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　　本篇論文介紹的分析利用了四輕子（輕子定義為電子或繆子）末態(tài)對希格斯粒子與Z玻色子的耦合常數(shù),以及ZZ產(chǎn)生的譜線進行了測量。使用的數(shù)據(jù)是在大型強子對撞機上ATLAS實驗采集的質(zhì)心能量為13TeV的數(shù)據(jù)。本文中的第一個數(shù)據(jù)分析是關(guān)于希格斯玻色子產(chǎn)生截面在四輕子末態(tài)中的測量。這一通道擁有本底小的特點,適合于對希格斯粒子的性質(zhì)進行精確測量。該分析利用了 2015到2018年采集的139fb-1的完整Run 2數(shù)據(jù)。根據(jù)簡化模板截面框架（STXS）,希格斯玻色子的產(chǎn)生模式和動力學(xué)變量被用于將事例在粒子階段和重建階段進行分類,以減少對理論誤差的依賴性。在每一個希格斯質(zhì)量窗的信號分類中,采用多變量分析進一步分離不同的希格斯產(chǎn)生模式和標(biāo)準(zhǔn)模型本底,輸出的判別式被用于同步擬合的觀測量。更進一步的,本文在質(zhì)量邊帶中優(yōu)化了若干個新的分類,以利用數(shù)據(jù)對標(biāo)準(zhǔn)模型的本底進行限制。總截面和各個粒子分類下的截面都得到了測量。在絕對快度小于2.5的區(qū)域,歸一化的縱截面測量結(jié)果是（σ.B）/（σ·B）SM=1.01±0.09,標(biāo)志著數(shù)據(jù)與理論估計存在著很好的一致性。本文介紹的第二個分析是利用2015和2016年采集的36... 

【文章來源】：中國科學(xué)技術(shù)大學(xué)安徽省 211工程院校 985工程院校

【文章頁數(shù)】：240 頁

【學(xué)位級別】：博士

【文章目錄】：
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 m_4（?） 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 M_4（?） Differential Distribution
4（?）-p_{T
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 m_4l-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 m_4l-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



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