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

TL;DR

This paper provides a comprehensive analysis of various radiative and decay processes involving $J/ar{ ext{psi}}$, light mesons, and photons using an effective Lagrangian approach, updating mixing parameters and predicting decay outcomes.

Contribution

It introduces an updated set of mixing parameters for $ ext{eta}$ and $ ext{eta'}$ mesons and offers a unified analysis of multiple $J/ar{ ext{psi}}$ decay channels within a consistent theoretical framework.

Findings

Dominance of $J/\psi \to \eta_c \gamma^* \to \eta(\eta') \gamma^*$ mechanisms.

Predictions for $J/\psi \to P \mu^+ \mu^-$ decays.

Clarification of electromagnetic and strong transition interplay in $J/\psi \to VP$ decays.

Abstract

Within the framework of the effective Lagrangian approach, we perform a thorough analysis of the $J/\psi \to P\gamma(\gamma^*)$, $J/\psi \to VP$, $V\to P\gamma(\gamma^*)$, $P\to V\gamma(\gamma^*)$ and $P\to\gamma\gamma(\gamma^*)$ processes, where $V$ stand for light vector resonances, $P$ stand for light pseudoscalar mesons, and $\gamma^*$ subsequently decays into lepton pairs. The processes with light pseudoscalar mesons $\eta$ and $\eta'$ 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 $J/\psi \to \eta(\eta^{\prime})\gamma^{(*)}$ processes are predominantly dominated by the $J/\psi\to \eta_c \gamma^{*} \to \eta(\eta^{\prime})\gamma^{(*)}$ 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.