Putative light scalar nonet - art. no. 074026

We investigate the ''family'' relationship of a possible scalar nonet compo sed of the a(0)(980), the f(0)(980) and the sigma and kappa type states fou nd in recent treatments of pi pi and pi K scattering. We work in the effect ive Lagrangian framework, starting from terms which yield "ideal mixing" ac cording to Okubo's original formulation. It is noted that there is another solution corresponding to dual ideal mixing which agrees with Jaffe's pictu re of scalars as qq<(qq)over bar> states rather than q (q) over bar states. At the Lagrangian level there is no difference in the formulation of the t wo cases (other than the numerical values of the coefficients). Ln order to agree with experiment, additional mass and coupling terms which break idea l mixing are included. The resulting model turns out to be closer to dual i deal mixing than to conventional ideal mixing; the scalar mixing angle is r oughly -17 degrees in a convention where dual ideal mixing is 0 degrees. [S 0556-2821(99)05007-9].