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 (ttbarZ) = 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.
Measurement of top quark pair production in association with a Z boson in proton-proton collisions at sqrt(s) = 13 TeV
A. Vagnerini;P. Meridiani;N. Amapane;S. Argiro;R. Bellan;A. Cappati;M. Costa;R. Covarelli;B. Kiani;E. Migliore;V. Monaco;E. Monteil;M. M. Obertino;L. Pacher;G. L. Pinna Angioni;A. Romero;R. Sacchi;R. Salvatico;V. Sola;A. Solano;D. Soldi;K. Shchelina;P. Rumerio;F. Ravera;
2020-01-01
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 (ttbarZ) = 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.File | Dimensione | Formato | |
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JHEP03(2020)056.pdf
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