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

A measurement of the ZZ production cross section in proton-proton collisions at $sqrt{s} = 7TeV$ using data collected by the ATLAS experiment at the LHC is presented. In a data sample corresponding to an integrated luminosity of 1.02 fb-1, $12$ candidate events of purely leptonically decaying Z bosons with electrons and/or muons in the final state were observed. The expected background contribution is $0.3^{+0.9}_{-0.3} ext{(stat)} ^{+0.4}_{-0.3} ext{(syst)}$ events. %This %corresponds to an excess equivalent to a one sided Gaussian %significance of $ 4.5sigma$. The total cross section for on-shell ZZ production has been determined to be $sigma_{ZZ}^mathrm{tot}= 8.4^{+2.7}_{-2.3} ext{ (stat)}^{+0.4}_{-0.7} ext{ (syst) }pm 0.3 extrm{ (lumi) }pb$ and is compatible with the Standard Model expectation of $6.5^{+0.3}_{-0.2}~pb$ calculated at the next-to-leading order in QCD. Limits on anomalous neutral triple gauge boson couplings are derived.