On gluon and ghost propagators in linear covariant gauges

TL;DR

This paper computes gluon and ghost propagators in linear covariant gauges using Dyson-Schwinger equations, revealing gauge parameter effects on infrared behavior and providing a running coupling estimate.

Contribution

It extends the analysis of Yang-Mills propagators to linear covariant gauges, highlighting deviations from Landau gauge for small gauge fixing parameters.

Findings

Ghost dressing function shows infrared suppression at small gauge parameters

Gluon propagator remains finite at zero momentum in these gauges

A running coupling is extracted from the propagator data

Abstract

We compute the gluon and ghost propagators of Yang-Mills theory in linear covariant gauges from the coupled system of Dyson-Schwinger equations. For small values of the gauge fixing parameter $\xi\sim 0.1$, the deviations to the Landau gauge already become clearly visible. For the ghost dressing function, this is reflected in a logarithmic infrared suppression. Also, the gluon dressing function changes - but only quantitatively - and the gluon propagator remains finite at zero momentum. From the results, a running coupling is extracted.