E00-110 experiment at Jefferson Lab Hall A: Deeply virtual Compton scattering off the proton at 6 GeV

M. Defurne
M. Beaumel
E. Fuchey
T. Holmstrom, College of William and Mary
A. Kelleher, College of William and Mary
B. Moffit, College of William and Mary
V. Sulkosky, College of William and Mary

Abstract

We present final results on the photon electroproduction ((e) over right arrowp - > ep gamma) cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region from Jefferson Lab experiment E00-110. Results from an analysis of a subset of these data were published before, but the analysis has been improved, which is described here at length, together with details on the experimental setup. Furthermore, additional data have been analyzed, resulting in photon electroproduction cross sections at new kinematic settings for a total of 588 experimental bins. Results of the Q(2) and x(B) dependencies of both the helicity-dependent and the helicity-independent cross sections are discussed. The Q(2) dependence illustrates the dominance of the twist-2 handbag amplitude in the kinematics of the experiment, as previously noted. Thanks to the excellent accuracy of this high-luminosity experiment, it becomes clear that the unpolarized cross section shows a significant deviation from the Bethe-Heitler process in our kinematics, compatible with a large contribution from the leading twist-2