2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/177732We analyze the mixing of the scalar glueball with the scalar-isoscalar quarkonia states above 1 GeV in a non-local 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.28 pages, 6 figuresHigh Energy Physics - Phenomenologytext