A model of strong flavor dynamics for the top quark

We discuss a model in which the third generation fermions undergo a different SU(2) weak interaction from the first two generation fermions. In general, a flavor changing neutral current interaction is expected at tree level. Constrained by the precision low energy data, the mass (MZ′ = MW′) of the heavy gauge bosons is bounded from below to be about 1.1 TeV for αs = 0.125 and about 1.3 TeV for αs = 0.115, at the 3σ level. This model favors a larger Rb and a smaller Rc as compared with the Standard Model, but it does not explain the Rc data. If one takes the Rb data seriously, then MZ′ is bounded, at the 3σ level, to be 462 GeV < MZ′ cosΦ < 1481 GeV, where cosΦ is the mixing angle between the two SU(2)ʹs in the model. Effects predicted for high energy experiments at the Tevatron, LEP140, LEP-II, LHC, and future linear colliders are also discussed.