Neutrino mixing and CP violation from Dirac-Majorana mixing

الأصل · EN

We consider a minimal condition that predicts the 1-3 lepton mixing angle θ₁₃ ≃ θ C/√2 with θ C the Cabibbo angle, and give the improved prediction of θ₁₃. In the case of normal mass ordering, the theoretical value of θ₁₃ is predicted as θ₁₃=8.6∘, which is in good agreement with the current global best fit. In the case of inverted mass ordering, the theoretical value is predicted as θ₁₃=9.7∘, which is far from the current global best fit. We also study the leptonic CP violation. We show that any values of the leptonic Dirac CP phase δ CP can be obtained by fine tuning. Without fine tuning, |δ CP| should be very small, typically of O(λ²) where λ≡ θ C. Furthermore, a model-independent measure of CP violation is proposed, which is applicable to any flavor models.