Late time supernova neutrino signal and proto-neutron star radius

We discuss the possibility of reconstructing the newly formed proto-neutron star radius from the late time neutrino signal. A black-body emission is assumed for the neutron star cooling phase. We parametrize the neutrino time-integrated fluxes based on simulations of Roberts and Reddy. A likelihood analysis of the inverse-beta decay and elastic scattering events in Hyper-Kamiokande is performed in both three flavor and an effective one flavor scenario. We show that the precision achievable in the radius reconstruction strongly depends on a correlation with the pinching parameter and therefore the corresponding prior. Although this correlation hinders the precise measurement of the newly formed neutron star radius, it could help measure the pinching parameters with good accuracy in view of the current constraints on neutron star radius, or if the neutron star radius is precisely measured.