$D\to \pi \pi$ decays with Final State Interactions

Abstract

We study $D\to \pi \pi$ decays with final state interactions considered in one-particle-exchange method. A clear physical picture for final state interactions based on quark and hadronic level diagrams is presented. A strong phase is introduced for hadronic effective couplings, which is crucial for explaining the experimental data of $D^{+}\to {\pi }^{+}{\pi }^0$, $D^0\to {\pi }^{+}{\pi }^{-}$, and $D^0\to {\pi }^0{\pi }^0$. Rescattering effects between different $D$ decay channels are usually large. They are important for obtaining correct branching ratios for $D\to \pi \pi$ decays in theoretical calculation.

Comments: 14 Page, 8 figures, one table added