Detectability of the Supernova Relic Neutrinos and Neutrino Oscillation

We investigate the flux and the event rate of the supernova relic neutrino background (SRN) at the SuperKamiokande detector for various neutrino oscillation models with parameters inferred from recent experimental results. A realistic model of neutrino emission from supernova explosions and several models of the cosmic star formation history are adopted in the calculation. The number flux over entire energy range is found to be 11−15 cms. We discuss the detection possibility of SRN, comparing this SRN flux with other background neutrinos in more detail than previous studies. The only one possible energy window free from the other backgrounds is found in 8− 12 MeV, and in that range the most optimistic event rate at SuperKamiokande is ∼ 0.3 yr. However, this energy window is narrow compared with the energy resolution, and hence contamination of other background neutrinos from different Preprint submitted to Elsevier Science 29 February 2008 energy range makes the SRN detection quite difficult in practice.