Final-state interactions in the decays of charmed mesons

Decays of (charmed) $D$ mesons into two pseudoscalars are considered, with emphasis on final-state interactions. Uncertainties in the determination of final-state-interaction corrections that arise from theoretical ambiguities, and from incomplete meson-meson scattering data are discussed. Corrections for $\pi \pi$, $\overline{K}K$, and $\overline{K}\pi$ final states are evaluated. It is concluded that a quark-spectator model with final-state interactions cannot explain all of the unexpected rates for two-body decays of charmed pseudoscalars.