利用ATLAS探测器寻找标准模型下的希格斯玻色子到双缪子的衰变过程以及TeV能区下的新物理现象
发布时间：2023-12-21 07:37
2012年,希格斯玻色子(Higgs)由大型强子对撞机(LHC)上的ATLAS和CMS实验组通过研究双玻色子衰变道而发现。该粒子的发现完善了标准模型理论并开启了粒子物理研究的新时代。在此之后,为了检验所发现的Higgs是否与标准模型预言相稳合,实验物理学家开展了多项针对Higgs性质的研究,其中包括对Higgs量子数以及其与费米子耦合常数的测量。尽管标准模型可以成功地解释当前大多数存在的粒子以及现象,但它并不是一个完美的理论框架,仍然有一些观测到的现象无法用标准模型理论解释,例如中微子的质量,暗物质以及正反物质不对称等等。因而,寻找超越标准模型的新物理现象也是当前非常重要的研究课题。经过两年多的停机,2015年,LHC在质心系能量提高到13 TeV之后重新开启了第二阶段的取数(Run 2)。伴随着质心系能量的提高,相关物理过程的产生截面都有着显著的增加,从而为探索Higgs的稀有衰变道以及寻找TeV能区下的新物理现象提供了很好的契机。随后经过2015和2016两年的成功运行,LHC上的ATLAS探测器收集到了积分亮度为36.1 fb-1的大量数据。本论文所阐述的两项研究工作即是利用这些...
【文章页数】：173 页
【学位级别】：博士
【文章目录】：
摘要
Abstract
Acknowledgements
Chapter 1 Introduction
Chapter 2 Theory
2.1 The Standard Model of particle physics
2.1.1 Elementary particles in the Standard Model
2.1.2 Theoretical formalism of the Standard Model
2.1.3 The Higgs mechanism
2.2 The Related Theories Beyond the Standard Model
2.2.1 Sequential Standard Model
2.2.2 E6-motivated Z' models
2.2.3 Contact interactions
2.3 Physics at the Large Hadron Collider
2.3.1 Phenomenology of hadronic collision
2.3.2 Higgs boson production at the LHC
Chapter 3 The Large Hadron Collider and the ATLAS Detector
3.1 The Large Hadron Collider
3.1.1 General introduction of the Large Hadron Collider
3.1.2 Luminosity and pile-up
3.2 The ATLAS Detector
3.2.1 Physics requirements and detector overview
3.2.2 Magnet system
3.2.3 Inner Detector
3.2.3.1 Pixel detector
3.2.3.2 The semiconductor tracker
3.2.3.3 Transition radiation tracker
3.2.4 Calorimeters
3.2.4.1 LAr electromagnetic calorimeter
3.2.4.2 Hadronic calorimeters
3.2.5 Muon Spectrometer
3.2.5.1 Monitored drift tube chambers
3.2.5.2 Cathode strip chambers
3.2.5.3 Resistive plate chambers
3.2.5.4 Thin gap chambers
3.2.6 Forward detectors
3.2.7 Trigger system
3.2.7.1 Level-1 Trigger
3.2.7.2 High-level trigger
Chapter 4 Simulation and Object Reconstruction for the ATLAS Experiment
4.1 Detector Simulation
4.1.1 Event generation
4.1.2 Detector simulation
4.1.3 Digitization
4.2 Object Reconstruction
4.2.1 Track
4.2.1.1 Inner detector track
4.2.1.2 Muon spectrometer track
4.2.2 Primary vertex
4.2.3 Electron
4.2.3.1 Electron reconstruction
4.2.3.2 Electron identification
4.2.3.3 Electron isolation
4.2.4 Muon
4.2.4.1 Muon reconstruction
4.2.4.2 Muon identification
4.2.4.3 Muon isolation
4.2.4.4 Muon momentum scale and resolution
4.2.4.5 Impact of ID-MS alignment on high pT muon resolution
4.2.5 Jet
4.2.5.1 Jet reconstruction
4.2.5.2 Jet energy scale calibration
4.2.5.3 b-jet tagging
4.2.6 Missing transverse energy
Chapter 5 Search for Standard Model Higgs Boson with the Dimuon Final State
5.1 Introduction
5.2 Data and MC samples
5.3 Object and Event Selection
5.3.1 Object level selection
5.3.1.1 Muons
5.3.1.2 Jets
5.3.1.3 Electrons
5.3.1.4 ET
miss
5.3.1.5 Overlap removal between objects
5.3.2 Event level selection
5.3.2.1 Z control region
5.3.2.2 Z plus two jets control region
5.3.2.3 Data/MC comparisons for the kinematic variables in thesignal region
5.4 Categorization for the Signal Region
5.4.1 Selection for the VBF enriched categories
5.4.2 Selection for the ggF enriched categories
5.4.3 Event yields in eight signal categories
5.5 Signal and Background Modeling
5.5.1 Signal modeling
5.5.2 Background modeling
5.6 Systematic Uncertainties
5.6.1 Theoretical uncertainties on the signal
5.6.2 Experimental uncertainties on the signal
5.6.3 Spurious signal uncertainty from the background modeling
5.7 Statistical Analysis
5.8 Results
Chapter 6 Search for New Phenomena with the Dilepton Final State
6.1 Introduction
6.2 Monte Carlo Samples
6.2.1 Background samples
6.2.2 Signal samples
6.3 Event Selection
6.3.1 Electron channel
6.3.2 Muon channel
6.4 Background Estimation and Kinematic Distributions
