S-wave meson scattering up to sqrt{s} < 2 GeV from chiral Lagrangians

The problem of scalar mesons still remains a challenging puzzle, for which we do not even know which are the right pieces to set up. The proliferation of resonances (some of them are very broad and appear on top of hadronic thresholds) and of coupled channels that interact strongly among each other makes the study of this sector a hard task. Our objective is the study of the strongly interacting mesons in coupled channels with quantum numbers J^{PC} = 0^{++} and I=0 and I=1/2, up to a center of mass energy sqrt{s} < 2 GeV. Our framework is based on Unitary Chiral Perturbation Theory. We include for I=0 the channels: \pi\pi, K\bar{K}, \eta\eta, \sigma\sigma, \eta\eta', \rho\rho, \omega\omega, \eta'\eta', \omega\phi, \phi\phi, K^\ast \bar{K}^\ast, a_1(1260)\pi and \pi^{\star}(1300)\pi. In addition, and in order to constrain our fits, we also study the I=1/2, 3/2 channels given by K\pi, K\eta and K\eta'. We finally present the resonant content of our fits with the $\sigma$, $f_0(980)$, $f_0(1310)$, $f_(1500)$, $f_0(1710)$ and $f_0(1790)$.