Measurement of $t\bar{t}$ spin correlation and W polarization with the $t\bar{t}$ di-leptonic channel events at ATLAS

The Standard Model (SM) is a self-consistent theory that explains the elementary particles and interactions. To further confirm the SM theory, the Large Hadron Collider (LHC) was build at CERN to accurately validate the SM and search for the last SM particle, the Higgs boson.

Detalles Bibliográficos
Autor principal: Chen, Liming
Lenguaje:eng
Publicado: 2013
Materias:
Particle Physics - Experiment
Acceso en línea:http://cds.cern.ch/record/1632177
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author Chen, Liming
author_facet Chen, Liming
author_sort Chen, Liming
collection CERN
description The Standard Model (SM) is a self-consistent theory that explains the elementary particles and interactions. To further confirm the SM theory, the Large Hadron Collider (LHC) was build at CERN to accurately validate the SM and search for the last SM particle, the Higgs boson.
id cern-1632177
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2013
record_format invenio
spelling cern-16321772019-09-30T06:29:59Zhttp://cds.cern.ch/record/1632177engChen, LimingMeasurement of $t\bar{t}$ spin correlation and W polarization with the $t\bar{t}$ di-leptonic channel events at ATLASParticle Physics - ExperimentThe Standard Model (SM) is a self-consistent theory that explains the elementary particles and interactions. To further confirm the SM theory, the Large Hadron Collider (LHC) was build at CERN to accurately validate the SM and search for the last SM particle, the Higgs boson.The multipurpose ATLAS detector is set up at one of the LHC interaction point. It nearly covers the whole solid angle and detects particles over a wide range of energies with the help of well designed sub-detectors. The ATLAS is designed and quite capable of recording the proton-proton (pp) collision at a center-of-mass $\sqrt{s} = 14$ TeV allowing luminosity of $10^{34}\,cm^{-2}\,s^{-1}$, where a large number of $t\bar{t}$ events is produced per year for precise top quark property studies.Events that decay exactly two opposite sign isolated leptons, at least two high transverse momentum jets and large missing $E_T$, are considered as di-leptonic $t\bar{t}$ signal events. To suppress the background at least one of jets must be b-tagged. This channel has a lesser branching ratio with respect to other channels but its features are able to reject the QCD and W+jet backgrounds significantly.This thesis presents the differential measurement of $t\bar{t}$ spin correlation and W boson polarization using the 4.6 $\ifb$ pp collision data at $\sqrt{s} = 7$ TeV recorded in 2011. Both of the measurements apply Bayesian Unfolding algorithm to extract the parton "true" spectrum from the "observed" one. The regularization is well studied in the different analyses. The combined unfolded spectrum of $t\bar{t}$ spin correlation agrees with the SM NLO prediction at differential level. The extracted W boson helicity combined results of $F_0$, $F_L$ and $F_R$ fractions are also consistent with SM NLO values.CERN-THESIS-2013-215oai:cds.cern.ch:16321772013-11-28T14:12:16Z
spellingShingle Particle Physics - Experiment
Chen, Liming
Measurement of $t\bar{t}$ spin correlation and W polarization with the $t\bar{t}$ di-leptonic channel events at ATLAS
title Measurement of $t\bar{t}$ spin correlation and W polarization with the $t\bar{t}$ di-leptonic channel events at ATLAS
title_full Measurement of $t\bar{t}$ spin correlation and W polarization with the $t\bar{t}$ di-leptonic channel events at ATLAS
title_fullStr Measurement of $t\bar{t}$ spin correlation and W polarization with the $t\bar{t}$ di-leptonic channel events at ATLAS
title_full_unstemmed Measurement of $t\bar{t}$ spin correlation and W polarization with the $t\bar{t}$ di-leptonic channel events at ATLAS
title_short Measurement of $t\bar{t}$ spin correlation and W polarization with the $t\bar{t}$ di-leptonic channel events at ATLAS
title_sort measurement of $t\bar{t}$ spin correlation and w polarization with the $t\bar{t}$ di-leptonic channel events at atlas
topic Particle Physics - Experiment
url http://cds.cern.ch/record/1632177
work_keys_str_mv AT chenliming measurementoftbartspincorrelationandwpolarizationwiththetbartdileptonicchanneleventsatatlas

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