Electroweak baryogenesis from chargino transport in the supersymmetric model

We study the baryon asymmetry of the universe in the supersymmetric standard model (SSM). At the electroweak phase transition, the fermionic partners of the charged SU(2) gauge bosons and Higgs bosons are reflected from or transmitted to the bubble wall of the broken phase. Owing to a physical complex phase in their mass matrix, these reflections and transmissions have asymmetries between CP-conjugate processes. Equilibrium conditions in the symmetric phase are then shifted to favor a non-vanishing value for the baryon number density, which is realized through an electroweak anomaly. We show that the resultant ratio of the baryon number to the entropy is consistent with its present observed value within reasonable ranges of SSM parameters, provided that the CP-violating phase intrinsic in the SSM is not suppressed too greatly. Compatibility with the constraints on the parameters from the electric dipole moment of the neutron is also discussed.