Neutrinos from Stellar Collapse: Effects of flavour mixing

Abstract

We study the effect of non-vanishing masses and mixings among neutrino flavours on the detection of neutrinos from stellar collapse by a water Cerenkov detector. We consider a realistic framework in which there are three neutrino flavours whose mass squared differences and mixings are constrained by the present understanding of solar and atmospheric neutrinos. We also include the effects of high dense matter within the supernova core. We find that the number of events due to the dominant process involving electron-antineutrinos may change dramatically for some allowed mixing parameters. Furthermore, contributions from charged-current scattering off oxygen atoms in the detector can be considerably enhanced due to flavour mixing; such events have a distinct experimental signature since they are backward-peaked. Hence, mixing has a non-trivial effect on the signature of neutrinos (and antineutrinos) from stellar collapse.