Observation of electron neutrino appearance in a muon neutrino beam

Abe, K. and Adam, J. and Aihara, H. and Akiri, T. and Andreopoulos, C. and Aoki, S. and Ariga, A. and Ariga, T. and Assylbekov, S. and Autiero, D. and Barbi, M. and Barker, G. J. and Barr, G. and Bass, M. and Batkiewicz, M. and Bay, F. and Bentham, S. W. and Berardi, V. and Berger, B. E. and Berkman, S. and Bertram, I. and Bhadra, S. and Blaszczyk, F. D. M. and Blondel, A. and Bojechko, C. and Bordoni, S. and Boyd, S. B. and Brailsford, Dominic and Bravar, A. and Bronner, C. and Buchanan, N. and Calland, R. G. and Caravaca Rodriguez, J. and Cartwright, S. L. and Castillo, R. and Catanesi, M. G. and Cervera, A. and Cherdack, D. and Christodoulou, G. and Clifton, A. and Coleman, J. and Dealtry, Thomas and Finch, A. J. and Grant, N. and Kormos, L. L. and Lamont, I. and O'Keeffe, H. M. and Ratoff, P. N. and Reeves, M. and Southwell, L. (2014) Observation of electron neutrino appearance in a muon neutrino beam. Physical review letters, 112 (6): 061802. ISSN 0031-9007

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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 +/- 0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles theta(12), theta(23), theta(13), a mass difference vertical bar Delta m(32)(2)vertical bar and a CP violating phase delta(CP). In this neutrino oscillation scenario, assuming vertical bar Delta m(32)(2)vertical bar = 2.4 x 10(-3) eV(2), sin theta(2)(23) = 0.5, and vertical bar Delta m(32)(2)vertical bar > 0 (vertical bar Delta m(32)(2)vertical bar <0), a best- fit value of sin2 theta(2)(13) = 0.140(- 0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at delta(CP) = 0. When combining the result with the current best knowledge of oscillation parameters including the world average value of theta(13) from reactor experiments, some values of delta(CP) are disfavored at the 90% C. L.

Item Type:
Journal Article
Journal or Publication Title:
Physical review letters
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© 2014 American Physical Society
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?? physics and astronomy(all) ??
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Deposited On:
16 Oct 2014 08:33
Last Modified:
24 Feb 2024 00:45