Measurement of the top quark polarization and $\mathrm{t \bar t}$ spin correlations in dilepton final states at $\sqrt{s}=13~\mathrm{TeV}$
| Autor: | CMS Collaboration |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
moment: dipole
p p: scattering CERN Lab lepton spin: correlation pair production [top] spin: dependence correlation [spin] final state [dilepton] chromomagnetic [dipole] quantum chromodynamics scattering [p p] dipole [moment] Nuclear Experiment density matrix polarization [top] CMS dilepton: final state High Energy Physics::Phenomenology higher-order: 1 Monte Carlo [numerical calculations] dipole: chromomagnetic CERN LHC Coll differential cross section dependence [spin] High Energy Physics::Experiment top: polarization top: pair production numerical calculations: Monte Carlo 1 [higher-order] Particle Physics - Experiment |
| DOI: | 10.3204/pubdb-2018-05726 |
| Popis: | 38 pp. (2018). Measurements of the top quark polarization and top quark pair ($\mathrm{t \bar t}$) spin correlations are presented using events containing two leptons produced in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13~\mathrm{TeV}$. The data were recorded by the CMS experiment at the CERN LHC in 2016 and correspond to an integrated luminosity of $35.9~\mathrm{fb}^{-1}$. A set of parton-level normalized differential cross sections, sensitive to each of the independent coefficients of the spin-dependent parts of the $\mathrm{t \bar t}$ production density matrix, is measured for the first time at $\sqrt{s}=13~\mathrm{TeV}$. The measured distributions and extracted coefficients are compared with standard model predictions from Monte Carlo simulations with next-to-leading-order (NLO) accuracy in quantum chromodynamics (QCD) and from NLO QCD calculations including weak and mixed QCD-weak corrections. All measurements are found to be consistent with the expectations of the standard model, and are used in a simultaneous fit to constrain the anomalous chromomagnetic dipole moment of the top quark to $-0.07 < C_\text{tG}/\Lambda^{2} < 0.16~\mathrm{TeV}^{-2}$ at $95\%$ confidence level. |
| Databáze: | OpenAIRE |
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