Scalar dark matter and radiative Dirac neutrino mass in an extended U(1)B−L model

We explore a gauged U(1)B−L extension of the standard model with inclusion of three right-handed neutrinos of exotic B−L charges to cancel the gauge anomaly. Non-trivial transformation of new particles under B−L symmetry forbids the generation of neutrino mass at tree level and hence a small Dirac mass can be generated radiatively at one loop with scalar, fermion doublets and singlet scalars. We also discuss the phenomenology of a scalar dark matter, which can be obtained from the mixing of neutral CP even component of a doublet scalar and a real singlet scalar. An adhoc Z2 symmetry is required in the current framework to stabilize the dark matter candidate. Presence of new particles with Z2 odd charges and small mass splitting, makes the phenomenology more interesting by governing the relic density with co-annihilation processes. We explore the spin-independent direct detection constraints on dark matter via the scalar mediation. Constraints from lepton flavor violating decay processes like μ→eγ are also discussed.