Measurement of Atmospheric Neutrino Flux Consistent with Tau Neutrino Appearance

摘要

A search for the appearance of tau neutrinos from v_μ reversible v_τ oscillations in the atmospheric neutrinos has been performed using 1489.2 days of atmospheric neutrino data from the Super-Kamiokande-I experiment. A best fit tau neutrino appearance signal of 138 ± 48(stat)_(-32)~(+15)(syst) events is obtained with an expectation of 78 ± 26(syst). The hypothesis of no tau neutrino appearance is disfavored by 2.4 sigma.