MESON 2014 - 13TH INTERNATIONAL WORKSHOP ON PRODUCTION, PROPERTIES AND INTERACTION OF MESONS
Issue Date:
2014
Abstract(summary):
Final results from an analysis of about 400 K-+/- -> pi(-/+) gamma gamma rare decay candidates collected by the NA48/2 and NA62 experiments at CERN during low intensity runs with minimum bias trigger configurations are presented. The results include a model-independent decay rate measurement and fits to Chiral Perturbation Theory (ChPT) description. The data support the ChPT prediction for a cusp in the di-photon invariant mass spectrum at the two pion threshold.