Study of the K± → π±γγ decay by the NA62 experiment

A study of the dynamics of the rare decayK±→π±γγhas been performed on a sample of 232 decaycandidates, with an estimated background of 17.4±1.1 events, collected by the NA62 experiment atCERN in 2007. The results are combined with those from a measurement conducted by the NA48/2Collaboration at CERN. The combined model-independent branching ratio in the kinematic rangez=(mγγ/mK)2>0.2isBMI(z>0.2)=(0.965±0.063)×10−6, and the combined branching ratio in the fullkinematic range assuming a Chiral Perturbation Theory description isB(Kπγγ)=(1.003±0.056)×10−6.A detailed comparison of the results with the previous measurements is performed. A study of the dynamics of the rare decayK±→π±γγhas been performed on a sample of 232 decaycandidates, with an estimated background of 17.4±1.1 events, collected by the NA62 experiment atCERN in 2007. The results are combined with those from a measurement conducted by the NA48/2Collaboration at CERN. The combined model-independent branching ratio in the kinematic rangez=(mγγ/mK)2>0.2isBMI(z>0.2)=(0.965±0.063)×10−6, and the combined branching ratio in the fullkinematic range assuming a Chiral Perturbation Theory description isB(Kπγγ)=(1.003±0.056)×10−6.A detailed comparison of the results with the previous measurements is performed