Jet energy scale and its systematic uncertainty for jets produced in proton-proton collisions at sqrt(s) = 7 TeV and measured with the ATLAS detector

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Journal Article


ATLAS Collaboration

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The first determination of the jet energy scale (JES) and the evaluation of its systematic uncertainty for inclusive jets measured in the ATLAS detector from proton-proton collisions at sqrt(s) = 7 TeV are described. The energy scale of jets measured in the ATLAS calorimeters is calibrated on average to the hadronic scale using a method based on a simulated Monte Carlo QCD jets sample. This Monte Carlo simulation has been validated with data collected by the ATLAS detector at sqrt(s) = 900 GeV and sqrt(s) = 7 TeV. The energy contribution of multiple proton-proton interactions to calorimeter jets is not accounted for in the current JES calibration; it is included as a separate contribution to the systematic uncertainty, and it is shown to contribute less than 2%. The JES systematic uncertainty is evaluated by comparing the nominal results to Monte Carlo simulations using alternative detector configurations, alternative hadronic shower and physics models, and by comparing the relative response of jets across pseudo-rapidity between data and simulation, using a total integrated luminosity of 7 nb-1. The calorimeter contribution to the JES uncertainty is verified with a method that propagates the uncertainties on the single energy deposits comprised in jets. This estimate is based on single particle studies, from in-situ and test beam measurements. For inclusive jets with transverse momentum greater than 20 GeV and pseudo-rapidity smaller than 2.8, the jet energy scale is determined with an uncertainty smaller than 10%.


Professor Perez worked in collaboration with the ATLAS collaboration.