A new realisation of light thermal self-interacting dark matter and detection prospects

TL;DR

This paper proposes a minimal model for GeV-scale self-interacting dark matter that achieves the correct thermal relic density by linking it to neutrino mass generation, offering new detection prospects across astrophysics, cosmology, and laboratory experiments.

Contribution

It introduces a novel minimal realization of light self-interacting dark matter connected to neutrino mass origin, resolving relic density issues and enhancing detection prospects.

Findings

Achieves correct thermal relic density for GeV-scale SIDM

Links dark matter properties to neutrino mass generation

Suggests multiple detection avenues in experiments and observations

Abstract

Light dark matter (DM) in the GeV ballpark faces weaker constraint from direct detection experiments. If such DM also has sufficient self-interactions due to a light mediator, it can alleviate the small-scale problems of the cold dark matter (CDM) paradigm while being consistent with the latter at large scales, as suggested by astrophysical observations. However, generating correct thermal relic for such light DM is challenging. While GeV scale CDM typically leads to thermal overproduction due to the absence of sufficient annihilation channels, self-interacting dark matter (SIDM) typically has under-abundant thermal relic due to its large annihilation rates into mediator particles. In this letter, we propose a minimal realisation of GeV scale SIDM with correct thermal relic, where one of the three singlet fermions, responsible for seesaw origin of light neutrino masses, assists in generating correct SIDM relic density via freeze-out. The setup thereby encompasses astrophysical as well as cosmological aspects of light DM while simultaneously providing a solution to the origin of light neutrino mass. Due to such connection to several frontiers, there exist exciting discovery prospects in terms of direct and indirect search of DM, laboratory and cosmology based dark photon signatures and effective light neutrino mass.