High Energy Neutrinos in Super-Kamiokande

The new analysis of Super-Kamiokande atmospheric neutrino data, based on a subsample of higher precision data is reported. The plot of the muon neutrino survival probability as a function of the ratio of the distance over neutrino energy displays a dip just where the first oscillation maximum is expected from the standard analysis. As a result the parameters of the transitions ν μ ↔ ν τ are better constrained: 1.9 × 10 −3 Δ m 2 3.0 × 10 −3 eV 2 and sin 2 2 θ > 0.90 at 90% C.L. A signal of WIMP annihilations in the Sun, the core of the Earth or the Galactic Center has been searched in a sample of upward through-going muons, produced by neutrino interactions outside of detector. No statistically significant signal has been observed. Upper limits of the muon fluxes are compared with results from other neutrino detectors. Also upper limits on cross section for the WIMP nucleon interaction are derived and compared with corresponding results from direct searches of dark matter particles.