Cross Sections for the Exclusive Photon Electroproduction on the Proton and Generalized Parton Distributions

H.S. Jo (1) , H Avakian (2) , M Garçon (3) , F.X. Girod (3, 2) , M Guidal (1) , V Kubarovsky (2) , S Niccolai (1) , P Stoler (4) , D Adikaram (5) , J Ball (3) , B Guegan (1) , N Guler (5) , K Hafidi (6) , H Hakobyan (7) , N Harrison (8) , M Hattawy (1) , K Hicks (9) , D Ho (10) , H Moutarde (3) , S. Procureur (3) , F. Sabatie (3) , E Voutier (1)

1 IPNO - Institut de Physique Nucléaire d'Orsay
2 Jefferson Lab - Thomas Jefferson National Accelerator Facility
3 DPHN - Département de Physique Nucléaire (ex SPhN)
4 RPI - Rensselaer Polytechnic Institute
5 ODU - Old Dominion University [Norfolk]
6 ANL - Argonne National Laboratory [Lemont]
7 UTFSM - Universidad Tecnica Federico Santa Maria [Valparaiso]
8 UCONN - University of Connecticut
9 Ohio University
10 CMU - Carnegie Mellon University [Pittsburgh]

Unpolarized and beam-polarized fourfold cross sections ðd4σ=dQ2dxBdtdϕÞ for the ep → e0p0γ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 (Q2; xB; t) bins over the widest phase space ever explored in the valencequark region. Several models of generalized parton distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD H, expected to be the dominant contributor to these observables. Through a leading-twist extraction of Compton form factors, these results support the model predictions of a larger nucleon size at lower quark-momentum fraction xB.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

H.S. Jo, H Avakian, M Garçon, F.X. Girod, M Guidal, et al.. Cross Sections for the Exclusive Photon Electroproduction on the Proton and Generalized Parton Distributions. Physical Review Letters, 2015, 115 (21), pp.212003. ⟨10.1103/PhysRevLett.115.212003⟩. ⟨hal-01230531⟩