Neutrino texture-zeros after JUNO's first results: Implications for long baseline neutrino experiments

TL;DR

This paper tests Majorana neutrino texture-zeros against JUNO's first results by working in a diagonal charged-lepton basis and leveraging NuFit-6.0 and JUNO constraints to assess one-zero and two-zero textures. It finds that JUNO does not modify the viability of one-zero textures but excludes one previously allowed two-zero texture (notably $B_1$ with NH), with cosmological and $0\nu\beta\beta$ bounds tightening the landscape further. The authors then study the prospects for probing the remaining textures with the upcoming DUNE experiment using a detailed $\chi^2$ framework that includes JUNO priors and reactor inputs, showing DUNE can substantially discriminate among textures by constraining correlated parameters like $\sin^2\theta_{23}$ and $\delta_{CP}$. These results inform model-building and UV completions of neutrino masses by narrowing the viable texture-zero scenarios and guiding future experimental tests in long-baseline neutrino oscillations.

Abstract

The recent results from the JUNO reactor neutrino experiment have significantly improved our knowledge of the solar mixing angle $θ_{12}$ and the solar mass splitting $Δm^2_{21}$. We study the impact of these improved estimates on the validity of texture-zeros in the light neutrino mass matrix by assuming neutrinos to be of Majorana nature. Considering a diagonal charged lepton basis, we revisit the previously allowed one-zero and two-zero textures and check their validity by using updated neutrino data from JUNO. While JUNO data rule out one previously allowed two-zero texture, they also make predictions for other neutrino parameters more precise. We finally study the prospects of probing the currently allowed texture-zeros and their predicted correlations among neutrino parameters at future long baseline neutrino experiments like the DUNE. The inclusion of JUNO and reactor experiments strengthens DUNE's ability to constrain the allowed parameter space of both one-zero and two-zero textures.

Figures (24)

• Figure 1: Correlations among neutrino parameters for a few one-zero textures, also showing the impact of JUNO 2025 data over the NuFit-6.0 (2024) data.
• Figure 2: Correlations among neutrino parameters for a few two-zero textures, also showing the impact of JUNO 2025 data over the NuFit-6.0 (2024) data.
• Figure 3: The $3\sigma$ allowed regions in the $\sin^{2}\theta_{23}$--$\delta_{\rm CP}$ plane for $G_1-G_4, G_6$ (NH) one-zero textures. Cyan shaded areas indicate model predictions, while blue contours show the NuFit 6.0 global-fit constraints. The impact of external information is illustrated by including the JUNO prior on $\sin^{2}\theta_{12}$ (green) and combined priors on $\sin^{2}\theta_{12}$ and $\sin^{2}\theta_{13}$ (purple).
• Figure 4: The $3\sigma$ allowed regions in the $\sin^{2}\theta_{23}$--$\delta_{\rm CP}$ plane for $G_2-G_6$ (IH) one-zero textures. Cyan shaded areas indicate model predictions, while blue contours show the NuFit 6.0 global-fit constraints. The impact of external information is illustrated by including the JUNO prior on $\sin^{2}\theta_{12}$ (green) and combined priors on $\sin^{2}\theta_{12}$ and $\sin^{2}\theta_{13}$ (purple).
• Figure 5: $3\sigma$ allowed regions in the $\sin^{2}\theta_{23}$--$\delta_{\rm CP}$ plane for $A_1$ (NH) and $B_2-B_4$ (NH) textures. Cyan shaded areas indicate model predictions, while blue contours show the NuFit 6.0 global-fit constraints. The impact of external information is illustrated by including the JUNO prior on $\sin^{2}\theta_{12}$ (green) and combined priors on $\sin^{2}\theta_{12}$ and $\sin^{2}\theta_{13}$ (purple).