Screened massive expansion of the quark propagator in the Landau gauge

TL;DR

This paper investigates the infrared behavior of the quark propagator in Landau gauge using a screened massive expansion, successfully modeling dynamical quark mass generation and comparing results with lattice data.

Contribution

It introduces a novel application of the screened massive expansion with non-standard renormalization to describe infrared quark mass generation in full QCD.

Findings

Quark mass function matches lattice data well.

Quark Z-function shows correct behavior only at high energies in some schemes.

Infrared quark mass is set by a parameter fit to lattice results.

Abstract

The infrared behavior of the quark propagator is studied at one loop and in the Landau gauge ($\xi=0$) using the screened massive expansion of full QCD and three different resummation schemes for the quark self-energy. The shift of the expansion point of perturbation theory, which defines the screened expansion, together with a non-standard renormalization of the bare parameters, proves sufficient to describe the dynamical generation of an infrared quark mass also in the chiral limit. Analytically, the scale for such a mass is set by a mass parameter $M$, whose value is fixed by a fit to the lattice data for quenched QCD. The quark mass function $\mathcal{M}(p^{2})$ is shown to be in very good agreement with the lattice results. The quark $Z$-function, on the other hand, shows the wrong qualitative behavior in all but one of the studied resummation schemes, where its behavior is qualitatively correct, but only at sufficiently high energies.