Measurement of the beam-spin azimuthal asymmetry associated with deeply-virtual Compton scattering - art. no. 182001

Authors
Airapetian, A Akopov, N Akopov, Z Amarian, M Achenauer, EC Avakian, H Avakian, R Avetissian, A Avetissian, E Bailey, P Bains, B Baturin, V Baumgarten, C Beckmann, M Belostotski, S Bernreuther, S Bianchi, N Bottcher, H Borissov, A Bouhali, O Bouwhuis, M Brack, J Brauksiepe, S Bruckner, W Brull, A Brunn, I Bulten, HJ Capitani, GP Chumney, P Cisbani, E Ciullo, G Court, GR Dalpiaz, PF De Leo, R De Nardo, L De Sanctis, E De Schepper, D Devitsin, E Huberts, PKAD Di Nezza, P Duren, M Ehrenfried, M Elbakian, G Ellinghaus, F Ely, J Fabbri, R Fantoni, A Fechtchenko, A Felawka, L Filippone, BW Fischer, H Fox, B Franz, J Frullani, S Garber, Y Garibaldi, F Garutti, E Gavrilov, G Gharibyan, V Golendukhin, A Graw, G Grebeniouk, O Green, PW Greeniaus, LG Gute, A Haeberli, W Hafidi, K Hartig, M Hasch, D Heesbeen, D Heinsius, FH Henoch, M Hertenberger, R Hesselink, WHA Hofman, G Holler, Y Holt, RJ Hommez, B Iarygin, G Izotov, A Jackson, HE Jgoun, A Jung, P Kaiser, R Kanesaka, J Kinney, E Kisselev, A Kitching, P Kobayashi, H Koch, N Konigsmann, K Kolster, H Korotkov, V Kotik, E Kozlov, V Krauss, B Krivokhijine, VG Kyle, G Lagamba, L Laziev, A Lenisa, P Liebing, P Lindemann, T Lorenzon, W Maas, A Makins, NCR Marukyan, H Masoli, F McAndrew, M McIlhany, K Meissner, F Menden, F Meyners, N Mikloukho, O Miller, CA Milner, R Muccifora, V Mussa, R Nagaitsev, A Nappi, E Naryshkin, Y Nass, A Negodaeva, K Nowak, WD Oganessyan, K O'Neill, TG Owen, BR Pate, SF Potashov, S Potterveld, DH Raithel, M Rakness, G Rappoport, V Redwine, R Reggiani, D Reolon, AR Rith, K Robinson, D Rostomyan, A Ruh, M Ryckbosch, D Sakemi, Y Sanjiev, I Sato, F Savin, I Scarlett, C Schafer, A Schill, C Schmidt, F Schnell, G Schuler, KP Schwind, A Seibert, J Seitz, B Shibata, TA Shutov, V Simani, MC Simon, A Sinram, K Steffens, E Steijer, JJM Stewart, J Stosslein, U Suetsugu, K Taroian, S Terkulov, A Tessarin, S Thomas, E Tipton, B Tytgat, M Urciuoli, GM van den Brand, JFJ van Steenhoven, G van Vyver, R van Hunen, JJ Vetterli, MC Vikhrov, V Vincter, MG Visser, J Weiskopf, C Wendland, J Wilbert, J Wise, T Yen, S Yoneyama, S Zohrabian, H
Citation
A. Airapetian et al., Measurement of the beam-spin azimuthal asymmetry associated with deeply-virtual Compton scattering - art. no. 182001, PHYS REV L, 8718(18), 2001, pp. 2001
Citations number
18
Categorie Soggetti
Physics
Journal title
PHYSICAL REVIEW LETTERS
ISSN journal
00319007 → ACNP
Volume
8718
Issue
18
Year of publication
2001
Database
ISI
SICI code
0031-9007(20011029)8718:18<2001:MOTBAA>2.0.ZU;2-E
Abstract
The beam-spin asymmetry in hard electroproduction of photons has been measu red. The data have been accumulated by the HERMES experiment at DESY using the HERA 27.6 GeV longitudinally polarized positron beam and an unpolarized hydrogen-gas target. The asymmetry in the azimuthal distribution of the pr oduced photons in the angle phi relative to the lepton scattering plane was determined with respect to the helicity state of the incoming positron bea m. The beam-spin analyzing power in the sin phi moment was measured to be - 0.23 +/- 0.04(stat) +/- 0.03(syst) in the missing-mass range below 1.7 GeV. The observed asymmetry is attributed to the interference of the Bethe-Heit ler and deeply virtual Compton scattering processes.