Maximal CP Violation Hypothesis and a Lepton Mixing Matrix
  Maximal CP violation hypothesis is applied to a simple lepton mixing matrix form U=V_{CKM}^\dagger U_{TB}, which has recently been speculated under an ansatz that U becomes an exact tribimaximal mixing U_{TB} in a limit of the quark mixing matrix V_{CKM} \to {\bf 1}. The prediction \tan^2 \theta_{12} =1/2 in the case of the exact tribimaximal mixing U=U_{TB} is onsiderably spoiled in the speculated mixing U=V_{CKM}^\dagger U_{TB}. However, the application of the hypothesis to the lepton sector can again recover the spoiled value to \tan^2 \theta_{12} \simeq 1/2 if the original Kobayashi-Maskawa phase convention for V_{CKM} is adopted. 
Yoshio Koide and Hiroyuki Nishiura