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
Four-lepton production in proton-proton collisions, pp → (Z/γ ∗)(Z/γ ∗) → 4, where = e or μ, 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, σ (pp → ZZ) = 17....
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English English |
| Published: |
Springer Link
2018
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/70434/ http://irep.iium.edu.my/70434/ http://irep.iium.edu.my/70434/ http://irep.iium.edu.my/70434/1/70434_Measurements%20of%20the%20pp%20%E2%86%92%20ZZ%20production%20cross%20section_article.pdf http://irep.iium.edu.my/70434/7/70434_Measurements%20of%20the%20pp%20%E2%86%92%20ZZ%20production%20cross%20section_wos.pdf |
| Summary: | Four-lepton production in proton-proton collisions, pp → (Z/γ ∗)(Z/γ ∗) → 4, where = e or μ, 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, σ (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+− < 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 → 4) = 4.83+0.23 −0.22(stat)
+0.32 −0.29(syst) ± 0.08(theo) ±
0.12(lumi) × 10−6 for events with a four-lepton invariant
mass in the range 80 < m4 < 100 GeV and a dilepton mass m > 4 GeV 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 ZZγ couplings at 95% confidence level: − 0.0012 < f Z
4 < 0.0010,
− 0.0010 < f Z
5 < 0.0013, − 0.0012 < f
γ
4 < 0.0013,
− 0.0012 < f
γ
5 < 0.0013. |
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