Phase transition in multi-scalar-singlet extensions of the Standard Model

We propose a generalization of the Standard Model (SM  ) by adding two real gauge-singlets S1S1, S2S2. The field S1S1 will improve the strength of the electroweak phase transition (EWPT  ). Imposing a Z2Z2 symmetry on the field S2S2 makes this field a possible candidate for dark matter. Both singlets interact with other observable fields through the Higgs boson. They are allowed to interact with each other as well. We find that by introducing two different scalar fields, the model is less vulnerable to experimental constraints.In this paper, we consider the effects of a heavy scalar (M1>MH)(M1>MH) on the electroweak phase transition. And we present configurations that produce a strong first order EWPT.