Electroweak production of two jets in association with a Z boson in proton–proton collisions at $\sqrt{s}=$ 13 $\phantom{\rule{0.166667em}{0ex}}\text{TeV}$

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.