector and axial-vector operators. This provides a test of systematic errors in the lattice QCD determination of the $B$ meson decay constants and form factors. We provide a new value for the $B$ and $B_s$ meson decay constants from lattice QCD calculations on ensembles that include $u$, $d$, $s$ and $c$ quarks in the sea and those which have the $u/d$ quark mass going down to its physical value. Our results are $f_B=0.196(6)$ GeV, $f_{B_s}=0.236(7)$ GeV and $f_{B_s}/f_B =1.207(7)$, agreeing well with earlier results using the temporal axial current. By combining with these previous results, we provide updated values of $f_B=0.190(4)$ GeV, $f_{B_s}=0.229(5)$ GeV and $f_{B_s}/f_B = 1.206(5)$.

  11. 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.

  12. 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...

  13. Baryonic resonances from baryon decuplet-meson octet interaction

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Sourav [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptd. 22085, 46071 Valencia (Spain)]. E-mail: sourav@ific.uv.es; Oset, E. [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptd. 22085, 46071 Valencia (Spain); Vacas, M.J. Vicente [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptd. 22085, 46071 Valencia (Spain)

    2005-04-04

    We study S-wave interactions of the baryon decuplet with the octet of pseudoscalar mesons using the lowest order chiral Lagrangian. In the S=1 sector, we find an attractive interaction in the {delta}K channel with I=1 while it is repulsive for I=2. The attractive interaction leads to a pole in the second Riemann sheet of the complex plane and is manifested as a large strength in the scattering amplitude close to the {delta}K threshold, which is not the case for I=2.We use the unitarized coupled channel approach to also investigate all the other possible values of strangeness and isospin. We find two bound states in the SU(3) limit corresponding to the octet and decuplet representations. These are found to split into eight different trajectories in the complex plane when the SU(3) symmetry is broken gradually. Finally, we are able to provide a reasonable description for a good number of 4-star 32- resonances listed by the Particle Data Group. In particular, the {xi}(1820), the {lambda}(1520) and the {sigma}(1670) states are well reproduced. We predict a few other resonances and also evaluate the couplings of the observed resonances to the various channels from the residues at the poles of the scattering matrix from where partial decay widths into different channels can be evaluated.

  14. 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.

  15. Glueball and meson propagators of any spin in large-N QCD

    Science.gov (United States)

    Bochicchio, Marco

    2013-10-01

    We prove an asymptotic structure theorem for glueball and meson propagators of any spin in large-N QCD and in N=1SUSY QCD with massless quarks, that determines asymptotically the residues of the poles of the propagators in terms of their anomalous dimensions and of the spectral density of the masses. The asymptotic theorem follows by the severe constraints on the propagators in large-N QCD with massless quarks, or in any large-N confining asymptotically-free gauge theory massless in perturbation theory, that arise by perturbation theory in conjunction with the renormalization group and by the OPE on the ultraviolet side. The asymptotic theorem is inspired by a recently proposed Topological Field Theory (TFT) underlying large-N pure YM, that computes sums of the scalar and of the pseudoscalar correlators satisfying the asymptotic theorem and that implies for the large-N joint scalar and pseudoscalar glueball spectrum exact linearity in the masses squared. On the infrared side we test the prediction of the exact linearity in the TFT by Meyer-Teper lattice numerical computation of the masses of the low-lying glueballs in SU(8)YM, finding accurate agreement. Besides, we employ the aforementioned ultraviolet and infrared constraints in order to compare critically the scalar or pseudoscalar glueball propagators computed in the framework of the AdS String/large-N Gauge Theory correspondence with those of the TFT underlying large-N YM. We find that only the TFT satisfies the ultraviolet and infrared constraints.

  16. Glueball and meson propagators of any spin in large-N QCD

    Energy Technology Data Exchange (ETDEWEB)

    Bochicchio, Marco, E-mail: marco.bochicchio@roma1.infn.it [Scuola Normale Superiore (SNS), Piazza dei Cavalieri 7, Pisa, I-56100 (Italy); INFN sez. Roma 1, Piazzale A. Moro 2, Roma, I-00185 (Italy)

    2013-10-21

    We prove an asymptotic structure theorem for glueball and meson propagators of any spin in large-N QCD and in N=1SUSY QCD with massless quarks, that determines asymptotically the residues of the poles of the propagators in terms of their anomalous dimensions and of the spectral density of the masses. The asymptotic theorem follows by the severe constraints on the propagators in large-N QCD with massless quarks, or in any large-N confining asymptotically-free gauge theory massless in perturbation theory, that arise by perturbation theory in conjunction with the renormalization group and by the OPE on the ultraviolet side. The asymptotic theorem is inspired by a recently proposed Topological Field Theory (TFT) underlying large-N pure YM, that computes sums of the scalar and of the pseudoscalar correlators satisfying the asymptotic theorem and that implies for the large-N joint scalar and pseudoscalar glueball spectrum exact linearity in the masses squared. On the infrared side we test the prediction of the exact linearity in the TFT by Meyer–Teper lattice numerical computation of the masses of the low-lying glueballs in SU(8)YM, finding accurate agreement. Besides, we employ the aforementioned ultraviolet and infrared constraints in order to compare critically the scalar or pseudoscalar glueball propagators computed in the framework of the AdS String/large-N Gauge Theory correspondence with those of the TFT underlying large-N YM. We find that only the TFT satisfies the ultraviolet and infrared constraints.

  17. 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...

  18. 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...

  19. Search for Two Omega Meson Decays of Charmonium Resonances Produced in Proton - Antiproton Annihilations

    Energy Technology Data Exchange (ETDEWEB)

    Kasper, Jason J. [Northwestern U.

    2002-01-01

    In Fermilab experiment E835 a search has been performed for two w(782) vector meson decays of charmonium produced via $p\\bar{p}$ annihilation. All states with even charge conjugation quantum number are theoretically accessible via $ww$. No charmonium signals were clearly visible. The large nonresonant continuum from fjp annihilation to ww was observed to be predominantly pseudoscalar. 903 upper limit confidence intervals were calculated for $B(\\eta_c \\to $ww$)$ assuming various phase shifts, $\\delta$, between the resonant and nonresonant $ww$ production giving a range from 0.543 for $\\delta$ = 180° to 18% for $\\delta$ = 0°. Upper limits on $B(\\bar{p}p \\to \\eta^{\\prime}_c$) x $B(\\eta^{\\prime}_c \\to ww$) are also given over a range of assumed masses and widths for the $\\eta^{\\prime}_c$.

  20. Baryonic resonances from the interactions of the baryon decuplet and meson octet

    Energy Technology Data Exchange (ETDEWEB)

    Oset, E.; Sarkar, S.; Vicente Vacas, M.J. [Universidad de Valencia-CSIC, Valencia (Spain). Institutos de Investigacion de Paterna. Dept. de Fisica Teorica; Instituto de Fisica Corpuscular (IFIC), Valencia (Spain). Centro Mixto

    2005-07-01

    We study S-wave interactions of the baryon decuplet with the octet of pseudoscalar mesons using the lowest order chiral Lagrangian. We find two bound states in the SU(3) limit corresponding to the octet and decuplet representations. These are found to split into eight different trajectories in the complex plane when the SU(3) symmetry is broken gradually. Finally, we are able to provide a reasonable description for a good number of 4-star 3{sup -}/2 resonances listed by the Particle Data Group. In particular, the {xi}(1820), the {lambda}(1520) and the {sigma}(1670) states are well reproduced. We predict a few other resonances and also evaluate the couplings of the observed resonances to the various channels from the residues at the poles of the scattering matrix from where partial decay widths into different channels can be evaluated. (author)

  1. One-loop analysis of the interactions between charmed mesons and Goldstone bosons

    Energy Technology Data Exchange (ETDEWEB)

    Yao, De-Liang [Institute for Advanced Simulation, Institut für Kernphysik andJülich Center for Hadron Physics, Forschungszentrum Jülich,Wilhelm-Johnen-Straße, D-52425 Jülich (Germany); Du, Meng-Lin [Helmholtz-Institut für Strahlen- und Kernphysik andBethe Center for Theoretical Physics, Universität Bonn,Nußallee 14-16, D-53115 Bonn (Germany); Guo, Feng-Kun [State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics, Chinese Academy of Science,Zhong Guan Cun East Street 55, Beijing 100190 (China); Helmholtz-Institut für Strahlen- und Kernphysik andBethe Center for Theoretical Physics, Universität Bonn,Nußallee 14-16, D-53115 Bonn (Germany); Meißner, Ulf-G. [Helmholtz-Institut für Strahlen- und Kernphysik andBethe Center for Theoretical Physics, Universität Bonn,Nußallee 14-16, D-53115 Bonn (Germany); Institute for Advanced Simulation, Institut für Kernphysik andJülich Center for Hadron Physics, Forschungszentrum Jülich,Wilhelm-Johnen-Straße, D-52425 Jülich (Germany)

    2015-11-09

    We derive the scattering amplitude for Goldstone bosons of chiral symmetry off the pseudoscalar charmed mesons up to leading one-loop order in a covariant chiral effective field theory, using the so-called extended-on-mass-shell renormalization scheme. Then we use unitarized chiral perturbation theory to fit to the available lattice data of the S-wave scattering lengths. The lattice data are well described. However, most of the low-energy constants determined from the fit bear large uncertainties. Lattice simulations in more channels are necessary to pin down these values which can then be used to make predictions in other processes related by chiral and heavy quark symmetries.

  2. A pseudoscalar decaying to photon pairs in the early LHC Run 2 data

    Energy Technology Data Exchange (ETDEWEB)

    Low, Matthew [School of Natural Sciences, Institute for Advanced Study,Princeton, NJ 08540 (United States); Tesi, Andrea [Department of Physics, Enrico Fermi Institute, University of Chicago,Chicago, IL 60637 (United States); Wang, Lian-Tao [Department of Physics, Enrico Fermi Institute, and Kavli Institute for Cosmological Physics,University of Chicago, Chicago, IL 60637 (United States)

    2016-03-16

    In this paper we explore the possibility of a pseudoscalar resonance to account for the 750 GeV diphoton excess observed both at ATLAS and at CMS. We analyze the ingredients needed from the low energy perspective to obtain a sufficiently large diphoton rate to explain the signal while avoiding constraints from other channels. Additionally, we point out composite Higgs models in which one can naturally obtain a pseudoscalar at the 750 GeV mass scale and we estimate the pseudoscalar couplings to standard model particles that one would have in such models. A generic feature of models that can explain the excess is the presence of new particles in addition to the 750 GeV state. Finally, we note that due to the origin of the coupling of the resonance to photons, one expects to see comparable signals in the Zγ, ZZ, and WW channels.

  3. Renormalization group equation analysis of a pseudoscalar portal dark matter model

    Science.gov (United States)

    Ghorbani, Karim

    2017-10-01

    We investigate the vacuum stability and perturbativity of a pseudoscalar portal dark matter (DM) model with a Dirac DM candidate, through the renormalization group equation analysis at one-loop order. The model has a particular feature which can evade the direct detection upper bounds measured by XENON100 and even that from planned experiment XENON1T. We first find the viable regions in the parameter space which will give rise to correct DM relic density and comply with the constraints from Higgs physics. We show that for a given mass of the pseudoscalar, the mixing angle plays no significant role in the running of the couplings. Then we study the running of the couplings for various pseudoscalar masses at mixing angle θ =6^\\circ , and find the scale of validity in terms of the dark coupling, {λ }d. Depending on our choice of the cutoff scale, the resulting viable parameter space will be determined.

  4. 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

  5. Covariant spectator theory of quark-antiquark bound states: Mass spectra and vertex functions of heavy and heavy-light mesons

    Science.gov (United States)

    Leitão, Sofia; Stadler, Alfred; Peña, M. T.; Biernat, Elmar P.

    2017-10-01

    We use the covariant spectator theory with an effective quark-antiquark interaction, containing Lorentz scalar, pseudoscalar, and vector contributions, to calculate the masses and vertex functions of, simultaneously, heavy and heavy-light mesons. We perform least-square fits of the model parameters, including the quark masses, to the meson spectrum and systematically study the sensitivity of the parameters with respect to different sets of fitted data. We investigate the influence of the vector confining interaction by using a continuous parameter controlling its weight. We find that vector contributions to the confining interaction between 0% and about 30% lead to essentially the same agreement with the data. Similarly, the light quark masses are not very tightly constrained. In all cases, the meson mass spectra calculated with our fitted models agree very well with the experimental data. We also calculate the mesons wave functions in a partial wave representation and show how they are related to the meson vertex functions in covariant form.

  6. 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.

  7. 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.)

  8. 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.

  9. 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.

  10. 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.

  11. 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%.

  12. 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.

  13. 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.

  14. Isospin breaking in the decay constants of heavy mesons from QCD sum rules

    Directory of Open Access Journals (Sweden)

    Wolfgang Lucha

    2017-02-01

    Full Text Available We present a study of the strong isospin-breaking (IB effect, due in QCD to the difference between u- and d-quark masses, in the leptonic decay constants of charmed and beauty pseudoscalar and vector mesons using the method of QCD sum rules. We apply the sum-rule analysis to the decay constants of mesons containing one heavy quark and one light quark with the light mass in the range from the average u/d quark mass to the strange-quark mass. We then analyse the dependence of the decay constants on the light-quark mass and extract with good accuracy the IB ratios of decay constants at leading order in the mass difference (md−mu, obtaining: (fD+−fD0/fD=0.0047(6, (fD⁎+−fD⁎0/fD⁎=0.0068(9, (fB0−fB+/fB=0.0047(6, and (fB⁎0−fB⁎+/fB⁎=0.0045(5, which yield: fD+−fD0=0.97±0.13 MeV, fD⁎+−fD⁎0=1.73±0.27 MeV, fB0−fB+=0.90±0.13 MeV, fB⁎0−fB⁎+=0.81±0.11 MeV. In the case of the D-meson our finding is consistent with recent lattice QCD results, whereas it is much lower in the case of the B-meson showing a tension of ≈3 standard deviations.

