A Measurement of Atmospheric Neutrino Flux Consistent with Tau Neutrino Appearance

TL;DR

This paper reports a measurement of atmospheric tau neutrino appearance using Super-Kamiokande data, providing evidence consistent with neutrino oscillations and tau neutrino production.

Contribution

First measurement of tau neutrino appearance in atmospheric neutrinos using extensive data, supporting neutrino oscillation models.

Findings

Tau neutrino appearance signal of 138 ± 48 events.

No tau neutrino appearance hypothesis disfavored at 2.4 sigma.

Results align with expectations from neutrino oscillation theory.

Abstract

A search for the appearance of tau neutrinos from \mutau 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 $\pm$ 48 (stat.) $^{+15}_{-32}$ (sys.) events is obtained with an expectation of 78 $\pm$ 26 (sys.). The hypothesis of no tau neutrino appearance is disfavored by 2.4 sigma.