On the consistency of a BRST quantization — The rôle of the antiBRST symmetry

Abstract

The inclusion of the antiBRST symmetry in addition to the BRST symmetry in the quantization of a gauge theory is considered. It is proven that in all cases where the BRST symmetry ensures ghost decoupling, it is also permissible to impose antiBRST invariance. A general ghost decoupling theorem is furthermore proven using the BRST and antiBRST symmetry. This theorem is shown to yield ghost decoupling even in theories where the BRST symmetry by itself does not. An example of such a theory is given. There the addition of the antiBRST symmetry removes the unphysical ghost degeneracy and one finds the expected result.