On the Gribov problem in Yang-Mills theory

I briefly review the Gribov ambiguity of Yang-Mills theory, some of its features and attempts to control it, in particular the Gribov-Zwanziger proposal to restrict the functional integration in the Landau gauge to the Gribov region. This proposal is extended to an arbitrary gauge in such a way as to guarantee BRST invariance. The key insight is that any gauge change in the generating functional can be effected by a suitable field-dependent BRST transformation. I derive a simple analytic formula for the Jacobian of such a transformation, which yields an explicit recipe for the required transformation-parameter functional and allows for the computation of the Gribov horizon functional in any gauge, as I illustrate for the class of R_xi gauges.