Renormalization of CP-Violating Pure Gauge Operators in Perturbative QCD Using the Gradient Flow

Abstract

We use the Yang-Mills gradient flow to study the mixing of CP-violating pure gauge operators in continuum QCD with special attention to Weinberg's d=6 purely gluonic operator. The gradient flow allows for a relatively clear derivation of the Wilson coefficients of the CP-violating effective Hamiltonian. This calculation is the first step towards a high-energy matching of matrix elements involving the CP-violating operators between the perturbative and lattice regimes.