Ground and excited scalar isoscalar meson states in a U(3) x U(3) quark model with a glueball

Ground and first radially excited scalar isoscalar meson states and a scalar glueball are described in a nonlocal U(3) x U(3) quark model. The glueball is introduced into the effective meson Lagrangian by means of the dilaton model on the base of the scale invariance of the meson Lagrangian. The scale invariance breaking by current quark masses and gluon anomalies is taken into account. The glueball anomalies turn out to be important for the description of the glueball-quarkonia mixing. The masses of five scalar isoscalar meson states and their strong decay widths are calculated. The state f0(1500) is shown to be composed mostly of the scalar glueball. (orig.)