Determining the Jet Energy Scale uncertainty in the ATLAS detector

Using jets from proton–proton collisions at a centre of mass energy of s = 7 TeV measured with the ATLAS detector at the LHC the Jet Energy Scale and its systematic uncertainty have been determined. Using 2010 data a Jet Energy Scale systematic uncertainty between 2–4% for jet p T > 20 GeV in the pseudo-rapidity region up to | η | = 4.5 has been obtained. This uncertainty was derived from a combination of systematic variations in Monte Carlo simulations and single hadron response measurements performed in situ and using test beam data. The uncertainty is confirmed in in situ methods using 2011 data where a well measured reference object is balanced against the jet.