Effect of the Quark-Gluon Vertex on Dynamical Chiral Symmetry Breaking

TL;DR

This study examines how different models of the quark-gluon vertex influence the quantitative understanding of chiral symmetry breaking in quantum chromodynamics, ensuring robustness across various truncation schemes.

Contribution

It introduces a comprehensive analysis of the quark-gluon vertex's role in chiral symmetry breaking using improved models consistent with key QCD principles.

Findings

Qualitative and quantitative patterns of chiral symmetry breaking are consistent across different vertex models.

The approach remains robust and reliable for describing hadron properties.

Various truncation schemes yield similar results, supporting the method's validity.

Abstract

In this work, we investigate how the details of the quark-gluon interaction vertex affect the quantitative description of chiral symmetry breaking through the gap equation for quarks. We start from two gluon propagator models widely used in literature and constructed in direct connection with our gradually improved understanding of infrared quantum chromodynamics coupled with its exact one-loop limit. The gap equation is then solved by employing a variety of vertex \emph{Ans\"atze}, which have been constructed in order to implement some of the key aspects of quantum chromodynamics, namely, multiplicative renormalizability of the quark propagator, gauge invariance, matching with perturbation theory in the weak coupling regime, independence from unphysical kinematic singularities as well as manifestly correct transformation properties under charge conjugation and parity operations. On general grounds, all truncation schemes exhibit the same qualitative and quantitative pattern of chiral symmetry breaking, ensuring the overall robustness of this approach and its potentially reliable description of the hadron spectrum and properties.