Revisiting the OZI-forbidden Radiative Decays of Orthoquarkonia

It is interesting to investigate the OZI-forbidden radiative orthoquarkonium decays $J\mathrm{/}\psi \to \gamma {\pi }^0,\gamma \eta$ and $\gamma {\eta }^{\mathrm{\prime }}$ in perturbative QCD. In this work without the approximations adopted in literature we carry out a full one-loop calculation which involves integrations of 4-point and 5-point loop functions. Our numerical results are in agreement with the present data. We also briefly discuss the decays of $J\mathrm{/}\psi \to \gamma +{\rho }^0$, as well as $\mathrm{{\rm Y}}\to {\pi }^0\gamma ,\eta \gamma ,{\eta }^{\mathrm{\prime }}\gamma$.