Measurement of deeply virtual Compton scattering off He4 with the CEBAF Large Acceptance Spectrometer at Jefferson Lab

Dupré, R. et al. (2021) Measurement of deeply virtual Compton scattering off He4 with the CEBAF Large Acceptance Spectrometer at Jefferson Lab. Physical Review C, 104(2), 025203. (doi: 10.1103/PhysRevC.104.025203)

Abstract

We report on the measurement of the beam spin asymmetry in the deeply virtual Compton scattering off 4 He using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab using a 6 GeV longitudinally polarized electron beam incident on a pressurized 4 He gaseous target. We detail the method used to ensure the exclusivity of the measured reactions, in particular the upgrade of CLAS with a radial time projection chamber to detect the low-energy recoiling 4 He nuclei and an inner calorimeter to extend the photon detection acceptance at forward angles. Our results confirm the theoretically predicted enhancement of the coherent ( e 4 He → e ′ ' 4 He γ ′ ) beam spin asymmetries compared to those observed on the free proton, while the incoherent ( e 4 He → e ′ p ′ γ ′ X ′ ) asymmetries exhibit a 30 % suppression. From the coherent data, we were able to extract, in a model-independent way, the real and imaginary parts of the only 4 He Compton form factor, H A , leading the way toward 3D imaging of the partonic structure of nuclei.

• Item Type: Articles
• Additional Information: This work has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 804480). The Southeastern Universities Research Association operates the Thomas Jefferson National Accelerator Facility for the United States Department of Energy under Contract No. DE-AC05- 06OR23177.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sokhan, Dr Daria and MacGregor, Professor Douglas and McKinnon, Dr Bryan and Livingston, Dr Kenneth and Ireland, Professor David and Rosner, Professor Guenther and Wishart, Robert
• Authors: Dupré, R., Hattawy, M., Baltzell, N. A., 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., Amaryan, M. J., Armstrong, W. R., Atac, H., Ayerbe Gayoso, C., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondi, M., Bossù, F., Boiarinov, S., Briscoe, W. J., Bulumulla, D., Burkert, V., Carman, D. S., Carvajal, J. C., Caudron, M., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clary, B. A., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., Defurne, M., Deur, A., Diehl, S., Djalali, C., Ehrhart, M., Elouadrhiri, L., Eugenio, P., Fegan, S., Filippi, A., Forest, T. A., Ghandilyan, Y., Gilfoyle, G. P., Gothe, R. W., Griffioen, K. A., Hakobyan, H., Hayward, T. B., Hicks, K., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Joo, K., Joosten, S., Keller, D., Khachatryan, G., Khanal, A., Khandaker, M., Kim, A., Kim, W., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Livingston, K., Kabir, M. L., Leali, M., Lenisa, P., MacGregor, I.J. D., Marchand, D., Markov, N., Mascagna, V., Mayer, M., McKinnon, B., Mirazita, M., Mokeev, V. I., Neupane, K., Niccolai, S., O'Connell, T. R., Osipenko, M., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Payette, D., Phelps, W., Pivnyuk, N., Pogorelko, O., Poudel, J., Prok, Y., Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Rossi, P., Rowley, J., Sabatié, F., Salgado, C., Schmidt, A., Schumacher, R., Sergeyeva, V., Sharabian, Y., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Strakovsky, I. I., Strauch, S., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Vossen, A., Watts, D., Wei, K., Wei, X., Weinstein, L. B., Wishart, R., Wood, M. H., Yale, B., Zachariou, N., and Zhang, J.
• 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