Effects of neutrino temperatures and mass hierarchies on the detection of supernova neutrinos

Abstract

Possible outcomes of neutrino events at both Super-Kamiokande and SNO for a type-II supernova are analyzed considering the uncertainties in SN neutrino spectra (temperature) at emission, which may complicate the interpretation of the observed events. With the input of parameters deduced from the current solar and atmospheric experiments, consequences of direct-mass hierarchy $m_{\nu_{\tau}} \gg m_{\nu_{\mu}} > m_{\nu_{e}}$ and inverted-mass hierarchy $m_{\nu_{e}} > m_{\nu_{\mu}} \gg m_{\nu_{\tau}}$ are investigated. Even if the $\nu$ temperatures are not precisely known, we found that future experiments are likely to be able to separate the currently accepted solutions to the solar neutrino problem (SNP): large angle MSW, small angle MSW, and the vacuum oscillation, as well as to distinguish between the direct and inverted mass hierarchies of the neutrinos.