Search for Differences in Oscillation Parameters for Atmospheric Neutrinos and Antineutrinos at Super-Kamiokande

Abstract

We present a search for differences in the oscillations of antineutrinos and neutrinos in the Super-Kamiokande-I, -II, and -III atmospheric neutrino sample. Under a two-flavor disappearance model with separate mixing parameters between neutrinos and antineutrinos, we find no evidence for a difference in oscillation parameters. Best-fit antineutrino mixing is found to be at $(\ensuremath{\Delta}{\overline{m}}^{2},{\mathrm{sin}}^{2}2\overline{\ensuremath{\theta}})=\phantom{\rule{0ex}{0ex}}(2.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }{\mathrm{eV}}^{2},1.0)$ and is consistent with the overall Super-K measurement.