Unquenching the infrared sector of QCD

TL;DR

This paper explores how the infrared behavior of non-Abelian Yang-Mills theories changes when dynamical quarks are included, combining continuum predictions with lattice simulation results.

Contribution

It derives an equation predicting the impact of dynamical quarks on the gluon propagator and compares continuum and lattice results for unquenched QCD.

Findings

Continuum equation predicts gluon propagator modifications due to dynamical quarks.

Lattice simulations with light and heavy quarks provide data for unquenched gluon and ghost sectors.

Comparison shows consistency between continuum predictions and lattice results.

Abstract

We discuss the recent progress made in understanding how some fundamental results valid in the quenched infrared sector of non-Abelian Yang-Mills theories generalize to the unquenched case. In particular, we derive in the continuum an equation that allows to predict how the momentum dependence of the quenched gluon propagator is affected by the presence of a small number of dynamical quarks. In addition, we present the most recent lattice simulations of the (Landau gauge) gluon and ghost two-point sector obtained using gauge field configurations with two light and two light plus two heavy twisted-mass quark flavors. A comparison between the results obtained by these two complementary methods is then carried out.