Cross sections for the exclusive photon electroproduction on the proton and Generalized Parton Distributions

Abstract

Unpolarized and beam-polarized four-fold cross sections $\frac{d^4\ddot{I}ƒ}{d{Q}^{2}d{x}_{B}dtd\ddot{I}•}$ for the $ep\to e^{\prime }{p}^{\prime }{\hat{I}}^3$ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 ($Q^2,x_B,t$) 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 reveal a tomographic image of the nucleon.

7 pages, 5 figures