Speaker
Description
Light dark matter (LDM) below the WIMP scale has attracted growing interest, as it can be produced by comparatively low-energy accelerator beams through portal mediators such as the dark photon. A sensitivity study for the Deep Underground Neutrino Experiment (DUNE) near detector demonstrated that an off-axis "PRISM" configuration can effectively separate a dark matter signal from the neutrino background. In this work, we evaluate the LDM sensitivity of the Intermediate Water Cherenkov Detector (IWCD), a movable near detector under construction for the J-PARC. We simulate dark photon production from neutral-meson decays and proton bremsstrahlung, analyze the expected signal and neutrino background, and perform a profile-likelihood analysis with a realistic detector response at multiple off-axis positions. Our results indicate that IWCD can achieve a sensitivity comparable with that of DUNE-PRISM, with improved reach in certain dark photon mass regions.