Indirect detection of boosted light scalar dark matter

Abstract: We explore the possibilities of detecting MeV-scale boosted dark matter (DM) via astrophysical observations. Given a particular model framework, using gamma-ray data from \texttt{COMPTEL} and \texttt{EGRET}, as well as neutrino constraints from the \texttt{Super-Kamiokande}, \texttt{Hyper-Kamiokande}, \texttt{JUNO}, diffuse supernova neutrino background (\texttt{DSNB}), and atmospheric neutrino observations, we find that boosted light scalar DM could be probed within the mass range of $\sim 20!-!80$ MeV, satisfying the Planck observed relic abundance. Our study shows, indirect search can play a key role in the detection of MeV-scale boosted DM, which are otherwise beyond the reach of usual collider or DM scattering experiments.