Model independent analysis of the simultaneous mixing of gauge bosons   and mixing of fermions
  We discuss the case of simultaneous mixing of gauge bosons and mixing of fermions in a model independent way and for a variety of extra-fermion representations.   In this context we analyze a class of lepton family violating processes, namely Z --> e tau, Z --> mu tau, Z --> e mu, mu --> e e e, tau --> e e e, tau --> mu mu mu, tau --> e mu mu and tau --> mu e e in the presence of one extra neutral gauge boson, Z', with universal, non-universal or family changing couplings.   We derive bounds on the combined effect of Z-Z' mixing and ordinary--exotic lepton mixing. 
Umberto Cotti and Arnulfo Zepeda (CINVESTAV, Mexico)