Searching for Diffused Supernova Neutrino Background at Super-Kamiokande
This event is part of the HEE Seminar Series.
Supernova relic neutrinos, also called the diffused supernova neutrino backgrounds (DSNB), are emitted from core-collapse supernovae throughout the universe, providing a unique probe into the stellar evolution and supernova burst mechanism in the absence of supernova bursts in our galaxy for decades. Super-Kamiokande-IV (SK-IV) searches for these neutrinos by tagging inverse beta interactions with neutron captures on hydrogen using a special triggering. Backgrounds to this search include accidental coincidence events, cosmic-ray muon induced spallation, and atmospheric neutrino CC and NC (dominated by NC quasi-elastic). The use of vertex reconstruction of the 2.2 MeV photon emitted by the neutron captures and a multivariate analysis significantly enhanced the separation of signal and background. The upgrade project SK-Gd, which takes place in April this year, is expected to boost the efficiency of IBD neutron detection by loading Gd. In this seminar, we will talk about the latest status of DSNB search at SK and the prospect for SK-Gd.