  15. Isospin breaking in the decay constants of heavy mesons from QCD sum rules

    Science.gov (United States)

    Lucha, Wolfgang; Melikhov, Dmitri; Simula, Silvano

    2017-02-01

    We present a study of the strong isospin-breaking (IB) effect, due in QCD to the difference between u- and d-quark masses, in the leptonic decay constants of charmed and beauty pseudoscalar and vector mesons using the method of QCD sum rules. We apply the sum-rule analysis to the decay constants of mesons containing one heavy quark and one light quark with the light mass in the range from the average u / d quark mass to the strange-quark mass. We then analyse the dependence of the decay constants on the light-quark mass and extract with good accuracy the IB ratios of decay constants at leading order in the mass difference (md -mu), obtaining: (fD+ -fD0) /fD = 0.0047 (6), (fD*+ -fD*0) /fD* = 0.0068 (9), (fB0 -fB+) /fB = 0.0047 (6), and (fB*0 -fB*+) /fB* = 0.0045 (5), which yield: fD+ -fD0 = 0.97 ± 0.13 MeV, fD*+ -fD*0 = 1.73 ± 0.27 MeV, fB0 -fB+ = 0.90 ± 0.13 MeV, fB*0 -fB*+ = 0.81 ± 0.11 MeV. In the case of the D-meson our finding is consistent with recent lattice QCD results, whereas it is much lower in the case of the B-meson showing a tension of ≈3 standard deviations.

  16. 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.

  17. 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.

  18. Eta photoproduction as a test of the extended chiral symmetry

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-09

    We analyze the {gamma}p->{eta}p process from threshold up to 1.2 GeV, employing an effective Lagrangian approach that allows for a mixing of eta couplings of pseudoscalar and pseudovector nature. The mixing ratio of the couplings may serve as a quantitative estimation of the SU{sub L}(3)xSU{sub R}(3) extended chiral symmetry violation in this energy regime. The data analyzed (differential cross sections and asymmetries) show a preference for the pseudoscalar coupling-91% of pseudoscalar coupling component for the best fit. We stress that a more conclusive answer to this question requires a more complete electromagnetic multipole database than the presently available one.

  19. 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

  20. 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 ...

  1. 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.)

  2. 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...

  3. 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...

  4. One-loop renormalization of Resonance Chiral Theory: scalar and pseudoscalar resonances

    Energy Technology Data Exchange (ETDEWEB)

    Rosell, Ignasi [Departament de FIsica Teorica, IFIC, CSIC - Universitat de Valencia, Edifici d' Instituts de Paterna, Apt. Correus 22085, E-46071 Valencia (Spain); Ruiz-FemenIa, Pedro [Theory Division, Max-Planck-Institut fuer Physik, Foehringer Ring 6, D-80805 Munich (Germany); Portoles, Jorge [Departament de FIsica Teorica, IFIC, CSIC - Universitat de Valencia, Edifici d' Instituts de Paterna, Apt. Correus 22085, E-46071 Valencia (Spain)

    2005-12-15

    We consider the Resonance Chiral Theory with one multiplet of scalar and pseudoscalar resonances, up to bilinear couplings in the resonance fields, and evaluate its {beta}-function at one-loop with the use of the background field method. Thus we also provide the full set of operators that renormalize the theory at one loop and render it finite.

  5. Pseudoscalar-photon mixing and the large scale alignment of QsO ...

    Indian Academy of Sciences (India)

    Pseudoscalar-photon mixing and the large scale alignment of QsO optical polarizations. PANKAJ JAIN, sUKANTA PANDA and s sARALA. Physics Department, Indian Institute of Technology, Kanpur 208 016, India. Abstract. We review the observation of large scale alignment of QSO optical polariza- tions. Alignment is seen ...

  6. 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.)

  7. 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.

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

    Energy Technology Data Exchange (ETDEWEB)

    Hrayr Matevosyan; Anthony Thomas; Peter Tandy

    2007-04-01

    We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. With the more consistent vertex used here, the error in ladder-rainbow truncation for vector mesons is never more than 10% as the current quark mass is varied from the u/d region to the b region.

  17. Nonperturbative comparison of clover and highly improved staggered quarks in lattice QCD and the properties of the ϕ meson

    Science.gov (United States)

    Chakraborty, Bipasha; Davies, C. T. H.; Donald, G. C.; Koponen, J.; Lepage, G. P.; Hpqcd Collaboration

    2017-10-01

    We compare correlators for pseudoscalar and vector mesons made from valence strange quarks using the clover quark and highly improved staggered quark (HISQ) formalisms in full lattice QCD. We use fully nonperturbative methods to normalize vector and axial vector current operators made from HISQ quarks, clover quarks and from combining HISQ and clover fields. This allows us to test expectations for the renormalization factors based on perturbative QCD, with implications for the error budget of lattice QCD calculations of the matrix elements of clover-staggered b -light weak currents, as well as further HISQ calculations of the hadronic vacuum polarization. We also compare the approach to the (same) continuum limit in clover and HISQ formalisms for the mass and decay constant of the ϕ meson. Our final results for these parameters, using single-meson correlators and allowing an uncertainty for the neglect of quark-line disconnected diagrams are: Mϕ=1.023 (6 ) GeV and fϕ=0.238 (3 ) GeV in good agreement with experiment. The results come from calculations in the HISQ formalism using gluon fields that include the effect of u , d , s and c quarks in the sea with three lattice spacing values and mu /d values going down to the physical point.

  18. 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^...

  19. 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.

  20. 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

  1. 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.

  2. Status of the MILC calculation of electromagnetic contributions to pseudoscalar masses

    CERN Document Server

    Basak, S; Bernard, C; DeTar, C; Freeland, E; Freeman, W; Foley, J; Gottlieb, Steven; Heller, U M; Hetrick, J E; Laiho, J; Levkova, L; Oktay, M; Osborn, J; Sugar, R L; Torok, A; Toussaint, D; Van de Water, R S; Zhou, R

    2012-01-01

    We calculate pseudoscalar masses on gauge configurations containing the effects of 2+1 flavors of dynamical asqtad quarks and quenched electromagnetism. The lattice spacings vary from 0.12 to 0.06 fm. The masses are fit with staggered chiral perturbation theory including NLO electromagnetic terms. We attempt to extract the fit parameters for the electromagnetic contributions, while taking into account the finite volume effects, and extrapolate them to the physical limit.

