Generalized Parton Distributions from Deeply Virtual Compton Scattering at HERMES

TL;DR

This paper analyzes HERMES data on Deeply Virtual Compton Scattering to extract constraints on the nucleon's Generalized Parton Distributions using a model-independent fit within leading-order QCD.

Contribution

It provides the first model-independent extraction of Compton Form Factors from HERMES data in the leading-order approximation.

Findings

Constraints on the H GPD were obtained.

The analysis demonstrates the feasibility of extracting GPDs from experimental asymmetries.

Results are consistent with theoretical expectations.

Abstract

The HERMES collaboration has recently published a set of (correlated) beam charge, beam spin and target spin relative asymmetries for the Deeply Virtual Compton Scattering process. This reaction allows in principle to access the Generalized Parton Distributions of the nucleon. We have fitted, in the QCD leading-order and leading-twist handbag approximation, but in a model independent way, this set of data and we report our results for the extracted Compton Form Factors. In particular, we are able to extract constrains on the $H$ GPD.