Removing Ambiguities in the Neutrino Mass Matrix
  We suggest that the weak-basis independent condition det(M_nu)=0 for the effective neutrino mass matrix can be used in order to remove the ambiguities in the reconstruction of the neutrino mass matrix from input data available from present and future feasible experiments. In this framework, we study the full reconstruction of M_nu with special emphasis on the correlation between the Majorana CP-violating phase and the various mixing angles. The impact of the recent KamLAND results on the effective neutrino mass parameter is also briefly discussed. 
G.C. Branco, R. Gonzalez Felipe, F. R. Joaquim, T. Yanagida