Quark Masses and Chiral Symmetry

TL;DR

This paper explores the phase structure of quark-gluon interactions, focusing on how quark masses and the CP-violating parameter influence phase transitions, with implications for lattice fermion formulations.

Contribution

It analyzes the conditions under which a first order phase transition occurs at =, especially with multiple light flavors, and discusses how flavor-breaking affects this transition.

Findings

First order transition expected at = with degenerate light flavors

Flavor-breaking can eliminate the phase transition

Implications for Wilson's lattice fermions discussed

Abstract

I discuss the global structure of the strongly interacting gauge theory of quarks and gluons as a function of the quark masses and the CP violating parameter $\theta$. I concentrate on whether a first order phase transition occurs at $\theta=\pi.$ I show why this is expected when multiple flavors have a small degenerate mass. This transition can be removed by sufficient flavor-breaking. I speculate on the implications of this structure for Wilson's lattice fermions.