Light Dark Matter, Light Higgs and the Electroweak Phase Transition

Abstract: We propose a minimal extension of the Standard Model by two real singlet fields that could provide a good candidate for light Dark Matter, and give a strong first order electroweak phase transition. As a result, there are two CP even scalars; one is lighter than \sim 70 GeV, and the other one with mass in the range of 280-400 GeV; and consistent with electroweak precision tests. We show that the light scalar mass can be as small as 25 GeV while still being consistent with the LEP data. The predicted dark matter scattering cross section is large enough to accommodate CoGeNT and can be probed by future XENON experiment. We also show that for dark matter mass around 2 GeV, the branching fraction of the process (B^+\rightarrowK^++2(DM)) can be accessible in SuperB factories.