Top-quark couplings to TeV resonances at future lepton colliders

We study the processes W_LW_L→tt̄ and W_LZ_L→tb̄(t̄b) at future lepton colliders as probes of the couplings of the top quark to resonances at the TeV scale. We consider the cases in which the dominant low energy feature of a strongly interacting electroweak symmetry breaking sector is either a scalar or a vector resonance with mass near 1 TeV. We find that future lepton colliders with high energy and high luminosity have great potential to sensitively probe these physics scenarios. In particular, at a 1.5 TeV linear collider with an integrated luminosity of 200 fb^-1, we expect about 120 events for either a scalar or a vector to decay to tt̄,tb. Their leading partial decay widths, which characterize the coupling strengths, can be statistically determined to about 10% level.