J/psi->VP decays and the quark and gluon content of the eta and eta'

TL;DR

This paper analyzes $J/ $ decays into vector and pseudoscalar mesons to determine the $b5$-$b5'$ mixing angle and gluonium content of the $b5'$ meson, updating previous phenomenological models with new experimental data.

Contribution

It provides updated values for the $b5$-$b5'$ mixing angle and gluonium content of the $b5'$ meson based on recent decay data, refining understanding of meson structure.

Findings

Mixing angle without gluonium: $b5_P=(40.7\u0000b1 2.3)^\u00b0$

With gluonium: $b5_P=(44.6\u0000b1 4.4)^\u00b0$ and gluonic content $Z^2_{b5'}=0.29^{+0.18}_{-0.26}$

Recent $J/a4 o ho\u0000a0 ext{pi}$ decay data are crucial for analysis.

Abstract

The $\eta$-$\eta^\prime$ pseudoscalar mixing angle and the gluonium content of the $\eta^\prime$ meson are deduced from an updated phenomenological analysis of $J/\psi$ decays into a vector and a pseudoscalar meson. In absence of gluonium, the value of the mixing angle in the quark-flavour basis is found to be $\phi_P=(40.7\pm 2.3)^\circ$. In presence of gluonium, the values for the mixing angle and the gluonic content of the $\eta^\prime$ wave function are $\phi_P=(44.6\pm 4.4)^\circ$ and $Z^2_{\eta^\prime}=0.29^{+0.18}_{-0.26}$, respectively. The newly reported values of $B(J/\psi\to\rho\pi)$ by the BABAR and BES Collaborations are crucial to get a consistent description of data.