Properties of light resonances from unitarized Chiral perturbation theory: Nc behavior and quark mass dependence

Abstract

We review the unitarization of Chiral Perturbation Theory with dispersion relations and how it describes meson-meson scattering data, generating light resonances whose mass, width and nature can be related to QCD parameters like quark masses and the number of colors.Comment: Invited review talk for the New Frontiers in QCD 2010, Yukawa International Program for Quark-Hadron Sciences (YIPQS), January 18 (Mon) - March 19 (Fri), 2010 Yukawa Institute for Theoretical Physics, Kyoto, Japan. To appear in Progress of Theoretical Physic