Chiral loops and a(0)(980) exchange in phi -> pi(0)eta gamma

The radiative phi --> pi (0)eta gamma decay is discussed emphasizing the ef fects of the a(0)(980) scalar resonance which dominates the high values of the pi (0)eta invariant mass spectrum. In its lowest part, the proposed amp litude coincides with the reliable and ChPT-inspired contribution coming fr om chiral loops. The a(0)(980) resonance is then incorporated exploiting th e complementarity between ChPT and the linear sigma model for this channel. The recently reported experimental invariant mass distribution and branchi ng ratio can be satisfactorily accommodated in our framework. For the latte r, a value of B(phi --> pi (0)eta gamma) in the range (0.75-0.95) x 10(-4) is predicted. (C) 2000 Published by Elsevier Science B.V.