Spin Polarization in Single Top Events

We discuss the optimal spin bases for describing angular correlations in single top quark events at the Fermilab Tevatron. We define spin bases that exploit the fact that the top quarks are produced with 100% polarization along the momenta of the d-type quarks in these events. For single top production through an s-channel W boson, 98% of the top quarks have their spins in the antiproton direction. For single top production via Wg-fusion, 96% of the top quarks have their spins in the spectator jet direction. The direction of the top quark spin is reflected in the angular correlations of its decay products.