Study of W-Exchange Mode D⁰ → ФK⁰

We calculate the branching ratio of rare decay D⁰ → ФK⁰ using the perturbative QCD factorization approach based on k_T factorization. Our result shows this branching ratio is (8.7±1.4)× 10^-3, which is consistent with experimental data. We hope that the CLEO-C and BES-III can measure it more accurately, which will help us to understand QCD dynamics and D meson weak decays.