Sub-GeV Dark Matter Under Pressure from Direct Detection

Abstract: The DAMIC-M collaboration recently reported impressive bounds on sub-GeV dark matter, robustly testing both thermal and non-thermal models for the very first time. In this work we derive novel bounds from the recent PandaX-4T ionization S2-only search for Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS). We find that the PandaX-4T S2-only data is able to compete with the DAMIC-M results, providing the best constraints for scalar and asymmetric thermal dark matter models for masses between 20 to 200 MeV. We further discuss the implications of recent direct detection results for several other sub-GeV dark matter models, highlighting their complementarity with astrophysical, cosmological and laboratory probes.