  We propose a generalization of the Standard Model (SM) by adding two real
gaugesinglets S1, S2. The field S1 will improve the strength of the electroweak
phase transition (EWPT). Imposing a Z2 symmetry on the field S2 makes this
field a possible candidate for dark matter. Both singlets interact with other
observable fields through 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) on the electroweak phase
transition. And we present configurations that produce a strong first order
EWPT.
