Covariant constituent quark-gluon model for the glueball-quarkonia content of scalar-isoscalar mesons

Abstract
We analyze the mixing of the scalar glueball with the scalar-isoscalar quarkonia states above 1 GeV in a nonlocal covariant constituent approach. Similarities and differences to the point-particle Klein-Gordon limit and to the quantum mechanical case are elaborated. Model predictions for the two-photon decay rates in the covariant mixing scheme are indicated.