Measurements of electroweak $W^{\pm }Z$ boson pair production in association with two jets in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

Abstract

Measurements of integrated and differential cross-sections for electroweak $W^{\pm }Z$ production in association with two jets ($W^{\pm }Zjj$) in proton$-$proton collisions are presented. The data collected by the ATLAS detector at the Large Hadron Collider from $2015$ to $2018$ at a centre-of-mass energy of $\sqrt{s}=13$ TeV are used, corresponding to an integrated luminosity of $140$ fb${}^{-1}$. The $W^{\pm }Zjj$ candidate events are reconstructed using leptonic decay modes of the gauge bosons. Events containing three identified leptons, either electrons or muons, and two jets are selected. Processes involving pure electroweak $W^{\pm }Zjj$ production at Born level are separated from $W^{\pm }Zjj$ production involving a strong coupling. The measured integrated fiducial cross-section of electroweak $W^{\pm }Zjj$ production per lepton flavour is ${\sigma }_{WZjj-\mathrm{EW}\to {\ell }^{{}^{\prime }}\nu \ell \ell jj}=0.368\pm 0.037(stat.)\pm 0.059(syst.)\pm 0.003(lumi.)\mathrm{fb}$, where $\ell$ and ${\ell }^{{}^{\prime }}$ are either an electron or a muon. Respective cross-sections of electroweak and strong $W^{\pm }Zjj$ production are measured separately for events with exactly two jets or with more than two jets, and in three bins of the invariant mass of the two jets. The inclusive $W^{\pm }Zjj$ production cross-section, without separating electroweak and strong production, is also measured to be ${\sigma }_{WZjj\to {\ell }^{{}^{\prime }}\nu \ell \ell jj}=1.462\pm 0.063(stat.)\pm 0.118(syst.)\pm 0.012(lumi.)\mathrm{fb}$, per lepton flavour. The inclusive $W^{\pm }Zjj$ production cross-section is measured differentially for several kinematic observables. Finally, the measurements are used to constrain anomalous quartic gauge couplings by extracting 95% confidence level intervals on dimension-$8$ operators.

54 pages in total, author list starting page 37, 13 figures, 5 tables, published in JHEP 06 (2024) 192. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2018-35/