Measurement of Unpolarized and Polarized Cross Sections for Deeply Virtual Compton Scattering on the Proton at Jefferson Laboratory with CLAS

TL;DR

This study measures unpolarized and polarized cross sections for Deeply Virtual Compton Scattering on the proton at Jefferson Lab, providing data that support the generalized parton distribution framework and compare well with phenomenological models.

Contribution

First comprehensive measurement of polarized and unpolarized DVCS cross sections at Jefferson Lab across broad kinematics, testing GPD models and expanding existing data sets.

Findings

Results are consistent with previous CLAS data.

Data are compatible with VGG and KMSC models.

Provides new constraints for GPD parametrizations.

Abstract

This paper reports the measurement of polarized and unpolarized cross sections for the ep -> e'p' reaction, which is comprised of Deeply Virtual Compton Scattering (DVCS) and Bethe-Heitler (BH) processes, at an electron beam energy of 5.88 GeV at the Thomas Jefferson National Accelerator Facility using the Large Acceptance Spectrometer CLAS. The unpolarized cross sections and polarized cross section differences have been measured over broad kinematics, 0.10 < x_B < 0.58, 1.0 < Q^2 < 4.8 GeV^2, and 0.09 < -t < 2.00 GeV^2. The results are found to be consistent with previous CLAS data, and these new data are discussed in the framework of the generalized parton distribution approach. Calculations with two widely used phenomenological models, denoted VGG and KMSC, are approximately compatible with the experimental results over a large portion of the kinematic range of the data.