A possible experimental determination of $m_s/{\hat m}$ from $K_{\mu 4}$ decays

Abstract

$K\pi$ scattering and $K_{\mu 4}$ decays are studied at leading order of improved chiral perturbation theory. It is shown that high precision $K_{\mu 4}$ experiments at, e.g., DA$\Phi$NE should allow for a direct measurement of the quark mass ratio $m_s$/${\hat m}$.