Dark matter in three-Higgs-doublet models with S3 symmetry

Abstract:

Models with two or more scalar doublets with discrete or global symmetries can have vacua with vanishing vacuum expectation values in the bases where symmetries are imposed. If a suitable symmetry stabilises such vacua, these models may lead to interesting dark matter candidates, provided that the symmetry prevents couplings among the dark matter candidates and the fermions. We analyse three-Higgs-doublet models with an underlying S3 symmetry and discuss all possible vacua.

Two models, with and without CP violation, are explored in detail. In our framework the stability of the dark matter sector results from a Z2 symmetry which survives the spontaneous symmetry breakdown of the initial S3 symmetry. One of the doublets provides the DM sector, while the other two are active.