RESONANCES IN THE WEAK CHIRAL LAGRANGIAN

We consider the weak interactions of the octet of pseudoscalar mesons with meson resonances with spin 0,1 to lowest order in the derivative expansion. We determine the resonance contributions to the O(p4) weak coupling constants. In general, the resonance contributions imply only relations between these constants. If additional assumptions such as factorization or weak deformation are imposed, a more detailed comparison with experiment becomes possible. In contrast to the strong sector, available data do not suggest that all the weak couplings of the p4-lagrangian are dominated by resonance exchange in the factorization approximation. We also give a treatment of singlet external fields.