{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.35365.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/815724"}},{"@id":"https://doi.org/10.1016/j.physletb.2009.05.040","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"NA48/2 Collaboration"},"creator":{"@type":"Organization","name":"NA48/2 Collaboration"},"datePublished":"2015","description":"CERN-NA-048.  A sample of 7253 $K^\\pm\\to\\pi^\\pm e^+e^-(\\gamma)$ decay candidates with 1.0% background contamination has been collected by the NA48/2 experiment at the CERN SPS, allowing a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be ${\\rm BR}=(3.11\\pm0.12)\\times 10^{-7}$, where the uncertainty includes also the model dependence. The shape of the form factor $W(z)$, where $z=(M_{ee}/M_K)^2$, was parameterized according to several models, and, in particular, the slope $\\delta$ of the linear form factor $W(z)=W_0(1+\\delta z)$ was determined to be $\\delta=2.32\\pm0.18$. A possible CP violating asymmetry of $K^+$ and $K^-$ decay widths was investigated, and a conservative upper limit of $2.1\\times 10^{-2}$ at 90% CL was established.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.35365.v1/t1","@type":"Dataset","description":"The $d\\Gamma_{\\pi ee}/dz$ spectrum (background subtracted, corrected for trigger efficiency). Systematic errors, notably the external one due to the branching...","name":"Table 1"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins815724?version=1"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/35365"}],"inLanguage":"en","name":"Precise measurement of the K+- --> pi+-e+e- decay","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins815724?version=1","version":1}