  3. Combined search for anomalous pseudoscalar HVV couplings in VH production and H $\\rightarrow$ VV decay

    CERN Document Server

    Khachatryan, Vardan; Tumasyan, Armen; Adam, Wolfgang; Aşılar, Ece; Bergauer, Thomas; Brandstetter, Johannes; Brondolin, Erica; Dragicevic, Marko; Erö, Janos; Flechl, Martin; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hartl, Christian; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Knünz, Valentin; König, Axel; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Matsushita, Takashi; Mikulec, Ivan; Rabady, Dinyar; Rad, Navid; Rahbaran, Babak; Rohringer, Herbert; Schieck, Jochen; Schöfbeck, Robert; Strauss, Josef; Treberer-Treberspurg, Wolfgang; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Alderweireldt, Sara; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Knutsson, Albert; Lauwers, Jasper; Luyckx, Sten; Van De Klundert, Merijn; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Abu Zeid, Shimaa; Blekman, Freya; D'Hondt, Jorgen; Daci, Nadir; De Bruyn, Isabelle; Deroover, Kevin; Heracleous, Natalie; Keaveney, James; Lowette, Steven; Moreels, Lieselotte; Olbrechts, Annik; Python, Quentin; Strom, Derek; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Van Parijs, Isis; Barria, Patrizia; Brun, Hugues; Caillol, Cécile; Clerbaux, Barbara; De Lentdecker, Gilles; Fasanella, Giuseppe; Favart, Laurent; Goldouzian, Reza; Grebenyuk, Anastasia; Karapostoli, Georgia; Lenzi, Thomas; Léonard, Alexandre; Maerschalk, Thierry; Marinov, Andrey; Perniè, Luca; Randle-conde, Aidan; Seva, Tomislav; Vander Velde, Catherine; Vanlaer, Pascal; Yonamine, Ryo; Zenoni, Florian; Zhang, Fengwangdong; Beernaert, Kelly; Benucci, Leonardo; Cimmino, Anna; Crucy, Shannon; Dobur, Didar; Fagot, Alexis; Garcia, Guillaume; Gul, Muhammad; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Poyraz, Deniz; Ryckbosch, Dirk; Salva Diblen, Sinem; Sigamani, Michael; Tytgat, Michael; Van Driessche, Ward; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Beluffi, Camille; Bondu, Olivier; Brochet, Sébastien; Bruno, Giacomo; Caudron, Adrien; Ceard, Ludivine; Delaere, Christophe; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Jafari, Abideh; Jez, Pavel; Komm, Matthias; Lemaitre, Vincent; Mertens, Alexandre; Musich, Marco; Nuttens, Claude; Perrini, Lucia; Piotrzkowski, Krzysztof; Popov, Andrey; Quertenmont, Loic; Selvaggi, Michele; Vidal Marono, Miguel; Beliy, Nikita; Hammad, Gregory Habib; Aldá Júnior, Walter Luiz; Alves, Fábio Lúcio; Alves, Gilvan; Brito, Lucas; Correa Martins Junior, Marcos; Hamer, Matthias; Hensel, Carsten; Moraes, Arthur; Pol, Maria Elena; Rebello Teles, Patricia; Belchior Batista Das Chagas, Ewerton; Carvalho, Wagner; Chinellato, Jose; Custódio, Analu; Melo Da Costa, Eliza; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Huertas Guativa, Lina Milena; Malbouisson, Helena; Matos Figueiredo, Diego; Mora Herrera, Clemencia; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Sznajder, Andre; Tonelli Manganote, Edmilson José; Vilela Pereira, Antonio; Ahuja, Sudha; Bernardes, Cesar Augusto; De Souza Santos, Angelo; Dogra, Sunil; Tomei, Thiago; De Moraes Gregores, Eduardo; Mercadante, Pedro G; Moon, Chang-Seong; Novaes, Sergio F; Padula, Sandra; Romero Abad, David; Ruiz Vargas, José Cupertino; Aleksandrov, Aleksandar; Hadjiiska, Roumyana; Iaydjiev, Plamen; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Vutova, Mariana; Dimitrov, Anton; Glushkov, Ivan; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Ahmad, Muhammad; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Chen, Mingshui; Cheng, Tongguang; Du, Ran; Jiang, Chun-Hua; Leggat, Duncan; Plestina, Roko; Romeo, Francesco; Shaheen, Sarmad Masood; Spiezia, Aniello; Tao, Junquan; Wang, Chunjie; Wang, Zheng; Zhang, Huaqiao; Asawatangtrakuldee, Chayanit; Ban, Yong; Li, Qiang; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Wang, Dayong; Xu, Zijun; Avila, Carlos; Cabrera, Andrés; Chaparro Sierra, Luisa Fernanda; Florez, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Puljak, Ivica; Ribeiro Cipriano, Pedro M; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Kadija, Kreso; Luetic, Jelena; Micanovic, Sasa; Sudic, Lucija; Attikis, Alexandros; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Rykaczewski, Hans; Bodlak, Martin; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Mahmoud, Mohammed; Calpas, Betty; Kadastik, Mario; Murumaa, Marion; Raidal, Martti; Tiko, Andres; Veelken, Christian; Eerola, Paula; Pekkanen, Juska; Voutilainen, Mikko; Härkönen, Jaakko; Karimäki, Veikko; Kinnunen, Ritva; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Wendland, Lauri; Talvitie, Joonas; Tuuva, Tuure; Besancon, Marc; Couderc, Fabrice; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard; Faure, Jean-Louis; Favaro, Carlotta; Ferri, Federico; Ganjour, Serguei; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Machet, Martina; Malcles, Julie; Rander, John; Rosowsky, André; Titov, Maksym; Zghiche, Amina; Antropov, Iurii; Baffioni, Stephanie; Beaudette, Florian; Busson, Philippe; Cadamuro, Luca; Chapon, Emilien; Charlot, Claude; Davignon, Olivier; Filipovic, Nicolas; Granier de Cassagnac, Raphael; Jo, Mihee; Lisniak, Stanislav; Mastrolorenzo, Luca; Miné, Philippe; Naranjo, Ivo Nicolas; Nguyen, Matthew; Ochando, Christophe; Ortona, Giacomo; Paganini, Pascal; Pigard, Philipp; Regnard, Simon; Salerno, Roberto; Sauvan, Jean-Baptiste; Sirois, Yves; Strebler, Thomas; Yilmaz, Yetkin; Zabi, Alexandre; Agram, Jean-Laurent; Andrea, Jeremy; Aubin, Alexandre; Bloch, Daniel; Brom, Jean-Marie; Buttignol, Michael; Chabert, Eric Christian; Chanon, Nicolas; Collard, Caroline; Conte, Eric; Coubez, Xavier; Fontaine, Jean-Charles; Gelé, Denis; Goerlach, Ulrich; Goetzmann, Christophe; Le Bihan, Anne-Catherine; Merlin, Jeremie Alexandre; Skovpen, Kirill; Van Hove, Pierre; Gadrat, Sébastien; Beauceron, Stephanie; Bernet, Colin; Boudoul, Gaelle; Bouvier, Elvire; Carrillo Montoya, Camilo Andres; Chierici, Roberto; Contardo, Didier; Courbon, Benoit; Depasse, Pierre; El Mamouni, Houmani; Fan, Jiawei; Fay, Jean; Gascon, Susan; Gouzevitch, Maxime; Ille, Bernard; Lagarde, Francois; Laktineh, Imad Baptiste; Lethuillier, Morgan; Mirabito, Laurent; Pequegnot, Anne-Laure; Perries, Stephane; Ruiz Alvarez, José David; Sabes, David; Sgandurra, Louis; Sordini, Viola; Vander Donckt, Muriel; Verdier, Patrice; Viret, Sébastien; Toriashvili, Tengizi; Tsamalaidze, Zviad; Autermann, Christian; Beranek, Sarah; Feld, Lutz; Heister, Arno; Kiesel, Maximilian Knut; Klein, Katja; Lipinski, Martin; Ostapchuk, Andrey; Preuten, Marius; Raupach, Frank; Schael, Stefan; Schulte, Jan-Frederik; Verlage, Tobias; Weber, Hendrik; Zhukov, Valery; Ata, Metin; Brodski, Michael; Dietz-Laursonn, Erik; Duchardt, Deborah; Endres, Matthias; Erdmann, Martin; Erdweg, Sören; Esch, Thomas; Fischer, Robert; Güth, Andreas; Hebbeker, Thomas; Heidemann, Carsten; Hoepfner, Kerstin; Knutzen, Simon; Kreuzer, Peter; Merschmeyer, Markus; Meyer, Arnd; Millet, Philipp; Mukherjee, Swagata; Olschewski, Mark; Padeken, Klaas; Papacz, Paul; Pook, Tobias; Radziej, Markus; Reithler, Hans; Rieger, Marcel; Scheuch, Florian; Sonnenschein, Lars; Teyssier, Daniel; Thüer, Sebastian; Cherepanov, Vladimir; Erdogan, Yusuf; Flügge, Günter; Geenen, Heiko; Geisler, Matthias; Hoehle, Felix; Kargoll, Bastian; Kress, Thomas; Künsken, Andreas; Lingemann, Joschka; Nehrkorn, Alexander; Nowack, Andreas; Nugent, Ian Michael; Pistone, Claudia; Pooth, Oliver; Stahl, Achim; Aldaya Martin, Maria; Asin, Ivan; Bartosik, Nazar; Behnke, Olaf; Behrens, Ulf; Borras, Kerstin; Burgmeier, Armin; Campbell, Alan; Contreras-Campana, Christian; Costanza, Francesco; Diez Pardos, Carmen; Dolinska, Ganna; Dooling, Samantha; Dorland, Tyler; Eckerlin, Guenter; Eckstein, Doris; Eichhorn, Thomas; Flucke, Gero; Gallo, Elisabetta; Garay Garcia, Jasone; Geiser, Achim; Gizhko, Andrii; Gunnellini, Paolo; Hauk, Johannes; Hempel, Maria; Jung, Hannes; Kalogeropoulos, Alexis; Karacheban, Olena; Kasemann, Matthias; Katsas, Panagiotis; Kieseler, Jan; Kleinwort, Claus; Korol, Ievgen; Lange, Wolfgang; Leonard, Jessica; Lipka, Katerina; Lobanov, Artur; Lohmann, Wolfgang; Mankel, Rainer; Melzer-Pellmann, Isabell-Alissandra; Meyer, Andreas Bernhard; Mittag, Gregor; Mnich, Joachim; Mussgiller, Andreas; Naumann-Emme, Sebastian; Nayak, Aruna; Ntomari, Eleni; Perrey, Hanno; Pitzl, Daniel; Placakyte, Ringaile; Raspereza, Alexei; Roland, Benoit; Sahin, Mehmet Özgür; Saxena, Pooja; Schoerner-Sadenius, Thomas; Seitz, Claudia; Spannagel, Simon; Trippkewitz, Karim Damun; Walsh, Roberval; Wissing, Christoph; Blobel, Volker; Centis Vignali, Matteo; Draeger, Arne-Rasmus; Erfle, Joachim; Garutti, Erika; Goebel, Kristin; Gonzalez, Daniel; Görner, Martin; Haller, Johannes; Hoffmann, Malte; Höing, Rebekka Sophie; Junkes, Alexandra; Klanner, Robert; Kogler, Roman; Kovalchuk, Nataliia; Lapsien, Tobias; Lenz, Teresa; Marchesini, Ivan; Marconi, Daniele; Meyer, Mareike; Nowatschin, Dominik; Ott, Jochen; Pantaleo, Felice; Peiffer, Thomas; Perieanu, Adrian; Pietsch, Niklas; Poehlsen, Jennifer; Rathjens, Denis; Sander, Christian; Scharf, Christian; Schleper, Peter; Schlieckau, Eike; Schmidt, Alexander; Schumann, Svenja; Schwandt, Joern; Sola, Valentina; Stadie, Hartmut; Steinbrück, Georg; Stober, Fred-Markus Helmut; Tholen, Heiner; Troendle, Daniel; Usai, Emanuele; Vanelderen, Lukas; Vanhoefer, Annika; Vormwald, Benedikt; Barth, Christian; Baus, Colin; Berger, Joram; Böser, Christian; Butz, Erik; Chwalek, Thorsten; Colombo, Fabio; De Boer, Wim; Descroix, Alexis; Dierlamm, Alexander; Fink, Simon; Frensch, Felix; Friese, Raphael; Giffels, Manuel; Gilbert, Andrew; Haitz, Dominik; Hartmann, Frank; Heindl, Stefan Michael; Husemann, Ulrich; Katkov, Igor; Kornmayer, Andreas; Lobelle Pardo, Patricia; Maier, Benedikt; Mildner, Hannes; Mozer, Matthias Ulrich; Müller, Thomas; Müller, Thomas; Plagge, Michael; Quast, Gunter; Rabbertz, Klaus; Röcker, Steffen; Roscher, Frank; Schröder, Matthias; Sieber, Georg; Simonis, Hans-Jürgen; Ulrich, Ralf; Wagner-Kuhr, Jeannine; Wayand, Stefan; Weber, Marc; Weiler, Thomas; Williamson, Shawn; Wöhrmann, Clemens; Wolf, Roger; Anagnostou, Georgios; Daskalakis, Georgios; Geralis, Theodoros; Giakoumopoulou, Viktoria Athina; Kyriakis, Aristotelis; Loukas, Demetrios; Psallidas, Andreas; Topsis-Giotis, Iasonas; Agapitos, Antonis; Kesisoglou, Stilianos; Panagiotou, Apostolos; Saoulidou, Niki; Tziaferi, Eirini; Evangelou, Ioannis; Flouris, Giannis; Foudas, Costas; Kokkas, Panagiotis; Loukas, Nikitas; Manthos, Nikolaos; Papadopoulos, Ioannis; Paradas, Evangelos; Strologas, John; Bencze, Gyorgy; Hajdu, Csaba; Hazi, Andras; Hidas, Pàl; Horvath, Dezso; Sikler, Ferenc; Veszpremi, Viktor; Vesztergombi, Gyorgy; Zsigmond, Anna Julia; Beni, Noemi; Czellar, Sandor; Karancsi, János; Molnar, Jozsef; Szillasi, Zoltan; Bartók, Márton; Makovec, Alajos; Raics, Peter; Trocsanyi, Zoltan Laszlo; Ujvari, Balazs; Choudhury, Somnath; Mal, Prolay; Mandal, Koushik; Sahoo, Deepak Kumar; Sahoo, Niladribihari; Swain, Sanjay Kumar; Bansal, Sunil; Beri, Suman Bala; Bhatnagar, Vipin; Chawla, Ridhi; Gupta, Ruchi; Bhawandeep, Bhawandeep; Kalsi, Amandeep Kaur; Kaur, Anterpreet; Kaur, Manjit; Kumar, Ramandeep; Mehta, Ankita; Mittal, Monika; Singh, Jasbir; Walia, Genius; Kumar, Ashok; Bhardwaj, Ashutosh; Choudhary, Brajesh C; Garg, Rocky Bala; Malhotra, Shivali; Naimuddin, Md; Nishu, Nishu; Ranjan, Kirti; Sharma, Ramkrishna; Sharma, Varun; Bhattacharya, Satyaki; Chatterjee, Kalyanmoy; Dey, Sourav; Dutta, Suchandra; Majumdar, Nayana; Modak, Atanu; Mondal, Kuntal; Mukhopadhyay, Supratik; Roy, Ashim; Roy, Debarati; Roy Chowdhury, Suvankar; Sarkar, Subir; Sharan, Manoj; Abdulsalam, Abdulla; Chudasama, Ruchi; Dutta, Dipanwita; Jha, Vishwajeet; Kumar, Vineet; Mohanty, Ajit Kumar; Pant, Lalit Mohan; Shukla, Prashant; Topkar, Anita; Aziz, Tariq; Banerjee, Sudeshna; Bhowmik, Sandeep; Chatterjee, Rajdeep Mohan; Dewanjee, Ram Krishna; Dugad, Shashikant; Ganguly, Sanmay; Ghosh, Saranya; Guchait, Monoranjan; Gurtu, Atul; Jain, Sandhya; Kole, Gouranga; Kumar, Sanjeev; Mahakud, Bibhuprasad; Maity, Manas; Majumder, Gobinda; Mazumdar, Kajari; Mitra, Soureek; Mohanty, Gagan Bihari; Parida, Bibhuti; Sarkar, Tanmay; Sur, Nairit; Sutar, Bajrang; Wickramage, Nadeesha; Chauhan, Shubhanshu; Dube, Sourabh; Kapoor, Anshul; Kothekar, Kunal; Sharma, Seema; Bakhshiansohi, Hamed; Behnamian, Hadi; Etesami, Seyed Mohsen; Fahim, Ali; Khakzad, Mohsen; Mohammadi Najafabadi, Mojtaba; Naseri, Mohsen; Paktinat Mehdiabadi, Saeid; Rezaei Hosseinabadi, Ferdos; Safarzadeh, Batool; Zeinali, Maryam; Felcini, Marta; Grunewald, Martin; Abbrescia, Marcello; Calabria, Cesare; Caputo, Claudio; Colaleo, Anna; Creanza, Donato; Cristella, Leonardo; De Filippis, Nicola; De Palma, Mauro; Fiore, Luigi; Iaselli, Giuseppe; Maggi, Giorgio; Maggi, Marcello; Miniello, Giorgia; My, Salvatore; Nuzzo, Salvatore; Pompili, Alexis; Pugliese, Gabriella; Radogna, Raffaella; Ranieri, Antonio; Selvaggi, Giovanna; Silvestris, Lucia; Venditti, Rosamaria; Abbiendi, Giovanni; Battilana, Carlo; Benvenuti, Alberto; Bonacorsi, Daniele; Braibant-Giacomelli, Sylvie; Brigliadori, Luca; Campanini, Renato; Capiluppi, Paolo; Castro, Andrea; Cavallo, Francesca Romana; Chhibra, Simranjit Singh; Codispoti, Giuseppe; Cuffiani, Marco; Dallavalle, Gaetano-Marco; Fabbri, Fabrizio; Fanfani, Alessandra; Fasanella, Daniele; Giacomelli, Paolo; Grandi, Claudio; Guiducci, Luigi; Marcellini, Stefano; Masetti, Gianni; Montanari, Alessandro; Navarria, Francesco; Perrotta, Andrea; Rossi, Antonio; Rovelli, Tiziano; Siroli, Gian