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English
Committee for collaboration of Czech Republic

with Joint Institute for Nuclear Research in Dubna Login
Measurements of the pp -> ZZ production cross section and the Z -> 4l branching fraction, and constraints on anomalous triple gauge couplings at root s=13TeV

Author
Sirunyan A.M. Yerevan Physics Institute, Armenia
Finger Miroslav, prof. Ing. DrSc. Faculty of Mathematics and Physics, Charles University in Prague
Finger Michael, M.Sc. CSc. Faculty of Mathematics and Physics, Charles University in Prague, JINR Dubna
et al.  CMS collaboration

Year
2018

Scientific journal
European Physical Journal C, 78 (2), 165

Web


Abstract
Four-lepton production in proton-proton collisions, pp -> (Z/gamma*)(Z/gamma*) -> 4l, where l = e or mu, is studied at a center-of-mass energy of 13 TeV with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 35.9 fb(-1). The ZZ production cross section, sigma(pp -> ZZ) = 17.2 +/- 0.5 (stat) +/- 0.7 (syst) +/- 0.4 (theo) +/- 0.4 (lumi) pb, measured using events with two opposite-sign, same-flavor lepton pairs produced in the mass region 60 < m(l+l-) < 120 GeV, is consistent with standard model predictions. Differential cross sections are measured and are well described by the theoretical predictions. The Z boson branching fraction to four leptons is measured to be B(Z -> 4l) = 4.83(-0.22)(+0.23) (stat)(-0.29)(+0.32) (syst) +/- 0.08 (theo) +/- 0.12(lumi) x 10(-6) for events with a four-lepton invariant mass in the range 80 < m(4l) < 100 GeV and a dilepton mass m(ll) > 4GeV for all opposite-sign, same-flavor lepton pairs. The results agree with standard model predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous ZZZ and ZZ. couplings at 95% confidence level: -0.0012 < f(4)(Z) < 0.0010, -0.0010 < f(5)(Z) < 0.0013, -0.0012 < f(4)(gamma) < 0.0013, -0.0012 < f(5)(gamma) < 0.0013.

Cite article as:
A. Sirunyan, M. Finger, M. Finger, . et al., "Measurements of the pp -> ZZ production cross section and the Z -> 4l branching fraction, and constraints on anomalous triple gauge couplings at root s=13TeV", European Physical Journal C, 78 (2), 165 (2018)