I have a question about Fadeev-Popov (FP) ghosts. FP ghosts brake the gauge symmetry of the lagrangian and solve the problem of the divergence of the physical amplitudes, due to the gauge equivalence of the states. My question is: is it a renormalization process? I mean, the renormalization group is based on a rescaling of the parameters of the theory (fields, coupling constants, etc..) but not (as far as I know) on the introduction of new fields (physical or not, like FP).. So how can I see the FP ghosts in the contest of renormalization? Am I wrong on something? Sorry for my english.. Thanks in advice!