NuFit-6.0: updated global analysis of three-flavor neutrino oscillations

A bstract We present an updated global analysis of neutrino oscillation data as of September 2024. The parameters θ 12 , θ 13 , Δ m₂₁² ∆ m 21 2 , and Δ m₃² ∣ ∆ m 3 ℓ 2 ∣ ( ℓ = 1 , 2) are well-determined with relative precision at 3 σ of about 13%, 8%, 15%, and 6%, respectively. The third mixing angle θ 23 still suffers from the octant ambiguity, with no clear indication of whether it is larger or smaller than 45 ° . The determination of the leptonic CP phase δ CP depends on the neutrino mass ordering: for normal ordering the global fit is consistent with CP conservation within 1 σ , whereas for inverted ordering CP-violating values of δ CP around 270 ° are favored against CP conservation at more than 3 . 6 σ . While the present data has in principle 2 . 5–3 σ sensitivity to the neutrino mass ordering, there are different tendencies in the global data that reduce the discrimination power: T2K and NOvA appearance data individually favor normal ordering, but they are more consistent with each other for inverted ordering. Conversely, the joint determination of Δ m₃² ∣ ∆ m 3 ℓ 2 ∣ from global disappearance data prefers normal ordering. Altogether, the global fit including long-baseline, reactor and IceCube atmospheric data results into an almost equally good fit for both orderings. Only when the χ 2 table for atmospheric neutrino data from Super-Kamiokande is added to our χ 2 , the global fit prefers normal ordering with ∆ χ 2 = 6 . 1. We provide also updated ranges and correlations for the effective parameters sensitive to the absolute neutrino mass from β -decay, neutrinoless double-beta decay, and cosmology.