The MiniBooNE experiment at Fermilab reports results from an analysis of ν¯e appearance data from 11.27×10²⁰ protons on target in the antineutrino mode, an increase of approximately a factor of 2 over the previously reported results. An event excess of 78.4±28.5 events (2.8σ) is observed in the energy range 200QEν<1250 MeV. If interpreted in a two-neutrino oscillation model, ν¯μ→ν¯e, the best oscillation fit to the excess has a probability of 66% while the background-only fit has a χ² probability of 0.5% relative to the best fit. The data are consistent with antineutrino oscillations in the 0.01<Δm²<1.0 eV² range and have some overlap with the evidence for antineutrino oscillations from the Liquid Scintillator Neutrino Detector. All of the major backgrounds are constrained by in situ event measurements so nonoscillation explanations would need to invoke new anomalous background processes. The neutrino mode running also shows an excess at low energy of 162.0±47.8 events (3.4σ) but the energy distribution of the excess is marginally compatible with a simple two neutrino oscillation formalism. Expanded models with several sterile neutrinos can reduce the incompatibility by allowing for CP violating effects between neutrino and antineutrino oscillations.
Aguilar-Arevalo, A. A., et al. "Improved Search for ν̄<sub>μ</sub>→ν̄<sub>e</sub> Oscillations in the MiniBooNE Experiment." Physical Review Letters, vol. 110, no. 16, Apr. 2013. https://doi.org/10.1103/PhysRevLett.110.161801
Aguilar-Arevalo, A. A., Brown, B. C., Bugel, L., Cheng, G., Church, E. D., Conrad, J. M., Dharmapalan, R., Djurcic, Z., Finley, D. A., Ford, R., Garcia, F. G., Garvey, G. T., Grange, J., Huelsnitz, W., Ignarra, C., Imlay, R., Johnson, R. A., Karagiorgi, G., ... Zimmerman, E. D. (2013). Improved Search for ν̄<sub>μ</sub>→ν̄<sub>e</sub> Oscillations in the MiniBooNE Experiment. Physical Review Letters, 110(16). https://doi.org/10.1103/PhysRevLett.110.161801
Aguilar-Arevalo, A. A., Brown, B. C., Bugel, L., et al., "Improved Search for ν̄<sub>μ</sub>→ν̄<sub>e</sub> Oscillations in the MiniBooNE Experiment," Physical Review Letters 110, no. 16 (2013), https://doi.org/10.1103/PhysRevLett.110.161801
@article{osti_1102076,
author = {Aguilar-Arevalo, A. A. and Brown, B. C. and Bugel, L. and Cheng, G. and Church, E. D. and Conrad, J. M. and Dharmapalan, R. and Djurcic, Z. and Finley, D. A. and Ford, R. and others},
title = {Improved Search for ν̄<sub>μ</sub>→ν̄<sub>e</sub> Oscillations in the MiniBooNE Experiment},
annote = {The MiniBooNE experiment at Fermilab reports results from an analysis of ν¯e appearance data from 11.27×10²⁰ protons on target in the antineutrino mode, an increase of approximately a factor of 2 over the previously reported results. An event excess of 78.4±28.5 events (2.8σ) is observed in the energy range 200QEνμ→ν¯e, the best oscillation fit to the excess has a probability of 66% while the background-only fit has a χ² probability of 0.5% relative to the best fit. The data are consistent with antineutrino oscillations in the 0.01<Δm²<1.0 eV² range and have some overlap with the evidence for antineutrino oscillations from the Liquid Scintillator Neutrino Detector. All of the major backgrounds are constrained by in situ event measurements so nonoscillation explanations would need to invoke new anomalous background processes. The neutrino mode running also shows an excess at low energy of 162.0±47.8 events (3.4σ) but the energy distribution of the excess is marginally compatible with a simple two neutrino oscillation formalism. Expanded models with several sterile neutrinos can reduce the incompatibility by allowing for CP violating effects between neutrino and antineutrino oscillations.},
doi = {10.1103/PhysRevLett.110.161801},
url = {https://www.osti.gov/biblio/1102076},
journal = {Physical Review Letters},
issn = {ISSN PRLTAO},
number = {16},
volume = {110},
place = {United States},
publisher = {American Physical Society},
year = {2013},
month = {04}}
Aguilar-Arevalo, A. A.; Anderson, C. E.; Bartoszek, L. M.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 599, Issue 1https://doi.org/10.1016/j.nima.2008.10.028
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 608, Issue 1https://doi.org/10.1016/j.nima.2009.06.064