相对论重离子碰撞中净质子，质子和反质子数分布的高阶矩和关联函数测量

发布时间：2021-06-22 19:19

　　强相互作用力（也被称为核力）,是自然界四种基本相互作用力之一,它将核子（质子与中子）束缚形成原子核并支配着自然界中90%以上的可见物质。量子色动力学（Quantum Chromodynamics,QCD）是描述强作用力的现代理论。组成物质的基本单元—夸克与胶子,被强作用力禁闭在核子中,因此在自然界没有发现自由的夸克与胶子。高温高密核物质相图是核物理研究领域的前沿和热点。格点QCD预言在高温低重子密度区域,强子物质和夸克胶子等离子体之间发生的相变是平滑穿越,而基于量子色动力学（QCD）有效模型计算表明在高重子密度区域,他们之间是—阶相变。因此,如果平滑穿越和—阶相变边界真的如理论所预言,那么在—阶相变边界延伸到平滑穿越区—定会存在—个终结点,被称为QCD相变临界点。QCD临界点的实验确认将是探索强相互作用物质相结构的里程碑,具有重要科学意义。为了在这一具有潜在重大发现的研究方向上占据领先地位、取得突破,各个国家纷纷建造大型粒子探测器、开展重离子碰撞实验（包括:美国RHIC-STAR能量扫描实验,德国CBM实验、俄罗斯NICA实验、日本J-PARC实验以及中国兰州CSR外靶CEE实验）,其... 

【文章来源】：华中师范大学湖北省 211工程院校 教育部直属院校

【文章页数】：116 页

【学位级别】：博士

【文章目录】：
摘要
Abstract
1 Introduction
    1.1 Quantum Chromodynamics
    1.2 QCD Phase Transition and Critical Point
    1.3 Relativistic Heavy Ion Collisions
    1.4 Critical Signature
    1.5 Experimental Observables
    1.6 Definition of Statistical Observables
        1.6.1 Moments
        1.6.2 Cumulants
        1.6.3 Properities of Cumulants
        1.6.4 Factorial Moments
        1.6.5 Correlation Functions
    1.7 Statistical Baseline
        1.7.1 Binomial Distribution
        1.7.2 Poisson Distribution
        1.7.3 Skellam Distribution
        1.7.4 Gaussian Distribution
2 The STAR Experiment
    2.1 The Relativistic Heavy-Ion Collider (RHIC)
    2.2 The STAR Detector
        2.2.1 Time Projection Chamber(TPC)
        2.2.2 Time of Flight (TOF)
        2.2.3 Vertex Position Detector (VPD)
    2.3 The Fixed-Target(FXT)Program at STAR
3 Analysis Details
    3.1 Data Sets
        3.1.1 Run by Run QA
        3.1.2 Signed DCA_(xy) Cuts
        3.1.3 Event Selection
        3.1.4 Track Quality Cuts
    3.2 Particle Indentification
        3.2.1 For Au+Au Collisions
        3.2.2 For Fixed-Target Collisions
        3.2.3 For Cu+Cu collisions
    3.3 Centrality Determination
        3.3.1 For Au+Au Collisions
        3.3.2 For Fixed-Target Collisions
        3.3.3 For Cu+Cu Collisions
    3.4 Net-Proton Multiplicity Distributions
        3.4.1 For Au+Au Collisions
        3.4.2 For Fixed-Target Collisions
        3.4.3 For Cu+Cu Collisions
    3.5 Centrality Bin Width Correction
    3.6 Efficiency Correction
        3.6.1 For Au+ Au Collisions
        3.6.2 For Fixed-Target Collisions
    3.7 Uncertainty Estimation
        3.7.1 Statistical Error Estimation
        3.7.2 Systematic Error Estimation
        3.7.3 Barlow Check on Net-Proton Systematic Errors
    3.8 Model Study
        3.8.1 Hadron Resonance Gas Model
        3.8.2 UrQMD Model
4 Results
    4.1 Results for Au+Au collisions
        4.1.1 Centrality Dependence
        4.1.2 Rapidity Dependence
        4.1.3 Transverse Momentum (p_T) Dependence
        4.1.4 Acceptance Dependence
        4.1.5 Energy Dependence
    4.2 Results for Fixed-Target Collisions
    4.3 Cumulants and Cumulant Ratios for Cu+Cu collisions
5 Summary and Outlook
    5.1 Summary
    5.2 Future Prospects
Reference
Publications and Presentations
Acknowledgements
Appendix
    A Formula
        A.1 Formula for Moments
        A.2 Formula for Cumulants
        A.3 Relationship between Cumulants and Moments
        A.4 Formula for Factorial Moments
        A.5 Formula for Correlation Function
        A.6 Formula for Moments of Binomial Distributions
        A.7 Formula for Cumulants of Binomial Distributions
    B Tables for Details



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