Discovery of tau Neutrino Appearance in the CNGS Neutrino Beam with the OPERA Experiment

Agafonova N., Aleksandrov A., Anokhina A., Aoki S., Ariga A., Ariga T., ...More

PHYSICAL REVIEW LETTERS, vol.115, no.12, 2015 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 115 Issue: 12
  • Publication Date: 2015
  • Doi Number: 10.1103/physrevlett.115.121802
  • Journal Indexes: Science Citation Index Expanded, Scopus


The OPERA experiment was designed to search for nu(mu) -> nu(tau) oscillations in appearance mode, i.e., by detecting the tau leptons produced in charged current nu(tau) interactions. The experiment took data from 2008 to 2012 in the CERN Neutrinos to Gran Sasso beam. The observation of the nu(mu) -> nu(tau) appearance, achieved with four candidate events in a subsample of the data, was previously reported. In this Letter, a fifth nu(tau) candidate event, found in an enlarged data sample, is described. Together with a further reduction of the expected background, the candidate events detected so far allow us to assess the discovery of nu(mu) -> nu(tau) oscillations in appearance mode with a significance larger than 5 sigma.