Decoupling Property of SUSY Extended Higgs Sectors and Implication for   Electroweak Baryogenesis
  One-loop contributions to the Higgs potential at finite temperatures are discussed in the supersymmetric standard model with four Higgs doublet chiral superfields as well as a pair of charged singlet chiral superfields. The mass of the lightest Higgs boson $h$ is determined only by the D-term at the tree-level in this model, while the triple Higgs boson coupling for $hhh$ can receive a significant radiative correction. The same nondecoupling effect can also contribute to realize the sufficient first order electroweak phase transition, which is required for a successful scenario of electroweak baryogenesis. This model can be a new candidate for a model in which the baryon asymmetry of the Universe is explained at the electroweak scale. We also discuss the implication for the measurement of the triple Higgs boson coupling at the ILC. 
Shinya Kanemura, Eibun Senaha and Tetsuo Shindou
hep-ph