Aspects of the confinement mechanism in Landau gauge QCD

TL;DR

This paper investigates the infrared fixed point structure of Landau gauge QCD, revealing that certain singularities crucial for confinement in quenched approximation are absent in dynamical QCD, affecting confinement and deconfinement mechanisms.

Contribution

It demonstrates that the IR singularities responsible for confinement in quenched QCD are absent in dynamical QCD, impacting the understanding of confinement and deconfinement.

Findings

IR fixed point with strong kinematic singularity is absent in dynamical QCD

Long-range interaction is screened by unquenching loops at quark mass scales

Results inform the qualitative form of the heavy quark potential

Abstract

I analyze the IR fixed point structure of Landau gauge QCD. Precisely the fixed point with a strong kinematic singularity of the quark-gluon vertex that proved crucial for the recently proposed confinement mechanism in the quenched approximation is absent in dynamical QCD. Therefore, the IR singularities do not induce asymptotic quark confinement but the long-range interaction is screened by unquenching loops at scales of the order of the quark mass. This provides the prerequisite for a microscopic description of deconfinement and string breaking. The fixed points determine the qualitative form of the heavy quark potential and may be relevant for hot and dense matter.