  We propose techniques to observe the correlation of the spins of top quarks
and antiquarks at the Tevatron and the LHC. Observation of the spin correlation
would confirm that the top quark decays before its spin flips, and would place
a lower bound on the top-quark width and V_tb. The spin correlation may also be
a useful tool to study the weak decay amplitude of the top quark.

High Energy Physics - Phenomenology