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

We extend the Higgs triplet model so as to include dark matter candidates and a simple suppression mechanism for the vacuum expectation value (upsilon(Delta)) of the triplet scalar field. The smallness of neutrino masses can be naturally explained with the suppressed value of upsilon(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, upsilon(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.