We present a scenario where neutrino masses and Dark Matter are related due to a global U(1) _(B-L) symmetry. Specifically we consider neutrino mass generation via the Zee-Babu two-loop mechanism, augmented by a scalar singlet whose VEV breaks the global U(1) _(B-L) symmetry. In order to obtain a Dark Matter candidate we introduce two Standard Model singlet fermions. They form a Dirac particle and are stable because of a remnant Z _2 symmetry. Hence, in this model the stability of Dark Matter follows from the global U(1) _(B-L) symmetry. We discuss the Dark Matter phenomenology of the model, and compare it to similar models based on gauged U(1) _(B-L). We argue that in contrast to the gauged versions, the model based on the global symmetry does not suffer from severe constraints from Z ' searches.
展开▼
