Decay of top quarks in e+e^- → tt̄ near threshold

We discuss the physics involved in the production and decay chain of top quarks in e⁺e^- → tt̄ → bl⁺νb̄W^- near the top quark threshold. We elucidate the effects of the final-state interactions. Namely, we clarify how the evolution and decay of t in this process are affected by the chromostatic field generated by the other color charge (t̄ or b̄) nearby. Furthermore, we propose and calculate inclusive and exclusive observables in the threshold region. The latter depends only on the decay of free polarized top quarks, and thus it can be calculated without knowledge of bound-state effects or the final-state interactions.