Lepton Mass Hierarchy and Neutrino Mixing

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We speculate that the mass spectrum of three neutrinos might have a normal hierarchy as that of three charged leptons or that of three up-type (or down-type) quarks. In this spirit, we propose a novel parametrization of the 3× 3 lepton flavor mixing matrix. Its mixing angles θₗ and θν can be related to the mass ratios mₑ/mμ and m₁/m₂ in a specific texture of lepton mass matrices with vanishing (1,1) elements: θₗ = √mₑ/mμ and θν= √m₁/m₂. The latter relation, together with solar and atmospheric neutrino oscillation data, predicts 0.0030 eV m₁ 0.0073 eV, 0.009 eV m₂ 0.012 eV and 0.042 eV m₃ 0.058 eV. The smallest neutrino mixing angle is found to be θ₁₃ ≈ θₗ/√2 ≈ 3∘, which is experimentally accessible in the near future.