臺灣博碩士論文加值系統

傳統上 被視為研究Pomeron-exchange 動力學的一種工具，為了測試VDM是有根據的，而其他的重子機制皆被 OZI rule 抑制著了。但是這個反應在小角度接近閥值能量的區域仍舊是複雜且未知的，在SPring-8的雷射電子光子設施提供了一個好的機會去研究這個LG 模式的Pomeron exchange。從LEPS偵測器和電子裝置以及Monte Carlo模擬所收集的數據，我們完成PID和從三種偵測模式重建 介子的事件，以及在不同的偵測模式之間比較動力學變數。此外，我們檢測在每一個實驗階段的穩定性。在未來的工作中，我們將專注在三種偵測模式接受度上的研究，在 介子光致產生的反應截面上，期望得到一個一致性的量測。

Traditionally, this reaction, , is considered as a tool to study the Pomeron-exchange dynamics for testing that the VDM is valid, and other hadronic mechanisms are suppressed by OZI rule. But the reaction at small angel near the threshold energy is still complicated and unknown. The Laser Electron Photon facility at SPring-8 provides a good opportunity to study the Pomeron exchange of LG mode. Base on the collected data from LEPS detector and electronic devices and Monte Carlo simulation, we done the PID studies, reconstructed the meson events from three detection modes, and compared the kinematics variables between different detection modes. In addition, we checked the experimental stability for each experimental period. In the future study, it would be focused on the acceptance of three detection modes for a consistent measurement of meson photoproduction cross-section.

Contents
中文摘要 I
Abstract II
Contents III
Table Contents V
Figure Contents VI
Chapter 1 Introduction 1
1.1 Point-like 1
1.2 The Standard Model of Particle Physics 2
1.3 The Four Interactions 3
1.4 Hadrons 4
1.5 Meson Photoproduction 5
1.6 Pomeron Exchange 6
Chapter 2 Experimental Setup 9
2.1 Light Source 9
2.1.1 Backward-Compton Scattering 9
2.1.2 Synchrotron Radiation 10
2.1.3 The SPring-8 10
2.1.4 Laser System 12
2.2 Detectors 13
2.2.1 Silicon Strip Detector 14
2.2.2 Drift Chamber 14
2.2.3 Aerogel Cerenkov Counter 15
2.2.4 Dipole Magnet 15
2.2.5 Plastic Scintillator and Time-of-Flight Wall 16
Chapter 3 Method of Analysis 17
3.1 Particle Identification 17
3.1.1 Invariant mass and missing mass 17
3.1.2 Mandelstam variables 19
3.1.2.1 variable 21
3.1.2.2 variable 21
3.1.2.3 variable 22
3.1.3 Particle Identification 23
3.1.3.1 Distribution of square of mass 24
3.1.3.2 Momentum slice and get fitting parameters 25
3.1.4 Energy loss correction 28
3.1.5 Stability 28
3.2 Mass Check 29
3.2.1 Single particle check 29
3.2.2 Two-tracks event check 30
3.3 Monte Carlo simulation 30
3.4 The comparison of acceptance for single particle 31
3.5 Three detection modes in two-tracks event 33
3.5.1 Mode 34
3.5.2 Mode 34
3.5.3 Mode 35
3.5.4 Mandelstam variables in different modes 35
3.5.5 The Acceptance 35
Chapter 4 Results and Discussion 37
4.1 Data samples 48
4.2 Selection conditions 48
4.3 Particle Identification 40
4.4 Mass Check 48
4.4.1 Single particle check 48
4.4.1.1 Mass peak position and mass distribution width 48
4.4.1.2 Normalized yields 54
4.4.1.3 Normalized yields fluctuation 60
4.4.2 Two-tracks event check 63
4.5 The comparison of acceptance for single particle 69
4.6 Study of three detection modes in two-tracks event 72
4.6.1 Invariant mass, missing mass and box-cut 72
4.6.1.1 Mode 72
4.6.1.2 Mode 74
4.6.1.3 Mode 76
4.6.2 Mandelstam variable 78
4.6.2.1 variable 78
4.6.2.2 variable 79
4.6.2.3 variable 80
4.6.2.4 Cross-term 81
4.7 Acceptance 82
Chapter 5 Summary 83
Reference 85
Table Contents
1.1 The Generation of Matter 2
1.2 Four Interactions 3
3.1 4-momenta in Lab system and center-of-mass system 20
4.1 All the fitting parameters 41
4.2 Seven periodic mass peak position of five charged particles 48
4.3 Five normalized yield periods of events 63
4.4 Two types of photon energy slices 69

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