Piero; Tosi, Nicolò; Travaglini, Riccardo; Cappello, Gigi; Chiorboli, Massimiliano; Costa, Salvatore; Di Mattia, Alessandro; Giordano, Ferdinando; Potenza, Renato; Tricomi, Alessia; Tuve, Cristina; Barbagli, Giuseppe; Ciulli, Vitaliano; Civinini, Carlo; D'Alessandro, Raffaello; Focardi, Ettore; Gori, Valentina; Lenzi, Piergiulio; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Viliani, Lorenzo; Benussi, Luigi; Bianco, Stefano; Fabbri, Franco; Piccolo, Davide; Primavera, Federica; Calvelli, Valerio; Ferro, Fabrizio; Lo Vetere, Maurizio; Monge, Maria Roberta; Robutti, Enrico; Tosi, Silvano; Brianza, Luca; Dinardo, Mauro Emanuele; Fiorendi, Sara; Gennai, Simone; Gerosa, Raffaele; Ghezzi, Alessio; Govoni, Pietro; Malvezzi, Sandra; Manzoni, Riccardo Andrea; Marzocchi, Badder; Menasce, Dario; Moroni, Luigi; Paganoni, Marco; Pedrini, Daniele; Ragazzi, Stefano; Redaelli, Nicola; Tabarelli de Fatis, Tommaso; Buontempo, Salvatore; Cavallo, Nicola; Di Guida, Salvatore; Esposito, Marco; Fabozzi, Francesco; Iorio, Alberto Orso Maria; Lanza, Giuseppe; Lista, Luca; Meola, Sabino; Merola, Mario; Paolucci, Pierluigi; Sciacca, Crisostomo; Thyssen, Filip; Azzi, Patrizia; Bacchetta, Nicola; Benato, Lisa; Bisello, Dario; Boletti, Alessio; Branca, Antonio; Carlin, Roberto; Checchia, Paolo; Dall'Osso, Martino; Dorigo, Tommaso; Dosselli, Umberto; Fanzago, Federica; Gasparini, Fabrizio; Gasparini, Ugo; Gozzelino, Andrea; Kanishchev, Konstantin; Lacaprara, Stefano; Margoni, Martino; Meneguzzo, Anna Teresa; Pazzini, Jacopo; Pozzobon, Nicola; Ronchese, Paolo; Simonetto, Franco; Torassa, Ezio; Tosi, Mia; Zanetti, Marco; Zotto, Pierluigi; Zucchetta, Alberto; Zumerle, Gianni; Braghieri, Alessandro; Magnani, Alice; Montagna, Paolo; Ratti, Sergio P; Re, Valerio; Riccardi, Cristina; Salvini, Paola; Vai, Ilaria; Vitulo, Paolo; Alunni Solestizi, Luisa; Bilei, Gian Mario; Ciangottini, Diego; Fanò, Livio; Lariccia, Paolo; Mantovani, Giancarlo; Menichelli, Mauro; Saha, Anirban; Santocchia, Attilio; Androsov, Konstantin; Azzurri, Paolo; Bagliesi, Giuseppe; Bernardini, Jacopo; Boccali, Tommaso; Castaldi, Rino; Ciocci, Maria Agnese; Dell'Orso, Roberto; Donato, Silvio; Fedi, Giacomo; Foà, Lorenzo; Giassi, Alessandro; Grippo, Maria Teresa; Ligabue, Franco; Lomtadze, Teimuraz; Martini, Luca; Messineo, Alberto; Palla, Fabrizio; Rizzi, Andrea; Savoy-Navarro, Aurore; Serban, Alin Titus; Spagnolo, Paolo; Tenchini, Roberto; Tonelli, Guido; Venturi, Andrea; Verdini, Piero Giorgio; Barone, Luciano; Cavallari, Francesca; D'imperio, Giulia; Del Re, Daniele; Diemoz, Marcella; Gelli, Simone; Jorda, Clara; Longo, Egidio; Margaroli, Fabrizio; Meridiani, Paolo; Organtini, Giovanni; Paramatti, Riccardo; Preiato, Federico; Rahatlou, Shahram; Rovelli, Chiara; Santanastasio, Francesco; Traczyk, Piotr; Amapane, Nicola; Arcidiacono, Roberta; Argiro, Stefano; Arneodo, Michele; Bellan, Riccardo; Biino, Cristina; Cartiglia, Nicolo; Costa, Marco; Covarelli, Roberto; Degano, Alessandro; Demaria, Natale; Finco, Linda; Kiani, Bilal; Mariotti, Chiara; Maselli, Silvia; Migliore, Ernesto; Monaco, Vincenzo; Monteil, Ennio; Obertino, Maria Margherita; Pacher, Luca; Pastrone, Nadia; Pelliccioni, Mario; Pinna Angioni, Gian Luca; Ravera, Fabio; Romero, Alessandra; Ruspa, Marta; Sacchi, Roberto; Solano, Ada; Staiano, Amedeo; Belforte, Stefano; Candelise, Vieri; Casarsa, Massimo; Cossutti, Fabio; Della Ricca, Giuseppe; Gobbo, Benigno; La Licata, Chiara; Marone, Matteo; Schizzi, Andrea; Zanetti, Anna; Kropivnitskaya, Anna; Nam, Soon-Kwon; Kim, Dong Hee; Kim, Gui Nyun; Kim, Min Suk; Kong, Dae Jung; Lee, Sangeun; Oh, Young Do; Sakharov, Alexandre; Son, Dong-Chul; Brochero Cifuentes, Javier Andres; Kim, Hyunsoo; Kim, Tae Jeong; Song, Sanghyeon; Cho, Sungwoong; Choi, Suyong; Go, Yeonju; Gyun, Dooyeon; Hong, Byung-Sik; Kim, Hyunchul; Kim, Yongsun; Lee, Byounghoon; Lee, Kisoo; Lee, Kyong Sei; Lee, Songkyo; Park, Sung Keun; Roh, Youn; Yoo, Hwi Dong; Choi, Minkyoo; Kim, Hyunyong; Kim, Ji Hyun; Lee, Jason Sang Hun; Park, Inkyu; Ryu, Geonmo; Ryu, Min Sang; Choi, Young-Il; Goh, Junghwan; Kim, Donghyun; Kwon, Eunhyang; Lee, Jongseok; Yu, Intae; Dudenas, Vytautas; Juodagalvis, Andrius; Vaitkus, Juozas; Ahmed, Ijaz; Ibrahim, Zainol Abidin; Komaragiri, Jyothsna Rani; Md Ali, Mohd Adli Bin; Mohamad Idris, Faridah; Wan Abdullah, Wan Ahmad Tajuddin; Yusli, Mohd Nizam; Casimiro Linares, Edgar; Castilla-Valdez, Heriberto; De La Cruz-Burelo, Eduard; Heredia-De La Cruz, Ivan; Hernandez-Almada, Alberto; Lopez-Fernandez, Ricardo; Sánchez Hernández, Alberto; Carrillo Moreno, Salvador; Vazquez Valencia, Fabiola; Pedraza, Isabel; Salazar Ibarguen, Humberto Antonio; Morelos Pineda, Antonio; Krofcheck, David; Butler, Philip H; Ahmad, Ashfaq; Ahmad, Muhammad; Hassan, Qamar; Hoorani, Hafeez R; Khan, Wajid Ali; Khurshid, Taimoor; Shoaib, Muhammad; Bialkowska, Helena; Bluj, Michal; Boimska, Bożena; Frueboes, Tomasz; Górski, Maciej; Kazana, Malgorzata; Nawrocki, Krzysztof; Romanowska-Rybinska, Katarzyna; Szleper, Michal; Zalewski, Piotr; Brona, Grzegorz; Bunkowski, Karol; Byszuk, Adrian; Doroba, Krzysztof; Kalinowski, Artur; Konecki, Marcin; Krolikowski, Jan; Misiura, Maciej; Olszewski, Michal; Walczak, Marek; Bargassa, Pedrame; Beirão Da Cruz E Silva, Cristóvão; Di Francesco, Agostino; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Hollar, Jonathan; Leonardo, Nuno; Lloret Iglesias, Lara; Nguyen, Federico; Rodrigues Antunes, Joao; Seixas, Joao; Toldaiev, Oleksii; Vadruccio, Daniele; Varela, Joao; Vischia, Pietro; Afanasiev, Serguei; Bunin, Pavel; Gavrilenko, Mikhail; Golutvin, Igor; Gorbunov, Ilya; Kamenev, Alexey; Karjavin, Vladimir; Lanev, Alexander; Malakhov, Alexander; Matveev, Viktor; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Shmatov, Sergey; Shulha, Siarhei; Skatchkov, Nikolai; Smirnov, Vitaly; Zarubin, Anatoli; Golovtsov, Victor; Ivanov, Yury; Kim, Victor; Kuznetsova, Ekaterina; Levchenko, Petr; Murzin, Victor; Oreshkin, Vadim; Smirnov, Igor; Sulimov, Valentin; Uvarov, Lev; Vavilov, Sergey; Vorobyev, Alexey; Andreev, Yuri; Dermenev, Alexander; Gninenko, Sergei; Golubev, Nikolai; Karneyeu, Anton; Kirsanov, Mikhail; Krasnikov, Nikolai; Pashenkov, Anatoli; Tlisov, Danila; Toropin, Alexander; Epshteyn, Vladimir; Gavrilov, Vladimir; Lychkovskaya, Natalia; Popov, Vladimir; Pozdnyakov, Ivan; Safronov, Grigory; Spiridonov, Alexander; Vlasov, Evgueni; Zhokin, Alexander; Bylinkin, Alexander; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Leonidov, Andrey; Mesyats, Gennady; Rusakov, Sergey V; Baskakov, Alexey; Belyaev, Andrey; Boos, Edouard; Bunichev, Viacheslav; Dubinin, Mikhail; Dudko, Lev; Ershov, Alexander; Gribushin, Andrey; Klyukhin, Vyacheslav; Kodolova, Olga; Lokhtin, Igor; Miagkov, Igor; Obraztsov, Stepan; Petrushanko, Sergey; Savrin, Viktor; Azhgirey, Igor; Bayshev, Igor; Bitioukov, Sergei; Kachanov, Vassili; Kalinin, Alexey; Konstantinov, Dmitri; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Cirkovic, Predrag; Milosevic, Jovan; Rekovic, Vladimir; Alcaraz Maestre, Juan; Calvo, Enrique; Cerrada, Marcos; Chamizo Llatas, Maria; Colino, Nicanor; De La Cruz, Begona; Delgado Peris, Antonio; Escalante Del Valle, Alberto; Fernandez Bedoya, Cristina; Fernández Ramos, Juan Pablo; Flix, Jose; Fouz, Maria Cruz; Garcia-Abia, Pablo; Gonzalez Lopez, Oscar; Goy Lopez, Silvia; Hernandez, Jose M; Josa, Maria Isabel; Navarro De Martino, Eduardo; Pérez-Calero Yzquierdo, Antonio María; Puerta Pelayo, Jesus; Quintario Olmeda, Adrián; Redondo, Ignacio; Romero, Luciano; Santaolalla, Javier; Senghi Soares, Mara; Albajar, Carmen; de Trocóniz, Jorge F; Missiroli, Marino; Moran, Dermot; Cuevas, Javier; Fernandez Menendez, Javier; Folgueras, Santiago; Gonzalez Caballero, Isidro; Palencia Cortezon, Enrique; Vizan Garcia, Jesus Manuel; Cabrillo, Iban Jose; Calderon, Alicia; Castiñeiras De Saa, Juan Ramon; De Castro Manzano, Pablo; Fernandez, Marcos; Garcia-Ferrero, Juan; Gomez, Gervasio; Lopez Virto, Amparo; Marco, Jesus; Marco, Rafael; Martinez Rivero, Celso; Matorras, Francisco; Piedra Gomez, Jonatan; Rodrigo, Teresa; Rodríguez-Marrero, Ana Yaiza; Ruiz-Jimeno, Alberto; Scodellaro, Luca; Trevisani, Nicolò; Vila, Ivan; Vilar Cortabitarte, Rocio; Abbaneo, Duccio; Auffray, Etiennette; Auzinger, Georg; Bachtis, Michail; Baillon, Paul; Ball, Austin; Barney, David; Benaglia, Andrea; Bendavid, Joshua; Benhabib, Lamia; Berruti, Gaia Maria; Bloch, Philippe; Bocci, Andrea; Bonato, Alessio; Botta, Cristina; Breuker, Horst; Camporesi, Tiziano; Castello, Roberto; Cerminara, Gianluca; D'Alfonso, Mariarosaria; D'Enterria, David; Dabrowski, Anne; Daponte, Vincenzo; David Tinoco Mendes, Andre; De Gruttola, Michele; De Guio, Federico; De Roeck, Albert; De Visscher, Simon; Di Marco, Emanuele; Dobson, Marc; Dordevic, Milos; Dorney, Brian; Du Pree, Tristan; Duggan, Daniel; Dünser, Marc; Dupont, Niels; Elliott-Peisert, Anna; Franzoni, Giovanni; Fulcher, Jonathan; Funk, Wolfgang; Gigi, Dominique; Gill, Karl; Giordano, Domenico; Girone, Maria; Glege, Frank; Guida, Roberto; Gundacker, Stefan; Guthoff, Moritz; Hammer, Josef; Harris, Philip; Hegeman, Jeroen; Innocente, Vincenzo; Janot, Patrick; Kirschenmann, Henning; Kortelainen, Matti J; Kousouris, Konstantinos; Krajczar, Krisztian; Lecoq, Paul; Lourenco, Carlos; Lucchini, Marco Toliman; Magini, Nicolo; Malgeri, Luca; Mannelli, Marcello; Martelli, Arabella; Masetti, Lorenzo; Meijers, Frans; Mersi, Stefano; Meschi, Emilio; Moortgat, Filip; Morovic, Srecko; Mulders, Martijn; Nemallapudi, Mythra Varun; Neugebauer, Hannes; Orfanelli, Styliani; Orsini, Luciano; Pape, Luc; Perez, Emmanuelle; Peruzzi, Marco; Petrilli, Achille; Petrucciani, Giovanni; Pfeiffer, Andreas; Pierini, Maurizio; Piparo, Danilo; Racz, Attila; Reis, Thomas; Rolandi, Gigi; Rovere, Marco; Ruan, Manqi; Sakulin, Hannes; Schäfer, Christoph; Schwick, Christoph; Seidel, Markus; Sharma, Archana; Silva, Pedro; Simon, Michal; Sphicas, Paraskevas; Steggemann, Jan; Stieger, Benjamin; Stoye, Markus; Takahashi, Yuta; Treille, Daniel; Triossi, Andrea; Tsirou, Andromachi; Veres, Gabor Istvan; Wardle, Nicholas; Wöhri, Hermine Katharina; Zagoździńska, Agnieszka; Zeuner, Wolfram Dietrich; Bertl, Willi; Deiters, Konrad; Erdmann, Wolfram; Horisberger, Roland; Ingram, Quentin; Kaestli, Hans-Christian; Kotlinski, Danek; Langenegger, Urs; Renker, Dieter; Rohe, Tilman; Bachmair, Felix; Bäni, Lukas; Bianchini, Lorenzo; Casal, Bruno; Dissertori, Günther; Dittmar, Michael; Donegà, Mauro; Eller, Philipp; Grab, Christoph; Heidegger, Constantin; Hits, Dmitry; Hoss, Jan; Kasieczka, Gregor; Lecomte, Pierre; Lustermann, Werner; Mangano, Boris; Marionneau, Matthieu; Martinez Ruiz del Arbol, Pablo; Masciovecchio, Mario; Meister, Daniel; Micheli, Francesco; Musella, Pasquale; Nessi-Tedaldi, Francesca; Pandolfi, Francesco; Pata, Joosep; Pauss, Felicitas; Perrozzi, Luca; Quittnat, Milena; Rossini, Marco; Schönenberger, Myriam; Starodumov, Andrei; Takahashi, Maiko; Tavolaro, Vittorio Raoul; Theofilatos, Konstantinos; Wallny, Rainer; Aarrestad, Thea Klaeboe; Amsler, Claude; Caminada, Lea; Canelli, Maria Florencia; Chiochia, Vincenzo; De Cosa, Annapaola; Galloni, Camilla; Hinzmann, Andreas; Hreus, Tomas; Kilminster, Benjamin; Lange, Clemens; Ngadiuba, Jennifer; Pinna, Deborah; Rauco, Giorgia; Robmann, Peter; Ronga, Frederic Jean; Salerno, Daniel; Yang, Yong; Cardaci, Marco; Chen, Kuan-Hsin; Doan, Thi Hien; Jain, Shilpi; Khurana, Raman; Konyushikhin, Maxim; Kuo, Chia-Ming; Lin, Willis; Lu, Yun-Ju; Pozdnyakov, Andrey; Yu, Shin-Shan; Kumar, Arun; Chang, Paoti; Chang, You-Hao; Chang, Yu-Wei; Chao, Yuan; Chen, Kai-Feng; Chen, Po-Hsun; Dietz, Charles; Fiori, Francesco; Grundler, Ulysses; Hou, George Wei-Shu; Hsiung, Yee; Liu, Yueh-Feng; Lu, Rong-Shyang; Miñano Moya, Mercedes; Petrakou, Eleni; Tsai, Jui-fa; Tzeng, Yeng-Ming; Asavapibhop, Burin; Kovitanggoon, Kittikul; Singh, Gurpreet; Srimanobhas, Norraphat; Suwonjandee, Narumon; Adiguzel, Aytul; Cerci, Salim; Demiroglu, Zuhal Seyma; Dozen, Candan; Dumanoglu, Isa; Gecit, Fehime Hayal; Girgis, Semiray; Gokbulut, Gul; Guler, Yalcin; Gurpinar, Emine; Hos, Ilknur; Kangal, Evrim Ersin; Kayis Topaksu, Aysel; Onengut, Gulsen; Ozcan, Merve; Ozdemir, Kadri; Ozturk, Sertac; Tali, Bayram; Topakli, Huseyin; Zorbilmez, Caglar; Bilin, Bugra; Bilmis, Selcuk; Isildak, Bora; Karapinar, Guler; Yalvac, Metin; Zeyrek, Mehmet; Gülmez, Erhan; Kaya, Mithat; Kaya, Ozlem; Yetkin, Elif Asli; Yetkin, Taylan; Cakir, Altan; Cankocak, Kerem; Sen, Sercan; Vardarlı, Fuat Ilkehan; Grynyov, Boris; Levchuk, Leonid; Sorokin, Pavel; Aggleton, Robin; Ball, Fionn; Beck, Lana; Brooke, James John; Clement, Emyr; Cussans, David; Flacher, Henning; Goldstein, Joel; Grimes, Mark; Heath, Greg P; Heath, Helen F; Jacob, Jeson; Kreczko, Lukasz; Lucas, Chris; Meng, Zhaoxia; Newbold, Dave M; Paramesvaran, Sudarshan; Poll, Anthony; Sakuma, Tai; Seif El Nasr-storey, Sarah; Senkin, Sergey; Smith, Dominic; Smith, Vincent J; Bell, Ken W; Belyaev, Alexander; Brew, Christopher; Brown, Robert M; Calligaris, Luigi; Cieri, Davide; Cockerill, David JA; Coughlan, John A; Harder, Kristian; Harper, Sam; Olaiya, Emmanuel; Petyt, David; Shepherd-Themistocleous, Claire; Thea, Alessandro; Tomalin, Ian R; Williams, Thomas; Worm, Steven; Baber, Mark; Bainbridge, Robert; Buchmuller, Oliver; Bundock, Aaron; Burton, Darren; Casasso, Stefano; Citron, Matthew; Colling, David; Corpe, Louie; Dauncey, Paul; Davies, Gavin; De