Probe of new physics in top-quark pair production ate−e+colliders

We describe how to probe new physics through examination of the form factors describing the $Z-t-\overline{t}$ couplings via the scattering process $e^{-}{e}^{+}\to t\overline{t}$. 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 $t\overline{t}$ pairs through the angular correlations in the final state leptons. We also study the dependence on the energy and luminosity of an $e^{-}{e}^{+}$ collider to probe a $\mathrm{CP}$-violating asymmetry at the ${10}^{-2\mathrm{}}$ level.