19GeV/c质子-铅碰撞中领头粒子Λ和Δ产生和相对论重离子碰撞中非均匀集体纵向膨胀流的研究

摘要

p+A作用中入射质子的碎裂是一直是一个重要的物理研究课题,这是因为它与核作用中重子数输运机制密切相关.而如今还没有完全了解此机制.详细研究领头粒子的产生可以帮助我们认识核碎裂和重子数输运机制.E941实验组专门从事领头粒子测量和研究,它的主要特点是：能够测量中子以及集中对向前较大快度区间的粒子进行测量.该文通过分析在AGS上工作的E864/E941的实验数据,给出了在19GeV/c能量下最小无偏（minimum bias）p+Pb碰撞的领头奇异超子（Λ）和共振态重子（Δ<'++>）的不变多重数分布和dn/dy分布.该实验所给出的Λ和Δ<'++>的快度和模动量范围分别对应的2.2的产生与质子和中子的产生,以及与其它实验进行比较将会帮助我们了解p+A作用中质子碎裂机制.

目录

文摘

英文文摘

致谢

1 Introduction

1.1 Relativivistic Heavy Ion Collisions

1.2 Leading Baryon, ∧ and △++ Production

1.3 Flow in Relativistic Heavy Ion Collisions

2 Physics

2.1 Proton Feagmentation into Leading Baryons

2.2 Features of ∧ Production in Nuclear Collisions

2.3 Novel Mechanism due to String Junction Interaction

2.4 Features of △++ Production in Nuclear Collisions

3 Apparatus

3.1 Overview

3.2 Trigger and Data Acquisition System

3.3 Beam Counter

3.4 Tracking System

3.5 Calorimeter

4 Calibration of Tracking System

4.1 Overview

4.2 Beam Counters

4.3 Calibration of Tracking System

5 Data Analysis

5.1 Definition of Invariant Multiplicity

5.2 Counting of ∧

5.3 Counting of △++

6 Acceptance and Efficiency

6.1 ∧'s and △++'s Acceptance

6.2 ∧'s and △++'s Efficiency

7 Results and Discussion

8 Flow

8.1 Introduction

8.2 One Dimensional Non-Uniform Longitudinal Flow

8.3 Two Dimensional Non-Uniform Longitudinal Flow

8.4 Summary and Conclusions

9 Summary and Outlook

Reference

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