## Tuesday, November 22, 2011

### first tau-neutrino “appearing” out of several billion of billions muon neutrinos

 Layout of the CNGS beam line.
The OPERA neutrino experiment [1] at the underground Gran Sasso Laboratory (LNGS) was designed to perform the first detection of neutrino oscillations in direct appearance mode in the νμ→ντ channel, the signature being the identification of the τ− lepton created by its charged current (CC) interaction [2]. See: Measurement of the neutrino velocity with the OPERA detector in the CNGS beam-

 Computer reconstruction of the tau candidate event detected in the OPERA experiment. The light blue track is the one likely induced by the decay of a tau lepton produced by a tau-neutrino. See: The OPERA experiment

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