We describe how to probe new physics through examination of the form factors describing the Ztt couplings via the scattering process e^-e^+->t+tbar. We focus on experimental methods on how the top quark momentum can be determined and show how this can be applied to select polarized samples of $t\bar{ t}$ pairs through the angular correlations in the final state leptons. We also study the dependence on the energy and luminosity of an \ee\ collider to probe a CP violating asymmetry at the $10^{ -2}$ level.}
Categories: hep-ph