Muon neutrino disappearance probability as a function of neutrino flight length $L$ over neutrino energy $E$ was studied. A dip in the $L/E$ distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed $L/E$ distribution constrained ${\ensuremath{\nu}}_{\ensuremath{\mu}}\ensuremath{\leftrightarrow}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ neutrino oscillation parameters; $1.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}<\ensuremath{\Delta}{m}^{2}<3.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }{\mathrm{e}\mathrm{V}}^{2}$ and ${sin }^{2}2\ensuremath{\theta}>0.90$ at 90% confidence level.
Evidence for an Oscillatory Signature in Atmospheric Neutrino Oscillations | Litlas