6.4.1 Background estimation
6.4.2 Kinematic distributions
6.5 Systematic Uncertainties
6.6 Statistical Analysis
6.6.1 Log-likelihood ratio test
6.6.2 Exclusion limits with Bayesian approach
6.7 Results
Chapter 7 Summary and Outlook
Bibliography
本文编号：3874011
【文章页数】：173 页
【学位级别】：博士
【文章目录】：
摘要
Abstract
Acknowledgements
Chapter 1 Introduction
Chapter 2 Theory
2.1 The Standard Model of particle physics
2.1.1 Elementary particles in the Standard Model
2.1.2 Theoretical formalism of the Standard Model
2.1.3 The Higgs mechanism
2.2 The Related Theories Beyond the Standard Model
2.2.1 Sequential Standard Model
2.2.2 E6-motivated Z' models
2.2.3 Contact interactions
2.3 Physics at the Large Hadron Collider
2.3.1 Phenomenology of hadronic collision
2.3.2 Higgs boson production at the LHC
Chapter 3 The Large Hadron Collider and the ATLAS Detector
3.1 The Large Hadron Collider
3.1.1 General introduction of the Large Hadron Collider
3.1.2 Luminosity and pile-up
3.2 The ATLAS Detector
3.2.1 Physics requirements and detector overview
3.2.2 Magnet system
3.2.3 Inner Detector
3.2.3.1 Pixel detector
3.2.3.2 The semiconductor tracker
3.2.3.3 Transition radiation tracker
3.2.4 Calorimeters
3.2.4.1 LAr electromagnetic calorimeter
3.2.4.2 Hadronic calorimeters
3.2.5 Muon Spectrometer
3.2.5.1 Monitored drift tube chambers
3.2.5.2 Cathode strip chambers
3.2.5.3 Resistive plate chambers
3.2.5.4 Thin gap chambers
3.2.6 Forward detectors
3.2.7 Trigger system
3.2.7.1 Level-1 Trigger
3.2.7.2 High-level trigger
Chapter 4 Simulation and Object Reconstruction for the ATLAS Experiment
4.1 Detector Simulation
4.1.1 Event generation
4.1.2 Detector simulation
4.1.3 Digitization
4.2 Object Reconstruction
4.2.1 Track
4.2.1.1 Inner detector track
4.2.1.2 Muon spectrometer track
4.2.2 Primary vertex
4.2.3 Electron
4.2.3.1 Electron reconstruction
4.2.3.2 Electron identification
4.2.3.3 Electron isolation
4.2.4 Muon
4.2.4.1 Muon reconstruction
4.2.4.2 Muon identification
4.2.4.3 Muon isolation
4.2.4.4 Muon momentum scale and resolution
4.2.4.5 Impact of ID-MS alignment on high pT muon resolution
4.2.5 Jet
4.2.5.1 Jet reconstruction
4.2.5.2 Jet energy scale calibration
4.2.5.3 b-jet tagging
4.2.6 Missing transverse energy
Chapter 5 Search for Standard Model Higgs Boson with the Dimuon Final State
5.1 Introduction
5.2 Data and MC samples
5.3 Object and Event Selection
5.3.1 Object level selection
5.3.1.1 Muons
5.3.1.2 Jets
5.3.1.3 Electrons
5.3.1.4 ET
miss
5.3.2 Event level selection
5.3.2.1 Z control region
5.3.2.2 Z plus two jets control region
5.3.2.3 Data/MC comparisons for the kinematic variables in thesignal region
5.4 Categorization for the Signal Region
5.4.1 Selection for the VBF enriched categories
5.4.2 Selection for the ggF enriched categories
5.4.3 Event yields in eight signal categories
5.5 Signal and Background Modeling
5.5.1 Signal modeling
5.5.2 Background modeling
5.6 Systematic Uncertainties
5.6.1 Theoretical uncertainties on the signal
5.6.2 Experimental uncertainties on the signal
5.6.3 Spurious signal uncertainty from the background modeling
5.7 Statistical Analysis
5.8 Results
Chapter 6 Search for New Phenomena with the Dilepton Final State
6.1 Introduction
6.2 Monte Carlo Samples
6.2.1 Background samples
6.2.2 Signal samples
6.3 Event Selection
6.3.1 Electron channel
6.3.2 Muon channel
6.4 Background Estimation and Kinematic Distributions
6.4.1 Background estimation
6.4.2 Kinematic distributions
6.5 Systematic Uncertainties
6.6 Statistical Analysis
6.6.1 Log-likelihood ratio test
6.6.2 Exclusion limits with Bayesian approach
6.7 Results
Chapter 7 Summary and Outlook
Bibliography
本文编号：3874011
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