Pulse Shape Discrimination in JSNS^2

JSNS^2 (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source)is an experiment that is searching for sterile neutrinos via the observation ofν̅_μ→ν̅_e appearance oscillations usingneutrinos with muon decay-at-rest. For this search, rejectingcosmic-ray-induced neutron events by Pulse Shape Discrimination (PSD) isessential because the JSNS^2 detector is located above ground, on the thirdfloor of the building. We have achieved 95% rejection of neutron eventswhile keeping 90% of signal, electron-like events using a data drivenlikelihood method.