TTP95-48 Top Quark Polarization in Polarized <EM>e+e-</EM> Annihilation near Threshold

e+e-</EM> Annihilation near Threshold > Top quark polarization in $e^+e^-$ annihilation into $t\bar t$ is calculated for linearly polarized beams. The Green function formalism is applied to this reaction near threshold. The Lippmann–Schwinger equations for the $S$-wave and $P$-wave Green functions are solved numerically for the QCD chromostatic potential given by the two-loop formula for large momentum transfer and Richardson's ansatz for intermediate and small momenta. $S$-$P$–wave interference contributes to all components of the top quark polarization vector. Rescattering of the decay products is considered. The mean values $\langle n \ell \rangle$ of the charged lepton four-momentum projections on appropriately chosen directions $n$ in semileptonic top decays are proposed as experimentally observable quantities sensitive to top quark polarization. The results for $\langle n \ell \rangle$ are obtained including $S$-$P$–wave interference and rescattering of the decay products. It is demonstrated that for the longitudinally polarized electron beam a highly polarized sample of top quarks can