arXiv2025
We perform an updated global analysis of the known and unknown parameters of the standard $3ν$ framework as of 2025. The known oscillation parameters include three mixing angles $(θ_{12},\,θ_{23},\,θ_{13})$ and two squared mass gaps, chosen as $δm^2=m^2_2-m^2_1>0$ and $Δm^2=m^2_3-{\textstyle\frac{1}{2}}(m^2_1+m^2_2)$, where $α=\mathrm{sign}(Δm^2)$ distinguishes normal ordering (NO, $α=+1$) from inverted ordering (IO, $α=-1$). With respect to our previous 2021 update, the combination of oscillation data leads to appreciably reduced uncertainties for $θ_{23}$, $θ_{13}$ and $|Δm^2|$. In particular, $|Δm^2|$ is the first $3ν$ parameter to enter the domain of subpercent precision (0.8\% at $1σ$). We underline some issues about systematics, that might affect this error estimate. Concerning oscillation unknowns, we find a relatively weak preference for NO versus IO (at $2.2σ$), for CP violation versus conservation in NO (1.3$σ$) and for the first $θ_{23}$ octant versus the second in NO ($1.1σ$). We discuss the status and qualitative prospects of the mass ordering hint in the plane $(δm^2,\,Δm^2_{ee})$, where $Δm^2_{ee}=|Δm^2|+{\textstyle\frac{1}{2}}α(\cos^2θ_{12}-\sin^2θ_{12})δm^2$, to be measured by the JUNO experiment with subpercent precision. We also discuss upper bounds on nonoscillation observables. We report $m_β<0.50$~eV and $m_{ββ}<0.086$~eV ($2σ$). Concerning the sum of neutrino masses $Σ$, we discuss representative combinations of data, with or without augmenting the $Λ$CDM model with extra parameters accounting for possible systematics or new physics. The resulting $2σ$ upper limits are roughly spread around the bound $Σ< 0.2$~eV within a factor of three. [Abridged]