Speaker
Description
The Diffuse Supernova Neutrino Background (DSNB) is the flux of neutrinos and antineutrinos emitted by all past core-collapse supernovae throughout cosmic history. Its detection would provide a unique probe of the inner dynamics of core-collapse and the resulting supernova neutrino emission.
We present the latest results of the DSNB search at Super-Kamiokande (SK), based on a spectral fit of data from SK-I through SK-VIII experimental phases. The dataset corresponds to a total exposure of 7790 kton-days (22.5-kton fiducial volume), including approximately 1000 additional live days beyond the previous search and 1600 days with enhanced neutron tagging following gadolinium loading.
Key improvements over previous searches include enhanced rejection of atmospheric neutral-current backgrounds using machine learning techniques, updated evaluations of systematic uncertainties, and refined spectral fitting methods designed to lower the analysis energy threshold. These advances improve the sensitivity of the DSNB search and strengthen Super-Kamiokande's discovery potential.