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Prospects of Observing the Decay B_c -> J/psi + pi and the Alignment Performance in the ATLAS Experiment

Ji, Weina LU (2010)
Abstract
This thesis contains two main aspects of my research work towards physics in proton-proton collisions in the ATLAS experiment at the LHC. First, a Monte Carlo based analysis of the event yield and the mass shape for the ground state of the B_c meson in the hadronic decay channel B_c -> J/psi + pi was studied. The selection criteria have been optimised, the total number of signal events, and the significance of the observation have been estimated for the detector configuration and backgrounds expected at the centre-of-mass energy of 10 TeV with 1 fb^{-1} of integrated luminosity. As the momenta of these decay products are relatively low, compared with the main objectives of the ATLAS physics program, the performance of the inner detector... (More)
This thesis contains two main aspects of my research work towards physics in proton-proton collisions in the ATLAS experiment at the LHC. First, a Monte Carlo based analysis of the event yield and the mass shape for the ground state of the B_c meson in the hadronic decay channel B_c -> J/psi + pi was studied. The selection criteria have been optimised, the total number of signal events, and the significance of the observation have been estimated for the detector configuration and backgrounds expected at the centre-of-mass energy of 10 TeV with 1 fb^{-1} of integrated luminosity. As the momenta of these decay products are relatively low, compared with the main objectives of the ATLAS physics program, the performance of the inner detector is crucial for the low p_T tracking. As a result, the second part of the thesis is focused on the impact of the inner detector alignment on physics. Monte Carlo studies were performed by looking at the reconstructions of the well-known resonances, K_s^0, J/psi, Upsilon and Z^0 in misalignments, particularly the systematic misalignments. Then the performance of two different alignments that have been applied subsequently in ATLAS since the start up of the LHC were investigated using K_s^0 -> pi^+ pi^- events in the current 7 TeV collisions. Finally, I summarise the performance of the inner detector on the early J/psi -> µ^+ µ^- reconstruction in collisions, which is essential for the coming B physics measurements. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Shipsey, Ian, Purdue University, USA
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Weak modes, Inner Detector alignment, B_c ground state, ATLAS, LHC, Resonances, Fysicumarkivet A:2010:Ji
pages
144 pages
defense location
Sal B, Fysiska Institutionen
defense date
2010-09-24 14:00
ISBN
978-91-7473-017-3
language
English
LU publication?
yes
id
985042a9-450e-49bf-ad25-c975b4ca3ba4 (old id 1662451)
date added to LUP
2010-08-31 12:10:42
date last changed
2016-09-19 08:45:18
@phdthesis{985042a9-450e-49bf-ad25-c975b4ca3ba4,
  abstract     = {This thesis contains two main aspects of my research work towards physics in proton-proton collisions in the ATLAS experiment at the LHC. First, a Monte Carlo based analysis of the event yield and the mass shape for the ground state of the B_c meson in the hadronic decay channel B_c -> J/psi + pi was studied. The selection criteria have been optimised, the total number of signal events, and the significance of the observation have been estimated for the detector configuration and backgrounds expected at the centre-of-mass energy of 10 TeV with 1 fb^{-1} of integrated luminosity. As the momenta of these decay products are relatively low, compared with the main objectives of the ATLAS physics program, the performance of the inner detector is crucial for the low p_T tracking. As a result, the second part of the thesis is focused on the impact of the inner detector alignment on physics. Monte Carlo studies were performed by looking at the reconstructions of the well-known resonances, K_s^0, J/psi, Upsilon and Z^0 in misalignments, particularly the systematic misalignments. Then the performance of two different alignments that have been applied subsequently in ATLAS since the start up of the LHC were investigated using K_s^0 -> pi^+ pi^- events in the current 7 TeV collisions. Finally, I summarise the performance of the inner detector on the early J/psi -> µ^+ µ^- reconstruction in collisions, which is essential for the coming B physics measurements.},
  author       = {Ji, Weina},
  isbn         = {978-91-7473-017-3},
  keyword      = {Weak modes,Inner Detector alignment,B_c ground state,ATLAS,LHC,Resonances,Fysicumarkivet A:2010:Ji},
  language     = {eng},
  pages        = {144},
  school       = {Lund University},
  title        = {Prospects of Observing the Decay B_c -> J/psi + pi and the Alignment Performance in the ATLAS Experiment},
  year         = {2010},
}