Delta-rho in an SU(2) X U(1) chiral Yukawa model

We report on a simulation in progress of an SU(2) X U(1) fermion-Higgs model with two non-degenerate fermion doublets. The Zaragoza proposal for chiral lattice fermions is used; naive fermions are studied for comparison. The aims of this simulation are a non-perturbative study of the decoupling of species doublers, of triviality bounds on the Higgs and fermion masses and of the phenomenological quantity Delta-rho.