Evidence for an oscillatory signature in atmospheric neutrino oscillations

Abstract

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 nu(mu)<---->nu(tau) neutrino oscillation parameters; 1.9x10(-3)<Deltam(2)<3.0x10(-3) eV(2) and sin(2)2theta>0.90 at 90% confidence level.