Wit, Adinda; Della Negra, Michel; Dunne, Patrick; Elwood, Adam; Futyan, David; Hall, Geoffrey; Iles, Gregory; Lane, Rebecca; Lucas, Robyn; Lyons, Louis; Magnan, Anne-Marie; Malik, Sarah; Nash, Jordan; Nikitenko, Alexander; Pela, Joao; Pesaresi, Mark; Raymond, David Mark; Richards, Alexander; Rose, Andrew; Seez, Christopher; Tapper, Alexander; Uchida, Kirika; Vazquez Acosta, Monica; Virdee, Tejinder; Zenz, Seth Conrad; Cole, Joanne; Hobson, Peter R; Khan, Akram; Kyberd, Paul; Leslie, Dawn; Reid, Ivan; Symonds, Philip; Teodorescu, Liliana; Turner, Mark; Borzou, Ahmad; Call, Kenneth; Dittmann, Jay; Hatakeyama, Kenichi; Liu, Hongxuan; Pastika, Nathaniel; Charaf, Otman; Cooper, Seth; Henderson, Conor; Rumerio, Paolo; Arcaro, Daniel; Avetisyan, Aram; Bose, Tulika; Gastler, Daniel; Rankin, Dylan; Richardson, Clint; Rohlf, James; Sulak, Lawrence; Zou, David; Alimena, Juliette; Berry, Edmund; Cutts, David; Ferapontov, Alexey; Garabedian, Alex; Hakala, John; Heintz, Ulrich; Jesus, Orduna; Laird, Edward; Landsberg, Greg; Mao, Zaixing; Narain, Meenakshi; Piperov, Stefan; Sagir, Sinan; Syarif, Rizki; Breedon, Richard; Breto, Guillermo; Calderon De La Barca Sanchez, Manuel; Chauhan, Sushil; Chertok, Maxwell; Conway, John; Conway, Rylan; Cox, Peter Timothy; Erbacher, Robin; Funk, Garrett; Gardner, Michael; Ko, Winston; Lander, Richard; Mclean, Christine; Mulhearn, Michael; Pellett, Dave; Pilot, Justin; Ricci-Tam, Francesca; Shalhout, Shalhout; Smith, John; Squires, Michael; Stolp, Dustin; Tripathi, Mani; Wilbur, Scott; Yohay, Rachel; Cousins, Robert; Everaerts, Pieter; Florent, Alice; Hauser, Jay; Ignatenko, Mikhail; Saltzberg, David; Takasugi, Eric; Valuev, Vyacheslav; Weber, Matthias; Burt, Kira; Clare, Robert; Ellison, John Anthony; Gary, J William; Hanson, Gail; Heilman, Jesse; Paneva, Mirena Ivova; Jandir, Pawandeep; Kennedy, Elizabeth; Lacroix, Florent; Long, Owen Rosser; Malberti, Martina; Olmedo Negrete, Manuel; Shrinivas, Amithabh; Wei, Hua; Wimpenny, Stephen; Yates, Brent; Branson, James G; Cerati, Giuseppe Benedetto; Cittolin, Sergio; D'Agnolo, Raffaele Tito; Derdzinski, Mark; Holzner, André; Kelley, Ryan; Klein, Daniel; Letts, James; Macneill, Ian; Olivito, Dominick; Padhi, Sanjay; Pieri, Marco; Sani, Matteo; Sharma, Vivek; Simon, Sean; Tadel, Matevz; Vartak, Adish; Wasserbaech, Steven; Welke, Charles; Würthwein, Frank; Yagil, Avraham; Zevi Della Porta, Giovanni; Bradmiller-Feld, John; Campagnari, Claudio; Dishaw, Adam; Dutta, Valentina; Flowers, Kristen; Franco Sevilla, Manuel; Geffert, Paul; George, Christopher; Golf, Frank; Gouskos, Loukas; Gran, Jason; Incandela, Joe; Mccoll, Nickolas; Mullin, Sam Daniel; Richman, Jeffrey; Stuart, David; Suarez, Indara; West, Christopher; Yoo, Jaehyeok; Anderson, Dustin; Apresyan, Artur; Bornheim, Adolf; Bunn, Julian; Chen, Yi; Duarte, Javier; Mott, Alexander; Newman, Harvey B; Pena, Cristian; Spiropulu, Maria; Vlimant, Jean-Roch; Xie, Si; Zhu, Ren-Yuan; Andrews, Michael Benjamin; Azzolini, Virginia; Calamba, Aristotle; Carlson, Benjamin; Ferguson, Thomas; Paulini, Manfred; Russ, James; Sun, Menglei; Vogel, Helmut; Vorobiev, Igor; Cumalat, John Perry; Ford, William T; Gaz, Alessandro; Jensen, Frank; Johnson, Andrew; Krohn, Michael; Mulholland, Troy; Nauenberg, Uriel; Stenson, Kevin; Wagner, Stephen Robert; Alexander, James; Chatterjee, Avishek; Chaves, Jorge; Chu, Jennifer; Dittmer, Susan; Eggert, Nicholas; Mirman, Nathan; Nicolas Kaufman, Gala; Patterson, Juliet Ritchie; Rinkevicius, Aurelijus; Ryd, Anders; Skinnari, Louise; Soffi, Livia; Sun, Werner; Tan, Shao Min; Teo, Wee Don; Thom, Julia; Thompson, Joshua; Tucker, Jordan; Weng, Yao; Wittich, Peter; Abdullin, Salavat; Albrow, Michael; Apollinari, Giorgio; Banerjee, Sunanda; Bauerdick, Lothar AT; Beretvas, Andrew; Berryhill, Jeffrey; Bhat, Pushpalatha C; Bolla, Gino; Burkett, Kevin; Butler, Joel Nathan; Cheung, Harry; Chlebana, Frank; Cihangir, Selcuk; Elvira, Victor Daniel; Fisk, Ian; Freeman, Jim; Gottschalk, Erik; Gray, Lindsey; Green, Dan; Grünendahl, Stefan; Gutsche, Oliver; Hanlon, Jim; Hare, Daryl; Harris, Robert M; Hasegawa, Satoshi; Hirschauer, James; Hu, Zhen; Jayatilaka, Bodhitha; Jindariani, Sergo; Johnson, Marvin; Joshi, Umesh; Klima, Boaz; Kreis, Benjamin; Lammel, Stephan; Linacre, Jacob; Lincoln, Don; Lipton, Ron; Liu, Tiehui; Lopes De Sá, Rafael; Lykken, Joseph; Maeshima, Kaori; Marraffino, John Michael; Maruyama, Sho; Mason, David; McBride, Patricia; Merkel, Petra; Mrenna, Stephen; Nahn, Steve; Newman-Holmes, Catherine; O'Dell, Vivian; Pedro, Kevin; Prokofyev, Oleg; Rakness, Gregory; Sexton-Kennedy, Elizabeth; Soha, Aron; Spalding, William J; Spiegel, Leonard; Stoynev, Stoyan; Strobbe, Nadja; Taylor, Lucas; Tkaczyk, Slawek; Tran, Nhan Viet; Uplegger, Lorenzo; Vaandering, Eric Wayne; Vernieri, Caterina; Verzocchi, Marco; Vidal, Richard; Wang, Michael; Weber, Hannsjoerg Artur; Whitbeck, Andrew; Acosta, Darin; Avery, Paul; Bortignon, Pierluigi; Bourilkov, Dimitri; Carnes, Andrew; Carver, Matthew; Curry, David; Das, Souvik; Field, Richard D; Furic, Ivan-Kresimir; Gleyzer, Sergei V; Konigsberg, Jacobo; Korytov, Andrey; Kotov, Khristian; Ma, Peisen; Matchev, Konstantin; Mei, Hualin; Milenovic, Predrag; Mitselmakher, Guenakh; Rank, Douglas; Rossin, Roberto; Shchutska, Lesya; Snowball, Matthew; Sperka, David; Terentyev, Nikolay; Thomas, Laurent; Wang, Jian; Wang, Sean-Jiun; Yelton, John; Hewamanage, Samantha; Linn, Stephan; Markowitz, Pete; Martinez, German; Rodriguez, Jorge Luis; Ackert, Andrew; Adams, Jordon Rowe; Adams, Todd; Askew, Andrew; Bein, Samuel; Bochenek, Joseph; Diamond, Brendan; Haas, Jeff; Hagopian, Sharon; Hagopian, Vasken; Johnson, Kurtis F; Khatiwada, Ajeeta; Prosper, Harrison; Weinberg, Marc; Baarmand, Marc M; Bhopatkar, Vallary; Colafranceschi, Stefano; Hohlmann, Marcus; Kalakhety, Himali; Noonan, Daniel; Roy, Titas; Yumiceva, Francisco; Adams, Mark Raymond; Apanasevich, Leonard; Berry, Douglas; Betts, Russell Richard; Bucinskaite, Inga; Cavanaugh, Richard; Evdokimov, Olga; Gauthier, Lucie; Gerber, Cecilia Elena; Hofman, David Jonathan; Kurt, Pelin; O'Brien, Christine; Sandoval Gonzalez, Irving Daniel; Turner, Paul; Varelas, Nikos; Wu, Zhenbin; Zakaria, Mohammed; Bilki, Burak; Clarida, Warren; Dilsiz, Kamuran; Durgut, Süleyman; Gandrajula, Reddy Pratap; Haytmyradov, Maksat; Khristenko, Viktor; Merlo, Jean-Pierre; Mermerkaya, Hamit; Mestvirishvili, Alexi; Moeller, Anthony; Nachtman, Jane; Ogul, Hasan; Onel, Yasar; Ozok, Ferhat; Penzo, Aldo; Snyder, Christina; Tiras, Emrah; Wetzel, James; Yi, Kai; Anderson, Ian; Barnett, Bruce Arnold; Blumenfeld, Barry; Eminizer, Nicholas; Fehling, David; Feng, Lei; Gritsan, Andrei; Maksimovic, Petar; Martin, Christopher; Osherson, Marc; Roskes, Jeffrey; Cocoros, Alice; Sarica, Ulascan; Swartz, Morris; Xiao, Meng; Xin, Yongjie; You, Can; Baringer, Philip; Bean, Alice; Benelli, Gabriele; Bruner, Christopher; Kenny III, Raymond Patrick; Majumder, Devdatta; Malek, Magdalena; Mcbrayer, William; Murray, Michael; Sanders, Stephen; Stringer, Robert; Wang, Quan; Ivanov, Andrew; Kaadze, Ketino; Khalil, Sadia; Makouski, Mikhail; Maravin, Yurii; Mohammadi, Abdollah; Saini, Lovedeep Kaur; Skhirtladze, Nikoloz; Toda, Sachiko; Lange, David; Rebassoo, Finn; Wright, Douglas; Anelli, Christopher; Baden, Drew; Baron, Owen; Belloni, Alberto; Calvert, Brian; Eno, Sarah Catherine; Ferraioli, Charles; Gomez, Jaime; Hadley, Nicholas John; Jabeen, Shabnam; Kellogg, Richard G; Kolberg, Ted; Kunkle, Joshua; Lu, Ying; Mignerey, Alice; Shin, Young Ho; Skuja, Andris; Tonjes, Marguerite; Tonwar, Suresh C; Apyan, Aram; Barbieri, Richard; Baty, Austin; Bierwagen, Katharina; Brandt, Stephanie; Busza, Wit; Cali, Ivan Amos; Demiragli, Zeynep; Di Matteo, Leonardo; Gomez Ceballos, Guillelmo; Goncharov, Maxim; Gulhan, Doga; Iiyama, Yutaro; Innocenti, Gian Michele; Klute, Markus; Kovalskyi, Dmytro; Lai, Yue Shi; Lee, Yen-Jie; Levin, Andrew; Luckey, Paul David; Marini, Andrea Carlo; Mcginn, Christopher; Mironov, Camelia; Narayanan, Siddharth; Niu, Xinmei; Paus, Christoph; Roland, Christof; Roland, Gunther; Salfeld-Nebgen, Jakob; Stephans, George; Sumorok, Konstanty; Varma, Mukund; Velicanu, Dragos; Veverka, Jan; Wang, Jing; Wang, Ta-Wei; Wyslouch, Bolek; Yang, Mingming; Zhukova, Victoria; Dahmes, Bryan; Evans, Andrew; Finkel, Alexey; Gude, Alexander; Hansen, Peter; Kalafut, Sean; Kao, Shih-Chuan; Klapoetke, Kevin; Kubota, Yuichi; Lesko, Zachary; Mans, Jeremy; Nourbakhsh, Shervin; Ruckstuhl, Nicole; Rusack, Roger; Tambe, Norbert; Turkewitz, Jared; Acosta, John Gabriel; Oliveros, Sandra; Avdeeva, Ekaterina; Bartek, Rachel; Bloom, Kenneth; Bose, Suvadeep; Claes, Daniel R; Dominguez, Aaron; Fangmeier, Caleb; Gonzalez Suarez, Rebeca; Kamalieddin, Rami; Knowlton, Dan; Kravchenko, Ilya; Meier, Frank; Monroy, Jose; Ratnikov, Fedor; Siado, Joaquin Emilo; Snow, Gregory R; Alyari, Maral; Dolen, James; George, Jimin; Godshalk, Andrew; Harrington, Charles; Iashvili, Ia; Kaisen, Josh; Kharchilava, Avto; Kumar, Ashish; Rappoccio, Salvatore; Roozbahani, Bahareh; Alverson, George; Barberis, Emanuela; Baumgartel, Darin; Chasco, Matthew; Hortiangtham, Apichart; Massironi, Andrea; Morse, David Michael; Nash, David; Orimoto, Toyoko; Teixeira De Lima, Rafael; Trocino, Daniele; Wang, Ren-Jie; Wood, Darien; Zhang, Jinzhong; Bhattacharya, Saptaparna; Hahn, Kristan Allan; Kubik, Andrew; Low, Jia Fu; Mucia, Nicholas; Odell, Nathaniel; Pollack, Brian; Schmitt, Michael Henry; Sung, Kevin; Trovato, Marco; Velasco, Mayda; Brinkerhoff, Andrew; Dev, Nabarun; Hildreth, Michael; Jessop, Colin; Karmgard, Daniel John; Kellams, Nathan; Lannon, Kevin; Marinelli, Nancy; Meng, Fanbo; Mueller, Charles; Musienko, Yuri; Planer, Michael; Reinsvold, Allison; Ruchti, Randy; Smith, Geoffrey; Taroni, Silvia; Valls, Nil; Wayne, Mitchell; Wolf, Matthias; Woodard, Anna; Antonelli, Louis; Brinson, Jessica; Bylsma, Ben; Durkin, Lloyd Stanley; Flowers, Sean; Hart, Andrew; Hill, Christopher; Hughes, Richard; Ji, Weifeng; Ling, Ta-Yung; Liu, Bingxuan; Luo, Wuming; Puigh, Darren; Rodenburg, Marissa; Winer, Brian L; Wulsin, Howard Wells; Driga, Olga; Elmer, Peter; Hardenbrook, Joshua; Hebda, Philip; Koay, Sue Ann; Lujan, Paul; Marlow, Daniel; Medvedeva, Tatiana; Mooney, Michael; Olsen, James; Palmer, Christopher; Piroué, Pierre; Stickland, David; Tully, Christopher; Zuranski, Andrzej; Malik, Sudhir; Barker, Anthony; Barnes, Virgil E; Benedetti, Daniele; Bortoletto, Daniela; Gutay, Laszlo; Jha, Manoj; Jones, Matthew; Jung, Andreas Werner; Jung, Kurt; Kumar, Ajay; Miller, David Harry; Neumeister, Norbert; Radburn-Smith, Benjamin Charles; Shi, Xin; Shipsey, Ian; Silvers, David; Sun, Jian; Svyatkovskiy, Alexey; Wang, Fuqiang; Xie, Wei; Xu, Lingshan; Parashar, Neeti; Stupak, John; Adair, Antony; Akgun, Bora; Chen, Zhenyu; Ecklund, Karl Matthew; Geurts, Frank JM; Guilbaud, Maxime; Li, Wei; Michlin, Benjamin; Northup, Michael; Padley, Brian Paul; Redjimi, Radia; Roberts, Jay; Rorie, Jamal; Tu, Zhoudunming; Zabel, James; Betchart, Burton; Bodek, Arie; de Barbaro, Pawel; Demina, Regina; Eshaq, Yossof; Ferbel, Thomas; Galanti, Mario; Garcia-Bellido, Aran; Han, Jiyeon; Harel, Amnon; Hindrichs, Otto; Khukhunaishvili, Aleko; Lo, Kin Ho; Petrillo, Gianluca; Tan, Ping; Verzetti, Mauro; Chou, John Paul; Contreras-Campana, Emmanuel; Ferencek, Dinko; Gershtein, Yuri; Halkiadakis, Eva; Heindl, Maximilian; Hidas, Dean; Hughes, Elliot; Kaplan, Steven; Kunnawalkam Elayavalli, Raghav; Lath, Amitabh; Nash, Kevin; Saka, Halil; Salur, Sevil; Schnetzer, Steve; Sheffield, David; Somalwar, Sunil; Stone, Robert; Thomas, Scott; Thomassen, Peter; Walker, Matthew; Foerster, Mark; Riley, Grant; Rose, Keith; Spanier, Stefan; Thapa, Krishna; Bouhali, Othmane; Castaneda Hernandez, Alfredo; Celik, Ali; Dalchenko, Mykhailo; De Mattia, Marco; Delgado, Andrea; Dildick, Sven; Eusebi, Ricardo; Gilmore, Jason; Huang, Tao; Kamon, Teruki; Krutelyov, Vyacheslav; Mueller, Ryan; Osipenkov, Ilya; Pakhotin, Yuriy; Patel, Rishi; Perloff, Alexx; Rose, Anthony; Safonov, Alexei; Tatarinov, Aysen; Ulmer, Keith; Akchurin, Nural; Cowden, Christopher; Damgov, Jordan; Dragoiu, Cosmin; Dudero, Phillip Russell; Faulkner, James; Kunori, Shuichi; Lamichhane, Kamal; Lee, Sung Won; Libeiro, Terence; Undleeb, Sonaina; Volobouev, Igor; Appelt, Eric; Delannoy, Andrés G; Greene, Senta; Gurrola, Alfredo; Janjam, Ravi; Johns, Willard; Maguire, Charles; Mao, Yaxian; Melo, Andrew; Ni, Hong; Sheldon, Paul; Tuo, Shengquan; Velkovska, Julia; Xu, Qiao; Arenton, Michael Wayne; Cox, Bradley; Francis, Brian; Goodell, Joseph; Hirosky, Robert; Ledovskoy, Alexander; Li, Hengne; Lin, Chuanzhe; Neu, Christopher; Sinthuprasith, Tutanon; Sun, Xin; Wang, Yanchu; Wolfe, Evan; Wood, John; Xia, Fan; Clarke, Christopher; Harr, Robert; Karchin, Paul Edmund; Kottachchi Kankanamge Don, Chamath; Lamichhane, Pramod; Sturdy, Jared; Belknap, Donald; Carlsmith, Duncan; Cepeda, Maria; Dasu, Sridhara; Dodd, Laura; Duric, Senka; Gomber, Bhawna; Grothe, Monika; Hall-Wilton, Richard; Herndon, Matthew; Hervé, Alain; Klabbers, Pamela; Lanaro, Armando; Levine, Aaron; Long, Kenneth; Loveless, Richard; Mohapatra, Ajit; Ojalvo, Isabel; Perry, Thomas; Pierro, Giuseppe Antonio; Polese, Giovanni; Ruggles, Tyler; Sarangi, Tapas; Savin, Alexander; Sharma, Archana; Smith, Nicholas; Smith, Wesley H; Taylor, Devin; Verwilligen, Piet; Woods, Nathaniel

