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Sirunyan A. M., Tumasyan A., Adam W., Ambrogi F., Bergauer T., Brandstetter J., ...More
JOURNAL OF HIGH ENERGY PHYSICS, vol.2020, no.3, 2020 (SCI-Expanded)
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Publication Type:
Article / Article
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Volume:
2020
Issue:
3
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Publication Date:
2020
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Doi Number:
10.1007/jhep03(2020)056
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Journal Name:
JOURNAL OF HIGH ENERGY PHYSICS
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Journal Indexes:
Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, INSPEC, zbMATH, Directory of Open Access Journals
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Keywords:
Hadron-Hadron scattering (experiments), Top physics, HELICITY FRACTIONS, CROSS-SECTION, ROOT-S=8, JETS, PLUS
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Istanbul University Affiliated:
Yes
Abstract
A measurement of the inclusive cross section of top quark pair production in association with a Z boson using proton-proton collisions at a center-of-mass energy of 13 TeV at the LHC is performed. The data sample corresponds to an integrated luminosity of 77.5 fb(-1), collected by the CMS experiment during 2016 and 2017. The measurement is performed using final states containing three or four charged leptons (electrons or muons), and the Z boson is detected through its decay to an oppositely charged lepton pair. The production cross section is measured to be sigma (ttZ) = 0.95 +/- 0.05 (stat) +/- 0.06 (syst) pb. For the first time, differential cross sections are measured as functions of the transverse momentum of the Z boson and the angular distribution of the negatively charged lepton from the Z boson decay. The most stringent direct limits to date on the anomalous couplings of the top quark to the Z boson are presented, including constraints on the Wilson coefficients in the framework of the standard model effective field theory.