On the gluon content of the η and η′ mesons

A phenomenological analysis of radiative $V\to P\gamma$ and $P\to V\gamma$decays is performed with the purpose of determining the gluonic content of the$\eta$ and $\eta^\prime$ wave functions. Our results show that within our modelthere is no evidence for a gluonium contribution in the $\eta$,$Z_\eta^2=0.00\pm 0.12$, or the $\eta^\prime$, $Z_{\eta^\prime}^2=0.04\pm0.09$. In terms of a mixing angle description this corresponds to$\phi_P=(41.4\pm 1.3)^\circ$ and $|\phi_{\eta^\prime G}|=(12\pm 13)^\circ$. Inaddition, the $\eta$-$\eta^\prime$ mixing angle is found to be $\phi_P=(41.5\pm1.2)^\circ$ if we don't allow for a gluonium component.Comment: 16 pages, 3 figures, JHEP style. First part of data fitting changed, conclusions not modifie