Gauge Model of Generation Nonuniversality Reexamined
  A gauge model of generation nonuniversality proposed in 1981 is reexamined in the light of present precision electroweak measurements. Two necessary features of this model are that the tau lifetime should be longer than predicted by the standard model and that the rho parameter measured at the Z peak should have an additional negative contribution. Both trends are noticeable in present data. A future decisive test of this model would be the discovery of new W and Z bosons with nearly degenerate masses of a few TeV. 
Xiaoyuan Li and Ernest Ma