SU(N)×SU(N) chiral models on asymmetric lattices with standard and improved actions

Using the background-field method we determine the relation between Λ parameters of symmetric and asymmetric lattices for SU(N)×SU(N) two-dimensional chiral models. We also evaluate the derivatives of the couplings with respect to the asymmetry factor which are useful in finite-temperature calculations. We consider the standard and the improved (Symanzik) actions.