SUSY Variants of the Electroweak Phase Transition ∗ Stephan

The MSSM with a light right-handed stop and supersymmetric models with a singlet whose vev is comparable to that of the SU(2)W Higgs allow for a strongly first-order electroweak phase transition even for a mass of the lightest Higgs around 100 GeV. After a short review of the standard model situation we discuss these supersymmetric models. We also compare perturbative calculations based on the dimensionally reduced 3-dimensional action with lattice results and present an analytic procedure based on an analogue of the stochastic vacuum model of QCD to estimate the nonperturbative contributions. Based on a talk presented by M. G. Schmidt at the First European Meeting “From the Planck scale to the electroweak scale” (Kasimierz, Poland, May 1998)