Quark and gluon TMD correlators in momentum and coordinate space

TL;DR

This paper reviews the leading-twist quark and gluon TMD correlators in both momentum and coordinate space, covering various polarization states of hadrons, to enhance understanding of parton distributions in quantum chromodynamics.

Contribution

It provides a comprehensive overview of TMD correlators in momentum and coordinate space, including polarization effects for different hadron spins, which is a novel synthesis in the field.

Findings

Detailed parametrization of TMDs in momentum space.

Extension of TMDs to coordinate ($b_T$) space.

Analysis of polarization effects in TMDs.

Abstract

Transverse momentum dependent (TMD) distribution correlators can be parametrized in terms of TMD parton distribution functions (PDFs), or TMDs for short. We provide an overview of the leading-twist quark and gluon TMDs, both in momentum space and in coordinate space (also called $b_T$-space, where $b_T$ is Fourier conjugate to the partonic momentum $k_T$). We consider unpolarized, vector polarized, as well as tensor polarized hadrons, which is relevant for spin-$0$, spin-$1/2$, and spin-$1$ hadrons.