アイテム詳細

要旨

Extensions of the Zee-Babu model are investigated to find a common framework for the neutrino mass problem and the dark matter issue of the universe. The particle content of the model is enlarged with a complex scalar singlet φ and a right-handed Majorana neutrino N_R which serves as a particle dark matter candidate. With a speci c baryon (B) minus lepton (L) number for φ, the model enjoys a U(1) _B-L symmetry. In a fi rst scenario, the U(1)_B-L is gauged. To prevent [U(1)_B-L³ gauge anomalies, N_R is a must. In a second scenario, a Z₄ symmetry is imposed. U(1)_B-L is global, i.e., a Majoron enters into the theory after spontaneous symmetry breaking. In both scenarios, light neutrino masses and the dark matter mass are generated at the U(1)_B-L symmetry breaking scale.The required thermal relic abundance of N_R is predominantly produced through the Higgs portal. It is shown that N_R could be directly detected. To complete, the veri cation of the model at the LHC is discussed.