Measurement of deeply virtual compton scattering beam-spin asymmetries

• Published in: Physical review letters 2008-04, Vol.100 (16), p.162002-162002, Article 162002
• Main Authors: Girod, F X, Niyazov, R A, Avakian, H, Ball, J, Bedlinskiy, I, Burkert, V D, De Masi, R, Elouadrhiri, L, Garçon, M, Guidal, M, Jo, H S, Joo, K, Kubarovsky, V, Kuleshov, S V, MacCormick, M, Niccolai, S, Pogorelko, O, Sabatié, F, Stepanyan, S, Stoler, P, Ungaro, M, Zhao, B, Amaryan, M J, Ambrozewicz, P, Anghinolfi, M, Asryan, G, Bagdasaryan, H, Baillie, N, Ball, J P, Baltzell, N A, Batourine, V, Battaglieri, M, Bellis, M, Benmouna, N, Berman, B L, Biselli, A S, Blaszczyk, L, Bouchigny, S, Boiarinov, S, Bradford, R, Branford, D, Briscoe, W J, Brooks, W K, Bültmann, S, Butuceanu, C, Calarco, J R, Careccia, S L, Carman, D S, Casey, L, Chen, S, Cheng, L, Cole, P L, Collins, P, Coltharp, P, Crabb, D, Crede, V, Dashyan, N, De Sanctis, E, De Vita, R, Degtyarenko, P V, Deur, A, Dharmawardane, K V, Dickson, R, Djalali, C, Dodge, G E, Donnelly, J, Doughty, D, Dugger, M, Dzyubak, O P, Egiyan, H, Egiyan, K S, El Fassi, L, Eugenio, P, Fedotov, G, Feldman, G, Funsten, H, Gavalian, G, Gilfoyle, G P, Giovanetti, K L, Goetz, J T, Gonenc, A, Gothe, R W, Griffioen, K A, Guler, N, Guo, L, Gyurjyan, V, Hafidi, K, Hakobyan, H, Hanretty, C, Hersman, F W, Hicks, K, Hleiqawi, I, Holtrop, M, Hyde, C E, Ilieva, Y, Ireland, D G, Ishkhanov, B S, Isupov, E L, Ito, M M, Jenkins, D
• Format: Article
• Language: English
• Subjects: ASYMMETRY; COMPTON EFFECT; ELECTROPRODUCTION; High Energy Physics - Experiment; High Energy Physics - Phenomenology; INTERFERENCE; Nuclear Experiment; PHOTONS; Physics; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PROTONS; QUARKS; SPIN
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.100.162002

The beam-spin asymmetries in the hard exclusive electroproduction of photons on the proton (e p-->epgamma) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (x(B) from 0.11 to 0.58, Q2 from 1 to 4.8 GeV2, -t from 0.09 to 1.8 GeV2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A approximately a sinphi/(1+c cosphi). This extensive set of data can thus be used to constrain significantly the generalized parton distributions of the nucleon in the valence quark sector.