Transitional CP Violation in the MSSM and Electroweak Baryogenesis

Electroweak baryogenesis depends on the profile of the bubble wall created in the first-order phase transition. It is pointed out that CP violation in the Higgs sector of the MSSM could become large enough to explain the baryon asymmetry. We confirm this by solving the equations of motion for the Higgs fields with the effective potential at the transition temperature. That is, we present an example such that the transitional CP violation is realized and show the possibility that the baryon asymmetry of the universe may be produced, if marginally, by the $\tau$ lepton interacting with the wall, when an explicit CP breaking in the Higgs sector, which is consistent with experimental bounds, is induced at the phase transition.