On theη′gluonic admixture

The ${\eta }^{\prime }$ which is an ${\mathrm{SU}\left(3\right)\mathrm{}}_F$ singlet state can contain a pure gluon component, gluonium. We examine this possibility by analyzing all available experimental data. It is pointed out that the ${\eta }^{\prime }$ gluonic component may be as large as 26%. We also show that the amplitude for $J/\overrightarrow{\psi }{\eta }^{\prime }\gamma$ decay obtains a notable contribution from gluonium.