Chiral symmetry and the large-Nclimit inKl4decays

The treatment of kaon decays using chiral symmetry yields predictions for thè form factors in $K\to \pi \pi e\nu$. In addition, the large-$N_c$ limit of QCD implies that a particular combination of low-energy constants should be suppressed. We present the chiral predictions for $K_{l4\mathrm{}}$ decays at next-to-leading order in the energy expansion. By combining the phenomenologies of $K_{l4\mathrm{}}$ and $\pi \pi$ scattering, we test these predictions and provide a determination of the parameters in the chiral Lagrangian of QCD.