{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.145665.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/2795514"}},{"@id":"https://doi.org/10.1088/1361-6633/ad7e4d","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"CMS Collaboration"},"creator":{"@type":"Organization","name":"CMS Collaboration"},"datePublished":"2024","description":"CERN-LHC. A measurement of the extent of entanglement in top quark-antiquark ($\\mathrm{t\\bar{t}}$) events produced in proton-proton collisions at a center-of-mass energy of 13 TeV is performed with the data recorded by the CMS experiment at the CERN LHC in 2016, and corresponding to an integrated luminosity of 36.3 $\\mathrm{fb^{-1}}$. An entanglement-sensitive observable $D$ is derived from the top quark spin-dependent parts of the $\\mathrm{t\\bar{t}}$ production density matrix and measured in the region of the invariant mass of the $\\mathrm{t\\bar{t}}$ ($m(\\mathrm{t\\bar{t}})$) being $345 < m(\\mathrm{t\\bar{t}}) < 400$ GeV and the relative velocity between the lab and $\\mathrm{t\\bar{t}}$ reference frames, $\\beta_z(\\mathrm{t\\bar{t}}) = |(p_z^{\\mathrm{t}} + p_z^{\\mathrm{\\bar{t}}}) / (E^{\\mathrm{t}} + E^{\\mathrm{\\bar{t}}})|$, being $\\beta_z(\\mathrm{t\\bar{t}}) < 0.9$ at the reconstruction level.  Values of $D < -1/3$ are evidence of entanglement. Both the expected and observed values are reported at the parton level for $m(\\mathrm{t\\bar{t}}) < 400$ and $\\beta_z(\\mathrm{t\\bar{t}}) < 0.9$.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.145665.v1/t1","@type":"Dataset","description":"Expected and observed values for the entanglement proxy D in the parton-level phase space of $m(\\mathrm{t\\bar{t}}) < 400$ and $\\beta_z(\\mathrm{t\\bar{t}})...","name":"Table 1"},{"@id":"https://doi.org/10.17182/hepdata.145665.v1/t2","@type":"Dataset","description":"Expected and observed values for the entanglement proxy D in the parton-level phase space of $m(\\mathrm{t\\bar{t}}) < 400$ and $\\beta_z(\\mathrm{t\\bar{t}})...","name":"Table 2"},{"@id":"https://doi.org/10.17182/hepdata.145665.v1/t3","@type":"Dataset","description":"Expected values from various Monte Carlo predictions for the entanglement proxy D in the parton-level phase space of $m(\\mathrm{t\\bar{t}}) <...","name":"Table 3"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins2795514?version=1"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/145665"}],"inLanguage":"en","name":"Observation of quantum entanglement in top quark pair production in proton-proton collisions at $\\sqrt{s}$ = 13 TeV","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins2795514?version=1","version":1}