Four-lepton production in proton-proton collisions, p p → (Z / γ∗) (Z / γ∗) → 4 ℓ, where ℓ= e or μ, is studied at a center-of-mass energy of 13TeV with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 35.9fb-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<mℓ+ℓ-<120GeV, 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=4.8±0.2(stat)±0.2(syst)±0.1(theo)±0.1(lumi)×10-6 for events with a four-lepton invariant mass in the range 80<m4ℓ<100GeV and a dilepton mass m4GeV 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<f4Z<0.0010, -0.0010<f5Z<0.0013, -0.0012<f4γ<0.0013, -0.0012<f5γ<0.0013

Sirunyan, A., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., et al. (2018). Measurements of the p p → Z Z production cross section and the Z → 4 ℓ branching fraction, and constraints on anomalous triple gauge couplings at √s=13TeV. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 78(2) [10.1140/epjc/s10052-018-5567-9].

Measurements of the p p → Z Z production cross section and the Z → 4 ℓ branching fraction, and constraints on anomalous triple gauge couplings at √s=13TeV

Brianza, L.;Brivio, F.;Ciriolo, V.;Dinardo, M. E.;Fiorendi, S.;Ghezzi, A.;Govoni, P.;Malberti, M.;Manzoni, R. A.;Moroni, L.;Paganoni, M.;Pigazzini, S.;Ragazzi, S.;de Fatis, T. Tabarelli;Lucchini, M. T.;Gerosa, R.;Massironi, A.;De Guio, F.;
2018

Abstract

Four-lepton production in proton-proton collisions, p p → (Z / γ∗) (Z / γ∗) → 4 ℓ, where ℓ= e or μ, is studied at a center-of-mass energy of 13TeV with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 35.9fb-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
Articolo in rivista - Articolo scientifico
Hadron, Hadron collisions (experiments)
English
2018
78
2
165
none
Sirunyan, A., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., et al. (2018). Measurements of the p p → Z Z production cross section and the Z → 4 ℓ branching fraction, and constraints on anomalous triple gauge couplings at √s=13TeV. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 78(2) [10.1140/epjc/s10052-018-5567-9].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/194473
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