Study of Z ll decays at s = 8 TeV with the ATLAS detector

Abstract This paper presents a study of Z ll Z → l l γ decays with the ATLAS detector at the Large Hadron Collider. The analysis uses a proton–proton data sample corresponding to an integrated luminosity of 20. 2 fb ^-1 - 1 collected at a centre-of-mass energy s s = 8 TeV. Integrated fiducial cross-sections together with normalised differential fiducial cross-sections, sensitive to the kinematics of final-state QED radiation, are obtained. The results are found to be in agreement with state-of-the-art predictions for final-state QED radiation. First measurements of Z ll Z → l l γ γ decays are also reported.