First Measurement of $\nu_\mu$ and $\nu_e$ Events in an Off-Axis Horn-Focused Neutrino Beam

TL;DR

This paper reports the first detection of off-axis neutrino interactions from the NuMI beamline at Fermilab using the MiniBooNE detector, confirming flux predictions and beam modeling accuracy.

Contribution

It provides the first measurement of off-axis $ u_$ and $ u_e$ interactions from the NuMI beam, validating flux models and beam composition predictions.

Findings

Observed neutrino interactions agree with expectations.

Validated the pion and kaon contribution to the neutrino flux.

Confirmed the accuracy of the off-axis beam modeling.

Abstract

We report the first observation of off-axis neutrino interactions in the MiniBooNE detector from the NuMI beamline at Fermilab. The MiniBooNE detector is located 745 m from the NuMI production target, at 110 mrad angle ($6.3^{\circ}$) with respect to the NuMI beam axis. Samples of charged current quasi-elastic $\nu_{\mu}$ and $\nu_e$ interactions are analyzed and found to be in agreement with expectation. This provides a direct verification of the expected pion and kaon contributions to the neutrino flux and validates the modeling of the NuMI off-axis beam.