Search for flavour-changing neutral-current couplings between the top quark and Higgs boson in multilepton final states with the ATLAS experiment / Marvin Emin Geyik. Wuppertal, Februar 2024
Inhalt
- Introduction
- 1 The Standard Model of Particle Physics
- 1.1 Theoretical formulation of the Standard Model
- 1.1.1 The Electroweak Interaction
- 1.1.2 The Higgs Mechanism
- 1.1.3 Quantum Chromodynamics
- 1.1.4 FCNC processes in the Standard Model
- 1.2 Experimental Evidence for the Standard Model
- 1.3 Limitations of the Standard Model
- 2 FCNC Interactions in Theories Beyond the Standard Model
- 2.1 Theoretical Models of Enhanced tHq FCNC Interactions
- 2.1.1 Two Higgs Doublet Models
- 2.1.2 Minimal Supersymmetric Standard Models
- 2.1.3 R-parity violating Supersymmetric Models
- 2.1.4 Randall-Sundrum Models
- 2.2 tHq FCNC Interactions in Effective Field Theories
- 2.2.1 FCNC Top-Quark Decay and Production
- 2.2.2 Observables of EFT FCNC Couplings
- 2.2.3 tHq FCNC Interactions in Multilepton Final States
- 2.3 Searches for tHq FCNC interactions at the LHC
- 3 The ATLAS Detector at the Large Hadron Collider
- 4 Simulation of Proton-Proton Collisions
- 4.1 Factorisation of PDFs and Cross-Section
- 4.2 Cross-sections at fixed order
- 4.3 Parton Shower and Hadronisation
- 4.4 Resolving of Ambiguities
- 4.5 Simulation of Detector Interaction and Pile-up
- 5 Samples of Data and Simulated Events
- 6 Event Reconstruction
- 6.1 Tracks and Primary Vertices
- 6.2 Electrons
- 6.3 Muons
- 6.4 Jets
- 6.5 Flavour Tagging
- 6.6 Overlap Removal
- 6.7 Missing Transverse Momentum
- 7 Background Estimation
- 7.1 Non-prompt Lepton Background
- 7.1.1 Definition of Non-prompt Lepton Templates
- 7.1.2 Heavy-Flavour Decay Leptons
- 7.1.3 Q-misID Electrons
- 7.2 Prompt Lepton Background Processes
- 8 Event Selection
- 9 Separation of Signal and Background Processes
- 9.1 High-level Reconstruction Algorithms
- 9.1.1 Combination of Basic Kinematic Parameters
- 9.1.2 Recursive Jigsaw Reconstruction
- 9.1.3 Dedicated Algorithms in the 3l Final State
- 9.2 Multivariate Analysis using Artificial Neural Networks
- 10 Systematic Uncertainties
- 10.1 Experimental Uncertainties
- 10.2 Modelling Uncertainties
- 10.3 Preprocessing of Systematic Uncertainties
- 11 Methods of Statistical Analysis
- 11.1 The Profile Likelihood Fit
- 11.2 Hypothesis Testing
- 11.3 Transformation of tHq FCNC Upper Limits
- 12 Results of the Statistical Analysis
- 12.1 Selection of Fitted Distributions
- 12.2 Background-Only Fit
- 12.3 Full Fit to Data
- 12.4 Upper Exclusion Limits on tHq FCNC Couplings
- Conclusion
- A The tHq FCNC Signal Process
- B Event Selection
- C Separation of Signal and Background
- D Systematic Uncertainties
- E Results of the Statistical Analysis
- Bibliography
- Acknowledgements