Measurement of the cross section for electroweak production of Zγ in association with two jets and constraints on anomalous quartic gauge couplings in proton–proton collisions at s=8 TeV

A measurement is presented of the cross section for the electroweak production of a Z boson and a photon in association with two jets in proton–proton collisions at s = 8 TeV . The Z bosons are identified through their decays to electron or muon pairs. The measurement is based on data collected with the CMS detector corresponding to an integrated luminosity of 19.7 fb −1 . The electroweak contribution has a significance of 3.0 standard deviations, and the measured fiducial cross section is 1.86 − 0.75 + 0.90 (stat) − 0.26 + 0.34 (syst) ± 0.05 (lumi) fb, while the summed electroweak and quantum chromodynamic total cross section in the same region is observed to be 5.94 − 1.35 + 1.53 (stat) − 0.37 + 0.43 (syst) ± 0.13 (lumi) fb. Both measurements are consistent with the leading-order standard model predictions. Limits on anomalous quartic gauge couplings are set based on the Z γ mass distribution.