Gauged U (1)X breaking as origin of neutrino masses, dark matter and leptogenesis at TeV scale

Abstract

We propose a new mechanism which simultaneously explains tiny neutrino masses, stability of dark matter and baryon asymmetry of the Universe via leptogenesis due to the common origin; a spontaneous breaking of a U(1)X gauge symmetry at TeV scale. The U(1)X breaking provides small Majorana masses of vectorlike leptons which generate small mass differences among them, and enhance their CP-violating decays via the resonant effect. Such CP-violation and lepton-number violation turns out to be a sufficient amount of the observed baryon asymmetry through leptogenesis. The Majorana masses from the U(1)X breaking also induce radiative generation of masses for active neutrinos at one-loop level. Furthermore, a Z2 symmetry appears as a remnant of the U(1)X breaking, which guarantees the stability of dark matter. We construct a simple renormalizable model to realize the above mechanism, and show a benchmark point which can explain observed neutrino oscillations, dark matter data and the baryon asymmetry at the same time.