Proton generalized parton distributions from lattice QCD

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 Nf = 2 + 1 + 1 maximally twisted mass fermions, with pion mass Mπ = 260 MeV and lattice spacing a ' 0.093 fm. Our calculations use the quasi-distribution formalism and the final distributions are presented in the MS scheme at a renormalization scale of 2 GeV.