Exploring the structure of the bound proton with deeply virtual Compton scattering

Hattawy, M. et al. (2019) Exploring the structure of the bound proton with deeply virtual Compton scattering. Physical Review Letters, 123(3), 032502. (doi: 10.1103/PhysRevLett.123.032502)

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In the past two decades, deeply virtual Compton scattering of electrons has been successfully used to advance our knowledge of the partonic structure of the free proton and investigate correlations between the transverse position and the longitudinal momentum of quarks inside the nucleon. Meanwhile, the structure of bound nucleons in nuclei has been studied in inclusive deep-inelastic lepton scattering experiments off nuclear targets, showing a significant difference in longitudinal momentum distribution of quarks inside the bound nucleon, known as the EMC effect. In this Letter, we report the first beam spin asymmetry (BSA) measurement of exclusive deeply virtual Compton scattering off a proton bound in 4He. The data used here were accumulated using a 6 GeV longitudinally polarized electron beam incident on a pressurized 4He gaseous target placed within the CLAS spectrometer in Hall-B at the Thomas Jefferson National Accelerator Facility. The azimuthal angle (ϕ) dependence of the BSA was studied in a wide range of virtual photon and scattered proton kinematics. The Q2, xB, and t dependencies of the BSA on the bound proton are compared with those on the free proton. In the whole kinematical region of our measurements, the BSA on the bound proton is smaller by 20% to 40%, indicating possible medium modification of its partonic structure.

Item Type:Articles
Additional Information:This work was supported in part by the Chilean Comisión Nacional de Investigación Científica y Tecnológica (CONICYT), by CONICYT PIA Grant No. ACT1413, the Italian Instituto Nazionale di Fisica Nucleare, the French Centre National de la Recherche Scientifique, the French Commissariat `a l’Energie Atomique, the U.S. Department of Energy under Contract No. DE-AC02-06CH11357, the United Kingdom Science and Technology Facilities Council (STFC), the Scottish Universities Physics Alliance (SUPA), the National Research Foundation of Korea, and the Office of Research and Economic Development at Mississippi State University. M. H. also acknowledges the support of the Consulat G´en´eral de France `a J´erusalem. The Southeastern Universities Research Association operates the Thomas Jefferson National Accelerator Facility for the United States Department of Energy under Contract No. DEAC05-06OR23177.
Glasgow Author(s) Enlighten ID:Sokhan, Dr Daria and McKinnon, Dr Bryan and Ireland, Professor David and Livingston, Dr Kenneth and MacGregor, Professor Douglas and Fegan, Mr Stuart and Montgomery, Dr Rachel and Protopopescu, Dr Dan and Rosner, Professor Guenther
Authors: Hattawy, M., Baltzell, N.A., Dupré, R., Bültmann, S., De Vita, R., El Alaoui, A., El Fassi, L., Egiyan, H., Girod, F.X., Guidal, M., Hafidi, K., Jenkins, D., Liuti, S., Perrin, Y., Stepanyan, S., Torayev, B., Voutier, E., Adhikari, S., Angelini, G., Ayerbe Gayoso, C., Barion, L., Battaglieri, M., Bedlinskiy, I., Biselli, A.S., Bossù, F., Brooks, W., Cao, F., Carman, D.S., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Cole, P.L., Contalbrigo, M., Crede, V., D’Angelo, A., Dashyan, N., De Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Ehrhart, M., Eugenio, P., Fegan, S., Filippi, A., Forest, T.A., Fradi, A., Garçon, M., Gavalian, G., Gevorgyan, N., Gilfoyle, G.P., Giovanetti, K.L., Golovatch, E., Gothe, R.W., Griffioen, K.A., Harrison, N., Hauenstein, F., Hayward, T.B., Heddle, D., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D.G., Isupov, E.L., Jo, H.S., Johnston, S., Keller, D., Khachatryan, G., Khachatryan, M., Khanal, A., Khandaker, M., Kim, C.W., Kim, W., Klein, F.J., Kubarovsky, V., Kuhn, S.E., Lanza, L., L. Kabir, M., Lenisa, P., Livingston, K., MacGregor, I.J.D., Marchand, D., Markov, N., Mayer, M., McKinnon, B., Meziani, Z.E., Mineeva, T., Mirazita, M., Montgomery, R.A., Munoz Camacho, C., Nadel-Turonski, P., Niccolai, S., Ostrovidov, A.I., Pappalardo, L.L., Paremuzyan, R., Pasyuk, E., Pogorelko, O., Poudel, J., Prok, Y., Protopopescu, D., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Rossi, P., Sabatié, F., Salgado, C., Schumacher, R.A., Sharabian, Y.G., Skorodumina, I., Sokhan, D., Soto, O., Sparveris, N., Strauch, S., Taiuti, M., Tan, J.A., Tyler, N., Ungaro, M., Voskanyan, H., Wang, R., Watts, D.P., Wei, X., Weinstein, L.B., Wood, M.H., Zachariou, N., Zhang, J., and Zhao, Z.W.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review Letters
Publisher:American Physical Society
ISSN (Online):1079-7114
Copyright Holders:Copyright © 2019 American Physical Society
First Published:First published in Physical Review Letters 123(3):032502
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
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