2-PHOTON DECAY OF THE GLUEBALL AND SCALAR ISOSCALAR MESONS IN A SCALED NJL MODEL

We use a modified version of the Nambu-Jona-Lasinio (NJL) model which implements the QCD trace anomaly to calculate the two photon decay wid th of the glueball (f(0)(1500)) and of the two scalar mesons (f(0)(137 0), f(J=0)(1710)) to which it is mixed. We investigate the effect of t he mixing over the coupling constants of the f(0) states to the quarks and over the widths. We show that mass and phase space effects are cr ucial, at least in the NJL model, in determining the relative strength of the 2 gamma widths. (C) 1998 Elsevier Science B.V.