Jet energy measurement and its systematic uncertainty in proton–proton collisions at s√=7 TeV with the ATLAS detector

Aad, G. et al. (2015) Jet energy measurement and its systematic uncertainty in proton–proton collisions at s√=7 TeV with the ATLAS detector. European Physical Journal C, 75, 17. (doi:10.1140/epjc/s10052-014-3190-y)

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Abstract

The jet energy scale (JES) and its systematic uncertainty are determined for jets measured with the ATLAS detector using proton–proton collision data with a centre-of-mass energy of s√=7 TeV corresponding to an integrated luminosity of 4.7 fb −1 . Jets are reconstructed from energy deposits forming topological clusters of calorimeter cells using the anti- kt algorithm with distance parameters R=0.4 or R=0.6 , and are calibrated using MC simulations. A residual JES correction is applied to account for differences between data and MC simulations. This correction and its systematic uncertainty are estimated using a combination of in situ techniques exploiting the transverse momentum balance between a jet and a reference object such as a photon or a Z boson, for 20≤pjetT<1000 GeV and pseudorapidities |η|<4.5 . The effect of multiple proton–proton interactions is corrected for, and an uncertainty is evaluated using in situ techniques. The smallest JES uncertainty of less than 1 % is found in the central calorimeter region ( |η|<1.2 ) for jets with 55≤pjetT<500 GeV . For central jets at lower pT , the uncertainty is about 3 %. A consistent JES estimate is found using measurements of the calorimeter response of single hadrons in proton–proton collisions and test-beam data, which also provide the estimate for pjetT>1 TeV. The calibration of forward jets is derived from dijet pT balance measurements. The resulting uncertainty reaches its largest value of 6 % for low- pT jets at |η|=4.5 . Additional JES uncertainties due to specific event topologies, such as close-by jets or selections of event samples with an enhanced content of jets originating from light quarks or gluons, are also discussed. The magnitude of these uncertainties depends on the event sample used in a given physics analysis, but typically amounts to 0.5–3 %.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Oropeza Barrera, Mrs Cristina and Buckley, Dr Andy and Thompson, Dr Stan and Robson, Professor Aidan and O'Shea, Professor Val and Moraes, Mr Arthur and Buzatu, Dr Adrian and Ferrando, Dr James and Saxon, Professor David and Kar, Dr Deepak and Collins-Tooth, Dr Christopher and Bussey, Dr Peter and Buttar, Professor Craig and D'Auria, Dr Saverio and Wright, Mr Michael and Wraight, Dr Kenneth and Smith, Professor Kenway and Doherty, Mr Thomas and Britton, Professor David and Doyle, Professor Anthony and Allwood-Spiers, Sarah and St Denis, Dr Richard and Gul, Dr Umar and Bates, Dr Richard and Ferreira De Lima, Dr Danilo and Ferrag, Dr Samir
Authors: Aad, G., Abajyan, T., Allwood-Spiers, S., Bates, R.L., Britton, D.I., Buckley, A., Bussey, P., Buttar, C.M., Buzatu, A., Collins-Tooth, C., D'Auria, S., Doherty, T., Doyle, A.T., Ferrag, S., Ferrando, J., Ferreira De Lima, D.E., Gemmell, A., Gul, U., Gutierrez Ortiz, N.G., Kar, D., Moraes, A., O'Shea, V., Oropeza Barrera, C., Quilty, D., Ravenscroft, T., Robson, A., Saxon, D.H., Smith, K., St Denis, R.D., Steele, G., Thompson, A.S., Wraight, K., and Wright, M.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:European Physical Journal C
Publisher:Springer
ISSN:1434-6044
ISSN (Online):1434-6052
Published Online:15 January 2015
Copyright Holders:Copyright © 2014 CERN for the benefit of the ATLAS Collaboration
First Published:First published in European Physical Journal C 75:17
Publisher Policy:Reproduced under a Creative Commons License
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