Neutrino Mass and Dark Matter from Gauged $U(1)_{B-L}$ Breaking

Understand

We propose a new model where the Dirac mass term for neutrinos, the Majorana mass term for right-handed neutrinos, and the other new fermion masses arise via the spontaneous breakdown of the $U(1)_{B-L}$ gauge symmetry.

• The anomaly-free condition gives four sets of assignment of the B-L charge to new particles, and three of these sets have an associated global $U(1)_{DM}$ symmetry which stabilizes dark matter candidates.
• The dark matter candidates contribute to generating the Dirac mass term for neutrinos at the one-loop level.
• Consequently, tiny neutrino masses are generated at the two-loop level via a Type-I-Seesaw-like mechanism.