Electroweak production of two jets in association with a Z boson in proton-proton collisions at √s = 13 TeV

Abstract

A measurement of the electroweak (EW) production of two jets in association with a \(Z\) boson in proton-proton collisions at \(\sqrt{s}=13\phantom{\rule{0.166667em}{0ex}}\text{TeV}\) is presented, based on data recorded in 2016 by the CMS experiment at the LHC corresponding to an integrated luminosity of 35.9 \(\phantom{\rule{0.166667em}{0ex}}{\text{fb}}^{\text{--}1}\). The measurement is performed in the \(\ell \ell \mathrm{jj}\) final state with \(\ell \) including electrons and muons, and the jets j corresponding to the quarks produced in the hard interaction. The measured cross section in a kinematic region defined by invariant masses \({m}_{\ell \ell }>50\phantom{\rule{0.166667em}{0ex}}\text{GeV}\), \({m}_{\mathrm{jj}}>120\phantom{\rule{0.166667em}{0ex}}\text{GeV}\), and transverse momenta \({p}_{Tj}>25\phantom{\rule{0.166667em}{0ex}}\text{GeV}\) is \({\sigma }_{\mathrm{EW}}\left(\ell \ell \mathrm{jj}\right)=534±20\phantom{\rule{0.166667em}{0ex}}\text{(stat)}±57\phantom{\rule{0.166667em}{0ex}}\text{(syst) fb}\), in agreement with leading-order standard model predictions. The final state is also used to perform a search for anomalous trilinear gauge couplings. No evidence is found and limits on anomalous trilinear gauge couplings associated with dimension-six operators are given in the framework of an effective field theory. The corresponding 95% confidence level intervals are \(-2.6<{c}_{\mathrm{WWW}}/{\Lambda }^{2}<2.6\phantom{\rule{0.166667em}{0ex}}{\text{TeV}}^{-2}\) and \(-8.4<{c}_{W}/{\Lambda }^{2}<10.1\phantom{\rule{0.166667em}{0ex}}{\text{TeV}}^{-2}\). The additional jet activity of events in a signal-enriched region is also studied, and the measurements are in agreement with predictions.