Aspects of the Higgs phase in SU(2) x U(1) lattice gauge Higgs theory

Using a simplified lattice version of the electroweak sector of the standard model, with dynamical fermions excluded, we determine at fixed Weinberg angle the transition line between the confined phase and the Higgs phase, the latter defined as the region where the global center subgroup of the gauge group is spontaneously broken, and "separation of charge" confinement disappears. We then search, via lattice Monte Carlo simulations, for possible neutral vector bosons in the Higgs region, apart from the photon and Z. There are numerical indications of a "light Z" in the lattice data (along with the photon and the Z), but a lack of the expected scaling of the light mass particle excludes any firm conclusions about the physical spectrum.