Deeply virtual Compton scattering using a positron beam in Hall-C at Jefferson Lab

TL;DR

This paper proposes a method to measure Deeply Virtual Compton Scattering using positron beams at Jefferson Lab, aiming to improve understanding of nucleon structure through precise cross section measurements.

Contribution

It introduces a novel experimental approach combining positron and electron beams to disentangle DVCS contributions, enhancing constraints on Generalized Parton Distributions.

Findings

Potential to precisely measure DVCS cross sections with positron beams.

Ability to separate DVCS$^2$ and interference terms in photon production.

Expanded kinematic coverage with 11 GeV beam.

Abstract

We propose to use the High Momentum Spectrometer of Hall C combined with the Neutral Particle Spectrometer (NPS) to perform high precision measurements of the Deeply Virtual Compton Scattering (DVCS) cross section using a beam of positrons. The combination of measurements with oppositely charged incident beams is the only unambiguous way to disentangle the contribution of the DVCS$^2$ term in the photon electroproduction cross section from its interference with the Bethe-Heitler amplitude. This provides a stronger way to constrain the Generalized Parton Distributions of the nucleon. A wide range of kinematics accessible with an 11 GeV beam off an unpolarized proton target will be covered. The $Q^2-$dependence of each contribution will be measured independently.