Search for Sterile Neutrinos in MINOS and MINOS+ Using a Two-Detector Fit

A search for mixing between active neutrinos and light sterile neutrinos has been performed by looking for muon neutrino disappearance in two detectors at baselines of 1.04 and 735 km, using a combined MINOS and MINOS+ exposure of $16.36\times {10}^{20}$ protons on target. A simultaneous fit to the charged-current muon neutrino and neutral-current neutrino energy spectra in the two detectors yields no evidence for sterile neutrino mixing using a $3+1$ model. The most stringent limit to date is set on the mixing parameter ${\sin }^2{\theta }_{24}$ for most values of the sterile neutrino mass splitting $\mathrm{\Delta }{m}_{41}^2>{10}^{-4}{\mathrm{eV}}^2$.

Figure 1

The summed MINOS and MINOS+ CC reconstructed energy spectra for events selected in the FD (left) and ND (right). Data points in black are compared to both the three-flavor prediction (red line) and the four-flavor best-fit prediction $({\sin }^2{\theta }_{24}=1.1\times {10}^{-4},\mathrm{\Delta }{m}_{41}^2=2.325\times {10}^{-3}{\mathrm{eV}}^2)$ and its systematic uncertainty (blue line and shaded region). Also shown are the ratios between data and simulation.

Figure 2

The summed MINOS and MINOS+ NC reconstructed energy spectra for events selected in the FD (left) and ND (right). Data points in black are compared to both the three-flavor prediction (red line) and the four-flavor best-fit prediction $({\sin }^2{\theta }_{24}=1.1\times {10}^{-4},\mathrm{\Delta }{m}_{41}^2=2.325\times {10}^{-3}{\mathrm{eV}}^2)$ and its systematic uncertainty (blue line and shaded region). Also shown are the ratios between data and simulation.

Figure 3

The MINOS and MINOS+ 90% Feldman-Cousins exclusion limit in the $({\sin }^2{\theta }_{24},\mathrm{\Delta }{m}_{41}^2)$ plane from the data (black line) compared to the expected sensitivity (blue line, $1\sigma$ green band, and $2\sigma$ yellow band). For $\mathrm{\Delta }{m}_{41}^2>{10}^3{\mathrm{eV}}^2$, the limits continue vertically upwards.

Figure 4

The MINOS and MINOS+ 90% Feldman-Cousins exclusion limit compared to the previous MINOS result [17] and results from other experiments [20, 69, 70, 71, 72]. The Gariazzo et al. region is the result of a global fit to neutrino oscillation data [73].