Large-Nc estimate of the chiral low-energy constants

Chiral low-energy constants incorporate short-distance information from the dynamics involving heavier degrees of freedom not present in the chiral Lagrangian. We have studied the contribution of the lightest resonances to the chiral low-energy constants, up to O(p^6), within a systematic procedure guided by the large-Nc limit of QCD and also including short-distance asymptotic constraints.