ASPECTS OF THE ELECTROWEAK PHASE-TRANSITION IN THE MINIMAL SUPERSYMMETRIC STANDARD MODEL

We study the finite-temperature effective potential of the Minimal Sup ersymmetric Standard Model in the full (M(A), tan beta) parameter spac e. As for the features of the electroweak phase transition, we identif y two possible sources of significant differences with respect to the Standard Model: a stop sector with little supersymmetry breaking makes the phase transition more strongly first-order, whereas a light CP-od d neutral boson weakens its first-order nature. After including the le ading plasma effects, T = 0 radiative corrections due to top and stop loops, and the most important experimental constraints, we find that t he danger of washing out any baryon asymmetry created at the electrowe ak scale is in general no less than in the Standard Model.