Measurement of the $ZZ$ Production Cross Section and $Z \to \ell^+ \ell^- \ell^{\prime +} \ell^{\prime -}$ Branching Fraction in $pp$ Collisions at $\sqrt{s}
Measurement of the $ZZ$ Production Cross Section and $Z \to \ell^+ \ell^- \ell^{\prime +} \ell^{\prime -}$ Branching Fraction in $pp$ Collisions at $\sqrt{s}

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Published: 2016

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Four-lepton production in proton-proton collisions, pp to (Z/gamma*)(Z/gamma*) to l+l-l'+l'-, where $l, 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 2.6 inverse femtobarns. The ZZ production cross section, sigma(pp to ZZ) = 14.6 +1.9/-1.8 (stat) +0.5/-0.3 (syst) +/- 0.2 (theo) +/- 0.4 (lumi) pb, is measured for events with two opposite-sign, same-flavor lepton pairs produced in the mass region 60 m[l+l-], m[l'+l'-]

Measurement of the ZZ Production Cross Section and Z {u2192} L+l{u2013}l'+l'{u2013} Branching Fraction in Pp Collisions at
Measurement of the ZZ Production Cross Section and Z {u2192} L+l{u2013}l'+l'{u2013} Branching Fraction in Pp Collisions at

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Published: 2016

Total Pages: 24

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Here, four-lepton production in proton–proton collisions, pp→(Z/?*)(Z/?*)→l+l–l'+l'–,where l,l'=e or ?, 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 2.6 fb–1. The ZZ production cross section, ?(pp → ZZ)=14.6–1.8+1.9(stat)–0.3+0.5(syst)±0.2(theo)±0.4(lumi)pb, is measured for events with two opposite-sign, same-flavor lepton pairs produced in the mass region 60msublsup+/suplsup–/sup/sub,ml'sup+/supl'sup–/sup120 GeV60mlsup+/suplsup–/sup,ml'sup+/supl'sup–/sup120 GeV. The Z boson branching fraction to four leptons is measured to be B(Z→lsup+/suplsup–/supl'sup+/supl'sup–/sup)=4.9sub–0.7/subsup+0.8/sup (stat)sub–0.2/subsup+0.3/sup (syst)–0.1+0.2(theo)±0.1(lumi)×10sup–6/sup for the four-lepton invariant mass in the range 80mlsup+/suplsup–/supl'sup+/supl'sup–/sup100 GeV80mlsup+/suplsup–/supl'sup+/supl'sup–/sup

Measurement of the $ZZ$ Production Cross Section in $pp$ Collisions at $\sqrt{s}$
Measurement of the $ZZ$ Production Cross Section in $pp$ Collisions at $\sqrt{s}$

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Published: 2016

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The ZZ production cross section in proton-proton collisions at 13 TeV center-of-mass energy is measured using 3.2 fb–1 of data recorded with the ATLAS detector at the Large Hadron Collider. The considered Z boson candidates decay to an electron or muon pair of mass 66–116 GeV. The cross section is measured in a fiducial phase space reflecting the detector acceptance. It is also extrapolated to a total phase space for Z bosons in the same mass range and of all decay modes, giving 16.7+2.2–2.0(stat)+0.9–0.7(syst)+1.0–0.7(lumi) pb. Lastly, the results agree with standard model predictions.

Measurement of the Inclusive W and Z Production Cross Sections in Pp Collisions at $ \sqrt {s}
Measurement of the Inclusive W and Z Production Cross Sections in Pp Collisions at $ \sqrt {s}

