Searching for GeV-scale Majorana Dark Matter: inter spem et metum

TL;DR

This paper proposes a minimal GeV-scale Majorana dark matter model interacting with leptons via a charged scalar, highlighting its detectable cross-section below current bounds and potential collider signatures.

Contribution

It introduces a simple model linking Majorana dark matter to leptons and explores its experimental and collider phenomenology.

Findings

DM-nucleus cross-section is below current bounds but above neutrino floor.

Model can be tested at high-energy lepton colliders via mono-Higgs and charged Higgs pair production.

Anti-correlation between relic density and scattering cross-section.

Abstract

We suggest a minimal model for GeV-scale Majorana Dark Matter (DM) coupled to the standard model lepton sector via a charged scalar singlet. We show that there is an anti-correlation between the spin-independent DM-Nucleus scattering cross-section ($\sigma_{\mathrm{SI}}$) and the DM relic density for parameters values allowed by various theoretical and experimental constraints. Moreover, we find that even when DM couplings are of order unity, $\sigma_{\mathrm{SI}}$ is below the current experimental bound but above the neutrino floor. Furthermore, we show that the considered model can be probed at high-energy lepton colliders using e.g. the mono-Higgs production and same-sign charged Higgs pair production.