Proton generalized parton distributions from lattice QCD

TL;DR

This paper presents the first lattice QCD calculations of the x-dependence of various proton GPDs, providing new insights into the internal structure of protons through advanced computational methods.

Contribution

It introduces novel lattice QCD results on proton GPDs using the quasi-distribution formalism with a specific fermion ensemble, advancing the understanding of hadron structure.

Findings

First lattice results on proton GPDs in x-dependence

Use of quasi-distribution formalism for GPDs

Results presented in MS-bar scheme at 2 GeV

Abstract

Momentum and spatial distributions of quarks and gluons inside hadrons are typically encoded in the so-called generalized parton distributions (GPDs). GPDs are multi-dimensional quantities that are very challenging to extract, both experimentally and within lattice QCD. We present the first lattice results on the $x$-dependence of isovector unpolarized, helicity and transversity GPDs of the proton, obtained from lattice QCD using an ensemble of $N_f=2+1+1$ maximally twisted mass fermions, with pion mass $M_\pi=260$ MeV and lattice spacing $a\simeq 0.093$ fm. Our calculations use the quasi-distribution formalism and the final distributions are presented in the MS-bar scheme at a renormalization scale of 2 GeV.