Electroweak baryogenesis in the MSSM with vector-like superfields
  Introducing heavy particles with strong couplings to the Higgs field can strengthen electroweak phase transition, through the entropy release mechanism from both bosons and fermions. We analyze the possibility of electroweak baryogenesis in the MSSM with new vector-like superfields. The new vector-like particles belong to the representation 5+5bar+10+10bar of SU(5). By analyzing in detail the effective potential at finite temperature, we show that a strongly first order electroweak phase transition in this model is ruled out by a combination of 125 GeV Higgs requirement, the bound for exotic quarks, the gluon fusion Higgs production rate and the Higgs diphoton decay rate as well as the electroweak precision measurement. 
Xue Chang and Ran Huo
hep-ph