Dynamical gluon mass generation and the IR sector of QCD

Abstract

We review the Pinch Technique - Background Field Method (PT-BFM) framework for formulating and solving the Schwinger-Dyson equations of Yang-Mills theories. In particular, we show how within this framework it is possible to write a new set of Schwinger-Dyson equations that (i) accommodate the dynamical gluon mass generation through Schwinger's mechanism, and (ii) have much better truncation properties than the the conventional equations. The resulting solutions show (in the Landau gauge) an infra-red saturating gluon propagator and ghost dressing function, in agreement with all lattice studies to date for both SU(2) and SU(3) gauge groups as well as 3 and 4 space-time dimensions. We also briefly discuss how a massive gluon enables self-consistently confinement through the condensation of thick vortices, and study other infra-red characteristic quantities such as the Kugo-Ojima function and the effective charge