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Eduard Avetisyan 《中国物理C(英文版)》2010,34(9)
The exclusive electroproduction of pseudoscalar and vector mesons was studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target.The results are compared to calculations based on generalized parton distributions,some of which are sensitive to the contribution of the total angular momentum of the quarks to the proton spin. 相似文献
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Eduard Avetisyan 《中国物理 C》2010,34(9):1472-1475
The exclusive electroproduction of pseudoscalar and vector mesons was studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target.The results are compared to calculations based on generalized parton distributions,some of which are sensitive to the contribution of the total angular momentum of the quarks to the proton spin. 相似文献
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It is shown that data of the BELLE Collaboration on the exclusive production of charmedmeson pairs via the one-photon mechanism of e+e? annihilation can be adequately described within the constituent quark model. It is also shown that the cross section for the central production of two D mesons in the process \(e^ + e^ - \to e^ + e^ - \gamma \gamma \to e^ + e^ - D\bar D + X\) is commensurate with the cross section for their production in one-photon annihilation. 相似文献
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M. Tytgat 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):451-453
Hard exclusive production of mesons in deep-inelastic scattering allows one to probe the so-far unknown Generalized Parton
Distributions (GPDs) of the nucleon. The HERMES experiment has measured several different observables in exclusive meson production
by scattering the 27.6GeV HERA lepton beam off an internal fixed gaseous target. Recent results on exclusive π
+, ρ
0 and pion pair production will be presented. 相似文献
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I. Fröhlich F. Balestra Y. Bedfer R. Bertini L. C. Bland A. Brenschede F. Brochard M. P. Bussa Seonho Choi M. L. Colantoni R. Dressler M. Dzemidzic J.-Cl Faivre A. Ferrero L. Ferrero J. Foryciarz V. Frolov R. Garfagnini A. Grasso S. Heinz W. W. Jacobs W. Kühn A. Maggiora M. Maggiora A. Manara D. Panzieri H.-W. Pfaff G. Piragino A. Popov J. Ritman P. Salabura V. Tchalyshev F. Tosello S. E. Vigdor G. Zosi 《The European Physical Journal A - Hadrons and Nuclei》2003,18(2-3):331-334
Angular distributions for the exclusive reaction
observed via the
decay channel have been measured at
GeV, 2.50 GeV and 2.85 GeV (excess energies Q = 324 MeV, 412 MeV and 554 MeV). The polar angle of the
shows an anisotropy with respect to the beam direction for the lowest energy, which vanishes for the higher energies. The anisotropy of the pp polar angle increases slightly with the beam energy.Received: 30 September 2002, Published online: 22 October 2003PACS:
13.75.Cs Nucleon-nucleon interactions (including antinucleons, deuterons, etc.) - 14.40.Aq
, K, and
mesons - 25.40.Ve Other reactions above meson production thresholds (energies > 400 MeV)Y. Bedfer: Present address: DAPNIA/SPhN, CEA Saclay, France.A. Brenschede: Present address: Syngenio AG, StuttgartF. Brochard: Present address: LPHNHE, Ecole Polytechnique 91128 Palaiseau, France.Seonho Choi: Present address: Temple University, Philadelphia, PA, USA.R. Dressler: Present address: Paul Scherrer Institut, Villigen, CH-5232.J. Foryciarz: Present address: Motorola Polska Software Center, Kraków, Poland.H.-W. Pfaff: Present address: d-fine GmbH, Eschborn. 相似文献
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This work extends our previous studies of two-photon annihilation into baryon-antibaryon pairs from spin-1/2 octet to spin-3/2 decuplet baryons. Our approach is based on perturbative QCD and treats baryons as quark-diquark systems. Using the same model parameters as in our previous work, supplemented by QCD sum-rule results for decuplet baryon wave functions, we are able to give absolute predictions for decuplet baryon cross sections without introducing new parameters. We find that the
cross section is of the same order of magnitude as the proton cross section, well within experimental bounds.Received: 11 November 2004, Published online: 11 January 2005C.F. Berger: Work supported in part by the Department of Energy, contract DE-AC02-76SF00515. 相似文献
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Results obtained by studying the properties of the leading-twist wave functions for the S- and P-wave states of charmonia are presented. Wave-function models that can be used to calculate various processes involving the
production of these mesons were constructed on the basis of these investigations. Calculations for some exclusive processes
of charmonium production were performed within the models in question. 相似文献
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Abe F Amidei D Apollinari G Atac M Auchincloss P Baden AR Bamberger A Barbaro-Galtieri A Barnes VE Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Bensinger J Beretvas A Berge JP Bertolucci S Bhadra S Binkley M Blair R Blocker C Booth AW Brandenburg G Brown D Buckley E Byon A Byrum KL Campagnari C Campbell M Carey R Carithers W Carlsmith D Carroll JT Cashmore R Cervelli F Chadwick K Chiarelli G Chinowsky W Cihangir S Clark AG Connor D Contreras M Cooper J Cordelli M Crane D Curatolo M 《Physical review letters》1989,63(7):720-723
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Petrov V. A. Ryutin R. A. 《The European Physical Journal C - Particles and Fields》2004,36(4):509-513
Exclusive double diffractive (EDD) Higgs boson production is analyzed in the framework of the Regge-eikonal approach. Total and differential cross-sections for the process
are calculated. Experimental possibilities to find the Higgs boson at LHC are discussed.Received: 5 November 2003, Revised: 16 April 2004, Published online: 30 July 2004
Correspondence to and send offprint requests to: R.A. Ryutin 相似文献
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A.D. Martin R.G. Roberts W.J. Stirling R.S. Thorne 《The European Physical Journal C - Particles and Fields》2000,14(1):133-145
W and Z bosons will be produced copiously at the LHC proton-proton collider. We study the parton distribution dependence of the total
production cross sections and rapidity distributions, paying particular attention to the uncertainties arising from uncertainties
in the parton distributions themselves. Variations in the gluon, the strong coupling, the sea quarks and the overall normalisation
are shown to lead to small but non-negligible variations in the cross section predictions. Ultimately, therefore, the measurement
of these cross sections will provide a powerful cross check on our knowledge of parton distributions and their evolution.
Received: 23 November 1999 / Published online: 6 April 2000 相似文献