We report a search for an anomalous excess of inclusive charged-current (CC) νe interactions using the Wire-Cell event reconstruction package in the MicroBooNE experiment, motivated by the previous observation of a low-energy excess (LEE) of electromagnetic events from the MiniBooNE experiment. With a single liquid argon time projection chamber detector, the measurements of νμ CC interactions as well as π0 interactions are used to constrain signal and background predictions of νe CC interactions. A data set collected from February 2016 to July 2018 corresponding to an exposure of 6.369 × 1020 protons on target from the Booster Neutrino Beam at FNAL is analyzed. With x representing an overall normalization factor and is referred to as the LEE strength parameter, we select 56 fully contained νe CC candidates while expecting 69.6 ± 8.0 (stat.) ± 5.0 (sys.) and 103.8 ± 9.0 (stat.) ± 7.4 (sys.) candidates after constraints, for the absence (eLEEx=0) and presence (eLEEx=1) respectively of the median signal prediction derived from the MiniBooNE observation. Under a nested hypothesis test using both rate and shape information in all available channels, the best-fit x is determined to be 0 (eLEEx=0) with 95.5% confidence level upper limits of x at 0.502. Under a simple-vs-simple hypotheses test, the eLEEx=1 hypothesis is rejected at 3.75σ, while the eLEEx=0 hypothesis is shown to be consistent with the observation at 0.45σ. In the context of the eLEE model, the estimated 68.3% confidence interval of the νe CC hypothesis to explain the LEE observed in the MiniBooNE experiment is disfavored at a significance level more than 2.6σ (3.0σ) considering their full (statistical) uncertainties.
A link to the paper submitted to Phys. Rev. D is posted on the archive at arXiv:2110.13978.
A link to the accompanying supplementary materials is available here.