Revisiting the A4 model for leptons in light of NuFIT 3.2

We revisit the |A₄| model for leptons in light of the new result of NuFIT 3.2. We introduce a new flavon |η| transforming as an |A₄| singlet |$1'$| or |$1''$|⁠, which couples to both charged leptons and neutrinos in next-to-leading-order operators. The model consists of five parameters: the lightest neutrino mass |m₁|⁠, the vacuum expectation value of |η|⁠, and three CP-violating phases after inputting the experimental values of |Δ mₐₜₘ²| and |Δ mₛₒₗ²|⁠. The model with the |$1''$| singlet flavon gives the prediction of |sin² θ₁₂| around the best fit of NuFIT 3.2 while staying near the maximal mixing of |θ₂₃|⁠. Inputting the experimental mixing angles with the |1\,σ| error-bar, the Dirac CP-violating phase is clearly predicted to be ||δCP|=50|–|120^∘|⁠, which will be tested by the precise observed value in the future. In order to get the best-fit value |sin²θ₂₃=0.538|⁠, the sum of three neutrino masses is predicted to be larger than |$90$|meV. The cosmological observation for the sum of the neutrino masses will also provide a crucial test of our predictions. It is remarked that the model is consistent with the experimental data only for the normal hierarchy of neutrino masses.