Low energy data and a model of flavor mixing

We consider a model in which the third family fermions are subjected to an SU(2) interaction different from the first two family fermions. Constrained by the Z-pole data, the heavy gauge boson mass is bounded from below to be about 1.7 TeV at the 2σ level. In this model, the flavor mixing between τ and μ can be so large that Br(τ → μν_μν_τ)/Br(τ → eν_eν_τ) and Br(τ → μμμ) provide a better constraint than the LEP/SLC data in some region of parameter space. Furthermore, flavor-changing neutral currents are unavoidable in the quark sector of the model. Significant effects to the B⁰-B⁰ mixing and the rare decays of the K and B mesons, such as K^± → π^±νν̄, b → sνv̄, B_s → τ⁺τ^-, μ⁺μ^- and B_s,d → μ^±μ±, are expected.