ATLAS谱仪上四轻子末态中希格斯玻色子产生截面与ZZ谱线的测量
发布时间：2020-12-11 00:47
本篇论文介绍的分析利用了四轻子（轻子定义为电子或缪子）末态对希格斯粒子与Z玻色子的耦合常数,以及ZZ产生的谱线进行了测量。使用的数据是在大型强子对撞机上ATLAS实验采集的质心能量为13TeV的数据。本文中的第一个数据分析是关于希格斯玻色子产生截面在四轻子末态中的测量。这一通道拥有本底小的特点,适合于对希格斯粒子的性质进行精确测量。该分析利用了 2015到2018年采集的139fb-1的完整Run 2数据。根据简化模板截面框架（STXS）,希格斯玻色子的产生模式和动力学变量被用于将事例在粒子阶段和重建阶段进行分类,以减少对理论误差的依赖性。在每一个希格斯质量窗的信号分类中,采用多变量分析进一步分离不同的希格斯产生模式和标准模型本底,输出的判别式被用于同步拟合的观测量。更进一步的,本文在质量边带中优化了若干个新的分类,以利用数据对标准模型的本底进行限制。总截面和各个粒子分类下的截面都得到了测量。在绝对快度小于2.5的区域,归一化的纵截面测量结果是（σ.B）/（σ·B）SM=1.01±0.09,标志着数据与理论估计存在着很好的一致性。本文介绍的第二个分析是利用2015和2016年采集的36...
【文章来源】：中国科学技术大学安徽省 211工程院校 985工程院校
【文章页数】：240 页
【学位级别】：博士
【文章目录】：
摘要
ABSTRACT
Acknowledgments
Chapter 1 Introduction
Chapter 2 The Standard Model of Particle Physics
2.1 Gauge field theory
2.1.1 Quantum electrodynamics
2.1.2 Quantum chromodynamics
2.1.3 Electroweak Unification
2.2 Spontaneous Symmetry Breaking and the Higgs Mechanism
2.2.1 Masses of fermions
Chapter 3 Phenomenology on the Large Hadron Collider
3.1 Cross Section and Luminosity
3.1.1 Parton Distribution Function
3.1.2 Luminosity
3.2 Simulated Event Generation at Hadron Colliders
3.3 Higgs Physics at the LHC
3.3.1 The SM Background in Four-lepton Final State
Chapter 4 Experimental Apparatus
4.1 The Large Hadron Collider
4.2 The ATLAS Detector
4.2.1 Inner Tracker
4.2.2 Calorimeters
4.2.3 Muon Spectrometer
4.2.4 Luminosity Measurement
4.2.5 Trigger and data acquisition system
4.2.6 ATLAS Detector Simulation
Chapter 5 Physics Object Reconstruction
5.1 Inner Detector Tracks and Vertices
5.1.1 Primary vertex
5.2 Muons
5.2.1 Muon Identification
5.3 Electrons
5.3.1 Electron Identification
5.4 Jets
5.4.1 b-tagging
5.5 Lepton Isolation
5.6 Missing transverse energy
Chapter 6 Data and MC Simulation Samples
6.1 Data samples
6.2 Higgs signal MC samples
6.3 The SM Four-lepton Background MC Samples
6.4 Other Background MC Samples
Chapter 7 Four-Lepton Event Selection and Background Estimation
7.1 Trigger
7.2 Object selection
7.3 Quadruplet selection
7.3.1 Optimization of isolation
7.4 Definition of the Fiducial Phase Space
7.5 Background estimation
Chapter 8 Statistical Methodology
8.1 Likelihood Construction
8.1.1 Unbinned Likelihood
8.1.2 Binned Likelihood
8.1.3 Model Parametrization
8.1.4 Systematic Uncertainties
8.2 Test statistics
8.2.1 Asymptotic Formulae for Test Statistics
8.2.2 Alternative Test Statistics
2 as test statistics"> 8.2.3 X2 as test statistics
8.2.4 Addressing Bias in Interpretation of Unfolded Spectrum
8.3 Technical Fitting Procedure
Chapter 9 Higgs Production Cross Section and Coupling Measure-ments with 4（?） Final State
9.1 Event Categorization
9.1.1 Production Bins
9.1.2 Reconstructed Categories
9.1.2.1 Optimization of ttH Categories
9.2 Multivariate Analysis
9.2.1 Neural Network
9.2.2 BDT in ttH Hadronic Category
9.3 Background Estimation
9.3.1 Using Data Side-Band Control Regions
