The η' meson as a pseudoscalar gluonium
Vainshtein A.I. , Zakharov V.I. , Novikov V.S., Shifman M.A.
It is shown that the sum rules of quantum chromodynamics for the current, which is constructed from the gluon field operators βαμνόαμν, are saturated with the η' meson. The mass of the meson and its contribution to the gluon current are estimated. A large difference between the η' meson as a gluonium and the classical quark states such as a ρ meson is observed.