Verifiable type-II seesaw and dark matter in a gauged $U(1)_{B-L}$ model

TL;DR

This paper introduces a gauged $U(1)_{B-L}$ extension of the standard model that explains neutrino masses via a type-II seesaw mechanism and provides a dark matter candidate, with testable collider signatures and consistency with observed dark matter abundance.

Contribution

It proposes a novel $U(1)_{B-L}$ model with a type-II seesaw mechanism involving TeV-scale scalar triplets and a unique anomaly cancellation scheme, also identifying a dark matter candidate.

Findings

Scalar triplet at TeV scale with large dilepton coupling

Right-handed neutrino as a viable dark matter candidate

Model consistent with observed dark matter abundance and detection constraints

Abstract

We propose a gauged $U(1)_{B-L}$ extension of the standard model (SM) to explain simultaneously the light neutrino masses and dark matter (DM). The generation of neutrino masses occurs through a variant of type-II seesaw mechanism in which one of the scalar triplets lies at the TeV scale yet have a large dilepton coupling, which paves a path for probing this model at colliders. The gauging of $U(1)_{B-L}$ symmetry in a type-II seesaw framework introduces $B-L$ anomalies. Therefore we invoke three right handed neutrinos $\nu_{R_{i}}$(i=1,2,3) with $B-L$ charges -4,-4,+5 to cancel the anomalies. We further show that the lightest one among the three right handed neutrinos can be a viable DM candidate. The stability of DM can be owed to a remnant $Z_2$ symmetry under which the right handed neutrinos are odd while all other particles are even. We then discuss the constraints on the model parameters from observed DM abundance and the search at direct detection experiments.