Measurement of the neutrino component of an anti-neutrino beam observed by a non-magnetized detector

TL;DR

This paper presents two independent methods to measure the neutrino contamination in an anti-neutrino beam using the MiniBooNE detector, revealing that the predicted neutrino flux is overestimated and demonstrating techniques for future non-magnetized detectors.

Contribution

The paper introduces two novel analysis techniques to accurately measure neutrino contamination in anti-neutrino beams with non-magnetized detectors.

Findings

Predicted neutrino flux is overestimated by about 24-35%.

The spectral shape of the neutrino flux is well modeled.

Techniques demonstrated are applicable to future non-magnetized detectors.

Abstract

Two independent methods are employed to measure the neutrino flux of the anti-neutrino-mode beam observed by the MiniBooNE detector. The first method compares data to simulated event rates in a high purity $\numu$ induced charged-current single $\pip$ (CC1$\pip$) sample while the second exploits the difference between the angular distributions of muons created in $\numu$ and $\numub$ charged-current quasi-elastic (CCQE) interactions. The results from both analyses indicate the prediction of the neutrino flux component of the pre-dominately anti-neutrino beam is over-estimated - the CC1$\pip$ analysis indicates the predicted $\numu$ flux should be scaled by $0.76 \pm 0.11$, while the CCQE angular fit yields $0.65 \pm 0.23$. The energy spectrum of the flux prediction is checked by repeating the analyses in bins of reconstructed neutrino energy, and the results show that the spectral shape is well modeled. These analyses are a demonstration of techniques for measuring the neutrino contamination of anti-neutrino beams observed by future non-magnetized detectors.