Kℓ4 decays and the low-energy expansion
Tha amplitudes for the Kℓ4 decays are calculated to next-to-leading order in Chiral Perturbation Theory. These are then compared with the available experimental results on these decays. The values of the parameters L1, 2, 3 previously determined from ππ scattering are compared with those obtained here. A short overview of the determination of the parameters of Chiral Perturbation Theory is include