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

Abstract

Within the framework of the effective Lagrangian approach, we perform a thorough analysis of the $J/\psi \to P\gamma ({\gamma }^{\ast })$, $J/\psi \to VP$, $V\to P\gamma ({\gamma }^{\ast })$, $P\to V\gamma ({\gamma }^{\ast })$ and $P\to \gamma \gamma ({\gamma }^{\ast })$ processes, where $V$ stand for light vector resonances, $P$ stand for light pseudoscalar mesons, and ${\gamma }^{\ast }$ subsequently decays into lepton pairs. The processes with light pseudoscalar mesons $\eta$ and ${\eta }^{\prime }$ 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 $J/\psi \to \eta ({\eta }^{\prime }){\gamma }^{(\ast )}$ processes are predominantly dominated by the $J/\psi \to {\eta }_c{\gamma }^{\ast }\to \eta ({\eta }^{\prime }){\gamma }^{(\ast )}$ mechanism. Predictions for the $J/\psi \to P{\mu }^{+}{\mu }^{-}$ are presented. A detailed discussion on the interplay between electromagnetic and strong transitions in the $J/\psi \to VP$ decays is given.

Comments: 29 pages, 8 figures and 6 tables. References added. Accepted by Phys.Rev.D