Measurement of top quark pair production in association with a Z boson in proton-proton collisions at <mml:msqrt>s</mml:msqrt>=13 TeV


Sirunyan A. M. , Tumasyan A., Adam W., Ambrogi F., Bergauer T., Brandstetter J., ...More

JOURNAL OF HIGH ENERGY PHYSICS, no.3, 2020 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: Issue: 3
  • Publication Date: 2020
  • Doi Number: 10.1007/jhep03(2020)056
  • Title of Journal : JOURNAL OF HIGH ENERGY PHYSICS

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.