A Possible Relation between the Neutrino Mass Matrix and the Neutrino   Mapping Matrix
  we explore the consequences of assuming a simple 3-parameter form, first without T-violation, for the neutrino mass matrix M in the basis $\nu_e, \nu_\mu, \nu_\tau$ with a new symmetry. This matrix determines the three neutrino masses m_1, m_2, m_3, as well as the mapping matrix U that diagonalizes M. Since U, without T-violation, yields three measurable parameters $s_{12}, s_{23}, s_{13}$, our form expresses six measurable quantities in terms of three parameters, with results in agreement with the experimental data. More precise measurements can give stringent tests of the model as well as determining the values of its three parameters. An extension incorporating T-violation is also discussed. 
R. Friedberg and T. D. Lee