{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.147259.v2","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/2718968"}},{"@id":"https://doi.org/10.1016/j.physletb.2024.138513","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"NA62 Collaboration"},"creator":{"@type":"Organization","name":"NA62 Collaboration"},"datePublished":"2024","description":"A sample of 3984 candidates of the $K^+\\to\\pi^+\\gamma\\gamma$ decay, with an estimated background of $291\\pm14$ events, was collected by the NA62 experiment at CERN during 2017-2018. In order to describe the observed di-photon mass spectrum, the next-to-leading order contribution in chiral perturbation theory was found to be necessary. The decay branching ratio in the full kinematic range is measured to be $(9.61\\pm0.17)\\times10^{-7}$. The first search for production and prompt decay of an axion-like particle with gluon coupling in the process $K^+\\to\\pi^+a$, $a\\to\\gamma\\gamma$ is also reported.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.147259.v2/t1","@type":"Dataset","description":"See caption of Figure 6.","name":"Table 1"},{"@id":"https://doi.org/10.17182/hepdata.147259.v2/t2","@type":"Dataset","description":"Upper limits at 90% CL of $B(K^+\\to\\pi^+a)\\times B(a\\to\\gamma\\gamma)$ in the prompt ALP decay assumption.","name":"Table 2"},{"@id":"https://doi.org/10.17182/hepdata.147259.v2/t3","@type":"Dataset","description":"See caption of Figure 9.","name":"Table 3"},{"@id":"https://doi.org/10.17182/hepdata.147259.v2/t4","@type":"Dataset","description":"See caption of Figure 9.","name":"Table 4"},{"@id":"https://doi.org/10.17182/hepdata.147259.v2/t5","@type":"Dataset","description":"See caption of Figure 9.","name":"Table 5"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins2718968?version=2"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/147259"}],"inLanguage":"en","name":"Measurement of the $K^+\\to\\pi^+\\gamma\\gamma$ decay","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins2718968?version=2","version":2}