Constraints on energy scales from dark matter decay in a gauged $B-L$ model

TL;DR

This paper explores how dark matter decay constraints in a gauged B-L model can limit the energy scales of new physics, especially when a light scalar decays into dark radiation affecting cosmological observations.

Contribution

It introduces a method to constrain energy scales of B-L models using dark matter decay limits and illustrates this with a specific gauged B-L scenario involving light neutrinos.

Findings

Limits on dark matter decay rate constrain new physics energy scales.

Light neutrinos as dark radiation impact cosmological observables.

Method applied to a gauged B-L model with implications for neutrino physics.

Abstract

Popular extensions of the standard model of particle physics feature new fields and symmetries which could, for example, dynamically generate neutrino masses from $B-L$ spontaneous symmetry breaking. If a new light scalar that decays into dark radiation appears in the spectrum of the theory, it could significantly modify the cosmological observables. In this case, cold dark matter could have a stable and a decaying component and limits on its decay rate $\Gamma_{\rm dcdm}$ can be used to put constraints on the new energy scales of a given model. We illustrate this idea using a gauged $B-L$ model where the dark radiation is in the form of light neutrinos.