Is eta' partially made of gluonium?

Abstract

A phenomenological analysis of radiative $V\to P\gamma$ and $P\to V\gamma$ decays is performed in order to determine the gluonic content of the ${\eta }^{\prime }$ wave function. Our result shows that there is no evidence for such a gluonium contribution, $Z_{{\eta }^{\prime }}^2=0.04\pm 0.09$. In terms of a mixing angle description this corresponds to ${\varphi }_P=(41.4\pm 1.3{)}^{\circ }$ and $|{\varphi }_{{\eta }^{\prime }G}|=(12\pm 13{)}^{\circ }$.

Comments: 8 pages, 2 figures, uses frascatiphys style. Talk presented at the XII International Conference on Hadron Spectroscopy (HADRON 07), Laboratori Nazionali di Frascati (Rome), Italy, 8-13 October 2007