Skip to Main content Skip to Navigation
Theses

Measurement of Top Pair Production Cross-Section in l + jets Channels in ATLAS at 7 TeV

Abstract : The essential purpose of the thesis is to measure the top pair cross section in lepton+jets channels in the Atlas experiment at Large Hadron Collider (LHC). The analysis is using the proton-proton collision data at 7 TeV collected in 2010 with a luminosity of 33.7 pb-1. The event selection is based on the signature of ttbar topology with 1 electron or muon, large missing transverse energy and at least 4 jets. The QCD multijet background is measured with the data driven “Matrix Method”. Three data driven methods are applied to measure the W+jets background, the charge asymmetry method, the Berends Scaling method and the method combining both. Other backgrounds are estimated from MC.The number of signal ttbar events are obtained by fitting the distribution of the number of b-tagged jet, when the b-tagging efficiency is simultaneously fitted. The ttbar cross section is measured to be 148.1±34.9 pb. It is consistent with the Standard Model prediction at NNLO calculated by Hathor tool. It also agrees with the measurements from other methods. With more collision data in 2011, one can expect a more precise measurement on ttbar cross section.
Complete list of metadatas

Cited literature [59 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00663207
Contributor : Abes Star :  Contact
Submitted on : Thursday, January 26, 2012 - 1:27:53 PM
Last modification on : Tuesday, July 7, 2020 - 3:04:50 AM
Long-term archiving on: : Friday, April 27, 2012 - 2:33:54 AM

File

VD_Yu_Jie_15052011.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-00663207, version 1

Collections

Citation

Jie Yu. Measurement of Top Pair Production Cross-Section in l + jets Channels in ATLAS at 7 TeV. Other [cond-mat.other]. Université Paris Sud - Paris XI; Nanjing University (Chine), 2011. English. ⟨NNT : 2011PA112055⟩. ⟨tel-00663207⟩

Share

Metrics

Record views

360

Files downloads

254