First Exclusive Measurement of Deeply Virtual Compton Scattering off $^4$He: Toward the 3D Tomography of Nuclei
Creators: name: Hattawy, M.
name: Baltzell, N. A.
name: Dupré, R.
name: Hafidi, K.
name: Stepanyan, S.
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: Jenkins, D.
name: Liuti, S.
name: Perrin, Y.
name: Torayev, B.
name: Voutier, E.
name: Adhikari, K. P.
name: Adhikari, S.
name: Adikaram, D.
name: Akbar, Z.
name: Amaryan, M. J.
name: Pereira, S. Anefalos
name: Armstrong, Whitney R.
name: Avakian, H.
name: Ball, J.
name: Bashkanov, M.
name: Battaglieri, M.
name: Batourine, V.
name: Bedlinskiy, I.
name: Biselli, A. S.
name: Boiarinov, S.
name: Briscoe, W. J.
name: Brooks, W. K.
name: Burkert, V. D.
name: Cao, Frank Thanh
name: Carman, D. S.
name: Celentano, A.
name: Charles, G.
name: Chetry, T.
name: Ciullo, G.
name: Clark, L.
name: Colaneri, L.
name: Cole, P. L.
name: Contalbrigo, M.
name: Cortes, O.
name: Crede, V.
name: D'Angelo, A.
name: Dashyan, N.
name: De Sanctis, E.
name: Deur, A.
name: Djalali, C.
name: Elouadrhiri, L.
name: Eugenio, P.
name: Fedotov, G.
name: Fegan, S.
name: Fersch, R.
name: Filippi, A.
name: Fleming, J. A.
name: Forest, T. A.
name: Fradi, A.
name: Garçon, M.
name: Gevorgyan, N.
name: Ghandilyan, Y.
name: Gilfoyle, G. P.
name: Giovanetti, K. L.
name: Gleason, C.
name: Gohn, W.
name: Golovatch, E.
name: Gothe, R. W.
name: Griffioen, K. A.
name: Guo, L.
name: Hakobyan, H.
name: Hanretty, C.
name: Harrison, N.
name: Heddle, D.
name: Hicks, K.
name: Holtrop, M.
name: Hughes, S. M.
name: Ireland, D. G.
name: Ishkhanov, B. S.
name: Isupov, E. L.
name: Jiang, H.
name: Joo, K.
name: Joosten, S.
name: Keller, D.
name: Khachatryan, G.
name: Khachatryan, M.
name: Khandaker, M.
name: Kim, A.
name: Kim, W.
name: Klein, A.
name: Klein, F. J.
name: Kubarovsky, V.
name: Kuhn, S. E.
name: Kuleshov, S. V.
name: Lanza, L.
name: Lenisa, P.
name: Livingston, K.
name: Lu, H. Y.
name: MacGregor, I . J . D.
name: Markov, N.
name: Mayer, M.
name: McCracken, M. E.
name: McKinnon, B.
name: Meyer, C. A.
name: Meziani, Z. E.
name: Mineeva, T.
name: Mirazita, M.
name: Mokeev, V.
name: Montgomery, R. A.
name: Moutarde, H.
name: Movsisyan, A
name: Camacho, C. Munoz
name: Nadel-Turonski, P.
name: Net, L. A.
name: Niccolai, S.
name: Niculescu, G.
name: Niculescu, I.
name: Osipenko, M.
name: Ostrovidov, A. I.
name: Paolone, M.
name: Paremuzyan, R.
name: Park, K.
name: Pasyuk, E.
name: Phelps, E.
name: Phelps, W.
name: Pisano, S.
name: Pogorelko, O.
name: Price, J. W.
name: Prok, Y.
name: Protopopescu, D.
name: Ripani, M.
name: Ritchie, B. G.
name: Rizzo, A.
name: Rosner, G.
name: Rossi, P.
name: Sabatié, F.
name: Salgado, C.
name: Schumacher, R. A.
name: Seder, E.
name: Sharabian, Y. G.
name: Simonyan, A.
name: Skorodumina, Iu.
name: Smith, G. D.
name: Sokhan, D.
name: Sparveris, N.
name: Strauch, S.
name: Taiuti, M.
name: Ungaro, M.
name: Voskanyan, H.
name: Walford, N. K.
name: Watts, D. P.
name: Wei, X.
name: Weinstein, L. B.
name: Wood, M. H.
name: Zachariou, N.
name: Zana, L.
name: Zhang, J.
name: Zhao, Z. W.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment used the 6 GeV electron beam from the CEBAF accelerator at Jefferson Lab incident on a pressurized $^4$He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron was detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber was used to detect the recoiling $^4$He nuclei. We measured beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we were able to extract, in a model-independent way, the real and imaginary parts of the only $^4$He Compton form factor, $\cal H_A$. This first measurement of coherent deeply virtual Compton scattering on the $^4$He nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.