Supersymmetric electroweak baryogenesis

We calculate the baryon asymmetry generated at the electroweak phase transition in the minimal supersymmetric standard model, using a new method to compute the CP-violating asymmetry in the Higgsino flux reflected into the unbroken phase. The method is based on a Higgs insertion expansion. We find that the CP asymmetry at leading order is proportional to the change in tan beta in the bubble wail, which is at most of order 10(-2), while at next-to-leading order this suppression factor disappears. This result may enhance the final baryon asymmetry generated during the electroweak phase transition for small Delta beta (< 10(-3)). (C) 2000 Elsevier Science B.V. All rights reserved.