Observation of nu_tau appearance in the CNGS beam with the OPERA experiment

Understand

The OPERA experiment is searching for nu_mu -> nu_tau oscillations in appearance mode i.e.

• via the direct detection of tau leptons in nu_tau charged current interactions.
• The evidence of nu_mu -> nu_tau appearance has been previously reported with three nu_tau candidate events using a sub-sample of data from the 2008-2012 runs.
• We report here a fourth nu_tau candidate event, with the tau decaying into a hadron, found after adding the 2012 run events without any muon in the final state to the data sample.