TeV-Scale Seesaw with Loop-Induced Dirac Mass Term and Dark Matter from U(1)_{B-L} Gauge Symmetry Breaking

TL;DR

This paper proposes a TeV-scale seesaw model where neutrino masses and dark matter stability originate from U(1)_{B-L} gauge symmetry breaking, predicting TeV-scale right-handed neutrinos and stable dark matter candidates detectable at colliders.

Contribution

It introduces a novel mechanism for neutrino mass generation and dark matter stability from U(1)_{B-L} symmetry breaking, with testable collider signatures.

Findings

Right-handed neutrinos can be at TeV-scale or below.

Dark matter stability is achieved without extra symmetries.

Enhanced Z' decay into dark matter candidates.

Abstract

We show a TeV-scale seesaw model where Majorana neutrino masses, the dark matter mass, and stability of the dark matter can be all originated from the U(1)_{B-L} gauge symmetry. Dirac mass terms for neutrinos are forbidden at the tree level by U(1)_{B-L}, and they are induced at the one-loop level by spontaneous U(1)_{B-L} breaking. The right-handed neutrinos can be naturally at the TeV-scale or below because of the induced Dirac mass terms with loop suppression. Such right-handed neutrinos would be discovered at the CERN Large Hadron Collider (LHC). On the other hand, stability of the dark matter is guaranteed without introducing an additional Z_2 symmetry by a remaining global U(1) symmetry after the U(1)_{B-L} breaking. A Dirac fermion Psi_1 or a complex neutral scalar s^0_1 is the dark matter candidate in this model. Since the dark matter (Psi_1 or s^0_1) has its own B-L charge, the invisible decay of the U(1)_{B-L} gauge boson Z' is enhanced. Experimental constraints on the model are considered, and the collider phenomenology at the LHC as well as future linear colliders is discussed briefly.