First Measurement of the Muon Anti-Neutrino Double-Differential Charged Current Quasi-Elastic Cross Section

The largest sample ever recorded of $\text{numub}$ charged-current quasi-elastic (CCQE, $\text{numub}+p\to \text{mup}+n$) candidate events is used to produce the minimally model-dependent, flux-integrated double-differential cross section $\frac{d^2\sigma }{d{T}_{\mu }d\text{uz}}$ for $\text{numub}$ incident on mineral oil. This measurement exploits the unprecedented statistics of the MiniBooNE anti-neutrino mode sample and provides the most complete information of this process to date. Also given to facilitate historical comparisons are the flux-unfolded total cross section $\sigma (E_{\nu })$ and single-differential cross section $\frac{d\sigma }{d\text{qsq}}$ on both mineral oil and on carbon by subtracting the $\text{numub}$ CCQE events on hydrogen. The observed cross section is somewhat higher than the predicted cross section from a model assuming independently-acting nucleons in carbon with canonical form factor values. The shape of the data are also discrepant with this model. These results have implications for intra-nuclear processes and can help constrain signal and background processes for future neutrino oscillation measurements.