Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1GeV2 . I. ep→eπ+n

Bosted, P. E. et al. (2017) Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1GeV2 . I. ep→eπ+n. Physical Review C, 95(3), 035206. (doi: 10.1103/PhysRevC.95.035206)

Abstract

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π + electroproduction reaction γ ∗ p → n π + . The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic range covered is 1.1 < W < 3 GeV and 1 < Q 2 < 6 GeV 2 . Results were obtained for about 6000 bins in W ,   Q 2 ,   cos ( θ ∗ ) , and ϕ ∗ . Except at forward angles, very large target-spin asymmetries are observed over the entire W region. Reasonable agreement is found with phenomenological fits to previous data for W < 1.6 GeV, but very large differences are seen at higher values of W . A generalized parton distributions (GPD)-based model is in poor agreement with the data. When combined with cross-sectional measurements, the present results provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q 2 , for resonances with masses as high as 2.4 GeV.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Murdoch, Mr Gavin and Sokhan, Dr Daria and McKinnon, Dr Bryan and Ireland, Professor David and Clark, Ms Louise and Livingston, Dr Kenneth and MacGregor, Professor Douglas and Montgomery, Dr Rachel and Rosner, Professor Guenther and Protopopescu, Dr Dan
• Authors: Bosted, P. E., Amaryan, M. J., Anefalos Pereira, S., Avakian, H., Badui, R. A., Ball, J., Baltzell, N. A., Battaglieri, M., Batourine, V., Bedlinskiy, I., Biselli, A. S., Briscoe, W. J., Bültmann, S., Burkert, V. D., Carman, D. S., Celentano, A., Chandavar, S., Charles, G., Ciullo, G., Clark, L., Colaneri, L., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., De Vita, R., Deur, A., De Sanctis, E., 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., Forest, T., Fradi, A., Gevorgyan, N., Ghandilyan, Y., Gilfoyle, G. P., Girod, F. X., Gleason, C., Gohn, W., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Hakobyan, H., Hattawy, M., Hicks, K., Holtrop, M., Hughes, S. M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jiang, H., Jo, H. S., Joo, K., Joosten, S., Khachatryan, G., Khandaker, M., Kim, A., Kim, W., Klein, F. J., Koirala, S., Kubarovsky, V., Kuhn, S. E., Lanza, L., Net, L. A., Lenisa, P., Livingston, K., MacGregor, I. J. D., McCracken, M. E., McKinnon, B., Meyer, C. A., Mirazita, M., Mokeev, V. I., Montgomery, R. A., Munevar, E., Munoz Camacho, C., Murdoch, G., Nadel-Turonski, P., Niccolai, S., Osipenko, M., Ostrovidov, A. I., Park, K., Pasyuk, E., Peng, P., Phelps, W., Pisano, S., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Puckett, A. J. R., Raue, B. A., Ripani, M., Rosner, G., Rossi, P., Schumacher, R. A., Seder, E., Skorodumina, I., Smith, G. D., Sokhan, D., Sparveris, N., Stankovic, I., Stepanyan, S., Strakovsky, I. I., Strauch, S., Taiuti, M., Tian, Y., Torayev, B., Ungaro, M., Voskanyan, H., Voutier, E., Walford, N. K., Wei, X., Weinstein, L. B., Zachariou, N., Zhang, J., Zhao, Z. W., and Zonta, I.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Physical Review C
• Publisher: American Physical Society
• ISSN: 2469-9985
• ISSN (Online): 2469-9993
• Published Online: 20 March 2017
• Copyright Holders: Copyright © 2017 American Physical Society
• First Published: First published in Physical Review C 95(3): 035206
• Publisher Policy: Reproduced in accordance with the publisher copyright policy

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