Speakers
Description
We propose a novel approach to utilize knockout neutrons from dark-matter interaction with a nucleus in neutrino experiments, while previous studies have focused on recoiling protons. This method is especially crucial for water Cerenkov detectors, where high proton Cerenkov threshold (~1 GeV) suppresses signal acceptance. The knockout neutrons produce gamma rays when captured by medium, which are detectable in coincidence with prompt gamma rays from oxygen de-excitation and secondary interactions of neutrons. Recently, Super-Kamiokande (SK) was doped with gadolinium (SK-Gd) to enhance neutron detection efficiency. Using SK-Gd as a target experiment, we demonstrate that this method increases sensitivity to boosted-dark-matter models by an order of magnitude compared to free proton-based analysis, and it allows exploration of a wider range of light dark-matter models previously inaccessible with proton-based analysis. We also present the projected sensitivity for the upcoming Hyper-Kamiokande detector.
