Spin correlations in WW pair production and decay

We discuss spin effects for W-pair production and decay at LEP2 and higher energies. As an example we use observables in the s (s) over bar c (c) over bar decay channel: the two-quark/jet invariant-mass distribution and cross section, in the case when the other two may escape detection. We show, the strong interplay of spin correlations and detector cut-offs resulting in narrowly peaked distributions.