On the phase structure of QCD with Wilson fermions

TL;DR

This paper investigates the phase structure of lattice QCD with Wilson fermions, providing analytic and numerical evidence for spontaneous symmetry breaking and its relation to pion mass and critical lines.

Contribution

It offers new numerical evidence for the multiple critical lines and explores the connection between phase structure and finite temperature transitions.

Findings

Spontaneous breaking of parity and flavor symmetry occurs.

Existence of massless pion at the critical hopping parameter.

Multiple critical lines in the weak coupling region.

Abstract

The phase structure of lattice QCD with Wilson fermions is discussed. Analytic and numerical evidences are given for the spontaneous breaking of parity and flavor symmetry, which naturally explains the existence of the massless pion at the critical hopping parameter $K_c$ without recourse to the chiral symmetry absent in the Wilson fermion formulation. New numerical evidences are also presented for the multiple structure of the critical lines in the weak coupling region. A connection between the phase structure and the finite temperature phase transition is briefly mentioned.