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

CLAS Collaboration, H. S. Jo*, F. X. Girod, H. Avakian, V. D. Burkert, M. Garcon, M. Guidal, V. Kubarovsky, S. Niccolai, P. Stoler, K. P. Adhikari, D. Adikaram, M. J. Amaryan, M. D. Anderson, S. Anefalos Pereira, J. Ball, N. A. Baltzell, M. Battaglieri, V. Batourine, I. BedlinskiyA. S. Biselli, S. Boiarinov, W. J. Briscoe, W. K. Brooks, D. S. Carman, A. Celentano, S. Chandavar, G. Charles, L. Colaneri, P. L. Cole, N. Compton, M. Contalbrigo, V. Crede, A. D'Angelo, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, R. Dupre, A. El Alaoui, L. El Fassi, L. Elouadrhiri, G. Fedotov, S. Fegan, A. Filippi, S. M. Hughes, D. Sokhan, D. P. Watts, N. Zachariou, L. Zana

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Unpolarized and beam-polarized fourfold cross sections (d4σ/dQ2dxBdtdφ) for the ep→e′p′γ 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 valence-quark 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.

Original languageEnglish
Article number212003
Number of pages7
JournalPhysical Review Letters
Issue number21
Publication statusPublished - 17 Nov 2015


  • HERA
  • CLAS


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