Measurement of ZZ production in pp collisions at sqrt(s)=7 TeV and limits on anomalous ZZZ and ZZgamma couplings with the ATLAS detector

TL;DR

This paper reports a measurement of ZZ production cross section at 7 TeV with the ATLAS detector, compares it to Standard Model predictions, and sets limits on anomalous ZZZ and ZZγ couplings.

Contribution

First measurement of ZZ production cross section at 7 TeV using ATLAS data, including limits on anomalous gauge couplings.

Findings

Measured total ZZ cross section: 6.7 pb with uncertainties.

Results are consistent with Standard Model predictions.

Set limits on anomalous neutral triple gauge couplings.

Abstract

A measurement of the ZZ production cross section in proton-proton collisions at sqrt(s) = 7 TeV using data recorded by the ATLAS experiment at the Large Hadron Collider is presented. In a data sample corresponding to an integrated luminosity of 4.6 fb-1 collected in 2011, events are selected that are consistent either with two Z bosons decaying to electrons or muons or with one Z boson decaying to electrons or muons and a second Z boson decaying to neutrinos. The ZZ*->llll and ZZ->llnunu cross sections are measured in restricted phase-space regions. These results are then used to derive the total cross section for ZZ events produced with both Z bosons in the mass range 66 to 116 GeV, sigmaZZtot = 6.7 +-0.7 +0.4-0.3 +-0.3 pb, which is consistent with the Standard Model prediction of 5.89+0.22-0.18 pb calculated at next-to-leading order in QCD. The normalized differential cross sections in bins of various kinematic variables are presented. Finally, 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.