Measurement of the ZZ production cross section and limits on anomalous neutral triple gauge couplings in proton-proton collisions at √s = 7 TeV with the ATLAS detector

A measurement of the ZZ production cross section in proton-proton collisions at √s = 7  TeV using data corresponding to an integrated luminosity of 1.02  fb-1 recorded by the ATLAS experiment at the LHC is presented. Twelve events containing two Z boson candidates decaying to electrons and/or muons are observed, with an expected background of 0.3 ± 0.3(stat) -0.3+0.4(syst) events. The cross section measured in a phase-space region with good detector acceptance and for dilepton masses within the range 66 to 116 GeV is σZZ→ℓ+ℓ-ℓ+ℓ-fid = 19.4 -5.2+6.3(stat) -0.7+0.9(syst) ±0.7(lumi) fb. The resulting total cross section for on-shell ZZ production, σZZtot = 8.5 -2.3+2.7(stat) -0.3+0.4(syst) ±0.3(lumi) pb, is consistent with the standard model expectation of 6.5 -0.2+0.3  pb calculated at the next-to-leading order in QCD. Limits on anomalous neutral triple gauge boson couplings are derived.