Sala Seminarios IFIC (Edf. Institutos de Investigación)
Sala Seminarios IFIC
Edf. Institutos de Investigación
Descripción
K_{l4} are semileptonic decays of K mesons with a branching ratio of some 10^{-5}. For several reasons, this is an especially interesting decay channel: K_{l4} decays allow an accurate measurement of a combination of S-wave pi-pi scattering lengths, one form factor of the decay is connected to the chiral anomaly and the decay allows the determination of low energy constants of ChPT. A dispersive approach to K_{l4} decays will be presented, which takes rescattering effects into account and provides advantages over a pure ChPT treatment in the determination of low energy constants. Some preliminary fits to NA48/2 measurements of K_{l4} decays will be shown.