Observation of νμ → ντ oscillations in the CNGS beam with the OPERA experiment
University of Bari & I.N.F.N. Bari, I-70126 Bari, Italy
a e-mail: Marilisa.Deserio@ba.infn.it
Published online: 29 May 2015
The OPERA long-baseline neutrino experiment was exposed to the CNGS νμ beam from 2008 to 2012, collecting 19505 interactions in the target. The evidence for oscillated ντ appearance, based on the observation of three ντ candidate events, has been previously reported. A fourth candidate event has been recently found in an extended data sample, corresponding to about 89% of the final statistics. The absence of a signal from νμ → ντ oscillations is currently excluded at 4.2σ. The status of the analysis is described in detail with special emphasis on the procedures applied for the selection of signal candidate events and the assessment of efficiencies and background. The fourth ντ candidate event is presented and the significance of the observation is discussed.
© Owned by the authors, published by EDP Sciences, 2015
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