Abstract
The OPERA experiment has conclusively observed the appearance of tau neutrinos in the muon neutrino CNGS beam. Exploiting the OPERA detector capabilities, it was possible to isolate high purity samples of $\nu_{e}$, $\nu_{\mu}$ and $\nu_{\tau}$ charged current weak neutrino interactions, as well as neutral current weak interactions. In this Letter, the full dataset is used for the first time to test the three-flavor neutrino oscillation model and to derive constraints on the existence of a light sterile neutrino within the framework of the $3+1$ neutrino model. For the first time, tau and electron neutrino appearance channels are jointly used to test the sterile neutrino hypothesis. A significant fraction of the sterile neutrino parameter space allowed by LSND and MiniBooNE experiments is excluded at 90% C.L. In particular, the best-fit values obtained by MiniBooNE combining neutrino and antineutrino data are excluded at 3.3 $\sigma$ significance.
Highlights
The OPERA experiment [1] was designed to conclusively observe the appearance of tau neutrino in the high purity muon neutrino CNGS beam [2,3], in the parameter region indicated by Super-Kamiokande [4] and MACRO [5] to explain the zenith dependence of the atmospheric neutrino deficit
The OPERA experiment has conclusively observed the appearance of tau neutrinos in the muon neutrino CNGS beam
the full dataset is used for the first time to test the three-flavor neutrino oscillation model
Summary
The OPERA experiment [1] was designed to conclusively observe the appearance of tau neutrino in the high purity muon neutrino CNGS beam [2,3], in the parameter region indicated by Super-Kamiokande [4] and MACRO [5] to explain the zenith dependence of the atmospheric neutrino deficit. A total of 19505 neutrino interaction events in the target were recorded by the electronic detectors, of which 5603 were fully reconstructed in the OPERA emulsion films. Five ντ candidate events [9–13] were observed, with an expected signal-tobackground ratio of ∼10 The analysis of these data lead to the exclusion of the background-only hypothesis with a significance of 5.1σ. The final samples of tau and electron neutrino CC interactions are used for the first time in a combined analysis to constrain standard oscillation parameters θ13, θ23, as well as the 3 þ 1 mixing model ones. A search for the νμ disappearance signal was performed using only electronic detector data, assuming three-flavor neutrino mixing
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