Two-body hadronic charmed meson decays

In this work we study the two-body hadronic charmed meson decays, including both the PP and VP modes. The latest experimental data are first analyzed in the diagrammatic approach. The magnitudes and strong phases of the flavor amplitudes are extracted from the Cabibbo-favored decay modes using χ² minimization. The best-fitted values are then used to predict the branching fractions of the singly Cabibbo-suppressed and doubly Cabibbo-suppressed decay modes in the flavor SU(3) symmetry limit. We observe significant SU(3) breaking effects in some of the singly Cabibbo-suppressed channels. In the case of VP modes, we point out that the A_P and A_V amplitudes cannot be completely determined based on currently available data. We conjecture that the quoted experimental results for both D_s⁺→K¯⁰K^*+ and D_s⁺→ρ⁺η^' are overestimated. We compare the sizes of color-allowed and color-suppressed tree amplitudes extracted from the diagrammatical approach with the effective parameters a₁ and a₂ defined in the factorization approach. The ratio |a₂/a₁| is more or less universal among the D→K¯π, K¯^*π, and K¯ρ modes. This feature allows us to discriminate between different solutions of topological amplitudes. For the long-standing puzzle about the ratio Γ(D⁰→K⁺K^-)/Γ(D⁰→π⁺π^-), we argue that, in addition to the SU(3) breaking effect in the spectator amplitudes, the long-distance resonant contribution through the nearby resonance f₀(1710) can naturally explain why D⁰ decays more copiously to K⁺K^- than π⁺π^- through the W-exchange topology. This has to do with the dominance of the scalar glueball content of f₀(1710) and the chiral-suppression effect in the decay of a scalar glueball into two pseudoscalar mesons. The same final-state interaction also explains the occurrence of D⁰→K⁰K¯⁰ and its vanishing amplitude when SU(3) flavor symmetry is exact. Owing to the G-parity selection rule, D_s⁺→π⁺ω does not receive contributions from the short-distance W-annihilation and resonant final-state interactions, but it can proceed through the weak decays D_s⁺→ρ⁺η^(') followed by the final-state rescattering of ρ⁺η^(') into π⁺ω through quark exchange.