Multi-Component Dark Matter Systems and Their Observation Prospects

TL;DR

This paper explores a three-component dark matter model with non-standard interactions, showing how these processes affect relic abundance and proposing neutrino observations as a detection method.

Contribution

It introduces a three-component dark matter model extending the radiative seesaw framework, analyzing the impact of semi-annihilations on relic abundance and neutrino signals.

Findings

Relic abundance is highly sensitive to non-standard annihilation processes.

Semi-annihilations produce monochromatic neutrinos detectable by IceCube.

Parameter space is expanded compared to two-component models.

Abstract

Conversions and semi-annihilations of dark matter (DM) particles in addition to the standard DM annihilations are considered in a three-component DM system. We find that the relic abundance of DM can be very sensitive to these non-standard DM annihilation processes, which has been recently found for two-component DM systems. To consider a concrete model of a three-component DM system, we extend the radiative seesaw model of Ma by adding a Majorana fermion \chi and a real scalar boson \phi, to obtain a Z_2 \times Z'_2 DM stabilizing symmetry, where we assume that the DM particles are the inert Higgs boson, \chi and \phi. It is shown how the allowed parameter space, obtained previously in the absence of \chi and \phi, changes. The semi-annihilation process in this model produces monochromatic neutrinos. The observation rate of these monochromatic neutrinos from the Sun at IceCube is estimated. Observations of high energy monochromatic neutrinos from the Sun may indicate a multi-component DM system.