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.

Comments: 31 pages, 3 figures, explanations and appendix added, matches published version