# Nonmaximal $\theta_{23}$ mixing at NOvA from neutrino decoherence

## TL;DR

The NOvA experiment's muon neutrino disappearance results suggest a deviation from maximal mixing, which can be explained by neutrino decoherence, indicating potential environmental effects on neutrino oscillations.

## Contribution

This paper proposes that neutrino decoherence explains the apparent nonmaximal mixing observed at NOvA, reconciling it with T2K measurements.

## Key findings

- NOvA observes a 2.6σ deviation from maximal mixing.
- Decoherence strength is measured as Γ = (2.3 ± 1.1) × 10^{-23} GeV.
- Decoherence accounts for the discrepancy with T2K results.

## Abstract

In study of muon neutrino disappearance at 810 km, the NOvA experiment finds flavor mixing of the atmospheric sector to deviate from maximal ($\sin^2\theta_{23} = 0.5$) by 2.6 $\sigma$. The result is in tension with the 295-km baseline measurements of T2K which are consistent with maximal mixing. We propose that $\theta_{23}$ is in fact maximal, and that the disagreement is harbinger of environmentally-induced decoherence. The departure from maximal mixing can be accounted for by an energy-independent decoherence of strength $\Gamma = (2.3 \pm 1.1) \times 10^{-23}$ GeV.