CERN Accelerating science

ATLAS Slides
Report number	ATL-PHYS-SLIDE-2011-106
Title	Jet Calibration at ATLAS
Author(s)	Camacho, R
Corporate author(s)	The ATLAS collaboration
Submitted by	reina.camacho@cern.ch on 30 Mar 2011
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Free keywords	Jet energy scale ; jets ; calibration ; jet resolution ; Global Sequential Calibration ; Local Cell Weighting ; Global Cell Weighting ; JETETMISS
Abstract	The accurate measurement of jets at high transverse momentum produced in proton proton collision at a centre of mass energy at \sqrt(s)=7 TeV is important in many physics analysis at LHC. Due to the non-compensating nature of the ATLAS calorimeter, signal losses due to noise thresholds and in dead material the jet energy needs to be calibrated. Presently, the ATLAS experiment derives the jet calibration from Monte Carlo simulation using a simple correction that relates the true and the reconstructed jet energy. The jet energy scale and its uncertainty are derived from in-situ measurements and variation in the Monte Carlo simulation. Other calibration schemes have been also developed, they use hadronic cell calibrations or the topology of the jet constituents to reduce hadronic fluctuations in the jet response, improving in that way the jet resolution. The performances of the various calibration schemes using data and simulation, the evaluation of the modelling of the properties used to derive each calibration and the validation in data of the corrections applied by each calibration are presented.