Generalized parton distributions through universal moment parameterization: non-zero skewness case

TL;DR

This paper introduces a comprehensive global analysis method for generalized parton distributions (GPDs) that integrates lattice QCD data and experimental measurements, extending previous models to include non-zero skewness and providing detailed quark distribution insights.

Contribution

The work extends the GPD parameterization framework to non-zero skewness and combines lattice QCD with experimental data for a more complete GPD analysis.

Findings

Successful extraction of sea and valence quark distributions.

First global analysis combining lattice QCD and experimental data.

Framework adaptable to additional off-forward constraints.

Abstract

We present the first global analysis of generalized parton distributions (GPDs) combing lattice quantum chromodynamics (QCD) calculations and experiment measurements including global parton distribution functions (PDFs), form factors (FFs) and deeply virtual Compton scattering (DVCS) measurements. Following the previous work where we parameterize GPDs in terms of their moments, we extend the framework to allow for the global analysis at non-zero skewness. Together with the constraints at zero skewness, we fit GPDs to global DVCS measurements from both the recent JLab and the earlier Hadron-Electron Ring Accelerator (HERA) experiments with two active quark flavors and leading order QCD evolution. With certain choices of empirical constraints, both sea and valence quark distributions are extracted with the combined inputs, and we present the quark distributions in the proton correspondingly. We also discuss how to extend the framework to accommodate more off-forward constraints beyond the small $\xi$ expansion, especially the lattice calculated GPDs.