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 uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized He-4 gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is 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 is used to detect the recoiling He-4 nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only He-4 Compton form factor, HA. This first measurement of coherent deeply virtual Compton scattering on the He-4 nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.

Hattawy, M., Baltzell, N.a., Dupre, R., Hafidi, K., Stepanyan, S., Bultmann, S., et al. (2017). First Exclusive Measurement of Deeply Virtual Compton Scattering off He 4: Toward the 3D Tomography of Nuclei. PHYSICAL REVIEW LETTERS, 119(20), 202004 [10.1103/PhysRevLett.119.202004].

First Exclusive Measurement of Deeply Virtual Compton Scattering off He 4: Toward the 3D Tomography of Nuclei

Colaneri L.;D'Angelo A.
Membro del Collaboration Group
;
Lanza L.;Pisano S.;Rizzo A.;
2017-11-15

Abstract

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 uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized He-4 gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is 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 is used to detect the recoiling He-4 nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only He-4 Compton form factor, HA. This first measurement of coherent deeply virtual Compton scattering on the He-4 nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.
15-nov-2017
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/04 - FISICA NUCLEARE E SUBNUCLEARE
English
Con Impact Factor ISI
GENERALIZED PARTON DISTRIBUTIONS; ELECTROPRODUCTION; PHOTONS;
CLAS Collaboration
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.119.202004
Hattawy, M., Baltzell, N.a., Dupre, R., Hafidi, K., Stepanyan, S., Bultmann, S., et al. (2017). First Exclusive Measurement of Deeply Virtual Compton Scattering off He 4: Toward the 3D Tomography of Nuclei. PHYSICAL REVIEW LETTERS, 119(20), 202004 [10.1103/PhysRevLett.119.202004].
Hattawy, M; Baltzell, Na; Dupre, R; Hafidi, K; Stepanyan, S; Bultmann, S; De Vita, R; El Alaoui, A; El Fassi, L; Egiyan, H; Girod, Fx; Guidal, M; Jenkins, D; Liuti, S; Perrin, Y; Torayev, B; Voutier, E; Adhikari, Kp; Adhikari, S; Adikaram, D; Akbar, Z; Amaryan, Mj; Anefalos Pereira, S; Armstrong, Wr; Avakian, H; Ball, J; Bashkanov, M; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, As; Boiarinov, S; Briscoe, Wj; Brooks, Wk; Burkert, Vd; Thanh Cao, F; Carman, Ds; Celentano, A; Charles, G; Chetry, T; Ciullo, G; Clark, L; Colaneri, L; Cole, Pl; Contalbrigo, M; Cortes, O; Crede, V; D'Angelo, A; Dashyan, N; De Sanctis, E; Deur, A; Djalali, C; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Fersch, R; Filippi, A; Fleming, Ja; Forest, Ta; Fradi, A; Garcon, M; Gevorgyan, N; Ghandilyan, Y; Gilfoyle, Gp; Giovanetti, Kl; Gleason, C; Gohn, W; Golovatch, E; Gothe, Rw; Griffioen, Ka; Guo, L; Hakobyan, H; Hanretty, C; Harrison, N; Heddle, D; Hicks, K; Holtrop, M; Hughes, Sm; Ireland, Dg; Ishkhanov, Bs; Isupov, El; Jiang, H; Joo, K; Joosten, S; Keller, D; Khachatryan, G; Khachatryan, M; Khandaker, M; Kim, A; Kim, W; Klein, A; Klein, Fj; Kubarovsky, V; Kuhn, Se; Kuleshov, Sv; Lanza, L; Lenisa, P; Livingston, K; Lu, Hy; Macgregor, Ijd; Markov, N; Mayer, M; Mccracken, Me; Mckinnon, B; Meyer, Ca; Meziani, Ze; Mineeva, T; Mirazita, M; Mokeev, V; Montgomery, Ra; Moutarde, H; Movsisyan, A; Munoz Camacho, C; Nadel-Turonski, P; Net, La; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, Ai; Paolone, M; Paremuzyan, R; Park, K; Pasyuk, E; Phelps, E; Phelps, W; Pisano, S; Pogorelko, O; Price, Jw; Prok, Y; Protopopescu, D; Ripani, M; Ritchie, Bg; Rizzo, A; Rosner, G; Rossi, P; Sabatie, F; Salgado, C; Schumacher, Ra; Seder, E; Sharabian, Yg; Simonyan, A; Skorodumina, I; Smith, Gd; Sokhan, D; Sparveris, N; Strauch, S; Taiuti, M; Ungaro, M; Voskanyan, H; Walford, Nk; Watts, Dp; Wei, X; Weinstein, Lb; Wood, Mh; Zachariou, N; Zana, L; Zhang, J; Zhao, Zw
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/195005
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