Helium Compton Form Factor Measurements at CLAS

• Main Author: Voutier, Eric
• Format: Journal Article
• Language: English
• Published: 30-06-2013
• Subjects: Physics - High Energy Physics - Experiment; Physics - Nuclear Experiment
• DOI: 10.48550/arxiv.1307.0222

The distribution of the parton content of nuclei, as encoded via the
generalized parton distributions (GPDs), can be accessed via the deeply virtual
Compton scattering (DVCS) process contributing to the cross section for
leptoproduction of real photons. Similarly to the scattering of light by a
material, DVCS provides information about the dynamics and the spatial
structure of hadrons. The sensitivity of this process to the lepton beam
polarization allows to single-out the DVCS amplitude in terms of Compton form
factors that contain GPDs information. The beam spin asymmetry of the
$^4$He($\vec {\mathrm e}$,e$' \gamma ^4$He) process was measured in the
experimental Hall B of the Jefferson Laboratory to extract the real and
imaginary parts of the twist-2 Compton form factor of the $^4$He nucleus. The
experimental results reported here demonstrate the relevance of this method for
such a goal, and suggest the dominance of the Bethe-Heitler amplitude to the
unpolarized process in the kinematic range explored by the experiment.