Three flavor neutrino oscillation analysis of atmospheric neutrinos in Super-Kamiokande

Abstract

We report on the results of a three-flavor oscillation analysis using Super-Kamiokande I atmospheric neutrino data, with the assumption of one mass scale dominance (Delta m(12)(2)=0). No significant flux change due to matter effect, which occurs when neutrinos propagate inside the Earth for theta(13)not equal 0, has been seen either in a multi-GeV nu(e)-rich sample or in a nu(mu)-rich sample. Both normal and inverted mass hierarchy hypotheses are tested and both are consistent with observation. Using Super-Kamiokande data only, 2-dimensional 90% confidence allowed regions are obtained: mixing angles are constrained to sin(2)theta(13)< 0.14 and 0.37 < sin(2)theta(23)< 0.65 for the normal mass hierarchy. Weaker constraints, sin(2)theta(13)< 0.27 and 0.37 < sin(2)theta(23)< 0.69, are obtained for the inverted mass hierarchy case.