9.3.1.1 Optimization of the ZZ Side-Band
9.3.1.2 Optimization of the tXX Side-Band
9.3.1.3 Optimization in Finalizing the Side-Bands
9.4 Systematic Uncertainties
9.4.1 Experimental uncertainties
9.4.2 Theoretical uncertainties
9.5 Statistical Analysis
9.5.1 STXS Parametrization
9.5.2 κ Framework
9.6 Results
9.6.1 Data and Monte Carlo Comparison
9.6.2 Signal Strength and Cross Section Measurement
9.6.3 Coupling Measurement in the κ Framework
4（?） Lineshape Measurement">Chapter 10 Inclusive m4（?） Lineshape Measurement
10.1 Introduction to Unfolding
10.1.1 Unfolding Methods
10.1.2 Statistical and Systematic Uncertainty Calculations
10.1.3 Optimization of Unfolding Method
10.2 Unfolding Observables
4（?） Differential Distribution"> 10.2.1 M4（?） Differential Distribution
4（?）-pT
4（?）Distribution"> 10.2.2 Double Differential M4（?）-pT
4（?）Distribution
4（?）-y4（?） Distribution"> 10.2.3 Double Differential m4（?）-y4（?） Distribution
4l-MELA Distribution"> 10.2.4 Double Differential m4l-MELA Distribution
10.2.4.1 Matrix Element Discriminant
10.2.4.2 Double Differential Distribution
4l-Final State Lepton Flavor"> 10.2.5 Differential m4l-Final State Lepton Flavor
10.3 Systematic Uncertainties
10.3.1 Data-driven Closure Test
10.4 Results
10.4.1 Unfolded Spectra
10.4.2 Interpretations
（*） Signal Extraction"> 10.4.2.1 gg→ZZ（*） Signal Extraction
10.4.2.2 Off Shell Higgs Boson Signal Strength
10.4.2.3 Z→4l Branching Ratio Extraction
10.4.2.4 Modified Higgs Coupling
Chapter 11 Conclusion and Prospects
Appendix A Study of high luminosity performance in MonitoredDrift Tube chambers
Appendix B Electronics integration and commissioning of thesTGC on NSW
Bibliography
Publications
本文编号：2909591
【文章来源】：中国科学技术大学安徽省 211工程院校 985工程院校
【文章页数】：240 页
【学位级别】：博士
【文章目录】：
摘要
ABSTRACT
Acknowledgments
Chapter 1 Introduction
Chapter 2 The Standard Model of Particle Physics
2.1 Gauge field theory
2.1.1 Quantum electrodynamics
2.1.2 Quantum chromodynamics
2.1.3 Electroweak Unification
2.2 Spontaneous Symmetry Breaking and the Higgs Mechanism
2.2.1 Masses of fermions
Chapter 3 Phenomenology on the Large Hadron Collider
3.1 Cross Section and Luminosity
3.1.1 Parton Distribution Function
3.1.2 Luminosity
3.2 Simulated Event Generation at Hadron Colliders
3.3 Higgs Physics at the LHC
3.3.1 The SM Background in Four-lepton Final State
Chapter 4 Experimental Apparatus
4.1 The Large Hadron Collider
4.2 The ATLAS Detector
4.2.1 Inner Tracker
4.2.2 Calorimeters
4.2.3 Muon Spectrometer
4.2.4 Luminosity Measurement
4.2.5 Trigger and data acquisition system
4.2.6 ATLAS Detector Simulation
Chapter 5 Physics Object Reconstruction
5.1 Inner Detector Tracks and Vertices
5.1.1 Primary vertex
5.2 Muons
5.2.1 Muon Identification
5.3 Electrons
5.3.1 Electron Identification
5.4 Jets
5.4.1 b-tagging
5.5 Lepton Isolation
5.6 Missing transverse energy
Chapter 6 Data and MC Simulation Samples
