Measurement of electroweak production of two jets in association with a Z boson in proton-proton collisions at sqrt(s) = 8 TeV

The purely electroweak (EW) cross section for the production of two jets in association with a Z boson, in proton–proton collisions at √s=8TeV, is measured using data recorded by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 19.7fb-1. The electroweak cross section for the ℓℓjj final state (with ℓ=e or μ and j representing the quarks produced in the hard interaction) in the kinematic region defined by Mℓℓ>50GeV, Mjj>120GeV, transverse momentum pTj>25GeV, and pseudorapidity |ηj|<5, is found to be σEW(ℓℓjj)=174±15(stat)±40(syst)\,fb, in agreement with the standard model prediction. The associated jet activity of the selected events is studied, in particular in a signal-enriched region of phase space, and the measurements are found to be in agreement with QCD predictions.