Observation of muon neutrino disappearance with the MINOS detectors and the NuMI neutrino beam

TL;DR

This paper reports the observation of muon neutrino disappearance using the MINOS detectors and the NuMI neutrino beam, providing evidence for neutrino oscillations and measuring key oscillation parameters.

Contribution

First measurement of muon neutrino disappearance with the MINOS detectors and NuMI beam, confirming neutrino oscillation parameters with initial data.

Findings

Observed fewer muon neutrino events at the far detector than expected without oscillations.

Measured oscillation parameters: | m^2_{23}|  2.74^{+0.44}_{-0.26} imes 10^{-3} eV^2/c^4.

Established a lower limit on   0.87 for sin^2(2 heta_{23}) at 60% confidence level.

Abstract

This letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rate and energy spectra of charged current muon neutrino interactions are compared in two detectors located along the beam axis at distances of 1 km and 735 km. With 1.27 x 10^{20} 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336 \pm 14.4 events. The data are consistent with muon neutrino disappearance via oscillation with |\Delta m^2_{23}| = 2.74^{+0.44}_{-0.26} x 10^{-3} eV^2/c^4 and sin^2(2\theta_{23}) > 0.87 (at 60% C.L.).