Large Nc behavior of light resonances in meson-meson scattering

By scaling the parameters of meson-meson unitarized Chiral Perturbation Theory amplitudes according to the QCD large N-0 rules, one can study the spectroscopic nature of light meson resonances. The scalars sigma, kappa f(0)(980) and, possibly, the a(0)(980) do not seem to behave as $(q) over bar $q states, in contrast to the vectors p(770) and K*(892). The behavior shown by the scalars is naturally explained in terms of diagrams with intermediate $(q) over bar $$(q) over bar $ qq-like states. Here we review our recent study and show how the results do not depend on the different fits to data.