Neutral kaons as decay products and analyzers of heavier flavors

Cascade decays of heavy flavor hadrons to states with neutral kaons are discussed as an instrument for detailed studies of the heavy hadron properties. For neutral flavored mesons the well-known kaon oscillations provide a unique experimental possibility of relating lighter/heavier eigenstate masses to (approximate) even/odd eigenstate CP-parities and to longer/shorter eigenstate lifetimes. As a result, they allow to eliminate sign ambiguities of CP-violating parameters and, therefore, to check the Standard Model (or to find New Physics). Specifically for charmed hadrons, both neutral/charged mesons and baryons, the secondary kaon oscillations permit unambiguous separation of Cabibbo-allowed and doubly-suppressed decay amplitudes, including measurement of their relative phases. For neutral $D$-meson decays the kaon oscillations can also discriminate, again unambiguously, between effects of $D$-meson mixing and interference of suppressed/allowed amplitudes. Another problem discussed is the influence of kaon CP-violation on the amplitude structure and on phenomenology of CP-violation in heavy hadron decays.