  We show that $Z$ polarization measurement is useful for distinguishing the
signal decay chain of the `golden region' in the minimal supersymmetric
standard model(MSSM) parameter space, which involves the stop decay of $\tilde
t_2 \to \tilde t_1 + Z$, from other decay chains involving the neutralino decay
of $\tilde\chi_2^0 \to \tilde\chi_1^0 + Z$ in different MSSM scenarios.
