Relating the neutrino mixing angles to a lepton mass hierarchy

We propose two phenomenological scenarios of lepton mass matrices and show that either of them can exactly give rise to tan^2theta_{13} = m_e/(m_e + 2m_mu), tan^2theta_{23} = m_mu/(m_e + m_mu) and tan^2theta_{12} = (m_e m_2 + 2m_mu m_1)/(m_e m_1 + 2m_mu m_2) in the standard parametrization of lepton flavor mixing. The third relation, together with current experimental data, predicts a normal but weak hierarchy for the neutrino mass spectrum. We also obtain theta_{13} approx 2.8^circ for the smallest neutrino mixing angle and J approx 1.1% for the Jarlskog invariant of leptonic CP violation, which will soon be tested in the long-baseline reactor and accelerator neutrino oscillation experiments. A seesaw realization of both scenarios is briefly discussed.