Reconstruction of the Neutrino Mixing Matrix and Leptonic Unitarity   Triangles from Long-baseline Neutrino Oscillations
  We derive a new set of sum rules between the neutrino mass and mixing parameters in vacuum and their effective counterparts in matter. The moduli of nine genuine lepton mixing matrix elements can then be calculated in terms of the matter-corrected ones, and the latter can directly be determined from a variety of long-baseline neutrino oscillations. We show that it is possible to reconstruct the leptonic unitarity triangles and CP violation in a similar parametrization-independent way. 
Zhi-zhong Xing, He Zhang