# Fermion Dark Matter and Radiative Neutrino Masses from Spontaneous Lepton Number Breaking

## TL;DR

This paper explores a fermion dark matter candidate within a radiative neutrino mass model, showing it can account for observed dark matter abundance and remain consistent with direct detection constraints.

## Contribution

It introduces a scenario where fermion dark matter and radiative neutrino masses are connected through spontaneous lepton number breaking, with viable mass regions below 1 TeV.

## Key findings

- Three dark matter mass regions below 1 TeV match observed abundance.
- Predicted spin-independent cross-sections are below current XENON1T limits.
- Model links dark matter properties with neutrino mass generation mechanisms.

## Abstract

In this paper, we study the viability of having a fermion Dark Matter particle below the TeV mass scale in connection to the neutrino mass generation mechanism. The simplest realization is achieved within the scotogenic model where neutrino masses are generated at the 1-loop level. Hence, we consider the case where the dark matter particle is the lightest $\mathbb{Z}_2$-odd Majorana fermion running in the neutrino mass loop. We assume that lepton number is broken dynamically due to a lepton number carrier scalar singlet which acquires a non-zero vacuum expectation value. In the present scenario the Dark Matter particles can annihilate via $t$- and $s$-channels. The latter arises from the mixing between the new scalar singlet and the Higgs doublet. We identify three different Dark Matter mass regions below 1 TeV that can account for the right amount of dark matter abundance in agreement with current experimental constraints. We compute the Dark Matter-nucleon spin-independent scattering cross-section and find that the model predicts spin-independent cross-sections ``naturally'' dwelling below the current limit on direct detection searches of Dark Matter particles reported by XENON1T.