Comment on the claim of physical irrelevance of the topological term

TL;DR

This paper refutes a claim that a topological term in QCD has no physical effects, clarifying that CP violation effects are indeed present and the standard understanding remains valid.

Contribution

It clarifies the misunderstanding regarding the physical relevance of the topological term in QCD and reaffirms the correctness of standard results about CP violation.

Findings

The topological term in QCD can lead to CP violation effects.

The claim of physical irrelevance of the topological term is based on a misunderstanding.

Standard results about CP violation in QCD are correct.

Abstract

We argue that the claim of the absence of charge-conjugation-parity (CP) violating effects due to a topological term in quantum chromodynamics (QCD) is based upon a misunderstanding, and the standard results in the field are correct.