30 Aralık 2024 Dergi makalesi Açık Erişim

CERN İşbirliği

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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>CERN İşbirliği</dc:creator>
  <dc:date>2024-12-30</dc:date>
  <dc:description>Measurements of the polarization and spin correlation in top quark pairs ($t\overline{t}$) 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 $\sqrt{s}=13\text{}\text{}\mathrm{TeV}$ collected by the CMS experiment, corresponding to an integrated luminosity of $138\text{}\text{}{\mathrm{fb}}^{-1}$. 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 $t\overline{t}$ system and the top quark scattering angle in the $t\overline{t}$ rest frame. The measured polarization and spin correlation are in agreement with the standard model. From the measured spin correlation, conclusions on the $t\overline{t}$ spin entanglement are drawn by applying the Peres-Horodecki criterion. The standard model predicts entangled spins for $t\overline{t}$ states at the production threshold and at high masses of the $t\overline{t}$ system. Entanglement is observed for the first time in events at high $t\overline{t}$ mass, where a large fraction of the $t\overline{t}$ decays are spacelike separated, with an expected and observed significance of above 5 standard deviations.</dc:description>
  <dc:identifier>https://aperta.ulakbim.gov.trrecord/274467</dc:identifier>
  <dc:identifier>oai:aperta.ulakbim.gov.tr:274467</dc:identifier>
  <dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
  <dc:rights>http://www.opendefinition.org/licenses/cc-by</dc:rights>
  <dc:source>Physical Review D 110(11)</dc:source>
  <dc:title>Measurements of polarization and spin correlation and observation of entanglement in top quark pairs using $\mathrm{lepton}+\text{jets}$ events from proton-proton collisions at $\sqrt{s}=13\text{}\text{}\mathrm{TeV}$</dc:title>
  <dc:type>info:eu-repo/semantics/article</dc:type>
  <dc:type>publication-article</dc:type>
</oai_dc:dc>