Dark Matter and Vector-like Leptons From Gauged Lepton Number

TL;DR

This paper explores a model where gauged lepton number leads to a stable dark matter candidate and vector-like leptons, analyzing its phenomenology, detection prospects, and effects on Higgs decays.

Contribution

It introduces a simple gauged lepton number model that naturally includes a viable dark matter candidate and exotic leptons, with detailed phenomenological analysis.

Findings

Dark matter is a Dirac neutrino singlet stabilized by an accidental symmetry.

The model predicts detectable signals in direct and indirect detection experiments.

Exotic leptons influence Higgs decay channels and could be observed at the LHC.

Abstract

We investigate a simple model where Lepton number is promoted to a local $U(1)_L$ gauge symmetry which is then spontaneously broken, leading to a viable thermal DM candidate and vector-like leptons as a byproduct. The dark matter arises as part of the exotic lepton sector required by the need to satisfy anomaly cancellation and is a Dirac electroweak (mostly) singlet neutrino. It is stabilized by an accidental global symmetry of the renormalizable Lagrangian which is preserved even after the gauged lepton number is spontaneously broken and can annihilate efficiently to give the correct thermal relic abundance. We examine the ability of this model to give a viable DM candidate and discuss both direct and indirect detection implications. We also examine some of the LHC phenomenology of the associated exotic lepton sector and in particular its effects on Higgs decays.