Inert dark matter and strong electroweak phase transition

We find, taking into account recent indications from the LHC and the constraints from the electroweak precision data, that for a light DM (40-60 GeV) particle H0 and heavy, almost degenerate additional scalars H± and A0 this is indeed possible but the two parameters most important for the strength of the phase transition: the common mass of H± and A0 and the trilinear coupling of the Higgs particle h0 to DM are then strongly constrained. H± and A0 must weight less than ∼440 GeV if the inert minimum is to be the lowest one and the value of the h0H0H0 coupling is limited by the XENON 100 data. We stress the important role of the zero-temperature part of the effective potential for the strength of the phase transition.