Minimal 3-3-1 model, lepton mixing and muonium-antimuonium conversion
  The recent experimental results on neutrino oscillation and on muonium-antimuonium conversion require extension of the minimal 3-3-1 model. We review the constraints imposed to the model by those measurements and suggest a pattern of leptonic mixing, with charged leptons in a non-diagonal basis, which accounts for the neutrino physics and circumvents the tight muonium-antimuonium bounds on the model. We also illustrate a scenario where this pattern could be realized. 
A. Gusso, C.A. de S. Pires and P.S. Rodrigues da Silva