Measurement of the ZZ Production Cross Section in Proton-Proton Collisions at √s̅=8 TeV Using the ZZ→ ℓ⁺ℓ⁻ℓ′⁻ℓ′⁺ and ZZ→ ℓ⁻ℓ⁺νν̅ Decay Channels with the ATLAS Detector

A measurement of the ZZ production cross section in the ℓ⁺ℓ⁻ℓ′⁻ℓ′⁺ and ℓ⁻ℓ⁺νν̅ channels (ℓ = e, μ) in proton-proton collisions at √s̅ = 8 TeV at the Large Hadron Collider at CERN, using data corresponding to an integrated luminosity of 20.3 fb⁻¹ collected by the ATLAS experiment in 2012 is presented. The fiducial cross sections for ZZ → ℓ⁺ℓ⁻ℓ′⁻ℓ′⁺ and ZZ→ ℓ⁻ℓ⁺νν̅ are measured in selected phase-space regions. The total cross section for ZZ events produced with both Z bosons in the mass range 66 to 116 GeV is measured from the combination of the two channels to be 7.3 ± 0.4(stat) ± 0.3(syst) {-0.1}^{-0.2} (lumi) pb, which is consistent with the Standard Model prediction of 6. 6{−0.6}^{+ 0.7} pb. The differential cross sections in bins of various kinematic variables are presented. The differential event yield as a function of the transverse momentum of the leading Z boson is used to set limits on anomalous neutral triple gauge boson couplings in ZZ production.