Dimensional Regularisation with Non-Anticommuting $γ_5$: Status and Application to the Standard Model

Abstract

A consistent all-order treatment of $γ_5$ in dimensional regularisation (DReg), as provided by the Breitenlohner-Maison/'t Hooft-Veltman (BMHV) scheme, is essential for high-precision electroweak calculations, but comes at the cost of a regularisation-induced violation of gauge and BRST invariance that must be reinstated via symmetry-restoring counterterms. We report on the current status of our research on the BMHV scheme, from its $D$-dimensional realisation and its multi-loop behaviour up to the 4-loop order, to its most recent application: the complete 1-loop renormalisation of the Standard Model (SM), including both divergent and finite symmetry-restoring counterterms. For the latter, we discuss the main intricacies of the BMHV treatment and present a representative excerpt of the resulting counterterms.