CP violation in neutrino oscillations and L/E flatness of the e-like   event ratio at Super-Kamiokande
  We show that if the presently observed L/E-flatness of the electron-like event ratio in the Super-Kamiokande atmospheric neutrino data is confirmed then the indicated ratio must be {\em unity}. Further, it is found that once CP is violated the exact L/E flatness implies: (a) The CP-violating phase, in the standard parameterization, is narrowed down to two possibilities pm pi/2, and (b) The mixing between the second and the third generations must be maximal. With these results at hand, we argue that a dedicated study of the L/E-flatness of the electron-like event ratio by Super-Kamiokande can serve as an initial investigatory probe of CP violation in the neutrino sector. The assumptions under which these results hold are explicitly stated. 
D. V. Ahluwalia, Y. Liu, I. Stancu