Transverse momentum distributions of quarks from the lattice using extended gauge links

TL;DR

This paper reports preliminary lattice QCD calculations of the intrinsic transverse momentum distribution of quarks in the nucleon using non-local operators with Wilson lines, showing Gaussian-like distributions with root mean squared momentum around 560 MeV.

Contribution

It introduces a lattice QCD approach to compute transverse momentum distributions of partons using non-local operators with Wilson lines, providing initial results consistent with phenomenology.

Findings

Gaussian-like transverse momentum distribution observed

Root mean squared transverse momentum ~560 MeV

First x-moment of TMD f_1^{n=1}(k_T) obtained

Abstract

We present preliminary numerical studies in Lattice QCD related to the intrinsic transverse momentum distribution of partons in the nucleon. We employ non-local operators, consisting of spatially separated quark creation and annihilation operators connected by a straight Wilson line. A clear signal is already obtained from a small number of configurations at a pion mass of about 600 MeV. As an example, we demonstrate that we can obtain the first x-moment of the transverse momentum dependent parton distribution function f_1^{n=1}(k_T) from our data. Our results, which are not renormalized, show a Gaussian-like distribution. The root mean squared transverse momentum is about 560 MeV for a Gaussian fit, close to phenomenological values.