Multicomponent Dark Matter in Radiative Seesaw Model and Monochromatic Neutrino Flux

TL;DR

This paper explores a two-loop radiative seesaw model with multiple dark matter particles stabilized by a $Z_2 imes Z'_2$ symmetry, highlighting semi-annihilation processes that produce observable monochromatic neutrino fluxes from the Sun.

Contribution

It introduces a novel multi-component dark matter model with semi-annihilation processes that generate detectable neutrino signals, extending the inert scalar model of Ma.

Findings

Semi-annihilation significantly affects dark matter relic densities.

Monochromatic neutrino lines can originate from dark matter annihilation.

Potential observability of neutrino fluxes from the Sun.

Abstract

We consider a two loop radiative seesaw model with an exact $Z_2 \times Z'_2$ symmetry, which can stabilize two or three dark matter particles. The model is a simple extension of the inert scalar model of Ma, where the lepton-number violating mass term of the inert scalar, which is required to be small for small neutrino masses, is generated at the one-loop level. The semi-annihilation processes of different dark matter particles, which are present when there exist more than three different dark matter particles, not only play an important role for their relic densities, but also are responsible for the monochromatic neutrino lines resulting from the dark matter annihilation processes. The monochromatic neutrinos do not suffer from a chiral suppression, and we investigate the observational possibility of the monochromatic neutrino flux from the Sun.