Radiative Decays of Charmonium into Light Mesons

We apply perturbative QCD to the radiative decays of charmonia J/ψ and X_cJ into light mesons. We perform a complete numerical calculation for the quark--gluon loop diagrams involved in these processes. The calculated J/ψ decay branching ratios into p-wave mesons f₂(1270) and f₁(1285) fit the data well, while that of f₀(980) (if treated as an ss meson) is predicted to be 1.6×10^-4, which implies that f₀(1710) can not be the ss or (uu+dd)√2 meson. Decays of p-wave charmonia X_cJ → ρ (ω,Ф) γ (J=0,1,2) are also studied, and the branching ratio of X_cl → ρ γ is predicted to be 1.4×10^-5, which may be tested by CLEO-c ollaboration and BESIII collaboration with future experiments.