A Combined $ν_μ\to ν_e$ and $\barν_μ\to \barν_e$ Oscillation Analysis of the MiniBooNE Excesses

The MiniBooNE experiment at Fermilab reports results from an analysis of the combined $ν_e$ and $\bar ν_e$ appearance data from $6.46 \times 10^{20}$ protons on target in neutrino mode and $11.27 \times 10^{20}$ protons on target in antineutrino mode. A total excess of $240.3 \pm 34.5 \pm 52.6$ events ($3.8 σ$) is observed from combining the two data sets in the energy range $200<E_ν^{QE}<1250$ MeV. In a combined fit for CP-conserving $ν_μ\rightarrow ν_e$ and $\barν_μ\rightarrow\barν_e$ oscillations via a two-neutrino model, the background-only fit has a $χ^2$-probability of 0.03% relative to the best oscillation fit. The data are consistent with neutrino oscillations in the $0.01 < Δm^2 < 1.0$ eV$^2$ range and with the evidence for antineutrino oscillations from the Liquid Scintillator Neutrino Detector (LSND).