    2016-08-10

    A search for anomalous pseudoscalar couplings of the Higgs boson H to electroweak vector bosons V (= W or Z) in a sample of proton-proton collision events corresponding to an integrated luminosity of 18.9 fb$^{-1}$ at a center-of-mass energy of 8 TeV is presented. Events consistent with the topology of associated VH production, where the Higgs boson decays to a pair of bottom quarks and the vector boson decays leptonically, are analyzed. The consistency of data with a potential pseudoscalar contribution to the HVV interaction, expressed by the effective pseudoscalar cross section fractions $f_{a_3}$, is assessed by means of profile likelihood scans. Results are given for the VH channels alone and for a combined analysis of the VH and previously published H $\\rightarrow$ VV channels. Assuming the standard model ratio of the coupling strengths of the Higgs boson to top and bottom quarks, $ f_{a_3}^{\\mathrm{ZZ}}>0.0034$ is excluded at 95% confidence level in the combination.

  4. 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

  5. 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)

  6. 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.

  7. Evolved QCD predictions for the meson-photon transition form factors: beyond the semiclassical AdS/QCD approximation

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, Stanley J.; /SLAC; Cao, Fu-Guang; /Massey U. /Beijing Normal U.; de Teramond, Guy F.; /Costa Rica U.

    2011-11-04

    The QCD evolution of the pion distribution amplitude (DA) {phi}{sub {pi}} (x, Q{sup 2}) is computed for several commonly used models. Our analysis includes the nonperturbative form predicted by lightfront holographic QCD, thus combining the nonperturbative bound state dynamics of the pion with the perturbative ERBL evolution of the pion distribution amplitude. We calculate the meson-photon transition form factors for the {pi}{sup 0}, {eta} and {eta}' using the hard-scattering formalism. We point out that a widely-used approximation of replacing {phi} (x; (1 - x)Q) with {phi} (x;Q) in the calculations will unjustifiably reduce the predictions for the meson-photon transition form factors. It is found that the four models of the pion DA discussed give very different predictions for the Q{sup 2} dependence of the meson-photon transition form factors in the region of Q{sup 2} > 30 GeV{sup 2}. More accurate measurements of these transition form factors at the large Q{sup 2} region will be able to distinguish the four models of the pion DA. The rapid growth of the large Q{sup 2} data for the pion-photon transition form factor reported by the BABAR Collaboration is difficult to explain within the current framework of QCD. If the BABAR data for the meson-photon transition form factor for the {pi}{sup 0} is confirmed, it could indicate physics beyond-the-standard model, such as a weakly-coupled elementary C = + axial vector or pseudoscalar z{sup 0} in the few GeV domain, an elementary field which would provide the coupling {gamma}{sup *}{gamma} {yields} z{sup 0} {yields} {pi}{sup 0} at leading twist. Our analysis thus indicates the importance of additional measurements of the pion-photon transition form factor at large Q{sup 2}.

  8. 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.

  9. 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.

  10. 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).

  11. 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.).

  12. 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.

  13. 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.

  14. 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.

  15. $B$- and $D$-meson leptonic decay constants from four-flavor lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Bazavov, A. [Michigan State U.; Bernard, C. [Washington U., St. Louis; Brown, N. [Washington U., St. Louis; Detar, C. [Utah U.; El-Khadra, A. X. [Fermilab; Gámiz, E. [Granada U., Theor. Phys. Astrophys.; Gottlieb, Steven [Indiana U.; Heller, U. M. [APS, New York; Komijani, J. [TUM-IAS, Munich; Kronfeld, A. S. [TUM-IAS, Munich; Laiho, J. [Syracuse U.; Mackenzie, P. B. [Fermilab; Neil, E. T. [RIKEN BNL; Simone, J. N. [Fermilab; Sugar, R. L. [UC, Santa Barbara; Toussaint, D. [Glasgow U.; Van De Water, R. S. [Fermilab

    2017-12-26

    We calculate the leptonic decay constants of heavy-light pseudoscalar mesons with charm and bottom quarks in lattice quantum chromodynamics on four-flavor QCD gauge-field configurations with dynamical $u$, $d$, $s$, and $c$ quarks. We analyze over twenty isospin-symmetric ensembles with six lattice spacings down to $a\\approx 0.03$~fm and several values of the light-quark mass down to the physical value $\\frac{1}{2}(m_u+m_d)$. We employ the highly-improved staggered-quark (HISQ) action for the sea and valence quarks; on the finest lattice spacings, discretization errors are sufficiently small that we can calculate the $B$-meson decay constants with the HISQ action for the first time directly at the physical $b$-quark mass. We obtain the most precise determinations to-date of the $D$- and $B$-meson decay constants and their ratios, $f_{D^+} = 212.6 (0.5)$~MeV, $f_{D_s} = 249.8(0.4)$~MeV, $f_{D_s}/f_{D^+} = 1.1749(11)$, $f_{B^+} = 189.4(1.4)$~MeV, $f_{B_s} = 230.7(1.2)$~MeV, $f_{B_s}/f_{B^+} = 1.2180(49)$, where the errors include statistical and all systematic uncertainties. Our results for the $B$-meson decay constants are three times more precise than the previous best lattice-QCD calculations, and bring the QCD errors in the Standard-Model predictions for the rare leptonic decays $\\overline{\\mathcal{B}}(B_s \\to \\mu^+\\mu^-) = 3.65(11) \\times 10^{-9}$, $\\overline{\\mathcal{B}}(B^0 \\to \\mu^+\\mu^-) = 1.00(3) \\times 10^{-11}$, and $\\overline{\\mathcal{B}}(B^0 \\to \\mu^+\\mu^-)/\\overline{\\mathcal{B}}(B_s \\to \\mu^+\\mu^-) = 0.00264(7)$ to well below other sources of uncertainty. As a byproduct of our analysis, we also update our previously published results for the light-quark-mass ratios and the scale-setting quantities $f_{p4s}$, $M_{p4s}$, and $R_{p4s}$. We obtain the most precise lattice-QCD determination to date of the ratio $f_{K^+}/f_{\\pi^+} = 1.1950(^{+15}_{-22})$~MeV.

  16. 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.

  17. 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.

