Effective-Lagrangian study of ψ' (J=ψ) THORN → VP and the insights into the ρπ puzzle

Within the effective Lagrangian approach, we carry out a unified study of the J/psi(psi') VP, J/psi -> P gamma and relevant radiative decays of light-flavor hadrons. A large amount of experimental data, including the various decay widths and electromagnetic form factors, is fitted to constrain the numerous hadron couplings. Relative strengths between the strong and electromagnetic interactions are revealed in the J/psi -> VP and psi -> VP processes. The effect from the strong interaction is found to dominate in the J/psi -> p pi decay, while the electromagnetic interaction turns out to be the dominant effect in psi -> pp decay, which provides an explanation to the p pi puzzle. For the J/psi -> K*KK andJ/psi -> K * K thorn K *K, the former process is dominated by the strong interactions, and the effects from the electromagnetic parts are found to be comparable with those of strong interactions in the latter process. Different SUo3THORN breaking effects from the electromagnetic parts appear in the charged and neutral channels for the B(J/psi -> K* K-0(0) +K*(KK)-K-0-K-0*K thorn K * K processes explain the rather different ratios between Bo KthornK- thorn K* K--(+) )/B(J/psi -> K* K--(-) and B(J/psi -> K* K-0(0) +K*K-0(0) )/ B(J/psi'-> K* K-0(0) +K*K-0(0) ).

Automated summary

Using the effective Lagrangian approach, this study investigates the J/psi(psi') VP, J/psi -> P gamma, and related radiative decays of light-flavor hadrons. Experimental data is fitted to determine numerous hadron couplings and reveal the relative strengths of strong and electromagnetic interactions in different processes. The dominant effect in J/psi -> p pi is found to be from strong interaction, while the dominant effect in psi -> pp is from electromagnetic interaction, providing an explanation for the p pi puzzle. The processes J/psi -> K*KK and J/psi -> K * K thorn K *K are shown to be dominated by strong interactions and have comparable effects from electromagnetic interactions.