2024/09/09 by Choi, Koun, Park, Jong-Chul · 1 citation
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2409.05646
Large-volume neutrino experiments are ideal for testing boosted dark matter (BDM) scenarios. We propose, for the first time, an approach to utilize knockout neutrons by detecting de-excitation γ rays and coincident captured neutrons from dark-matter interactions with bound neutrons in oxygen, while previous studies have focused on knockout-protons and electrons. This method is especially crucial for water Čerenkov detectors, where high proton Čerenkov threshold (∼1 GeV) suppresses signal acceptance. Recently, Super-Kamiokande (SK) was doped with 0.03% gadolinium (SK-Gd) to enhance neutron tagging efficiency. Using SK-Gd as a target experiment, we demonstrate that this method increases sensitivity to BDM models by an order of magnitude compared to 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.