Measurement of deeply virtual Compton scattering off Helium-4 with CLAS at Jefferson Lab
Creators: name: Dupré, R.
name: Hattawy, M.
name: Baltzell, N. A.
name: Bültmann, S.
name: De Vita, R.
name: Alaoui, A. El
name: Fassi, L. El
name: Egiyan, H.
name: Girod, F. X.
name: Guidal, M.
name: Hafidi, K.
name: Jenkins, D.
name: Liuti, S.
name: Perrin, Y.
name: Stepanyan, S.
name: Torayev, B.
name: Voutier, E.
name: Amaryan, M. J.
name: Armstrong, W. R.
name: Atac, H.
name: Gayoso, C. Ayerbe
name: Barion, L.
name: Battaglieri, M.
name: Bedlinskiy, I.
name: Benmokhtar, F.
name: Bianconi, A.
name: Biselli, A. S.
name: Bondi, M.
name: Bossù, F.
name: Boiarinov, S.
name: Briscoe, W. J.
name: Bulumulla, D.
name: Burkert, V.
name: Carman, D. S.
name: Carvajal, J. C.
name: Caudron, M.
name: Celentano, A.
name: Chatagnon, P.
name: Chesnokov, V.
name: Chetry, T.
name: Ciullo, G.
name: Clary, B. A.
name: Cole, P. L.
name: Contalbrigo, M.
name: Costantini, G.
name: Crede, V.
name: D'Angelo, A.
name: Dashyan, N.
name: Defurne, M.
name: Deur, A.
name: Diehl, S.
name: Djalali, C.
name: Ehrhart, M.
name: Elouadrhiri, L.
name: Eugenio, P.
name: Fegan, S.
name: Filippi, A.
name: Forest, T. A.
name: Ghandilyan, Y.
name: Gilfoyle, G. P.
name: Gothe, R. W.
name: Griffioen, K. A.
name: Hakobyan, H.
name: Hayward, T. B.
name: Hicks, K.
name: Hobart, A.
name: Holtrop, M.
name: Ilieva, Y.
name: Ireland, D. G.
name: Isupov, E. L.
name: Jo, H. S.
name: Joo, K.
name: Joosten, S.
name: Keller, D.
name: Khachatryan, G.
name: Khanal, A.
name: Khandaker, M.
name: Kim, A.
name: Kim, W.
name: Kripko, A.
name: Kubarovsky, V.
name: Kuhn, S. E.
name: Lanza, L.
name: Livingston, K.
name: Kabir, M. L.
name: Leali, M.
name: Lenisa, P.
name: MacGregor, I. J. D.
name: Marchand, D.
name: Markov, N.
name: Mascagna, V.
name: Mayer, M.
name: McKinnon, B.
name: Mirazita, M.
name: Mokeev, V. I.
name: Neupane, K.
name: Niccolai, S.
name: O'Connell, T. R.
name: Osipenko, M.
name: Paolone, M.
name: Pappalardo, L. L.
name: Paremuzyan, R.
name: Pasyuk, E.
name: Payette, D.
name: Phelps, W.
name: Pivnyuk, N.
name: Pogorelko, O.
name: Poudel, J.
name: Prok, Y.
name: Ripani, M.
name: Ritman, J.
name: Rizzo, A.
name: Rosner, G.
name: Rossi, P.
name: Rowley, J.
name: Sabatié, F.
name: Salgado, C.
name: Schmidt, A.
name: Schumacher, R.
name: Sergeyeva, V.
name: Sharabian, Y.
name: Shrestha, U.
name: Sokhan, D.
name: Soto, O.
name: Sparveris, N.
name: Strakovsky, I. I.
name: Strauch, S.
name: Tyler, N.
name: Ungaro, M.
name: Venturelli, L.
name: Voskanyan, H.
name: Vossen, A.
name: Watts, D.
name: Wei, K.
name: Wei, X.
name: Weinstein, L. B.
name: Wishart, R.
name: Wood, M. H.
name: Yale, B.
name: Zachariou, N.
name: Zhang, J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: 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$~\to~e'$$^4$He$'γ'$) beam spin asymmetries compared to those observed on the free proton, while the incoherent ($e^4$He$~\to~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, $\cal H_A$, leading the way toward 3D imaging of the partonic structure of nuclei.