Gaussian corrections around the mean-field approximation for the mixed SU(2) lattice gauge theory

We analyze the mixed fundamental-adjoint SU(2) lattice gauge theory in four dimensions by the mean-field method including Gaussian corrections in the axial gauge. In previous papers we have shown, with the help of an Abelian model, that in order to apply this technique it is necessary to introduce different unconstrained variables for the various characters which appear in the action. The present calculation is an explicit example of this idea applied to a non-Abelian case. The phase diagram given by Monte Carlo simulations is accurately reproduced.