Chiral phase in fermionic measure and the resolution of the strong CP problem

TL;DR

This paper discusses how fixing the chiral phase ambiguity in the fermionic measure of gauge theories shows that such phases in QCD quark masses do not induce CP violation, addressing the strong CP problem.

Contribution

It clarifies the role of chiral phase fixing in the fermionic measure and its implications for the strong CP problem in QCD.

Findings

Chiral phase in the fermionic measure can be fixed to eliminate ambiguity.

A fixed chiral phase in the quark mass term does not lead to CP violation.

The resolution suggests no physical effect of the chiral phase on CP symmetry.

Abstract

The fermionic measure in the functional integral of a gauge theory suffers from an ambiguity in the form of a chiral phase. By fixing it, one is led once again to the conclusion that a chiral phase in the quark mass term of QCD has no effect and cannot cause CP violation.