Measurement of t-tbar Forward-backward Asymmetry in Large Hadron Collider

[摘要] This thesis presents a measurement of Forward-Backward Asymmetry($AFB$) in $tbar$ production. The data sample corresponds to $19.7,extrm{fb}^{-1}$ of integrated luminosity in proton-proton collisions at $sqrt{s} = 8,extrm{TeV}$ collected by the CMS experiment at the LHC. Events selected contain a single isolated muon or electron, with four or five jets of which two are b-tagged. A template technique is used to extract the asymmetry from the top quark kinematic distributions. This technique is based upon an extension of the tree-level cross section for $qqbar$ initial states that sensitively isolates $qqbar$ from $mathrm{gg/qg}$ initial states. The measured $AFB$ and relative aboundance of $qqbar$ initiated $tbar$ are measured and compared to both theoretical calculation and results from D0 and CDF experiments of Tevatron.

[发布机构] Johns Hopkins University

[效力级别] forward-backward asymmetry

[关键词] ttbar;forward-backward asymmetry;LHC;CMS;top physics;high energy physcis;Physics