Medium modifications of the bound nucleon GPDs and incoherent DVCS on nuclear targets

TL;DR

This paper investigates medium modifications of bound nucleon GPDs through incoherent DVCS on helium-4, predicting observable asymmetry ratios and their dependence on kinematic variables, with potential deviations up to 6%.

Contribution

It introduces a model linking bound nucleon GPD modifications to elastic form factors and calculates related DVCS observables for nuclear targets.

Findings

Predicted the ratio of bound to free proton asymmetries varies with kinematics.

Deviations from unity in asymmetry ratios can reach approximately 6%.

Provided a method to probe medium modifications of nucleon structure.

Abstract

We study incoherent DVCS on $^4$He in the $^4{\rm He}(e,e^{\prime}\gamma p)X$ reaction, which probes medium-modifications of the bound nucleon GPDs and elastic form factors. Assuming that the bound nucleon GPDs are modified in proportion to the corresponding bound nucleon elastic form factors, as predicted in the Quark-Meson Coupling model, we develop an approach to calculate various incoherent nuclear DVCS observables. As an example, we compute the beam-spin DVCS asymmetry, and predict the $x_B$- and $t$-dependence of the ratio of the bound to free proton asymmetries, $A_{\rm LU}^{p^{\ast}}(\phi)/A_{\rm LU}^{p}(\phi)$. We find that the deviation of $A_{\rm LU}^{p^{\ast}}(\phi)/A_{\rm LU}^{p}(\phi)$ from unity is as much as $\sim$ 6%.