Measurement of azimuthal asymmetries associated with deeply virtual Compton scattering on an unpolarized deuterium target

Airapetian, A.; Akopov, N.; Akopov, Z.; Amarian, M.; Aschenauer, E. C.; Augustyniak, W.; Avakian, R.; Avetissian, A.; Avetisyan, E.; Ball, B.; Belostotski, S.; Bianchi, N.; Blok, H. P.; Böttcher, H.; Borissov, A.; Bowles, J.; Bryzgalov, V.; Burns, J.; Capiluppi, Marco; Capitani, G. P.; Cisbani, E.; Ciullo, Giuseppe; Contalbrigo, Marco; Ferretti, Paola; Deconinck, W.; De Leo, R.; De Nardo, L.; De Sanctis, E.; Diefenthaler, M.; Di Nezza, P.; Dreschler, J.; Düren, M.; Ehrenfried, M.; Elbakian, G.; Ellinghaus, F.; Fabbri, R.; Fantoni, A.; Felawka, L.; Frullani, S.; Gabbert, D.; Gapienko, G.; Gapienko, V.; Garibaldi, F.; Gavrilov, G.; Gharibyan, V.; Giordano, F.; Gliske, S.; Hadjidakis, C.; Hartig, M.; Hasch, D.; Hasegawa, T.; Hill, G.; Hillenbrand, A.; Hoek, M.; Holler, Y.; Hristova, I.; Imazu, Y.; Ivanilov, A.; Izotov, A.; Jackson, H. E.; Jgoun, A.; H. S., Jo; Joosten, S.; Kaiser, R.; Karyan, G.; Keri, T.; Kinney, E.; Kisselev, A.; Kobayashi, N.; Korotkov, V.; Kozlov, V.; Krauss, B.; Kravchenko, P.; Krivokhijine, V. G.; Lagamba, L.; Lamb, R.; Lapikás, L.; Lehmann, I.; Lenisa, Paolo; Linden Levy, L. A.; López Ruiz, A.; Lorenzon, W.; X. G., Lu; X. R., Lu; B. Q., Ma; Mahon, D.; Makins, N. C. R.; Manaenkov, S. I.; Manfré, L.; Mao, Y.; Marianski, B.; de la Ossa, A. M.; Marukyan, H.; Miller, C. A.; Miyachi, Y.; Movsisyan, A.; Muccifora, V.; Müller, D.; Murray, M.; Mussgiller, A.; Nappi, E.; Naryshkin, Y.; Nass, A.; Negodaev, M.; Nowak, W. D.; Pappalardo, Luciano Libero; Perez Benito, R.; Pickert, N.; Raithel, M.; Reimer, P. E.; Reolon, A. R.; Riedl, C.; Rith, K.; Rosner, G.; Rostomyan, A.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Sanftl, F.; Schäfer, A.; Schnell, G.; Schüler, K. P.; Seitz, B.; Shibata, T. A.; Shutov, V.; Stancari, Michelle Dawn; Statera, Marco; Steffens, E.; Steijger, J. J. M.; Stenzel, H.; Stewart, J.; Stinzing, F.; Taroian, S.; Terkulov, A.; Trzcinski, A.; Tytgat, M.; Vandenbroucke, A.; Van der Nat, P. B.; Van Haarlem, Y.; Van Hulse, C.; Varanda, M.; Veretennikov, D.; Vikhrov, V.; Vilardi, I.; Vogel, C.; Wang, S.; Yaschenko, S.; Ye, H.; Ye, Z.; Yen, S.; Yu, W.; Zeiler, D.; Zihlmann, B.; Zupranski, P.

doi:10.1016/j.nuclphysb.2009.12.004

Azimuthal asymmetries in exclusive electroproduction of a real photon from an unpolarized deuterium target are measured with respect to beam helicity and charge. They appear in the distribution of these photons in the azimuthal angle φ{symbol} around the virtual-photon direction, relative to the lepton scattering plane. The extracted asymmetries are attributed to either the deeply virtual Compton scattering process or its interference with the Bethe-Heitler process. They are compared with earlier results on the proton target. In the measured kinematic region, the beam-charge asymmetry amplitudes and the leading amplitudes of the beam-helicity asymmetries on an unpolarized deuteron target are compatible with the results from unpolarized protons. © 2009 Elsevier B.V. All rights reserved.