Collider signatures of sterile neutrinos in models with a gauge-singlet Higgs

TL;DR

This paper investigates collider signatures of sterile neutrinos in a model where they gain mass through coupling with a singlet Higgs, leading to potential observable signals and cosmological implications.

Contribution

It introduces a simple extension of the Standard Model with a singlet Higgs that gives mass to sterile neutrinos, exploring collider signals and cosmological effects.

Findings

Heavy sterile neutrinos can be produced from Higgs decays in accelerators.

Decay of sterile neutrinos produces distinct collider signals.

Relic abundance of keV sterile neutrinos can originate from singlet Higgs decay.

Abstract

Sterile neutrinos have been invoked to explain the observed neutrino masses, but they can also have significant implications for cosmology and accelerator experiments. We explore the collider signatures of a simple extension of the Standard Model, where sterile neutrinos acquire their mass after electroweak symmetry breaking, via their coupling to a real singlet Higgs. In this model, heavy sterile neutrinos can be produced in accelerators from decays of the Higgs bosons. Their own decay can yield distinct signals, suggesting both the presence of an extended Higgs sector and the coupling of the singlet fermions to the latter. In the same scenario, a relic matter abundance arises from the decay of the singlet Higgs into weakly coupled keV sterile neutrinos. The coupling of the Higgs doublet to particles outside the Standard Model relaxes the current experimental bounds on its mass.