Studies of Zγ electroweak production in association with a high-mass di-jet system in pp collisions at √s = 8 TeV with the ATLAS detector LeptonPhoton Conference, 7-12 August 2017,GuangZhou China Motivation Test of the Electroweak (EWK) Sector search for anomalous quartic couplings (aQGC) First probe of neutral aQGC at ATLAS in 2->2 process in two decay channels: Charged lepton channel: cleaner final state, various fiducial cross sections measured (different fractions of EWK and QCD production) and aQGC limits Neutrino channel: complex backgrounds but large branching ratio allows extraction of aQGC limits, cross-section measured only in high 𝛾 ET region. Zγjj production topologies Zγjj cross section measurement Z(ll)γjj channel fid. cross section measured by a simultaneous likelihood fit to distributions of Zy-centrality in CR and SR, constraining Zγ-QCD bgd cross section measured in llγjj channel EWK-only in SR and EWK+QCD in both CR and SR Z(νν)γjj fid. cross section measured in an aQGC sensitive high Et(γ) region via log-likelihood fit Control regions (CR) Search regions (SR) Measured Z(l+l-)γjj phase space Measured Zγjj fiducial cross section Measured Z(νν)γjj phase space [1] aQGCs Methodology An effective field theory (EFT) [2] with higher-dimensional operators is adopted to parameterize the anomalous couplings The charged anomalous couplings of WWZγ can be induced by fM,x (x=0-7) , fT,x(x=0-7) Neutral aQGCs of ZZZγ and ZZγγ also possible via fM,x Photon ET spectrum is sensitive to aQGCs. EFT Lagrangian[2] aQGCs results Z(l+l-)γjj aQGCs region [1] Z(νν)γjj aQGCs region Reference: [1] The ATLAS Collaboration. , JHEP07(2017)107 [2] C. Degrande et al, Annals Phys. 335 (2013) 21 Zhijun Liang (Institute of High Energy Physics, CAS) On behalf of the ATLAS Collaboration