{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.153301.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/2829523"}},{"@id":"https://doi.org/10.1103/PhysRevD.110.112016","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"CMS Collaboration"},"creator":{"@type":"Organization","name":"CMS Collaboration"},"datePublished":"2024","description":"Measurements of the polarization and spin correlation in top quark pairs ($\\mathrm{t\\bar{t}}$) are presented using events with a single electron or muon and jets in the final state. The measurements are based on proton-proton collision data from the LHC at $\\sqrt{s}$ = 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb$^{-1}$. All coefficients of the polarization vectors and the spin correlation matrix are extracted simultaneously by performing a binned likelihood fit to the data. The measurement is performed inclusively and in bins of additional observables, such as the mass of the $\\mathrm{t\\bar{t}}$ system and the top quark scattering angle in the $\\mathrm{t\\bar{t}}$ rest frame. The measured polarization and spin correlation are in agreement with the standard model. From the measured spin correlation, conclusions on the $\\mathrm{t\\bar{t}}$ spin entanglement are drawn by applying the Peres-Horodecki criterion. The standard model predicts entangled spins for $\\mathrm{t\\bar{t}}$ states at the production threshold and at high masses of the $\\mathrm{t\\bar{t}}$ system. Entanglement is observed for the first time in events at high $\\mathrm{t\\bar{t}}$ mass, where a large fraction of the $\\mathrm{t\\bar{t}}$ decays are space-like separated, with an expected and observed significance of above 5 standard deviations.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.153301.v1/t1","@type":"Dataset","description":"Results for full matrix measurement inclusive from $m(t\\bar{t})$","name":"Results for full matrix inclusive from m(tt)"},{"@id":"https://doi.org/10.17182/hepdata.153301.v1/t2","@type":"Dataset","description":"Covariance for full matrix measurement inclusive from $m(t\\bar{t})$","name":"Covariance for full matrix inclusive from m(tt)"},{"@id":"https://doi.org/10.17182/hepdata.153301.v1/t3","@type":"Dataset","description":"Results for full matrix measurement all bins from $m(t\\bar{t})$ fit","name":"Results for full matrix fine bins from m(tt)"},{"@id":"https://doi.org/10.17182/hepdata.153301.v1/t4","@type":"Dataset","description":"Covariance 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