Minimal realization of light thermal Dark Matter

TL;DR

This paper introduces a minimal UV-complete model for light thermal Dark Matter that interacts via a two-Higgs-doublet mediator, linking DM relic abundance, muon g-2 anomaly, and neutrino oscillations, and is testable with upcoming experiments.

Contribution

It presents a novel minimal model connecting light thermal DM, muon g-2, and neutrino oscillations within a testable framework involving a two-Higgs-doublet and Zee model.

Findings

DM mass predicted close to lepton masses

Framework naturally addresses muon g-2 anomaly

Model is testable at future colliders and gamma-ray telescopes

Abstract

We propose a minimal UV-complete model for kinematically forbidden Dark Matter (DM) leading to a sub-GeV thermal relic. Our crucial realization is that the two-Higgs-doublet model can provide a light mediator through which the DM can annihilate into SM leptons, avoiding indirect detection constraints. The DM mass is predicted to be very close to the mass of the leptons, which can potentially be identified from DM annihilation into gamma-rays. Due to sizable couplings to muons in reproducing the DM relic abundance, this framework naturally favors a resolution to the $(g-2)_\mu$ anomaly. Furthermore, by embedding this setup to the Zee model, we show that the phenomenon of neutrino oscillations is inherently connected to the observed relic abundance of DM. All new physics involved in our framework lies at or below the electroweak scale, making it testable at upcoming colliders, beam-dump experiments, and future sub-GeV gamma-ray telescopes.