On the trace anomaly for Weyl fermions

TL;DR

This paper discusses the controversy over the existence of the odd-parity trace anomaly in four-dimensional Weyl fermion theories and explains why certain methods fail to detect it.

Contribution

It clarifies the limitations of previous methods in detecting the odd-parity trace anomaly in Weyl fermions.

Findings

Previous methods cannot detect the odd-parity trace anomaly

The paper clarifies the theoretical debate on Weyl fermion anomalies

Highlights methodological limitations in anomaly detection

Abstract

This note is a comment on some recent papers that have raised a controversy about the existence of the odd-parity trace anomaly in a four-dimensional theory of Weyl fermions. Without going into too technical details we explain why the methods employed in those papers cannot detect it.