One-loop unitarized Chiral Perturbation Theory (UChPT) calculations, suggest a different Nc behaviour for the σ or f_0(600) and p(770) mesons [I]: while the p meson becomes narrower with Nc, as is expected for a qq meson, the σ becomes broader, and its contribution to the total cross section is less and less important. On the other hand, local duality requires a cancellation between the σ and p amplitudes, but if there is a different Nc behaviour for them, there is a possible contradiction between the Inverse Amplitude Method (IAM) and local duality for large Nc. However, next to next to leading order UChPT calculations suggested a subdominant qq component for the σ with a mass around 1.2 GeV [2]. In this work, we show that this subdominant qq component is indeed needed to ensure local duality.
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