The x-dependence of hadronic parton distributions: A review on the progress of lattice QCD

TL;DR

This review discusses recent advances in lattice QCD calculations of the x-dependence of parton distributions, highlighting progress in flavor singlet PDFs, GPDs, and TMD PDFs, and their impact on phenomenology.

Contribution

It summarizes recent developments in lattice QCD methods for calculating hadronic parton distributions, including new approaches and their implications.

Findings

Progress in calculating flavor singlet PDFs.

First lattice calculations of GPDs.

Implementation of approaches for TMD PDFs.

Abstract

In this article, we review recent lattice calculations on the $x$-dependence of parton distributions, with the latter providing information on hadron structure. These calculations are based on matrix elements of boosted hadrons coupled to non-local operators and can be related to the standard, light-cone distribution functions via an appropriate factorization formalism. There is significant progress in several directions, including calculations of flavor singlet parton distribution functions (PDFs), first calculations of generalized parton distributions (GPDs), as well as the implementation of some of the approaches for the transverse-momentum-dependent PDFs (TMD PDFs). This new direction of lattice calculations is particularly interesting for phenomenological fits on experimental data sets, as the lattice results can help to improve the constraints on the distribution functions.