Semi-naive dimensional renormalization

We propose a treatment of $\gamma^5$ in dimensional regularization which is based on an algebraically consistent extension of the Breitenlohner-Maison-'t Hooft-Veltman (BMHV) scheme; we define the corresponding minimal renormalization scheme and show its equivalence with a non-minimal BMHV scheme. The restoration of the chiral Ward identities requires the introduction of considerably fewer finite counterterms than in the BMHV scheme. This scheme is the same as the minimal naive dimensional renormalization in the case of diagrams not involving fermionic traces with an odd number of $\gamma^5$, but unlike the latter it is a consistent scheme. As a simple example we apply our minimal subtraction scheme to the Yukawa model at two loops in presence of external gauge fields.Comment: 28 pages, 3 figure