Cascade Mixing, a New Kind of Particle Mixing Phenomenon

We discuss \cascade mixing", where one particle mixture, say a B 0 , leads to another, say a K 0. A simple analysis is possible in the amplitude approach, which avoids \collapses of the wavefunction " and is explicitly covariant. Some novel possibilities , both of conceptual and perhaps of experimental interest, arise. For example, we explain how such processes can allow one to \tune", in principle, the phase relations in a particle mixture. Also, eeects arise involving combinations of the mass diierences of two particle mixtures. We explain how an intermediate measurement may play the role of a regenerator, so that in principle regeneration-like eeects can be induced for the B 0 and D 0 systems , despite their short ight paths. The analysis of such process with respect to CP and the distinction between \direct" and \indirect" CP violation is discussed.