The B - L scotogenic models for Dirac neutrino masses

We construct the one-loop and two-loop scotogenic models for Dirac neutrino mass generation in the context of U(1)_B-L extensions of standard model. It is indicated that the total number of intermediate fermion singlets is uniquely fixed by the anomaly free condition and the new particles may have exotic B - L charges so that the direct SM Yukawa mass term anti ν_Lν_Rφ⁰ and the Majorana mass term (m_N/2)ν_R^Cν_R are naturally forbidden. After the spontaneous breaking of the U(1)_B-L symmetry, the discrete Z₂ or Z₃ symmetry appears as the residual symmetry and gives rise to the stability of intermediate fields as DM candidates. Phenomenological aspects of lepton flavor violation, DM, leptogenesis and LHC signatures are discussed. (orig.)