Dark matter and a suppression mechanism for neutrino masses in the Higgs triplet model

Abstract

We extend the Higgs triplet model so as to include dark matter candidates and a simple suppression mechanism for the vacuum expectation value (v_Delta) of the triplet scalar field. The smallness of neutrino masses can be naturally explained with the suppressed value of v_Delta even when the triplet fields are at the TeV scale. The Higgs sector is extended by introducing Z_2-odd scalars (an SU(2)_L doublet eta and a real singlet s_2^0) in addition to a Z_2-even complex singlet scalar s_1^0 whose vacuum expectation value violates the lepton number conservation by a unit. In our model, v_Delta is generated by the one-loop diagram to which Z_2-odd particles contribute. The lightest Z_2-odd scalar boson can be a candidate for the dark matter. We briefly discuss a characteristic signal of our model at the LHC.

Comments: 17 pages, 2 figures, references added