# Observation of Electron Neutrino Appearance in a Muon Neutrino Beam

Abstract : The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3$\sigma$ when compared to 4.92 $\pm$ 0.55 expected background events. In the PMNS mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles $\theta_{12}$, $\theta_{23}$, $\theta_{13}$, a mass difference $\Delta m^2_{32}$ and a CP violating phase $\delta_{\mathrm{CP}}$. In this neutrino oscillation scenario, assuming $|\Delta m^2_{32}| = 2.4 \times 10^{-3}$ $\rm eV^2$, $\sin^2 \theta_{23} = 0.5$, $\delta_{\mathrm{CP}}=0$, and $\Delta m^2_{32} >0$ ($\Delta m^2_{32} <0$), a best-fit value of $\sin^2 2 \theta_{13}$ = $0.140^{+0.038}_{-0.032}$ ($0.170^{+0.045}_{-0.037}$) is obtained.
Document type :
Journal articles

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Submitted on : Monday, December 2, 2013 - 10:37:47 AM
Last modification on : Wednesday, December 9, 2020 - 11:58:02 AM

### Citation

K. Abe, J. Adam, H. Aihara, T. Akiri, C. Andreopoulos, et al.. Observation of Electron Neutrino Appearance in a Muon Neutrino Beam. Physical Review Letters, American Physical Society, 2014, 112, pp.061802. ⟨10.1103/PhysRevLett.112.061802⟩. ⟨in2p3-00912454⟩

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