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

ttbar;forward-backward asymmetry;LHC;CMS;top physics;high energy physcis;Physics

Feng, LeiSwartz, Morris L. ;

Johns Hopkins University

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

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/59157/FENG-DISSERTATION-2018.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 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.