A search for ν̄μ→ν̄e oscillations has been conducted at the Los Alamos Meson Physics Facility using ν̄μ from μ+ decay at rest. The ν̄e are detected via the reaction ν̄ep→e+n, correlated with the 2.2 MeV γ from np→dγ. The use of tight cuts to identify e+ events with correlated γ rays yields 22 events with e+ energy between 36 and 60 MeV and only 4.6±0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1×10-8. A χ2 fit to the entire e+ sample results in a total excess of 51.0+20.2-19.5±8.0 events with e+ energy between 20 and 60 MeV. If attributed to ν̄μ→ν̄e oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of (0.31±0.12±0.05)%.
Publication Source (Journal or Book title)
Physical Review C - Nuclear Physics
Athanassopoulos, C., Auerbach, L., Burman, R., Cohen, I., Caldwell, D., Dieterle, B., Donahue, J., Eisner, A., Fazely, A., Federspiel, F., Garvey, G., Gray, M., Gunasingha, R., Imlay, R., Johnston, K., Kim, H., Louis, W., Majkic, R., Margulies, J., McIlhany, K., Metcalf, W., Mills, G., Reeder, R., Sandberg, V., Smith, D., Stancu, I., Strossman, W., Tayloe, R., VanDalen, G., Vernon, W., Wadia, N., Waltz, J., & Wang, Y. (1996). Evidence for neutrino oscillations from muon decay at rest. Physical Review C - Nuclear Physics, 54 (5), 2685-2708. https://doi.org/10.1103/PhysRevC.54.2685