Measurement of the WZ production cross section and limits on anomalous triple gauge couplings in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector

TL;DR

This paper measures the WZ production cross section in proton-proton collisions at 7 TeV using ATLAS data, and sets limits on possible deviations from the Standard Model in triple gauge couplings.

Contribution

First measurement of WZ production cross section at 7 TeV with ATLAS, including limits on anomalous triple gauge couplings.

Findings

Measured WZ cross section: 20.5 pb with uncertainties.

Observed 71 candidate events with expected background of 12.1 events.

Set limits on anomalous triple gauge couplings.

Abstract

This Letter presents a measurement of WZ production in 1.02 fb^-1 of pp collision data at sqrt(s) = 7 TeV collected by the ATLAS experiment in 2011. Doubly leptonic decay events are selected with electrons, muons and missing transverse momentum in the final state. In total 71 candidates are observed, with a background expectation of 12.1 +/- 1.4(stat.) +4.1/-2.0(syst) events. The total cross section for WZ production for Z gamma^* masses within the range 66 GeV to 116 GeV is determined to be sigma_WZ^tot = 20.5 +3.1/-2.8(stat.) +1.4/-1.3(syst.) +0.9/-0.8(lumi.)pb, which is consistent with the Standard Model expectation of 17.3 +1.3/-0.8 pb. Limits on anomalous triple gauge boson couplings are extracted.