Secluded scalar dark matter and the muon anomalous magnetic moment

We consider a dark matter (DM) model with a singlet scalar, χ, as our DM candidate, which is secluded from the standard model (SM) and annihilates to the singlet scalar, ϕ, via a contact interaction. The singlet scalar, ϕ, has a leptophilic interaction with the SM leptons and may decay leptonically at tree level, and decays into a pair of photons at loop level. The focus of this work is to consider DM masses below 10 GeV. A viable secluded region is found in the parameter space after imposing the observed relic density. There is a one-loop interaction between scalar DM and the atomic electron in this model. We then apply the available direct detection bounds from Xenon10, Xenon1T and DarkSide on the DM-electron elastic scattering cross section. While the model can explain the muon anomalous magnetic moment, we apply bounds from current and future lepton collider experiments.