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Measurement of ep-->ep[pi]0 beam spin asymmetries above the resonance region

2008; American Physical Society; Volume: 77; Linguagem: Inglês

1092-0145

R. De Masi, M. Garçon, Bo Zhao, Moscov Amaryan, M. J. Amaryan, P. Ambrozewicz, M. Anghinolfi, Gegham Asryan, Harutyun Avagyan, H. Baghdasaryan, N. Baillie, James Patrick Ball, J. Ball, James Patrick Ball, N. A. Baltzell, V. Baturin, M. Battaglieri, Ivan Bedlinskiy, M. Bellis, N. Benmouna, B. L. Berman, P.Y. Bertin, A. S. Biselli, L. Blaszczyk, S. Bouchigny, S.V. Boyarinov, R. Bradford, Derek Branford, W. J. Briscoe, W. K. Brooks, S. Bültmann, S. Bueltmann, Volker Burkert, C. Butuceanu, J. R. Calarco, Sharon Careccia, Daniel Carman, Liam Casey, Shifeng Chen, Lu Cheng, P. L. Cole, Patrick Collins, P. Coltharp, Donald G. Crabb, Volker Crede, Natalya Dashyan, E. De Sanctis, Raffaella De Vita, Pavel Degtiarenko, A. Deur, Kahanawita Dharmawardane, R. Dickson, C. Djalali, G. E. Dodge, J.P. Donnelly, D. Doughty, M. Dugger, O. P. Dzyubak, H. Egiyan, K. S. Egiyan, L. El-Fassi, L. Elouadrhiri, P. Eugenio, Gleb Fedotov, G. Feldman, A. Fradi, H. O. Funsten, Gagik Gavalian, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, A. Gönenç, R. W. Gothe, K. A. Griffioen, M. Guidal, Nevzat Guler, Lei Guo, V. Gyurjyan, Kawtar Hafidi, Hayk Hakobyan, C. Hanretty, F. W. Hersman, K. Hicks, I. Hleiqawi, M. Holtrop, C. E. Hyde-Wright, Yordanka Ilieva, D. G. Ireland, B. Ishkhanov, Evgeny Isupov, Mark Ito, D. G. Jenkins, Hyon-Suk Jo, J.R. Johnstone, K. Joo, Henry Juengst, N. Kalantarians, J.D. Kellie, M. Khandaker, Wooyoung Kim, A. Klein, Franz Klein, A. Klimenko, M. Kossov, Z. Krahn, L. H. Kramer, Valery Kubarovsky, J. Kühn, Sebastian Kuhn, Sergey Kuleshov, Jeff Lachniet, J.M. Laget, J. Langheinrich, David Lawrence, Tsung-Shung Lee, Kenneth Livingston, H. Y. Lu, M. MacCormick, N. V. Маrkov, P. Mattione, M. Mazouz, B. McKinnon, B. A. Mecking, Mac Mestayer, Curtis Meyer, T. Mibe, B. Michel, Konstantin Mikhaylov, M. Mirazita, R. Miskimen, V.I. Mokeev, B. Moreno, Kei Moriya, Steven Morrow, M. Moteabbed, Edwin Munevar Espitia, G.S. Mutchler, P. Nadel-Turoński, R. Nasseripour, Silvia Niccolai, G. Niculescu, Maria-Ioana Niculescu, B. Niczyporuk, M. R. Niroula, Rustam Niyazov, M. Nozar, M. Osipenko, A. Ostrovidov, K. Park, E. Pasyuk, Craig Paterson, S. Anefalos Pereira, Joshua Pierce, N. Pivnyuk, D. Počanić, Oleg Pogorelko, S.A. Pozdnyakov, J. W. Price, Sébastien Procureur, Yelena Prok, D. Protopopescu, B. A. Raue, G. Ricco, M. Ripani, B. G. Ritchie, F. Ronchetti, Guenther Rosner, Patrizia Rossi, F. Sabatié, J. Salamanca, C. Salgado, J. Santoro, V. Sapunenko, R. A. Schumacher, V.I. Serov, Youri Sharabian, D. Sharov, N. V. Shvedunov, E. S. Smith, Lee Smith, D. I. Sober, D. Sokhan, A.V. Stavinsky, Samuel Stepanyan, S. Stepanyan, Burnham Stokes, P. Stoler, Igor Strakovski, Steffen Strauch, M. Taiuti, D. Tedeschi, A. Tkabladze, Svyatoslav Tkachenko, C. Tur, Maurizio Ungaro, Michael Vineyard, Alexander V. Vlassov, E. Voutier, D. P. Watts, Lawrence Weinstein, Dennis Weygand, Michael E. Williams, E. Wolin, Michael Wood, A. Yegneswaran, Lorenzo Zana, Jixie Zhang, B. Zhao,

High-Energy Particle Collisions Research

The beam spin asymmetry (BSA) in the exclusive reaction e-vector p-->eppi0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer (CLAS). The xB,Q2,t, and phi dependences of the pi0 BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sinphi function and their amplitudes are extracted. Overall, they are of the order of 0.04â 0.11 and roughly independent of t. This is the signature of a nonzero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as the extension of a Regge formalism at high photon virtualities, are discussed.