  We use a nonperturbative approach which combines coupled channel Lippmann
Schwinger equations with meson-meson potentials provided by the lowest order
chiral Lagrangians. By means of one parameter, a cut off in the momentum of the
loop integrals, which results of the order of 1 GeV, we obtain singularities in
the S-wave amplitudes corresponding to the \sigma,f_0 and a_0 resonances. The
\pi\pi-->\pi\pi, \pi\pi-->K\bar{K} phase shifts and inelasticities in the T=0
scalar channel are well reproduced as well as the \pi^-\eta and K^-K^0 mass
distributions in the T=1 channel. Furthermore, the total and partial decay
widths of the f_0 and a_0 resonances are properly reproduced including also the
decay into the \gamma\gamma channel. The results seem to indicate that chiral
symmetry constraints at low energy and unitarity in coupled channels is the
basic information contained in the meson-meson interaction below \sqrt(s)=1.2
GeV.

High Energy Physics - Phenomenology