Observing Supernova Neutrino Light Curves with Super-Kamiokande.VI. A Practical Data Analysis Technique Considering Realistic Experimental Backgrounds

TL;DR

This paper develops a practical data analysis method for supernova neutrino signals in Super-Kamiokande, incorporating realistic backgrounds to improve the extraction of late-phase neutrino information and model discrimination.

Contribution

It introduces a new analysis framework that accounts for realistic backgrounds in supernova neutrino detection at Super-Kamiokande, enhancing practical applicability.

Findings

Optimized analysis framework considering signal and background events.

Demonstrated ability to identify the last observed neutrino event.

Explored model discrimination using timing of the final neutrino detection.

Abstract

Neutrinos from supernovae, especially those emitted during the late phase of core collapse, are essential for understanding the final stages of massive star evolution. We have been dedicated to developing methods for the analysis of neutrinos emitted during the late phase and observed at Super-Kamiokande (SK). Our previous studies have successfully demonstrated the potential of various analysis methods in extracting essential physical properties; however, the lack of background consideration has limited their practical application. In this study, we address this issue by incorporating a realistic treatment of the experimental signal and background events with the on-going SK experiment. We therefore optimize our analysis framework to reflect realistic observational conditions, including both signal and background events. Using this framework we study several long-time supernova models, simulating the late phase neutrino observation in SK and focusing in particular on the identification of the last observed event. We discuss the possibility of model discrimination methods using timing information from this last observed event.