Test of Chiral Perturbation Theory in kaon decays

This paper presents results obtained by the CERN experiment NA48/2. Sample of 7146 K-+/- -> pi(+/-)e(+)e(-) decays, of 1164 K-+/- -> pi(+/-)gamma gamma events and of 120 K-+/- -> pi(+/-)gamma e(+)e(-) events have been collected with small background contamination. Branching ratio and form factors for three different models have been obtained for K-+/- -> pi(+/-)e(+)e(-), plus a model-independent branching ratio. In addition, the first measurement of the direct CP violating asymmetry has been performed. A measurement of the branching ratio has been obtained for K-+/- -> pi(+/-)gamma gamma, and kinematic distributions have been compared to ChPT expectations. Finally, the branching ratio of K-+/- -> pi(+/-)gamma e(+)e(-) has been measured in the kinematically accessible region, representing the first observation of such a decay.