30 Aralık 2024 Dergi makalesi Açık Erişim

CERN İşbirliği

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{
  "@context": "https://schema.org/", 
  "@id": 274467, 
  "@type": "ScholarlyArticle", 
  "creator": [
    {
      "@type": "Person", 
      "affiliation": "CERN", 
      "name": "CERN \u0130\u015fbirli\u011fi"
    }
  ], 
  "datePublished": "2024-12-30", 
  "description": "<p>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.</p>", 
  "headline": "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 $\\sqrt{s}=13\\text{}\\text{}\\mathrm{TeV}$", 
  "identifier": 274467, 
  "image": "https://aperta.ulakbim.gov.tr/static/img/logo/aperta_logo_with_icon.svg", 
  "license": "http://www.opendefinition.org/licenses/cc-by", 
  "name": "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 $\\sqrt{s}=13\\text{}\\text{}\\mathrm{TeV}$", 
  "url": "https://aperta.ulakbim.gov.tr/record/274467"
}