The MiniBooNE experiment at Fermilab reports results from an analysis of ${\nu }_e$ appearance data from $12.84\times {10}^{20}$ protons on target in neutrino mode, an increase of approximately a factor of 2 over previously reported results. A ${\nu }_e$ charged-current quasielastic event excess of $381.2\pm 85.2$ events ($4.5\sigma$) is observed in the energy range $200<E_{\nu }^{\mathrm{QE}}<1250\mathrm{MeV}$. Combining these data with the ${\overline{\nu }}_e$ appearance data from $11.27\times {10}^{20}$ protons on target in antineutrino mode, a total ${\nu }_e$ plus ${\overline{\nu }}_e$ charged-current quasielastic event excess of $460.5\pm 99.0$ events ($4.7\sigma$) is observed. If interpreted in a two-neutrino oscillation model, ${\nu }_{\mu }\to {\nu }_e$, the best oscillation fit to the excess has a probability of 21.1%, while the background-only fit has a ${\chi }^2$ probability of $6\times {10}^{-7}$ 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 $6.0\sigma$. 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.

The MiniBooNE experiment at Fermilab reports results from an analysis of ${\overline{\nu }}_e$ appearance data from $11.27\times {10}^{20}$ protons on target in the antineutrino mode, an increase of approximately a factor of 2 over the previously reported results. An event excess of $78.4\pm 28.5$ events ($2.8\sigma$) is observed in the energy range $200<E_{\nu }^{\mathrm{QE}}<1250\mathrm{MeV}$. If interpreted in a two-neutrino oscillation model, ${\overline{\nu }}_{\mu }\to {\overline{\nu }}_e$, the best oscillation fit to the excess has a probability of 66% while the background-only fit has a ${\chi }^2$ probability of 0.5% relative to the best fit. The data are consistent with antineutrino oscillations in the $0.01<\Delta m^2<1.0{\mathrm{eV}}^2$ 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 $162.0\pm 47.8$ events ($3.4\sigma$) 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.

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 ($\frac{d^2\sigma }{d{T}_{\mu }d\cos {\theta }_{\mu }}$) 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 ($\sigma [E_{\nu }]$) and the single differential cross section ($\frac{d\sigma }{d{Q}^2}$) 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 a search for ${\overline{\nu }}_{\mu }\to {\overline{\nu }}_e$ oscillations, using a data sample corresponding to $5.66\times {10}^{20}$ protons on target. An excess of $20.9\pm 14.0$ events is observed in the energy range $475<E_{\nu }^{\mathrm{QE}}<1250\mathrm{MeV}$, which, when constrained by the observed ${\overline{\nu }}_{\mu }$ events, has a probability for consistency with the background-only hypothesis of 0.5%. On the other hand, fitting for ${\overline{\nu }}_{\mu }\to {\overline{\nu }}_e$ oscillations, the best-fit point has a ${\chi }^2$ probability of 8.7%. The data are consistent with ${\overline{\nu }}_{\mu }\to {\overline{\nu }}_e$ oscillations in the 0.1 to $1.0{\mathrm{eV}}^2$ $\Delta m^2$ range and with the evidence for antineutrino oscillations from the Liquid Scintillator Neutrino Detector at Los Alamos National Laboratory.

The MiniBooNE Collaboration reports first results of a search for ${\nu }_e$ appearance in a ${\nu }_{\mu }$ beam. With two largely independent analyses, we observe no significant excess of events above the background for reconstructed neutrino energies above 475 MeV. The data are consistent with no oscillations within a two-neutrino appearance-only oscillation model.