A Model of Neutrino Mass Matrix With δ= -π/2 and θ₂₃ = π/4

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Experimental data have provided stringent constraints on neutrino mixing parameters. In the standard parameterization the mixing angle θ₂₃ is close to π/4. There are also evidences show that the CP violating phase is close to -π/2. We study neutrino mass matrix reconstructed using this information and find several interesting properties. We show that a theoretical model based on the A₄ symmetry naturally predicts δ= -π/2 and θ₂₃ = π/4 when the Yukawa couplings and scalar vacuum expectation values are real reaching a μ-τ exchange and CP conjugate symmetry limit. In this case CP violation solely comes from the complex group theoretical Clebsh-Gordan coefficients. The model also predicts |Vₑ₂|=1/√3 consistent with data. With complex Yukawa couplings the values for δ and θ₂₃ can be significantly deviate away from the symmetry values -π/2 and π/4, respectively. But |Vₑ₂|= 1/√3 is not altered. This matrix is an excellent lowest order approximation for theoretical model buildings of neutrino mass matrix.