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

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 (${\sigma }_{\mathrm{S}\mathrm{I}}$) 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, ${\sigma }_{\mathrm{S}\mathrm{I}}$ 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.