1 Phase diagram of a lattice SU(2) × SU(2) scalar-fermion model using the

A lattice regularization of the Standard Model (SM) is necessary not only to establish the existence of chiral gauge theories outside perturbation theory, but also to understand various properties of the fermion mass generation by spontaneous symmetry breaking such as, for instance, the upper bounds on top and Higgs masses[1]. For this purpose it is sufficient to study the fermionscalar sector of the SM which is essentially a Chiral Yukawa Model (CYM). In this talk, we determine the phase structure of a SU(2) × SU(2) CYM, using Zaragoza fermions[2]. We decided to freeze the radial mode of the scalar field. This corresponds to the choice of an infinite bare quartic coupling. For a comparison with the phase structure of other related models see[1,3].