Discussion on the recent proton-DVCS results of Jefferson Lab

TL;DR

This paper reports recent Jefferson Lab measurements of proton Deep Virtual Compton Scattering, including beam spin asymmetries and cross sections, and discusses the difficulty of modeling these data with existing GPD models.

Contribution

It provides new experimental data on proton DVCS observables and highlights challenges in simultaneously describing them with current GPD models.

Findings

Data reveal complexities in GPD modeling.

Simultaneous description of all observables is challenging.

First global analysis at specific kinematic point.

Abstract

We present the recent data issued from the Halls A and B of Jefferson Laboratory for the Deep Virtual Compton Scattering Process on the proton. An important set of data for beam spin asymmetries, unpolarized cross sections and differences of polarized cross sections have been obtained. We modestly attempt a first "global" analysis of these three observables at a single $<x_B>$, $<Q^2>$ and $<-t>$ kinematic point. We find that it is extremely challenging to describe simultaneously these data in the framework of a few Generalized Parton Distributions models.