# Evidence of electron neutrino appearance in a muon neutrino beam

Abe, K, Abgrall, N, Aihara, H, Akiri, T, Albert, JB, Andreopoulos, C ORCID: 0000-0003-2020-8215, Aoki, S, Ariga, A, Ariga, T, Assylbekov, S
et al (show 348 more authors) (2013) Evidence of electron neutrino appearance in a muon neutrino beam. PHYSICAL REVIEW D, 88 (3).

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## Abstract

The T2K collaboration: reports evidence for electron neutrino appearance at the atmospheric mass splitting, |\Delta m_{32}^2|=2.4x10^{-3} eV^2. An excess of electron neutrino interactions over background is observed from a muon neutrino beam with a peak energy of 0.6 GeV at the Super-Kamiokande (SK) detector 295 km from the beam's origin. Signal and background predictions are constrained by data from near detectors located 280 m from the neutrino production target. We observe 11 electron neutrino candidate events at the SK detector when a background of 3.3\pm0.4(syst.) events is expected. The background-only hypothesis is rejected with a p-value of 0.0009 (3.1\sigma), and a fit assuming \nu_{\mu}->\nu_e oscillations with sin^2(2\theta_{23})=1, \delta_{CP}=0 and |\Delta m_{32}^2|=2.4x10^{-3} eV^2 yields sin^2(2\theta_{13})=0.088^{+0.049}_{-0.039}(stat.+syst.).

Item Type: Article 43 pages, 41 figures hep-ex, hep-ex Symplectic Admin 06 Apr 2016 16:14 16 Dec 2022 16:05 10.1103/PhysRevD.88.032002 https://livrepository.liverpool.ac.uk/id/eprint/3000047