  18. 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.

  19. 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)

  20. 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.)

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  5. Large loop-coupling enhancement of a heavy pseudoscalar from a light dark sector

    Energy Technology Data Exchange (ETDEWEB)

    Di Chiara, Stefano, E-mail: stefano.dichiara@kbfi.ee [National Institute of Chemical Physics and Biophysics, Rävala pst. 10, 10143 Tallinn (Estonia); Hektor, Andi; Kannike, Kristjan [National Institute of Chemical Physics and Biophysics, Rävala pst. 10, 10143 Tallinn (Estonia); Marzola, Luca; Raidal, Martti [National Institute of Chemical Physics and Biophysics, Rävala pst. 10, 10143 Tallinn (Estonia); Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia)

    2017-04-15

    The small background and the sensitivity to charged particles via a leading order loop coupling make the diphoton channel a privileged experimental test for new physics models. We propose a simple archetypal scenario to generate a sharp di-photon resonance as a result of threshold enhancements in the effective coupling between a heavy pseudoscalar particle and new vector-like leptons. We therefore study three different scenarios consistent with the current experimental limits and deviating from the Standard Model at the 2 σ level. The model also introduces a natural dark matter candidate able to match the observed dark matter abundance and comfortably respect the current direct detection constraints.

  6. Discovering a Light Scalar or Pseudoscalar at The Large Hadron Collider

    DEFF Research Database (Denmark)

    Frandsen, Mads Toudal; Sannino, Francesco

    2012-01-01

    The allowed standard model Higgs mass range has been reduced to a region between 114 and 130 GeV or above 500 GeV, at the 99% confidence level, since the Large Hadron Collider (LHC) program started. Furthermore some of the experiments at Tevatron and LHC observe excesses that could arise from...... a spin-0 particle with a mass of about 125 GeV. It is therefore timely to compare the standard model Higgs predictions against those of a more general new spin-0 state, either scalar or pseudo-scalar. Using an effective Lagrangian approach we investigate the ability to discriminate between a scalar...

  7. 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...

  8. 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.

  9. 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.

  10. 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.)

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. OPE, charm-quark mass, and decay constants of D and Ds mesons from QCD sum rules.

    Science.gov (United States)

    Lucha, Wolfgang; Melikhov, Dmitri; Simula, Silvano

    2011-06-27

    We present a sum-rule extraction of the decay constants of the charmed mesons D and Ds from the two-point correlator of pseudoscalar currents. First, we compare the perturbative expansion for the correlator and the decay constant performed in terms of the pole and the running MS¯ masses of the charm quark. The perturbative expansion in terms of the pole mass shows no signs of convergence whereas reorganizing this very expansion in terms of the MS¯ mass leads to a distinct hierarchy of the perturbative expansion. Furthermore, the decay constants extracted from the pole-mass correlator turn out to be considerably smaller than those obtained by means of the MS¯-mass correlator. Second, making use of the OPE in terms of the MS¯ mass, we determine the decay constants of both D and Ds mesons with an emphasis on the uncertainties in these quantities related both to the input QCD parameters and to the limited accuracy of the method of sum rules.

  17. OPE, charm-quark mass, and decay constants of D and D{sub s} mesons from QCD sum rules

    Energy Technology Data Exchange (ETDEWEB)

    Lucha, Wolfgang [HEPHY, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Melikhov, Dmitri, E-mail: dmitri_melikhov@gmx.de [HEPHY, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); SINP, Moscow State University, 119991 Moscow (Russian Federation); Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria); Simula, Silvano [INFN, Sezione di Roma III, Via della Vasca Navale 84, I-00146 Roma (Italy)

    2011-06-27

    We present a sum-rule extraction of the decay constants of the charmed mesons D and D{sub s} from the two-point correlator of pseudoscalar currents. First, we compare the perturbative expansion for the correlator and the decay constant performed in terms of the pole and the running MS-bar masses of the charm quark. The perturbative expansion in terms of the pole mass shows no signs of convergence whereas reorganizing this very expansion in terms of the MS-bar mass leads to a distinct hierarchy of the perturbative expansion. Furthermore, the decay constants extracted from the pole-mass correlator turn out to be considerably smaller than those obtained by means of the MS-bar-mass correlator. Second, making use of the OPE in terms of the MS-bar mass, we determine the decay constants of both D and D{sub s} mesons with an emphasis on the uncertainties in these quantities related both to the input QCD parameters and to the limited accuracy of the method of sum rules.

  18. 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.

  19. Lattice Calculation of D- and B-meson Semileptonic Decays, using the Clover Action at beta=6.0 on APE

    CERN Document Server

    Allton, C R; Lubicz, V; Martinelli, G; Rapuano, F; Stella, N; Vladikas, A; Bartoloni, A; Battista, C; Cabasino, S; Cabibbo, Nicola; Panizzi, E; Paolucci, P S; Sarno, R; Todesco, G M; Torelli, M; Vicini, P

    1995-01-01

    We present the results of a high statistics lattice calculation of hadronic form factors relevant for $D-$ and $B-$meson semi-leptonic decays into light pseudoscalar and vector mesons. The results have been obtained by averaging over 170 gauge field configurations, generated in the quenched approximation, at $\\beta=6.0$, on a $18^3 \\times 64$ lattice, using the $O(a)$-improved SW-Clover action.From the study of the matrix element $$, we obtain $f_+ (0)=0.78\\pm 0.08$ and from the matrix element $$ we obtain $V(0)=1.08\\pm 0.22$, $A_1(0)=0.67\\pm 0.11$ and $A_2(0)=0.49\\pm 0.34$. We also obtain the ratios $V(0)/A_1(0)=1.6\\pm 0.3$ and $A_2(0)/A_1(0)= 0.7\\pm 0.4$. Our predictions for the different form factors are in good agreement with the experimental data, although, in the case of $A_2(0)$, the errors are still too large to draw any firm conclusion. With the help of the Heavy Quark Effective Theory (HQET) we have also extrapolated the lattice results to $B$-meson decays. The form factors follow a behaviour compat...

  20. 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.

  1. Hyperon interaction in free space and nuclear matter within a SU(3) based meson exchange model

    Energy Technology Data Exchange (ETDEWEB)

    Dhar, Madhumita

    2016-06-15

    To establish the connection between free space and in-medium hyperon-nucleon interactions is the central issue of this thesis. The guiding principle is flavor SU(3) symmetry which is exploited at various levels. In first step hyperon-nucleon and hyperon- hyperon interaction boson exchange potential in free space are introduced. A new parameter set applicable for the complete baryon octet has been derived leading to an updated one-boson- exchange model, utilizing SU(3) flavor symmetry, optimizing the number of free parameters involved, and revising the set of mesons included. The scalar, pseudoscalar, and vector SU(3) meson octets are taken into account. T-matrices are calculated by solving numerically coupled linear systems of Lippmann-Schwinger equations obtained from a 3-D reduced Bethe-Salpeter equation. Coupling constants were determined by χ{sup 2} fits to the world set of scattering data. A good description of the few available data is achieved within the imposed SU(3) constraints. Having at hand a consistently derived vacuum interaction we extend the approach next to investigations of the in-medium properties of hyperon interaction, avoiding any further adjustments. Medium effect in infinite nuclear matter are treated microscopically by recalculating T-matrices by an medium-modified system of Lippmann-Schwinger equations. A particular important role is played by the Pauli projector accounting for the exclusion principle. The presence of a background medium induces a weakening of the vacuum interaction amplitudes. Especially coupled channel mixing is found to be affected sensitively by medium. Investigation on scattering lengths and effective range parameters are revealing the density dependence of the interaction on a quantitative level.

  2. Cornering pseudoscalar-mediated dark matter with the LHC and cosmology

    Science.gov (United States)

    Banerjee, Shankha; Barducci, Daniele; Bélanger, Geneviève; Fuks, Benjamin; Goudelis, Andreas; Zaldivar, Bryan

    2017-07-01

    Models in which dark matter particles communicate with the visible sector through a pseudoscalar mediator are well-motivated both from a theoretical and from a phenomenological standpoint. With direct detection bounds being typically subleading in such scenarios, the main constraints stem either from collider searches for dark matter, or from indirect detection experiments. However, LHC searches for the mediator particles themselves can not only compete with — or even supersede — the reach of direct collider dark matter probes, but they can also test scenarios in which traditional monojet searches become irrelevant, especially when the mediator cannot decay on-shell into dark matter particles or its decay is suppressed. In this work we perform a detailed analysis of a pseudoscalar-mediated dark matter simplified model, taking into account a large set of collider constraints and concentrating on the parameter space regions favoured by cos-mological and astrophysical data. We find that mediator masses above 100-200 GeV are essentially excluded by LHC searches in the case of large couplings to the top quark, while forthcoming collider and astrophysical measurements will further constrain the available parameter space.

  3. Collider signatures of a light NMSSM pseudoscalar in neutralino decays in the light of LHC results

    CERN Document Server

    Cerdeno, David G; Park, Chan Beom; Peiro, Miguel

    2014-01-01

    We investigate signatures induced by a very light pseudoscalar Higgs in neutralino decays in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and determine their observability at the LHC. We concentrate on scenarios which feature two light scalar Higgs bosons (one of them is SM-like with a mass of 125 GeV and a singlet-like lighter one) with a very light (singlet-like) pseudoscalar Higgs in the mass range 2m_tau X_1 a1, which leads to topologies involving multi-leptons and missing transverse energy. We determine a set of selection cuts that can effectively isolate the signal from backgrounds of the Standard Model or the Minimal Supersymmetric Standard Model. We also exemplify the procedure with a set of benchmark points, for which we compute the expected number of events and signal strength for LHC with 8 TeV center of mass energy. We show that this signal can already be probed for some points in the NMSSM parameter space.

  4. Study of the scalar-pseudoscalar interaction in the francium atom

    CERN Document Server

    Skripnikov, L V; Mosyagin, N S

    2016-01-01

    Fr atom can be successively used to search for the atomic permanent electric dipole moment (EDM) [Hyperfine Interactions 236, 53 (2015); Journal of Physics: Conference Series 691, 012017 (2016)]. It can be induced by the permanent electron EDM predicted by modern extensions of the standard model to be nonzero at the level accessible by the new generation of EDM experiments. We consider another mechanism of the atomic EDM generation in Fr. This is caused by the scalar-pseudoscalar nucleus-electron neutral current interaction with the dimensionless strength constant, $k_{T,P}$. Similar to the electron EDM this interaction violates both spatial parity and time-reversal symmetries and can also induce permanent atomic EDM. It was shown in [Phys. Rev. D 89, 056006 (2014)] that the scalar-pseudoscalar contribution to the atomic EDM can dominate over the direct contribution from the electron EDM within the standard model. We report high-accuracy combined all-electron and two-step relativistic coupled cluster treatmen...

  5. 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.

  6. 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

  7. 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.

  8. Measurement Of Two Body B Meson Decays To Pions And Kaons With The Cleo Iii Detector

    CERN Document Server

    Magerkurth, A

    2003-01-01

    We have measured the branching ratios of the decays of B mesons to pseudoscalar kaons and pions using data from the CLEO III detector. We combine our results with the CLEO II measurement and find the branching ratios for the decays BR(B0 → K+π−) = 18.0+2.3+1.2-2.1-0.9 × 10−6, BR(B + → K+π0) = 12.9+2.4+1.2-2.2-1.1 × 10−6, BR(B + → K0π+) = 18.8+3.7+2.1-3.3-1.8 × 10−6, BR(B 0 → K0π0) = 12.8+4.0+1.7-3.3-1.4 × 10−6, and BR( B0 → π+π−) = 4.5+1.4+0.5-1.2-0.4 × 10−6, BR(B 0 → π+π0) = 4.6+1.8+0.6-1.6-0.7 × 10−6, where the first error is statistical and the second is systematic. We set limits on the branching ratios BR(B0 → π0π 0) < 4.4 × 10−6, BR( B0 → K+ K−) < 0.8 × 1...

  9. Meson-exchange enhancement of the first forbidden $0^{+} \\leftrightarrow 0^{-} \\beta$-transitions

    CERN Document Server

    2002-01-01

    In the frame of the standard model of the weak interaction, it has been suggested by Kubodera, Delorme and Rho, that pion exchange should have a large effect on the rank-zero time-like component of the axial current A$_{0}$. The best case for the study of A$ _{0}$ is $0^{-} \\leftrightarrow 0^{+} \\beta$-decay since in this process only rank zero matrix elements of the time-like and space-like components of the axial current contribute to the transition rate. $0^{-} \\leftrightarrow 0^{+}$ decays have been studied in the vicinity of doubly closed-shell nuclei such as $^{16}$O, $^{96}$Zr, and $^{208}$Pb where s$_{1/2} \\leftrightarrow$ p$_{1/2}$ matrix elements were involved. In these cases, the meson-exchange correction to the one-body axial-charge density is significant. ISOLDE offers the possibility to perform sensitive measurements of the $0^{-} \\leftrightarrow 0^{+}$ pseudoscalar decay in nuclei where the p$_{3/2} \\rightarrow$ d$_{3/2}$ matrix elements are involved. We therefore propose a search of the $^{38}...

  10. 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.)

