Phenomenology of neutral D-meson decays and double-flavour oscillations

Decays of neutral D-mesons are considered phenomenologically without invoking any particular models. Special attention is given to cascade decays with intermediate neutral kaons where coherent double-flavour oscillations (CDFO) become possible. We show necessity and unique possibilities of experiments on CDFO. They allow to relate with each other widths and masses of D-meson eigenstates, to separate interference effects due to D0-¯D0 mixing and/or Cabibbo-favoured vs. doubly-suppressed transitions. Such experiments provide the only known ways to unambiguous model-independent measurements of all CP-violating parameters and of Cabibbo-doubly-suppressed amplitudes, where the New Physics may have more prominent manifestations. Similar experiments would be useful and interesting also for charged D-meson decays to neutral kaons.