UNITARITY VIOLATION IN NON-ABELIAN PAULI-VILLARS REGULARIZATION

We regularize QCD using the combination of higher covariant derivative s and Pauli-Villars determinants proposed by Slavnov. It is known that for pure Yang-Mills theory the Pauli-Villars determinants generate un physical logarithmic radiative corrections at one loop that modify the beta function. Here we prove that when the gauge fields are coupled t o fermions so that one has QCD, these unphysical corrections translate into a violation of unitarity. We provide an understanding of this by showing that Slavnov's choice for the Pauli-Villars determinants intr oduces extra propagating degrees of freedom that are responsible for t he unitarity breaking. This shows that Slavnov's regularization violat es unitarity, hence that it should be rejected.