Two-Higgs-doublet Model and its Scalar Dark Matter Extension

Abstract

As one of the simplest extensions of the Higgs sector, two-Higgs-doublet-model (2HDM) has been widely analyzed. In this talk the speaker begins with discussing to what extent the 2HDM is compatible with the latest measurement of the 125.5 GeV Higgs-like signal at the LHC8, assuming one of the two CP-even Higgs bosons is identified as the observed resonance. The prospects of additional (lighter) Higgs bosons searches at future colliders are followed by the discussion.

Next, he considers 2HDM with an extra gauge-singlet scalar S (2HDMS) and introduce an extra Z2 symmetry under which S is the only odd field. Thus S can be a stable dark matter (DM) candidate provided that it does not acquire a vacuum expectation value. He finds that the predicted DM-nucleon cross section, at the low-mass region, falls within the CDMS II signal region. This would be a success for the 2HDMS if it was not for the LUX and SuperCDMS limits. Possibilities for DM to be isospin-violating in this model and its impact on direct DM searches will also be commented.