Results from the OPERA experiment

Abstract

The OPERA neutrino experiment was designed to perform a unique vτ appearance measurement in the vμ CNGS beam to confirm the oscillation mechanism in the atmospheric sector vμ → vτ. The detection of vτ leptons produced in vτ CC interactions and of their decays is accomplished exploiting the high spatial resolution of nuclear emulsions. Five vτ candidate events have been detected in the full data sample from 2008-2012 CNGS runs, with an expected background of 0.25 events. The background only hypothesis is rejected with a significance larger than 5 σ. The analysis of the tau neutrino sample in the framework of the 3+1 neutrino model is also presented. Furthermore OPERA good capabilities in detecting electron neutrino interactions allow setting limits on the vμ → ve oscillation channel.