Observing Supernova Neutrino Light Curves with Super-Kamiokande. II. Impact of the Nuclear Equation of State

The late-time evolution of the neutrino event rate from supernovae is evaluated for Super-Kamiokande using simulated results of proto-neutron star (PNS) cooling. In the present work, we extend the result of Suwa et al., who studied the dependence of the neutrino event rate on the PNS mass, but focus on the impact of the nuclear equation of state (EOS). We find that the neutrino event rate depends on both the high-density and low-density EOS, where the former determines the radius of the PNS and the latter affects its surface temperature. Based on the present evaluation of the neutrino event rate, we propose a new analysis method to extract the time variability of the neutrino average energy taking into account the statistical error in the observation.

Automated summary

This study evaluates the late-time evolution of the neutrino event rate from supernovae using simulated results of proto-neutron star cooling. It extends previous research by examining the impact of the nuclear equation of state on the neutrino event rate. The study finds that both high-density and low-density EOS affect the neutrino event rate, with the former determining the radius of the proto-neutron star and the latter affecting its surface temperature. Based on the evaluation of the neutrino event rate, a new analysis method is proposed to extract the time variability of the neutrino average energy while accounting for statistical errors in observations.