Signal for supernova $ν_μ$ and $ν_τ$ neutrinos in water Čerenkov detectors

Abstract

We suggest that photons with energies between 5 and 10 MeV, generated by the ($ν,ν'pγ$) and ($ν,ν'nγ$) reactions on $^{16}$O, constitute a signal which allows a unique identification of supernova $ν_μ$ and $ν_τ$ neutrinos in water Čerenkov detectors. We calculate the yield of such $γ$ events and estimate that a few hundred of them would be detected in Superkamiokande for a supernova at 10 kpc distance.