The $B-L$ Scotogenic Models for Dirac Neutrino Masses

Abstract: We construct the one-loop and two-loop scotogenic models for Dirac neutrino mass generation in the context of $U(1)<em>{B-L}$ extensions of standard model. It is indicated that the total number of intermediate fermion singlets is uniquely fixed by anomaly free condition and the new particles may have exotic $B-L$ charges so that the direct SM Yukawa mass term $\bar{\nu}_L\nu_R\overline{\phi<sup>0}$ and the Majorana mass term $(m_N/2)\overline{\nu_R<sup>C}\nu_R$ are naturally forbidden. After the spontaneous breaking of $U(1)</em>{B-L}$ symmetry, the discrete $Z_{2}$ or $Z_{3}$ symmetry appears as the residual symmetry and give rise to the stability of intermediated fields as DM candidate. Phenomenological aspects of lepton flavor violation, DM, leptogenesis and LHC signatures are discussed.