Electroweak baryogenesis and dark matter from a singlet Higgs

Abstract

If the Higgs boson H couples to a singlet scalar S via lambda_m |H|^2 S^2, a\nstrong electroweak phase transition can be induced through a large potential\nbarrier that exists already at zero temperature. In this case properties of the\nphase transition can be computed analytically. We show that electroweak\nbaryogenesis can be achieved using CP violation from a dimension-6 operator\nthat couples S to the top-quark mass, suppressed by a new physics scale that\ncan be well above 1 TeV. Moreover the singlet is a dark matter candidate whose\nrelic density is < 3% of the total dark matter density, but which nevertheless\ninteracts strongly enough with nuclei (through Higgs exchange) to be just below\nthe current XENON100 limits. The DM mass is predicted to be in the range 80-160\nGeV.\n