Electroweak baryogenesis and Higgs mass

Assuming that the physics below about 10 TeV is described completely by the Weinberg-Salam model, we can show that no baryon asymmetry can exist at the present epoch regardless of the unification scheme. Specifically we have verified that with known top mass of 175 GeV, any preexisting baryon asymmetry is wiped out by sphaleron processes for Higgs mass in the entire range 10 GeV to 200 GeV. This is a strong indication that the W-S model is incomplete and perhaps the Higgs content is richer than single doublet. For two Higgs doublets, we show using a mechanism of McLerran et al that adequate baryon asymmetry can be produced at the electroweak scale and can survive to the present. (author)