Where is the pseudoscalar glueball

The pseudoscalar mesons ?(1300), K(1460), ?(1295), ?(1405) and ?(1475) are assumed to form the meson decuplet which includes the glueball as the basis state supplementing the standard SU(3)F nonet of light states (q = u, d, s). The decuplet is investigated by using the algebraic approach based on the hypothesis of vanishing exotic commutators of SU(3)F 'charges' and their time derivatives. This leads to a system of master equations determining: (a) octet contents of the physical isoscalar mesons, (b) the mass formula relating all masses of the decuplet and (c) the mass ordering rule. The states of the physical isoscalar mesons ?(1295), ?(1405), ?(1475) are expressed as superpositions of the 'ideal' (N and S) states and the glueball G one. The 'mixing matrix' realizing transformation from the unphysical states to the physical ones follows from the octet contents and is totally expressed by the decuplet meson masses. Among four one-parameter families of the resulting mixing matrices (multitude of the solutions arising from bad quality of data on the ?(1300) and K(1460) meson masses) there is a family attributing the glueball-dominated composition to the ?(1405) meson. The pseudoscalar decuplet is similar in some respects to the scalar one: both are composed of the excited states and G; the mass ordering of their N, S, G?dominated isoscalars is the same. Contrary to the lattice QCD and other predictions, the mass of the pseudoscalar pure glueball state is smaller than the scalar one.