1. Deeply virtual and exclusive electroproduction of $\omega$-mesons
- Author
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Morand, L, Dore, D, Garcon, M, Guidal, M, Laget, Jm, Morrow, S, Sabatie, F, Smith, E, Adams, G, Arnbrozewicz, P, Anghinolfi, Marco, Asryan, G, Audit, G, Avakian, H, Bagdasaryan, H, Ball, J, Ball, Jp, Baltzell, Na, Barrow, S, Batourine, V, Battaglieri, Marco, Bektasoglu, M, Bellis, M, Benmouna, N, Berman, Bl, Biselli, As, Boiarinov, S, Bonner, Be, Bouchigny, S, Bradford, R, Branford, D, Briscoe, Wj, Brooks, Wk, Bultmann, S, Burkert, Vd, Butuceanu, C, Calarco, Jr, Careccia, Sl, Carman, Ds, Cazes Antoine Jacques, Chen, S, Cole, Pl, Cords, D, Corvisiero, Pietro, Crabb, D, Cummings, Jp, De Sanctis Enzo, Devita, R, Degtyarenko, Pv, Denizli, H, Dennis, L, Deur, A, Dharmawardane, Kv, Dhuga, Ks, Djalali, C, Dodge, Ge, Donnelly, J, Doughty, D, Dugger, M, Dytman, S, Dzyubak, Op, Egiyan, H, Egiyan, Ks, Elouadrhiri, L, Eugenio, P, Fatemi, R, Feldman, Gerald, Fersch, Rg, Feuerbach, Rj, Funsten, H, Gavalian, G, Gilfoyle, Gp, Giovanetti, Kl, Girod, Fx, Goetz, Jt, Gordon, Cio, Gothe, Rw, Griffioen, Ka, Guillo, M, Guler, N, Guo, L, Gyurjyan, V, Hadjidakis, Cynthia, Hakobyan, Rs, Hardie, J, Heddle, D, Hersman, Fw, Hicks, K, Hleiqawi, I, Holtrop, M, Hyde Wright CE, Ilieva, Y, Ireland, Dg, Ito, Mm, Jenkins, D, Jo, Hs, Joo, K, Juengst, Hg, Kellie, Jd, Khandaker, M, Kim, W, Klein, A, Klein, Fj, Klimenko, Av, Kossov, M, Kubarovski, V, Kramer, Lh, Kuhn, Se, Kuhn, J, Lachniet, J, Langhenirich, J, Lawrence, D, Lee, T, Jun, Li, Livingston, K, Marchand, C, Maximon, Lc, Mcaleer, S, Mckinnon, B, Mcnabb, Jwc, Mecking, Ba, Mehrabyan, S, Melone, Jj, Mestayer, Md, Meyer, Ca, Mikhailov, K, Minehart, R, Mirazita, Marco, Miskimen, R, Mokeev, V, Mueller, J, Mutchler, Gs, Napolitano, J, Nasseripour, R, Niccolai, S, Niculescu, G, Niculescu, I, Niczyporuk, Bb, Niyazov, Ra, Nozar, M, O'Rielly, Gv, Osipenko, Mikhail, Ostrovidov, Ai, Park, K, Pasyuk, E, Philips, Sa, Pivnyuk, N, Pocanic, D, Pogorelko, O, Polli, Ermanno, Popa, I, Pozdniakov, S, Preedom, Bm, Price, Jw, Prok, Y, Protopopescu, D, Raue, Ba, Riccardi, G, Ricco, Giovanni, Ripani, Marco, Ritchie, Bg, Ronchetti, Federico, Rosner, G, Rossi, Patrizia, Rubin, Pd, Salgado Lopez Carlos Alberto, Santoro, Joseph, Sapunenko, Vladimir, Schumacher, Ra, Serov, Vs, Sharabian, Yg, Shaw, J, Skabelin, Av, Smith, Lc, Sober, Di, Stavinsky, A, Stepanyan, S, Stepanyan, Ss, Stokes, Be, Stoler, P, Strakovsky, Ii, Strauch, S, Taiuti, MAURO GINO, Tedeschi, Dj, Thoma, U, Tkabladze, A, Todor, L, Tur, C, Ungaro, M, Vineyard, Mf, Vlassov, Av, Weinstein, Lb, Weygand, Dp, Williams Meurig Crispin Stowe, Wolin, E, Wood, Mh, Yegneswaran, A, Zana, L., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and CLAS
- Subjects
Nuclear and High Energy Physics ,Particle physics ,Photon ,Meson ,Proton ,Nuclear Theory ,FOS: Physical sciences ,Parton ,13.60.Le - 12.40.Nn -12.38.Bx ,01 natural sciences ,Omega ,Resonance (particle physics) ,High Energy Physics - Experiment ,High Energy Physics - Experiment (hep-ex) ,GENERALIZED PARTON DISTRIBUTIONS ,CLAS ,0103 physical sciences ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,SCATTERING ,010306 general physics ,Nuclear Experiment ,Coupling ,Physics ,010308 nuclear & particles physics ,HYDROGEN ,PHOTON ,SPIN ,GENERALIZED PARTON DISTRIBUTIONS, VECTOR-MESONS, SCATTERING, PHOTON, HYDROGEN, SPIN, CLAS ,High Energy Physics::Experiment ,Nucleon ,VECTOR-MESONS - Abstract
The exclusive omega electroproduction off the proton was studied in a large kinematical domain above the nucleon resonance region and for the highest possible photon virtuality (Q2) with the 5.75 GeV beam at CEBAF and the CLAS spectrometer. Cross sections were measured up to large values of the four-momentum transfer (-t < 2.7 GeV2) to the proton. The contributions of the interference terms sigma_TT and sigma_TL to the cross sections, as well as an analysis of the omega spin density matrix, indicate that helicity is not conserved in this process. The t-channel pi0 exchange, or more generally the exchange of the associated Regge trajectory, seems to dominate the reaction gamma* p -> omega p, even for Q2 as large as 5 GeV2. Contributions of handbag diagrams, related to Generalized Parton Distributions in the nucleon, are therefore difficult to extract for this process. Remarkably, the high-t behaviour of the cross sections is nearly Q2-independent, which may be interpreted as a coupling of the photon to a point-like object in this kinematical limit., 15 pages,19 figures
- Published
- 2005