Measurement of Deeply Virtual Compton Scattering with a Polarized-Proton Target

S Chen,D Protopopescu,F W Hersman,K A Griffioen,P Rossi,M Bellis,P D Rubin,Y Prok,V Mokeev,H Hakobyan,K V Dharmawardane,G P Gilfoyle,J P Santoro,B E Stokes,F X Girod,P Corvisiero,E S Smith,C Paterson,S Bültmann,L El Fassi,D P Weygand,R Devita,E Golovatch,C A Meyer,R A Schumacher,R W Gothe,K Kim,R Suleiman,J Shaw,S Pozdniakov,G Asryan,Y Ilieva,S Bouchigny,W Kim,D Doughty,M Ripani,J Pierce,D Branford,M F Vineyard,V Kubarovsky,R Nasseripour,M Garçon,N A Baltzell,M Maccormick,K Joo,B Carnahan,Y G Sharabian,R Minehart,G Fedotov,D J Tedeschi,C Tur,L B Weinstein,C Keith,S Boiarinov,H Avakian,S Niccolai,H Bagdasaryan,L Todor,W J Briscoe,M Williams,N Natasha,V Sapunenko,N Guler,C Djalali,J Donnelly,E Wolin,R Fatemi,K S Dhuga,G Gavalian,N V Shvedunov,P Coltharp,G Rosner,K Mikhailov,M Ungaro,J W Price,N Baillie,A Tkabladze,K Lukashin,C Butuceanu,S Tkachenko,F J Klein,A S Biselli,W K Brooks,O Pogorelko,M Osipenko,H Denizli,M Dugger,L Elouadrhiri,M Guillo,K Hicks,V D Burkert,M Anghinolfi,A I Ostrovidov,M H Wood,B A Mecking,S Dytman,B L Berman,A Stavinsky,J M Laget,S Barrow,E Polli,M Mirazita,A Yegneswaran,L C Smith,L Morand,M Nozar,J Yun,B Mckinnon,E De Sanctis,M Khandaker,J Hardie,M Guidal,D Cords,R A Niyazov,M Amarian,E Pasyuk,I Niculescu,J Lachniet,N Benmouna,M Huertas,I Bedlinskiy,M Kossov,H Egiyan,P Ambrozewicz,D Crabb,S A Morrow,M D Mestayer,R Miskimen,P Bosted,M Battaglieri,F Sabatié,R J Feuerbach,S V Kuleshov,S A Philips,H G Juengst,R De Masi,P L Cole,I I Strakovsky,J Langheinrich,F Ronchetti,M M Ito,L Dennis,A V Vlassov,I Hleiqawi,H S Jo,G Niculescu,M Bektasoglu,J Napolitano,C Salgado,S Stepanyan,G S Mutchler,L M Qin,K Park,E L Isupov,K Y Kim,I Popa,M Taiuti,G V O’Rielly,P Eugenio,V Gyurjyan,D P Watts,N Markov,S Strauch,L Zana,P Stoler,O P Dzyubak,B Zhao,S Mcaleer,M Klusman,M Moteabbed,M Holtrop,H Crannell,B B Niczyporuk,A Cazes,P Collins,A Klein,D G Ireland,J D Kellie,S L Careccia,J T Goetz,U Thoma,D S Carman,A Deur,D Heddle,D Lawrence,G Ricco,K S Egiyan,V S Serov,K Hafidi,S E Kuhn,D I Sober,K L Giovanetti,G Riccardi,J R Calarco,K Beard,G E Dodge,M R Niroula,B E Bonner,G Feldman,J Zhang,T Mibe,L Guo,P V Degtyarenko,D Rowntree,A V Skabelin,R Bradford,C Hadjidakis,N Pivnyuk,K Livingston,B M Preedom,V Batourine,B A Raue,J W Mcnabb ,Tony A Forest ,J Li ,V Credé ,Б С Ишханов ,J Muêller ,L Kramer ,J Kühn ,C E Hyde‐Wright ,J Cummings ,H O Funsten ,David Jenkins ,D Počanić ,A C S Lima ,P Nadel-Turoński ,H Y Lu ,R Hakobyan ,Barry Ritchie ,Marc Vanderhaeghen ,J Ball ,A Gönenç ,G S Adams ,Z W Zhao

doi:10.1103/physrevlett.97.072002

Abstract

The longitudinal target-spin asymmetry AUL for the exclusive electroproduction of high-energy photons was measured for the first time in ep-->e;'pgamma. The data have been accumulated at JLab with the CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized NH3 target. A significant azimuthal angular dependence was observed, resulting from the interference of the deeply virtual Compton scattering and Bethe-Heitler processes. The amplitude of the sinvarphi moment is 0.252+/-0.042stat+/-0.020sys. Theoretical calculations are in good agreement with the magnitude and the kinematic dependence of the target-spin asymmetry, which is sensitive to the generalized parton distributions H and H.

Full Text