The nonperturbative quark-gluon vertex

TL;DR

This paper investigates the nonperturbative structure of the quark-gluon vertex in Landau gauge using lattice QCD with improved fermion action, focusing on form factors at zero gluon momentum and their mass dependence.

Contribution

It provides the first lattice QCD calculation of all three form factors of the quark-gluon vertex at zero gluon momentum with improved fermion action.

Findings

All three form factors are computed at zero gluon momentum.

The form factors show negligible dependence on quark mass within the studied range.

Comparison with the abelian vertex highlights nonperturbative effects.

Abstract

We show results for the quark-gluon vertex in the Landau gauge, using a mean-field improved Sheikholeslami-Wohlert fermion action. We compute all the three non-zero form factors of the vertex at zero gluon momentum, and compare them to the abelian vertex. The quark mass dependence of the vertex is also investigated and found to be negligible for the range of masses considered.