γ5 and infrared dimensional regularization

Abstract

We carefully discuss how to deal with γ 5 in the dimensional regularization scheme when IR singularities are present. The dimensional continuation of the Dirac algebra in odd-parity fermion traces leads to anomalous IR axial and charge conjugation contributions. In an explicit calculation, namely the O( α s 2) parity violating contributions to e +e -→ γ,Z 0 q qg, qg , we demonstrate that the IR charge conjugation anomaly vanishes and that the finite IR axial anomalies are spurious in the sense that they cancel among the real and virtual contributions to the p.v. cross sections as do the IR singular contributions.