On the gluon content of the η and η′ mesons

A phenomenological analysis of radiative V Pγ and PVγ decays is performed with the purpose of determining the gluonic content of the η and η′ wave functions. Our results show that within our model there is no evidence for a gluonium contribution in the η, Zη2 ≤ 0.00 0.12, or the η′, Zη′2 ≤ 0.04 0.09. In terms of a mixing angle description this corresponds to φP ≤ (41.4 1.3)° and |φη′G| ≤ (12 13)°. In addition, the η-η′ mixing angle is found to be φP ≤ (41.5 1.2)° if we don't allow for a gluonium component. © SISSA 2007.