Baryon Asymmetry from a Two Stage Electroweak Phase Transition ?

Abstract

We investigate an extension of the standard model with a second Higgs doublet, showing a two stage phase transition. Wash-out of a baryon asymmetry after the phase transition can be easily avoided in this class of models. B+L transitions are more strongly suppressed in the intermediate phase than in the high temperature symmetric phase,however. Therefore, it becomes more difficult if not impossible to generate a sufficient baryon asymmetry during the phase transition.