Determination of Low Energy Constants and testing Chiral Perturbation Theory at Next to Next to Leading Order

Summary, in English

We present the results of a search for relations between

observables that are independent of the Chiral Perturbation Theory (ChPT)

Next-to-Next-to-Leading Order (NNLO) Low-Energy Constants (LECs). We have found

some relations between observables in $\pi\pi$, $\pi K$ scattering and

$K_{l4}$ decay which have been evaluated numerically using the old fit (fit 10

in~\cite{Amoros:2001cp}) of the

NLO LECs.