GLUEBALLS AND INSTANTONS

Gluonic correlation functions and Bethe-Salpeter amplitudes are calcul ated in an instanton-based model of the QCD vacuum. We consider both t he pure gauge case and the situation for real QCD with two light quark flavors. We show that instantons lead to a strong attractive force in the J(PC) = 0(++) channel, which results in the scalar glueball being much smaller than other glueballs. Ln the 0(-+) channel the correspon ding force is repulsive, and in the 2(++) case it is absent. The resul ting correlators, masses, coupling constants, and wave functions are c ompared to the results of lattice simulations.