Cross Sections for the Exclusive Photon Electroproduction on the Proton and Generalized Parton Distributions
Abstract
Unpolarized and beam-polarized fourfold cross sections (d4σ /d Q2d xBd t d ϕ ) for the e p →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.
- Publication:
-
Physical Review Letters
- Pub Date:
- November 2015
- DOI:
- 10.1103/PhysRevLett.115.212003
- arXiv:
- arXiv:1504.02009
- Bibcode:
- 2015PhRvL.115u2003J
- Keywords:
-
- 12.38.-t;
- 13.40.Gp;
- 13.60.Fz;
- 13.60.Hb;
- Quantum chromodynamics;
- Electromagnetic form factors;
- Elastic and Compton scattering;
- Total and inclusive cross sections;
- High Energy Physics - Experiment;
- Nuclear Experiment
- E-Print:
- 7 pages, 5 figures