CPnonconservation inpp¯→tb¯Xat the Fermilab Tevatron

The reaction $p\overline{p}\to t\overline{b}X$ is found to be rather rich in exhibiting several different types of $\mathrm{CP}$ asymmetries. The spin of the top quark plays an important role. Asymmetries are related to form factors arising from radiative corrections of the $\mathrm{tbW}$ production vertex due to nonstandard physics. As illustrations, effects are studied in two Higgs doublet models and in supersymmetric models; asymmetries up to a few percent may be possible.