Unified study of $J\mathrm{/}\psi \to PV$, $P{\gamma }^{(\ast )}$ and light hadron radiative processes

Within the framework of the effective Lagrangian approach, we perform a thorough analysis of the $J\mathrm{/}\psi \to P\gamma ({\gamma }^{\ast })$, $J\mathrm{/}\psi \to VP$, $V\to P\gamma(\gamma^)$,$P\to V\gamma(\gamma^)$and$P\to\gamma\gamma(\gamma^)$processes,where$V$standforlightvectorresonances,$P$ stand for light pseudoscalar mesons, and ${\gamma }^{\ast }$ subsequently decays into lepton pairs. The processes with light pseudoscalar mesons $\eta$ and ${\eta }^{\mathrm{\prime }}$ are paid special attention to and the two-mixing-angle scheme is employed to describe their mixing. The four mixing parameters both in singlet-octet and quark-flavor bases are updated in this work. We confirm that the $J/\psi \to \eta(\eta^{\prime})\gamma^{()}$processesarepredominantlydominatedbythe$J/\psi\to \eta_c \gamma^{} \to \eta(\eta^{\prime})\gamma^{()}$ mechanism. Predictions for the $J\mathrm{/}\psi \to P{\mu }^{+}{\mu }^{-}$ are presented. A detailed discussion on the interplay between electromagnetic and strong transitions in the $J\mathrm{/}\psi \to VP$ decays is given.