Title Information
Title
Measurement of the Top Quark Mass in the Dilepton Channel at the CMS Experiment
Name: Personal
Name Part
Avetisyan, Aram
Role
Role Term: Text
creator
Origin Information
Copyright Date
2012
Physical Description
Extent
xviii, 157 p.
digitalOrigin
born digital
Note
Thesis (Ph.D. -- Brown University (2012)
Name: Personal
Name Part
Narain, Meenakshi
Role
Role Term: Text
Director
Name: Personal
Name Part
Cutts, David
Role
Role Term: Text
Reader
Name: Personal
Name Part
Guralnik, Gerald
Role
Role Term: Text
Reader
Name: Corporate
Name Part
Brown University. Physics
Role
Role Term: Text
sponsor
Genre (aat)
theses
Subject
Topic
CMS
Subject
Topic
LHC
Subject
Topic
Top Quark
Record Information
Record Content Source (marcorg)
RPB
Record Creation Date (encoding="iso8601")
20121023
Language
Language Term: Code (ISO639-2B)
eng
Language Term: Text
English
Abstract
The top quark is the heaviest of the six observed quarks in the Standard Model (SM). Its mass is more than an order of magnitude greater than any other SM fermion, and hence a precise measurement of this mass provides constraints on the Higgs boson and many other hypothetical particles. In this analysis, we measure the mass of the top quark using the 36 pb-1 of data collected by the CMS experiment from the collisions of the LHC at √s = 7 TeV center-of-mass energy during the year 2010.<br/> <br/> At the LHC, top-antitop quark pairs are expected to be produced predominantly through gluon fusion and decay almost exclusively to two W bosons and a bottom-antibottom quark pair. We consider a W boson decay leptonic if it results in a muon or an electron and label the decay channel based on the number of leptonic W decays. Here, we report on the measurement of the mass of the top quark in the dilepton channel.<br/> <br/> The dilepton final state consists of two jets originating from the bottom quarks, two charged leptons and two neutrinos. The latter are not visible to our detector, which results in six unknown parameters. Five of these can be solved for using constraints arising from transverse momentum conservation, the mass of the W boson and the equality of masses of the top and antitop quarks. To deal with the under-constrained system, we use the Analytical Matrix Weighting Technique. This method iterates over many values of the top quark mass and analytically solves the system using the top quark mass as the missing constraint. Each value of the mass is given a weight based on the kinematics of top quark production and decay. The mass estimator for each event is the value with the highest weight and the mass of the top quark is extracted from these estimators by performing a maximum likelihood fit to simulated templates constructed for various masses. The measured value of the top quark mass from this analysis is mt = 175.8 ± 4.9 (stat) ± 4.5 (syst) GeV/c2.
Identifier: DOI
10.7301/Z07D2SFG
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In Copyright
Access Condition: restriction on access
Collection is open for research.
Type of Resource (primo)
dissertations