Electroweak Phase Changes in Two Higgs Models

Abstract

As reviewed by Espinosa¹ in his contribution, a strongly first order electroweak phase transition is required in order that the baryon asymmetry, however generated, be not washed out by sphaleron transitions. In the standard one Higgs doublet model, perturbatively treated, this implies an unacceptably low Higgs mass of < 35 GeV. There are indications that non-perturbative calculations can push the bound up to around the current experimental lower limit of 60 GeV, but in view of the possibility that this may be only a temporary remission we investigate the extent to which it may be evaded in a general two doublet model. This has the advantage compared with other extensions of the standard model of allowing CP violation in the Higgs sector, a desideratum of several baryogenesis scenarios.

Presented by A.T. Davies