  11. Nonperturbative analysis of the spectrum of meson resonances in an ultraviolet-complete composite-Higgs model

    Science.gov (United States)

    Bizot, Nicolas; Frigerio, Michele; Knecht, Marc; Kneur, Jean-Loïc

    2017-04-01

    We consider a vectorlike gauge theory of fermions that confines at the multi-TeV scale, and that realizes the Higgs particle as a composite Goldstone boson. The weak interactions are embedded in the unbroken subgroup S p (4 ) of a spontaneously broken S U (4 ) flavor group. The meson resonances appear as poles in the two-point correlators of fermion bilinears, and include the Goldstone bosons plus a massive pseudoscalar η', as well as scalars, vectors and axial vectors. We compute the mass spectrum of these mesons, as well as their decay constants, in the chiral limit, in the approximation where the hypercolor S p (2 N ) dynamics is described by four-fermion operators, à la Nambu-Jona Lasinio. By resumming the leading diagrams in the 1 /N expansion, we find that the spin-one states lie beyond the LHC reach, while spin-zero electroweak-singlet states may be as light as the Goldstone-boson decay constant, f ˜1 TeV . We also confront our results with a set of available spectral sum rules. In order to supply composite top-quark partners, the theory contains additional fermions carrying both hypercolor and ordinary color, with an associated flavor symmetry-breaking pattern S U (6 )/S O (6 ). We identify and analyze several nontrivial features of the complete two-sector gauge theory: the 't Hooft anomaly matching conditions; the higher-dimension operator which incorporates the effects of the hypercolor axial-singlet anomaly; the coupled mass-gap equations; the mixing between the singlet mesons of the two sectors, resulting in an extra Goldstone boson η0, and novel spectral sum rules. Assuming that the strength of the four-fermion interaction is the same in the two sectors, we find that the colored vector and scalar mesons have masses ≳4 f , while the masses of colored pseudo-Goldstone bosons, induced by gluon loops, are ≳1.5 f . We discuss the scaling of the meson masses with the values of N , of the four-fermion couplings, and of a possible fermion mass.

  12. Baryonic Resonances from Baryon Decuplet-Meson Octet Interactions and the Exotic Resonance S=1, I=1, J{sup P}=32{sup -}

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Sourav [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutes de Investigacion de Paterna, Aptd. 22085, 46071 Valencia (Spain); Oset, E. [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutes de Investigacion de Paterna, Aptd. 22085, 46071 Valencia (Spain); Vacas, M.J. Vicente [Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutes de Investigacion de Paterna, Aptd. 22085, 46071 Valencia (Spain)

    2005-06-13

    Using the lowest order chiral Lagrangian we study s-wave interactions of the baryon decuplet with the octet of pseudoscalar mesons. We find two bound states in the flavour SU(3) limit corresponding to the octet and decuplet representations. These are found to split into eight different trajectories in the complex plane when the SU(3) symmetry is broken gradually. Finally, we are able to provide a reasonable description for a good number of 4-star 32{sup -} resonances listed by the Particle Data Group. In particular, the {xi}(1820), the {lambda}1520) and the {sigma}(1670) states are well reproduced. We predict a few other resonances and also evaluate the couplings of the observed resonances to the various channels from the residues at the poles of the scattering matrix from where partial decay widths into different channels can be evaluated.

  13. 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.

  14. 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...

  15. 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...

  16. 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.)

  17. 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.)

  18. 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.

  19. 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.

  20. 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.)

  1. 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.

  2. 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.

  3. Exploring the Quark-Gluon Content of Hadrons: From Mesons to Nuclear Matter

    Energy Technology Data Exchange (ETDEWEB)

    Matevosyan, Hrayr [Louisiana State Univ., Baton Rouge, LA (United States)

    2007-08-01

    Even though Quantum Chromodynamics (QCD) was formulated over three decades ago, it poses enormous challenges for describing the properties of hadrons from the underlying quark-gluon degrees of freedom. Moreover, the problem of describing the nuclear force from its quark-gluon origin is still open. While a direct solution of QCD to describe the hadrons and nuclear force is not possible at this time, we explore a variety of developed approaches ranging from phenomenology to first principle calculations at one or other level of approximation in linking the nuclear force to QCD. The Dyson Schwinger formulation (DSE) of coupled integral equations for the QCD Green’s functions allows a non-perturbative approach to describe hadronic properties, starting from the level of QCD n-point functions. A significant approximation in this method is the employment of a finite truncation of the system of DSEs, that might distort the physical picture. In this work we explore the effects of including a more complete truncation of the quark-gluon vertex function on the resulting solutions for the quark 2-point functions as well as the pseudoscalar and vector meson masses. The exploration showed strong indications of possibly large contributions from the explicit inclusion of the gluon 3- and 4-point functions that are omitted in this and previous analyses. We then explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime using phenomenological models of nucleon structure. Finally, we further developed the Quark Meson Coupling model for describing atomic nuclei and nuclear matter, where the quark-gluon structure of nucleons is modeled by the MIT bag model and the nucleon many body interaction is mediated by the exchange of scalar and vector mesons. This approach allows us to formulate a fully relativistic theory, which can be expanded in the nonrelativistic limit to reproduce the well known phenomenological Skyrme

  4. 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)

  5. Heavy neutral pseudoscalar decays into gauge bosons in the Littlest Higgs model

    Science.gov (United States)

    Aranda, J. I.; Cruz-Albaro, E.; Espinosa-Gómez, D.; Montaño, J.; Ramírez-Zavaleta, F.; Tututi, E. S.

    2017-10-01

    We study two-body decays of a new neutral pseudoscalar into standard model gauge bosons within the context of the Littlest Higgs model. The {{{Φ }}}{{P}}\\to {WW},{VV},{gg} processes induced at the one-loop level, with V=γ ,Z, are considered. Since the branching ratios of the {{{Φ }}}P\\to {VV} decays result were very suppressed, only the {{{Φ }}}{{P}}\\to {WW},{gg} processes are thoroughly studied. The branching ratios for the {{{Φ }}}{{P}}\\to {gg} and {{{Φ }}}{{P}}\\to {WW} decays are of the order of 10-5 and 10-7, respectively, for f around 3 TeV, which represents the global symmetry breaking scale of the theory. The production cross section of the {{{Φ }}}{{P}} boson via gluon fusion at the LHC is estimated.

  6. $SU(2)$ gauge theory with two fundamental flavours: scalar and pseudoscalar spectrum

    CERN Document Server

    Arthur, Rudy; Hietanen, Ari; Pica, Claudio; Sannino, Francesco

    2016-01-01

    We investigate the scalar and pseudoscalar spectrum of the $SU(2)$ gauge theory with $N_f=2$ flavours of fermions in the fundamental representation using non perturbative lattice simulations. We provide first benchmark estimates of the mass of the lightest $0(0^{+})$ ($\\sigma$), $0(0^{-})$ ($\\eta'$) and $1(0^+)$ ($a_0$) states, including estimates of the relevant disconnected contributions. We find $m_{a_0}/F_{\\rm{PS}}= 16.7(4.9)$, $m_\\sigma/F_{\\rm{PS}}=19.2(10.8)$ and $m_{\\eta'}/F_{\\rm{PS}} = 12.8(4.7)$. These values for the masses of light scalar states provide crucial information for composite extensions of the Standard Model from the unified Fundamental Composi te Higgs-Technicolor theory \\cite{Cacciapaglia:2014uja} to models of composite dark matter.

  7. 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.

  8. 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.)

  9. Heavy pseudoscalar twist-3 distribution amplitudes within QCD theory in background fields

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Tao [Henan Normal University, College of Physics and Materials Science, Xinxiang (China); Wu, Xing-Gang [Chongqing University, Department of Physics, Chongqing (China); Huang, Tao [Chinese Academy of Sciences, Institute of High Energy Physics and Theoretical Physics Center for Science Facilities, Beijing (China); Fu, Hai-Bing [Guizhou Minzu University, School of Science, Guiyang (China)

    2016-09-15

    In this paper, we study the properties of the twist-3 distribution amplitude (DA) of the heavy pseudoscalars such as η{sub c}, B{sub c}, and η{sub b}. New sum rules for the twist-3 DA moments left angle ξ{sup n}{sub P} right angle {sub HP} and left angle ξ{sup n}{sub σ} right angle {sub HP} up to sixth order and up to dimension-six condensates are deduced under the framework of the background field theory. Based on the sum rules for the twist-3 DA moments, we construct a new model for the two twist-3 DAs of the heavy pseudoscalar with the help of the Brodsky-Huang-Lepage prescription. Furthermore, we apply them to the B{sub c} → η{sub c} transition form factor (f{sub +}{sup B{sub c}→η{sub c}}(q{sup 2})) within the light-cone sum rules approach, and the results are comparable with other approaches. It has been found that the twist-3 DAs φ{sup P}{sub 3;η{sub c}} and φ{sup σ}{sub 3;η{sub c}} are important for a reliable prediction of f{sub +}{sup B{sub c}→η{sub c}}(q{sup 2}). For example, at the maximum recoil region, we have f{sub +}{sup B{sub c}→η{sub c}}(0) = 0.674 ± 0.066, in which those two twist-3 terms provide ∝33 and ∝22% contributions. Also we calculate the branching ratio of the semi-leptonic decay B{sub c} → η{sub c}lν Br(B{sub c} → η{sub c}lν) = (9.31{sup +2.27}{sub -2.01}) x 10{sup -3}. (orig.)

  10. 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.

  11. 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).

  12. 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

  13. 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.

  14. 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.)

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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,

  20. 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.

  1. 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.

  2. 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.

  3. 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 ...

  4. 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.

  5. 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.

  6. 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).

  7. 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.

  8. 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.

  9. 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.

  10. 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.)

  11. Combined search for anomalous pseudoscalar HVV couplings in VH(H→bb‾ production and H→VV decay

    Directory of Open Access Journals (Sweden)

    V. Khachatryan

    2016-08-01

    Full Text Available A search for anomalous pseudoscalar couplings of the Higgs boson H to electroweak vector bosons V (=W or Z in a sample of proton–proton collision events corresponding to an integrated luminosity of 18.9 fb−1 at a center-of-mass energy of 8 TeV is presented. Events consistent with the topology of associated VH production, where the Higgs boson decays to a pair of bottom quarks and the vector boson decays leptonically, are analyzed. The consistency of data with a potential pseudoscalar contribution to the HVV interaction, expressed by the effective pseudoscalar cross section fractions fa3, is assessed by means of profile likelihood scans. Results are given for the VH channels alone and for a combined analysis of the VH and previously published H→VV channels. Under certain assumptions, fa3ZZ>0.0034 is excluded at 95% confidence level in the combination. Scenarios in which these assumptions are relaxed are also considered.

  12. Constraining Dark Matter Interactions with Pseudoscalar and Scalar Mediators Using Collider Searches for Multijets plus Missing Transverse Energy.

    Science.gov (United States)

    Buchmueller, Oliver; Malik, Sarah A; McCabe, Christopher; Penning, Bjoern

    2015-10-30

    The monojet search, looking for events involving missing transverse energy (E_{T}) plus one or two jets, is the most prominent collider dark matter search. We show that multijet searches, which look for E_{T} plus two or more jets, are significantly more sensitive than the monojet search for pseudoscalar- and scalar-mediated interactions. We demonstrate this in the context of a simplified model with a pseudoscalar interaction that explains the excess in GeV energy gamma rays observed by the Fermi Large Area Telescope. We show that multijet searches already constrain a pseudoscalar interpretation of the excess in much of the parameter space where the mass of the mediator M_{A} is more than twice the dark matter mass m_{DM}. With the forthcoming run of the Large Hadron Collider at higher energies, the remaining regions of the parameter space where M_{A}>2m_{DM} will be fully explored. Furthermore, we highlight the importance of complementing the monojet final state with multijet final states to maximize the sensitivity of the search for the production of dark matter at colliders.

  13. 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.

  14. 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.

  15. 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.

  16. 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.)

  17. 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...

  18. 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

  19. 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.

  20. 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...

  1. Next-to-Next-to-Leading-Order QCD Corrections to the Hadronic Width of Pseudoscalar Quarkonium

    Science.gov (United States)

    Feng, Feng; Jia, Yu; Sang, Wen-Long

    2017-12-01

    We compute the next-to-next-to-leading-order QCD corrections to the hadronic decay rates of the pseudoscalar quarkonia, at the lowest order in velocity expansion. The validity of nonrelativistic QCD (NRQCD) factorization for inclusive quarkonium decay process, for the first time, is verified to relative order αs2. As a by-product, the renormalization group equation of the leading NRQCD four-fermion operator O1(1S0 ) is also deduced to this perturbative order. By incorporating this new piece of correction together with available relativistic corrections, we find that there exists severe tension between the state-of-the-art NRQCD predictions and the measured ηc hadronic width and, in particular, the branching fraction of ηc→γ γ . NRQCD appears to be capable of accounting for ηb hadronic decay to a satisfactory degree, and our most refined prediction is Br(ηb→γ γ )=(4.8 ±0.7 )×10-5.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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 $C_{J/\\psi K^0_S} = 0.03 \\pm 0.09 (\\text{stat})\\pm 0.01 (\\text{syst})$.

  7. 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.

  8. 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.

  9. 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.

  10. Single meson production in proton diffraction at 190 GeV/c at COMPASS

    Energy Technology Data Exchange (ETDEWEB)

    Weisrock, Tobias

    2015-08-28

    The quark model successfully describes all ground state baryons as members of SU(N) flavour multiplets. For excited baryon states the situation is totally different. There are much less states found in the experiment than predicted in most theoretical calculations. This fact has been known for a long time as the 'missing resonance problem'. In addition, many states found in experiments are only poorly measured up to now. Therefore, further experimental efforts are needed to clarify the situation. At COMPASS, reactions of a 190 GeV/c hadron beam impinging on a liquid hydrogen target are investigated. The hadron beam contains different species of particles (π,K,p). To distinguish these particles, two Cherenkov detectors are used. In this thesis, a new method for the identification of particles from the detector information is developed. This method is based on statistical approaches and allows a better kaon identification efficiency with a similar purity compared to the method, which was used before. The reaction pp→ppX with X=(π{sup 0},η,ω,φ) is used to study different production mechanisms. A previous analysis of ω and φ mesons is extended to pseudoscalar mesons. As the resonance contributions in pη are smaller than in pπ{sup 0} a different behaviour of these two final states is expected as a function of kinematic variables. The investigation of these differences allows to study different production mechanisms and to estimate the size of the resonant contribution in the different channels. In addition, the channel pp→ppX allows to study baryon resonances in the pX system. In the COMPASS energy regime, the reaction is dominated by Pomeron exchange. As a Pomeron carries vacuum quantum numbers, no isospin is transferred between the target proton and the beam proton. Therefore, the pX final state has isospin (1)/(2) and all baryon resonances in this channel are N* baryons. This offers the opportunity to do spectroscopy without taking

  11. 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.

  12. 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).

  13. 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)

  14. 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.)

  15. 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.

  16. 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.

  17. 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)

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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 de