A Simple Dirac Prescription for Two-Loop Anomalous Dimension Matrices

Abstract

A novel method to treat effects from evanescent operators in next-to-leading order (NLO) computations is introduced. The approach allows, besides further simplifications, to discard evanescent-to-physical mixing contributions in NLO calculations. The method is independent of the treatments of $\gamma_5$ and can therefore be combined with different renormalization schemes. We illustrate the utility of this result by reproducing literature results of two-loop anomalous dimension matrices for both $|\Delta F| = 1$ and $|\Delta F| = 2$ transitions.