# Neutrino Lines from Majoron Dark Matter

## TL;DR

This paper explores singlet majoron as a dark matter candidate, analyzing its neutrino flux signatures, flavor ratios, and constraints from decay channels, with implications for neutrino mass hierarchy and lepton flavor violation.

## Contribution

It provides a new parametrization for majoron couplings to charged fermions and discusses observable neutrino signals and flavor effects in the context of dark matter.

## Key findings

- Potential detection of monochromatic neutrino fluxes above MeV
- Flavor ratios depend strongly on neutrino mass hierarchy
- Majoron decay channels constrain model parameters

## Abstract

Models with spontaneously broken global lepton number can lead to a pseudo-Goldstone boson as a long-lived dark matter candidate. Here we revisit the case of singlet majoron dark matter and discuss multiple constraints. For masses above MeV, this model could lead to a detectable flux of monochromatic mass-eigenstate neutrinos, which have flavor ratios that depend strongly on the neutrino mass hierarchy. We provide a convenient parametrization for the loop-induced majoron couplings to charged fermions that allows us to discuss three-generation effects such as lepton flavor violation. These couplings are independent of the low-energy neutrino parameters but can be constrained by the majoron decays into charged fermions.