Electroweak baryogenesis and dark matter from a singlet Higgs

If the Higgs boson H couples to a singlet scalar S via lambda(m) vertical bar H vertical bar S-2(2), a strong electroweak phase transition can be induced through a large potential barrier that exists already at zero temperature. In this case properties of the phase transition can be computed analytically. We show that electroweak baryogenesis can be achieved using CP violation from a dimension-6 operator that couples S to the top-quark mass, suppressed by a new physics scale that can be well above 1TeV. Moreover the singlet is a dark matter candidate whose relic density is. less than or similar to of the total dark matter density, but which nevertheless interacts strongly enough with nuclei ( through Higgs exchange) to be just below the current XENON100 limits. The DM mass is predicted to be in the range 80-160 GeV.