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Luminosity determination and simulation of the LUCID detector at the ATLAS experiment

Groth-Jensen, Jacob LU (2010)
Abstract
The aim of this thesis is to describe how the luminosity can be measured in the ATLAS experiment at the Large Hadron Collider. Luminosity is a fundamental quantity that is used in most physics studies at the LHC. For example in order to measure cross sections. Firstly, the detector description of LUCID which has been implemented in the global ATLAS software framework is described and validated. Secondly, algorithms to determine the luminosity are derived and the simulation of LUCID is used to test the precision of these. Thirdly, the feasibility of using Z0 production as a alternative way to measure the luminosity or to calibrate LUCID is studied. The performance of LUCID is addressed by comparing results from the early 2010 data-taking... (More)
The aim of this thesis is to describe how the luminosity can be measured in the ATLAS experiment at the Large Hadron Collider. Luminosity is a fundamental quantity that is used in most physics studies at the LHC. For example in order to measure cross sections. Firstly, the detector description of LUCID which has been implemented in the global ATLAS software framework is described and validated. Secondly, algorithms to determine the luminosity are derived and the simulation of LUCID is used to test the precision of these. Thirdly, the feasibility of using Z0 production as a alternative way to measure the luminosity or to calibrate LUCID is studied. The performance of LUCID is addressed by comparing results from the early 2010 data-taking period with predictions from the simulations. Several techniques to calculate the efficiency of LUCID are described and the results for each method is presented. Several classes of luminosity algorithms studied and applied to the signals from the LUCID detector. The first class has been designed to be used online and to extract the luminosity using two different counting methods, namely event and hit counting. An empirical model is introduced as an attempt to parametrize the non-linear effect by polynomial fits to the event and hit rate. A final attempt to minimize the non-linear effects was presented by introducing a new method that uses the full hit multiplicity distribution to determine the luminosity offline. A method to measure the absolute luminosity using the production of Z0 boson is outlined . Each step of the procedure to select Z → μ+μ− events has been studied in detail using Monte Carlo simulations of the various background and signal samples. The selection procedure is applied to a data sample recorded by the ATLAS detector over a period of 5 month and the resulting integrated luminosity is determined from the number of reconstructed Z → μ+μ− events. (Less)
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author
supervisor
opponent
  • Dr. Camporesi, Tiziano, CERN
organization
publishing date
type
Thesis
publication status
published
subject
keywords
LHC, LUCID, Luminosity determination, Performance study, ATLAS, Gauge boson production, Fysicumarkivet A:2010:Groth-Jensen
pages
226 pages
publisher
Lund University , Department of physics
defense location
lecture hall B department of physics
defense date
2010-12-16 09:15
ISBN
978-91-7473-060-9
project
ATLAS
language
English
LU publication?
yes
id
d779d3d1-e2b5-4034-bba2-bd9f96a2847c (old id 1718706)
date added to LUP
2010-11-19 12:07:48
date last changed
2016-09-19 08:45:09
@phdthesis{d779d3d1-e2b5-4034-bba2-bd9f96a2847c,
  abstract     = {The aim of this thesis is to describe how the luminosity can be measured in the ATLAS experiment at the Large Hadron Collider. Luminosity is a fundamental quantity that is used in most physics studies at the LHC. For example in order to measure cross sections. Firstly, the detector description of LUCID which has been implemented in the global ATLAS software framework is described and validated. Secondly, algorithms to determine the luminosity are derived and the simulation of LUCID is used to test the precision of these. Thirdly, the feasibility of using Z0 production as a alternative way to measure the luminosity or to calibrate LUCID is studied. The performance of LUCID is addressed by comparing results from the early 2010 data-taking period with predictions from the simulations. Several techniques to calculate the efficiency of LUCID are described and the results for each method is presented. Several classes of luminosity algorithms studied and applied to the signals from the LUCID detector. The first class has been designed to be used online and to extract the luminosity using two different counting methods, namely event and hit counting. An empirical model is introduced as an attempt to parametrize the non-linear effect by polynomial fits to the event and hit rate. A final attempt to minimize the non-linear effects was presented by introducing a new method that uses the full hit multiplicity distribution to determine the luminosity offline. A method to measure the absolute luminosity using the production of Z0 boson is outlined . Each step of the procedure to select Z → μ+μ− events has been studied in detail using Monte Carlo simulations of the various background and signal samples. The selection procedure is applied to a data sample recorded by the ATLAS detector over a period of 5 month and the resulting integrated luminosity is determined from the number of reconstructed Z → μ+μ− events.},
  author       = {Groth-Jensen, Jacob},
  isbn         = {978-91-7473-060-9},
  keyword      = {LHC,LUCID,Luminosity determination,Performance study,ATLAS,Gauge boson production,Fysicumarkivet A:2010:Groth-Jensen},
  language     = {eng},
  pages        = {226},
  publisher    = {Lund University , Department of physics},
  school       = {Lund University},
  title        = {Luminosity determination and simulation of the LUCID detector at the ATLAS experiment},
  year         = {2010},
}