Detecting light dark matter with prompt-delayed events in neutrino experiments

Abstract We demonstrate that the prompt-delayed signals induced by knockout neutrons from quasi-elastic scattering in liquid scintillator neutrino experiments provide a new avenue for detecting light dark matter. As an illustration, we consider the detection of atmospheric dark matter, showing that the constraint on the DM-nucleon interaction from KamLAND is approximately one order of magnitude more stringent than those derived from elastic nuclear recoil signals in dark matter direct detection experiments. Furthermore, larger-volume neutrino detectors such as JUNO are expected to further enhance the sensitivity to light dark matter through quasi-elastic scattering.