UC Berkeley

The cross-section for the production of two jets in association with a leptonically decaying Z boson (Zjj ) is measured in proton–proton collisions at a centre-of-mass energy of 13 TeV, using data recorded with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 3.2 fb−1. The electroweak Zjj cross-section is extracted in a fiducial region chosen to enhance the electroweak contribution relative to the dominant Drell–Yan Zjj process, which is constrained using a data-driven approach. The measured fiducial electroweak cross-section is σ EW Z j j = 119 ± 16 ( s t a t . ) ± 20 ( s y s t . ) ± 2 ( l u m i . ) fb for dijet invariant mass greater than 250 GeV, and 34.2 ± 5.8 ( s t a t . ) ± 5.5 ( s y s t . ) ± 0.7 ( l u m i . ) fb for dijet invariant mass greater than 1 TeV. Standard Model predictions are in agreement with the measurements. The inclusive Zjj cross-section is also measured in six different fiducial regions with varying contributions from electroweak and Drell–Yan Zjj production.