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Published: 2011

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A measurement of inclusive W and Z production cross sections in pp collisions at sqrt(s)=7 TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. The measured inclusive cross sections are sigma(pp-> WX) B(W-> l nu) = 10.30 +/- 0.02 (stat.) +/- 0.10 (syst.) +/- 0.10 (th.) +/- 0.41 (lumi.) nb and sigma(pp -> ZX) B(Z-> l+̂l-̂) = 0.974 +/- 0.007 (stat.) +/- 0.007 (syst.) +/- 0.018 (th.) +/- 0.039 (lumi.) nb, limited to the dilepton invariant mass range 60 to 120 GeV. The luminosity-independent cross section ratios are [sigma(pp->WX) B(W-> l nu)]/[sigma(pp-> ZX) B(Z->l+̂l-̂)] = 10.54 +/- 0.07 (stat.) +/- 0.08 (syst.) +/- 0.16 (th.) and [sigma(pp->W+̂X) B(W+̂ -> l+̂nu)] / [sigma(pp->W-̂ X) B(W-̂ -> l-̂ nu)] = 1.421 +/- 0.006 (stat.) +/- 0.014 (syst.) +/- 0.029 (th.). The measured values agree with next-to-next-to-leading order QCD cross section calculations based on recent parton distribution functions.

Measurement of WZ and ZZ Production in Pp Collisions at $\sqrt{s}
Measurement of WZ and ZZ Production in Pp Collisions at $\sqrt{s}

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Published: 2014

Total Pages: 22

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Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at $\sqrt{s}$ = 8 TeV in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either $W \to e\nu, \mu\nu$ or $Z \to e^+ e^-, \mu^+ \mu^-$, or $\nu\bar{\nu})$. The results are based on data corresponding to an integrated luminosity of 18.9 inverse-femtobarns collected with the CMS detector at the Large Hadron Collider. The measured cross sections, $\sigma(pp \to WZ)$ = 30.7 $\pm$ 9.3 (stat.) $\pm$ 7.1 (syst.) $\pm$ 4.1 (th.) $\pm$ 1.0 (lum.) pb and $\sigma(pp \to ZZ)$ = 6.5 $\pm$ 1.7 (stat.) $\pm$ 1.0 (syst.) $\pm$ 0.9 (th.) $\pm$ 0.2 (lum.) pb, are consistent with next-to-leading order quantum chromodynamics calculations.

Measurements of Inclusive W and Z Cross Sections in Pp Collisions at Sqrt(s)
Measurements of Inclusive W and Z Cross Sections in Pp Collisions at Sqrt(s)

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Published: 2011

Total Pages: 38

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Measurements of inclusive W and Z boson production cross sections in pp collisions at sqrt(s)=7 TeV are presented, based on 2.9 inverse picobarns of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give sigma(pp to WX) times B(W to muon or electron + neutrino) = 9.95 \pm 0.07(stat.) \pm 0.28(syst.) \pm 1.09(lumi.) nb and sigma(pp to ZX) times B(Z to oppositely charged muon or electron pairs) = 0.931 \pm 0.026(stat.) \pm 0.023(syst.) \pm 0.102(lumi.) nb. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported.

Measurement of the $ZZ$ Production Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}
Measurement of the $ZZ$ Production Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}

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Published: 2011

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The authors present a new measurement of the production cross section [sigma](pp̄ = ZZ) at a center-of-mass energy √s = 1.96 TeV, obtained from the analysis of the four charged lepton final state l+l-l`+l`- (l, l` = e or [mu]). They observe ten candidate events with an expected background of 0.37 ± 0.13 events. The measured cross section [sigma](pp̄ =ZZ) = 1.26-0.37+0.47 (stat) ± 0.14 (syst) pb is in agreement with NLO QCD predictions. This result is combined with a previous result from the ZZ = l+l- [nu][̄nu] channel resulting in a combined cross section of [sigma](pp̄ = ZZ) = 1.40-0.37+0.43 (stat) ±0.14 (syst) pb.

Measurement of W and Z Boson Production Cross Sections in Proton-proton Collisions at [square Root] S
Measurement of W and Z Boson Production Cross Sections in Proton-proton Collisions at [square Root] S

Author: Stephanie Akemi Brandt

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Published: 2020

Total Pages: 160

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Measurements of W and Z boson production cross sections in pp collisions at [square root] s = 5.02TeV and [square root] s = 13TeV are presented. Data was collected by the CMS experiment at the LHC during low-pileup data taking periods in 2017. The corresponding integrated luminosity for the data is 299.1 ± 5 pb−1 ( [square root] s = 5.02TeV) and 199.3 ± 4 pb−1 ( [square root] s = 13TeV), with an average number of pile-up interactions [[mu] = 3 ([mu] = 2). Cross sections and cross section ratios are reported, with final states in electron and muon channels.