6.1 Data samples
6.2 Higgs signal MC samples
6.3 The SM Four-lepton Background MC Samples
6.4 Other Background MC Samples
Chapter 7 Four-Lepton Event Selection and Background Estimation
7.1 Trigger
7.2 Object selection
7.3 Quadruplet selection
7.3.1 Optimization of isolation
7.4 Definition of the Fiducial Phase Space
7.5 Background estimation
Chapter 8 Statistical Methodology
8.1 Likelihood Construction
8.1.1 Unbinned Likelihood
8.1.2 Binned Likelihood
8.1.3 Model Parametrization
8.1.4 Systematic Uncertainties
8.2 Test statistics
8.2.1 Asymptotic Formulae for Test Statistics
8.2.2 Alternative Test Statistics
2 as test statistics"> 8.2.3 X2 as test statistics
8.2.4 Addressing Bias in Interpretation of Unfolded Spectrum
8.3 Technical Fitting Procedure
Chapter 9 Higgs Production Cross Section and Coupling Measure-ments with 4（?） Final State
9.1 Event Categorization
9.1.1 Production Bins
9.1.2 Reconstructed Categories
9.1.2.1 Optimization of ttH Categories
9.2 Multivariate Analysis
9.2.1 Neural Network
9.2.2 BDT in ttH Hadronic Category
9.3 Background Estimation
9.3.1 Using Data Side-Band Control Regions
9.3.1.1 Optimization of the ZZ Side-Band
9.3.1.2 Optimization of the tXX Side-Band
9.3.1.3 Optimization in Finalizing the Side-Bands
9.4 Systematic Uncertainties
9.4.1 Experimental uncertainties
9.4.2 Theoretical uncertainties
9.5 Statistical Analysis
9.5.1 STXS Parametrization
9.5.2 κ Framework
9.6 Results
9.6.1 Data and Monte Carlo Comparison
9.6.2 Signal Strength and Cross Section Measurement
9.6.3 Coupling Measurement in the κ Framework
4（?） Lineshape Measurement">Chapter 10 Inclusive m4（?） Lineshape Measurement
10.1 Introduction to Unfolding
10.1.1 Unfolding Methods
10.1.2 Statistical and Systematic Uncertainty Calculations
10.1.3 Optimization of Unfolding Method
10.2 Unfolding Observables
4（?） Differential Distribution"> 10.2.1 M4（?） Differential Distribution
4（?）-pT
4（?）Distribution"> 10.2.2 Double Differential M4（?）-pT
4（?）Distribution
4（?）-y4（?） Distribution"> 10.2.3 Double Differential m4（?）-y4（?） Distribution
4l-MELA Distribution"> 10.2.4 Double Differential m4l-MELA Distribution
10.2.4.1 Matrix Element Discriminant
10.2.4.2 Double Differential Distribution
4l-Final State Lepton Flavor"> 10.2.5 Differential m4l-Final State Lepton Flavor
10.3 Systematic Uncertainties
10.3.1 Data-driven Closure Test
10.4 Results
10.4.1 Unfolded Spectra
10.4.2 Interpretations
（*） Signal Extraction"> 10.4.2.1 gg→ZZ（*） Signal Extraction
10.4.2.2 Off Shell Higgs Boson Signal Strength
10.4.2.3 Z→4l Branching Ratio Extraction
10.4.2.4 Modified Higgs Coupling
Chapter 11 Conclusion and Prospects
Appendix A Study of high luminosity performance in MonitoredDrift Tube chambers
Appendix B Electronics integration and commissioning of thesTGC on NSW
Bibliography
Publications
本文编号：2909591
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