  In the decay chain B(d) --> Psi + K --> Psi + (pi l nu), neutral K mixing
follows on the heels of neutral B mixing. This "cascade mixing" leads to an
interference which probes cos(2*beta), where beta is one of the three
CP-violating phase angles which characterize CP violation in the Standard
Model. Widely-discussed future B-system experiments will determine
trigonometric functions of these three phase angles, leaving the underlying
angles themselves discretely ambiguous. A determination of cos(2*beta) through
cascade mixing would eliminate all the discrete ambiguities entirely.
