Chiral symmetry breaking in continuum QCD

TL;DR

This paper provides a detailed quantitative analysis of chiral symmetry breaking in continuum QCD with two flavors, using non-perturbative functional renormalisation group methods to explore the transition from perturbative to hadronic regimes.

Contribution

It introduces a vertex expansion scheme based on gauge-invariant operators for studying chiral symmetry breaking in continuum QCD, including systematic error analysis.

Findings

Results for the quark propagator and tensor structure.

Momentum dependence of the quark-gluon vertex.

Analysis of four-fermi scatterings.

Abstract

We present a quantitative analysis of chiral symmetry breaking in two-flavour continuum QCD in the quenched limit. The theory is set-up at perturbative momenta, where asymptotic freedom leads to precise results. The evolution of QCD towards the hadronic phase is achieved by means of dynamical hadronisation in the non-perturbative functional renormalisation group approach. We use a vertex expansion scheme based on gauge-invariant operators and discuss its convergence properties and the remaining systematic errors. In particular we present results for the quark propagator, the full tensor structure and momentum dependence of the quark-gluon vertex, and the four-fermi scatterings.