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Event Excess in the MiniBooNE Search for ν ¯ μ → ν ¯ e Oscillations

2010; American Physical Society; Volume: 105; Issue: 18 Linguagem: Inglês

10.1103/physrevlett.105.181801

1092-0145

A. A. Aguilar-Arevalo, Carl E. Anderson, S. J. Brice, Bruce Brown, L. Bugel, J. M. Conrad, R. Dharmapalan, Z. Djurčić, B. T. Fleming, R. Ford, F. G. Garcia, G. T. Garvey, J. Mirabal, Joseph Grange, J. A. Green, R. Imlay, R. A. Johnson, G. Karagiorgi, T. Katori, T. Kobilarcik, Sara K. Lindén, W. C. Louis, K. B. M. Mahn, W. Marsh, C. Mauger, W. Metcalf, G.B. Mills, C. D. Moore, J. Mousseau, R. Nelson, V. Nguyen, P. Nienaber, J. Nowak, B. Osmanov, Ž. Pavlović, D. Perevalov, C. C. Polly, H. Ray, B.P. Roe, A. D. Russell, R. Schirato, M. H. Shaevitz, M. Sorel, J. Spitz, I. Stancu, R. Stefanski, R. Tayloe, M. Tzanov, R. G. Van de Water, M. O. Wascko, D. H. White, M. J. Wilking, Geralyn P. Zeller, E. D. Zimmerman,

Quantum Chromodynamics and Particle Interactions

The MiniBooNE experiment at Fermilab reports results from a search for ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ oscillations, using a data sample corresponding to $5.66\ifmmode\times\else\texttimes\fi{}{10}^{20}$ protons on target. An excess of $20.9\ifmmode\pm\else\textpm\fi{}14.0$ events is observed in the energy range $475<{E}_{\ensuremath{\nu}}^{\mathrm{QE}}<1250\text{ }\text{ }\mathrm{MeV}$, which, when constrained by the observed ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ events, has a probability for consistency with the background-only hypothesis of 0.5%. On the other hand, fitting for ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ oscillations, the best-fit point has a ${\ensuremath{\chi}}^{2}$ probability of 8.7%. The data are consistent with ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ oscillations in the 0.1 to $1.0\text{ }\text{ }{\mathrm{eV}}^{2}$ $\ensuremath{\Delta}{m}^{2}$ range and with the evidence for antineutrino oscillations from the Liquid Scintillator Neutrino Detector at Los Alamos National Laboratory.