Light Dark Matter: Models and Constraints

TL;DR

This paper evaluates the detection prospects for light dark matter below 1 MeV across various models, considering existing constraints, and identifies three scenarios with potentially detectable interactions.

Contribution

It introduces a comprehensive analysis of simplified models of sub-GeV dark matter, highlighting three scenarios with promising direct detection signals.

Findings

Three viable detection scenarios identified

Constraints significantly limit detection prospects for some models

Certain mediator masses allow for accessible cross sections

Abstract

We study the direct detection prospects for a representative set of simplified models of sub-GeV dark matter (DM), accounting for existing terrestrial, astrophysical and cosmological constraints. We focus on dark matter lighter than an MeV, where these constraints are most stringent, and find three scenarios with accessible direct detection cross sections: (i) DM interacting via an ultralight kinetically mixed dark photon, (ii) a DM sub-component interacting with nucleons or electrons through a light scalar or vector mediator, and (iii) DM coupled with nucleons via a mediator heavier than ~ 100 keV.