Search for Sterile Neutrinos Mixing with Muon Neutrinos in MINOS

TL;DR

This study searches for sterile neutrinos mixing with muon neutrinos using MINOS data, constraining mixing parameters and setting new limits, but finds no evidence of such oscillations.

Contribution

It provides the first constraints on sterile neutrino mixing parameters over long baselines using MINOS data, improving existing limits.

Findings

No evidence for muon neutrino to sterile neutrino oscillations.

Set world-leading limits on mixing angle θ24 for Δm²41 ≤ 1 eV².

Constrained elements of the neutrino mixing matrix under specific assumptions.

Abstract

We report results of a search for oscillations involving a light sterile neutrino over distances of 1.04 and $735\,\mathrm{km}$ in a $\nu_{\mu}$-dominated beam with a peak energy of $3\,\mathrm{GeV}$. The data, from an exposure of $10.56\times 10^{20}\,\textrm{protons on target}$, are analyzed using a phenomenological model with one sterile neutrino. We constrain the mixing parameters $\theta_{24}$ and $\Delta m^{2}_{41}$ and set limits on parameters of the four-dimensional Pontecorvo-Maki-Nakagawa-Sakata matrix, $|U_{\mu 4}|^{2}$ and $|U_{\tau 4}|^{2}$, under the assumption that mixing between $\nu_{e}$ and $\nu_{s}$ is negligible ($|U_{e4}|^{2}=0$). No evidence for $\nu_{\mu} \to \nu_{s}$ transitions is found and we set a world-leading limit on $\theta_{24}$ for values of $\Delta m^{2}_{41} \lesssim 1\,\mathrm{eV}^{2}$.