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A MEASUREMENT OF THE TRIPLE GAUGE BOSON
COUPLINGS AND W BOSON POLARISATION
IN W-PAIR PRODUCTION AT LEP2

JONATHAN P. COUCHMAN
UNIVERSITY COLLEGE LONDON

SUBMITTED TO THE UNIVERSITY OF LONDON
IN FULFILMENT OF THE REQUIREMENTS
FOR THE AWARD OF THE DEGREE OF
DOCTOR OF PHILOSOPHY.
OCTOBER 2000.

Abstract
Acknowledgements
Contents
List of Figures
List of Tables
The Standard Model
- The Fundamental Particles
  - The Fermions
    - The Leptons
    - The Quarks
  - Bosons: The Force-carrying Particles
- Spin, Helicity and Polarisation
- The Electroweak Theory
The LEP Accelerator and OPAL Detector
- The LEP Accelerator
- The OPAL Detector
Trilinear Gauge Boson Couplings and W-Pair Production.
- The TGC Lagrangian
  - Constraining the Number of Parameters
- TGCs and W Pair Production at LEP
  - Polarisation of the W-Pair System
- W Boson Decays
- Polarisation Properties
  - The Two-Particle Joint Spin Density Matrix
  - The Single W Spin Density Matrix
    - CPT and CP-Invariance
Application to Data Events
- Calculating the SDM Elements
- Calculating the Polarised Cross-Sections
- Considerations for Real Events
- Events with ${\rm q}\bar{\rm q}\ell\bar{\nu}_{\ell}$ Final States
Selection of Data
- Background Events
- Monte Carlo Generators
- Detector Simulation
- Data Selection and Reconstruction
Extracting the TGCs
- The $\chi ^{2}$ Fit to the Single W SDM Elements
  - Overcoming Problems of Detector Effects.
    - Reweighting Monte Carlo
  - Systematic Checks of the SDM Fit Method
- The $\chi ^{2}$ Fit to the $\cos\theta_{\rm W}$ Distribution
  - Systematic Checks of the $\cos\theta_{\rm W}$ Fit Method
- The Combined Fit
- Fit to Many Subsamples
TGCs from 189 GeV Data
- Fit to Single W SDM Elements
- Fit to the Normalised $\cos\theta_{\rm W}$ Distribution
- The Combined Fit
- Including Systematics
Method to Measure Polarised Cross-sections
- Correcting for Detector Effects
- Correction for Background
Measurements of Polarised Cross-sections from Data
- Individual W Polarised Cross-Sections
- W-Pair Polarised Cross-Sections
Evaluation of Systematic Uncertainties
- Uncertainties in Electroweak Modelling
- Jet Fragmentation
- Jet Reconstruction
- Background
- Detector Simulation and Lepton Response
- Overall Systematic Uncertainty
Conclusions
- Tests of CP-Invariance
- Measurement of TGCs
- Measurement of W Polarisation
Summations to Calculate SDM Elements
- Summation to Calculate Single W SDM Elements
- Summation to Calculate Two-Particle Joint W SDM Elements
Stability of the $\chi ^{2}$ fit
Bibliography
About this document ...

Jonathan Couchman 2002-11-04