A search forν µ →ν e oscillations was conducted by the Liquid Scintillator Neutrino Detector at the Los Alamos Neutron Science Center usingν µ from µ + decay at rest. A total excess of 87.9 ± 22.4 ± 6.0 events consistent withν e p → e + n scattering was observed above the expected background. This excess corresponds to an oscillation probability of (0.264 ± 0.067 ± 0.045)%, which is consistent with an earlier analysis. In conjunction with other known limits on neutrino oscillations, the LSND data suggest that neutrino oscillations occur in the 0.2 − 10 eV 2 /c 4 ∆m 2 range, indicating a neutrino mass greater than 0.4 eV/c 2 .2

The Booster Neutrino Experiment (MiniBooNE) searches for ν µ → ν e oscillations using the O(1 GeV) neutrino beam produced by the Booster synchrotron at the Fermi National Accelerator Laboratory (FNAL). The Booster delivers protons with 8 GeV kinetic energy (8.89 GeV/c momentum) to a beryllium target, producing neutrinos from the decay of secondary particles in the beam line. We describe the Monte Carlo simulation methods used to estimate the flux of neutrinos from the beamline incident on the MiniBooNE detector for both polarities of the focusing horn. The simulation uses the Geant4 framework for propagating particles, accounting for electromagnetic processes and hadronic interactions in the beamline materials, as well as the decay of particles.The absolute double differential cross sections of pion and kaon production in the simulation have been tuned to match external measurements, as have the hadronic cross sections for nucleons and pions. The statistical precision of the flux predictions is enhanced through reweighting and resampling techniques. Systematic errors in the flux estimation have been determined by varying parameters within their uncertainties, accounting for correlations where appropriate.

No abstract

A high-statistics sample of charged-current muon neutrino scattering events collected with the MiniBooNE experiment is analyzed to extract the first measurement of the double differential cross section ( d 2 σ dTµd cos θµ ) for charged-current quasielastic (CCQE) scattering on carbon. This result features minimal model dependence and provides the most complete information on this process to date. With the assumption of CCQE scattering, the absolute cross section as a function of neutrino energy (σ[Eν]) and the single differential cross section ( dσ dQ 2 ) are extracted to facilitate comparison with previous measurements. These quantities may be used to characterize an effective axial-vector form factor of the nucleon and to improve the modeling of low-energy neutrino interactions on nuclear targets. The results are relevant for experiments searching for neutrino oscillations.

The MiniBooNE experiment at Fermilab reports results from an analysis of νe appearance data from 12.84 × 10 20 protons on target in neutrino mode, an increase of approximately a factor of two over previously reported results. A νe charged-current quasielastic event excess of 381.2 ± 85.2 events (4.5σ) is observed in the energy range 200 < E QE ν < 1250 MeV. Combining these data with theνe appearance data from 11.27 × 10 20 protons on target in antineutrino mode, a total νe plus νe charged-current quasielastic event excess of 460.5 ± 99.0 events (4.7σ) is observed. If interpreted in a two-neutrino oscillation model, νµ → νe, the best oscillation fit to the excess has a probability of 21.1%, while the background-only fit has a χ 2 probability of 6 × 10 −7 relative to the best fit. The MiniBooNE data are consistent in energy and magnitude with the excess of events reported by the Liquid Scintillator Neutrino Detector (LSND), and the significance of the combined LSND and MiniBooNE excesses is 6.0σ. A two-neutrino oscillation interpretation of the data would require at least four neutrino types and indicate physics beyond the three neutrino paradigm. Although the data are fit with a two-neutrino oscillation model, other models may provide better fits to the data.Evidence for short-baseline neutrino anomalies at an L/E ν ∼ 1 m/MeV, where E ν is the neutrino energy and L is the distance that the neutrino traveled before detection, comes from both neutrino appearance and disappearance experiments. The appearance anomalies include the excess of ν e andν e charge-current quasielastic (CCQE) events observed by the LSND [1] and MiniBooNE [2,3] experiments, while the disappearance anomalies, although not completely consistent, include the deficit of ν e andν e events observed by reactor [4] and radioactive-source experiments [5]. As the masses and mixings within the 3-generation neutrino matrix have been attached to solar and long-baseline neutrino experiments, more exotic models are typically used to explain these anomalies, including, for example, 3+N neutrino oscillation models involving three active neutrinos and N additional sterile neutrinos [6][7][8][9][10][11][12][13][14], resonant neutrino oscillations [15], Lorentz violation [16], sterile neutrino decay [17], sterile neutrino nonstandard interactions [18], and sterile neutrino extra dimensions [19]. This Letter presents improved MiniBooNE ν e andν e appearance results, assuming two-neutrino oscillations with probability arXiv:1805.12028v2 [hep-ex]