The production of Z boson pairs in proton-proton ( pp ) collisions, pp→(Z/γ∗)(Z/γ∗)→2ℓ2ℓ' , where ℓ,ℓ'=e or μ , is studied at a center-of-mass energy of 13 TeV with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137 fb-1 , collected during 2016-2018. The ZZ production cross section, σtot(pp→ZZ)=17.4±0.3(stat)±0.5(syst)±0.4(theo)±0.3(lumi) pb , measured for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region 60<120GeV is consistent with standard model predictions. Differential cross sections are also measured and agree with theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous ZZZ and ZZγ couplings.
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