We report a search for cosmic-ray boosted dark matter with protons using the
0.37 megaton×years data collected at Super-Kamiokande experiment during
the 1996-2018 period (SKI-IV phase). We searched for an excess of proton
recoils above the atmospheric neutrino background from the vicinity of the
Galactic Center. No such excess is observed, and limits are calculated for two
reference models of dark matter with either a constant interaction
cross-section or through a scalar mediator. This is the first experimental
search for boosted dark matter with hadrons using directional information. The
results present the most stringent limits on cosmic-ray boosted dark matter and
exclude the dark matter-nucleon elastic scattering cross-section between
10−33 cm−2 and 10−27 cm−2 for dark matter mass
from 10 MeV/c2 to 1 GeV/c2.Comment: With 1-page appendi