Scalar glueball mixing and decay - art. no. 014022.

We provide the first explanation of the counter-intuitive scalar glueball c ouplings to pseudoscalar mesons found in lattice QCD and predict hitherto u ncalculated decay modes. Significant a(1)pi and (pi pi)(S)(pi pi)(S) coupli ngs are found. We demonstrate the equivalence of linear and quadratic mass matrices for glueball-quarkonium mixing. The equivalence of formalisms whic h deal with a glueball-quarkonium basis and only a quarkonium basis is demo nstrated. We show that the f(0)(1500) is not the heaviest state arising fro m glueball-quarkonium mixing for a glueball mass consistent with lattice QC D. The masses and couplings of scalar mesons, as well as their valence cont ent, are calculated. [S0556-2821(99)02401-7].