Aspects of the electroweak phase transition in the minimal supersymmetric standard model

Abstract We study the finite-temperature effective potential of the Minimal Supersymmetric Standard Model in the full ( m A , tan β ) parameter space. As for the features of the electroweak phase transition, we identify two possible sources of significant differences with respect to the Standard Model: a stop sector with little supersymmetry breaking makes the phase trasition more strongly first-order, whereas a light CP-odd neutral boson weakens its first-order nature. After including the leading plasma effects, T = 0 radiative corrections due to top and stop loops, and the most experimental constraints, we find that the danger of washing out any baryon asymmetry created at the electroweak scale is in general no less than in the Standard Model.