Meson-meson scattering from U(3) chiral perturbation theory

A complete one loop calculation of all the meson-meson scattering amplitudes in the framework of U(3) chiral perturbation theory with explicit resonance states is presented in this article. By performing the unitarization of the perturbative scattering amplitudes using a variant of the N/D method, we show that the approach can describe well the various scattering data. In the end, we use the parameters from the fit to determine the masses, widths and the corresponding residue of the relevant resonances.