Measurement of the cross-section for electroweak production of dijets in association with a Z boson in pp collisions at √s = 13TeV with the ATLAS detector

Abstract

The cross-section for the production of two jets in association with a leptonically decaying Zboson (Zj j) is measured in proton–proton collisions at a centre-of-mass energy of 13TeV, using data recorded with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 3.2fb⁻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 σZjjEW=119 ±16 (stat.)±20 (syst.)±2 (lumi.)fb for dijet invariant mass greater than 250GeV, and 34.2 ±5.8 (stat.)±5.5 (syst.)±0.7 (lumi.)fb for dijet invariant mass greater than 1TeV. 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.