NONPERTURBATIVE APPROACH TO EFFECTIVE CHIRAL LAGRANGIANS AND MESON INTERACTIONS

We develop a coupled channel unitary approach describing the behavior at higher energies of systems whose low-energy dynamics is given by ef fective O(p(2)) and O(p(4)) chiral Lagrangians. Our free parameters ar e those of the O(p(4)) Lagrangian. When applied to the meson-meson int eraction, it yields a remarkable agreement with data up to root s simi lar or equal to 1.2 GeV, dynamically generating the sigma, f(0), alpha (0), rho and K resonances. Further applications are also proposed.