Measurement of the neutrino mass splitting and flavor mixing by MINOS

TL;DR

This paper reports precise measurements of neutrino mass differences and mixing angles using MINOS data, confirming neutrino oscillations and excluding alternative hypotheses like decay and decoherence.

Contribution

It presents new analysis methods applied to an enlarged data set, providing improved measurements of neutrino oscillation parameters and strong evidence against decay and decoherence models.

Findings

Measured |Δm^2| = (2.32^{+0.12}_{-0.08})×10^{-3} eV^2

Sine squared of twice the mixing angle > 0.90 at 90% CL

Decay and decoherence hypotheses are excluded at 7 and 9 sigma

Abstract

Measurements of neutrino oscillations using the disappearance of muon neutrinos from the Fermilab NuMI neutrino beam as observed by the two MINOS detectors are reported. New analysis methods have been applied to an enlarged data sample from an exposure of $7.25 \times 10^{20}$ protons on target. A fit to neutrino oscillations yields values of $|\Delta m^2| = (2.32^{+0.12}_{-0.08})\times10^{-3}$\,eV$^2$ for the atmospheric mass splitting and $\rm \sin^2\!(2\theta) > 0.90$ (90%\,C.L.) for the mixing angle. Pure neutrino decay and quantum decoherence hypotheses are excluded at 7 and 9 standard deviations, respectively.