Lepton charge and neutrino mixing in pion decay processes
  We consider neutrino mixing and oscillations in quantum field theory and compute the neutrino lepton charge in decay processes where neutrinos are generated. We also discuss the proper definition of flavor charge and states and clarify the issues of the possibility of different mass parameters in field mixing. 
Massimo Blasone, Antonio Capolupo, Francesco Terranova and Giuseppe   Vitiello