Nested Radiative Seesaw Masses for Dark Matter and Neutrinos

TL;DR

This paper introduces a modified scotogenic model where neutrino masses and dark matter are generated via one-loop processes, with the dark matter candidate being a viable freeze-in particle produced through Higgs decay.

Contribution

It proposes a novel modification to the scotogenic model that generates the dark Majorana fermion in one loop and demonstrates its viability as a freeze-in dark matter candidate.

Findings

$S$ is a viable freeze-in dark matter candidate.

Neutrino masses are generated via one-loop processes.

The model incorporates a softly broken $Z_6$ lepton symmetry.

Abstract

The scotogenic model of neutrino mass is modified so that the dark Majorana fermion singlet $S$ which makes the neutrino massive is itself generated in one loop. This is accomplished by having $Z_6$ lepton symmetry softly broken to $Z_2$ in the scalar sector by a unique quadratic term. It is shown that $S$ is a viable freeze-in dark-matter candidate through Higgs decay.