Seesaw Enhancement of Bi-large Mixing in Two-Zero Textures
  The seesaw enhancement of the bi-large mixings are discussed for the two-zero textures of the neutrino mass matrix. There are no large mixings in both Dirac neutrino mass matrix $m_D$ and right-handed Majorana neutrino mass matrix $M_R$, however, the bi-large mixing is realized via the seesaw mechanism. We present twelve sets of $m_D$ and $M_R$ for the seesaw enhancement and discuss the related phenomena, the $\mu\to e+\gamma$ process and the leptogenesis. The decay rate of $\mu\to e+\gamma$ is enough suppressed due to zeros in the Dirac neutrino mass matrix. Six $m_D$ lead to the lepton asymmetry, which can explain the baryon number in the universe. Other six $m_D$ are the real matrices, which give no CP asymmetry. Modified Dirac neutrino mass matrices are also discussed. 
Mizue Honda, Satoru Kaneko and Morimitsu Tanimoto (Niigata)