Karlsruhe 2011 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 27: QCD II

T 27.3: Vortrag

Dienstag, 29. März 2011, 17:15–17:30, 30.33: 001

ATLAS jet energy scale intercalibration — •Serena Psoroulas, Jürgen Kroseberg, and Norbert Wermes — Physikalisches Institut, Universität Bonn

In the talk, we will show the results on the jet energy scale calibration, studied with the data taken in the 2010 LHC proton-proton collisions.

The ATLAS hadron calorimeter is a non-compensating calorimeter composed of several subdetectors, which use different techniques to measure the energy of hadronic particles. Its calibration is important for physics analysis to ensure a good reconstruction of final states involving jets.

One of the first jet studies performed with the 7 TeV data of LHC concerns the relative response of the calorimeter subdetectors. To perform this analysis, we have selected dijet events in the 2010 LHC data, and studied the imbalance between the transverse momentum of the two jets. In a perfectly reconstructed dijet event, no imbalance is expected: any asymmetry between the two jets is thus an effect of reconstruction inefficiency or of calibration uncertainties. The results of this analysis have been used to estimate the jet energy scale uncertainty of jets reconstructed in the forward region of the detector with respect to the performance of the central region.

Such a method can also be used, with higher integrated luminosity, to provide a data-driven intercalibration of the ATLAS calorimeter, and we will review the future plans in this direction.