高能重离子碰撞中末态粒子的极角分布

在反应平面内不同极角方向为z轴的质心坐标系中,分析了末态粒子方向角分布的非对称性,建立了一种确定集合侧向流流角的方法.在以流方向为z轴的质心坐标系中研究了Bevalac流光室1.2AGeV Ar+KCl、1.2AGeV Ne+NaF和2.1AGeV Ne+NaF三种反应中末态粒子的极角分布,对末态粒子非对称发射部分所占的比例及其在流方向的集中程度做出了定量的估计.     

高能重离子碰撞中末态粒子分布的非对称性

对Bevalac1.2A GeV Au+Au碰撞实验,根据以流方向为z轴的质心坐标系中末态粒子方位角分布的非对称性为极小的条件,确定了事件中五种质量范围(A=1,2,3,4,5-8)末态粒子的集合侧向流流角.在以流方向为z轴的质心坐标系中研究了不同质量末态粒子极角分布,结果表明质量越大的粒子在流方向分布得越集中,侧向流的“流”值越大.     

高能重离子碰撞中末态粒子的关联度与集合侧向流

提出了关联度概念,采用粒子群关联函数方法对Bevalac流光室1.2A GeV Ar+BaI₂碰撞事件中关联度不同的粒子对集合侧向流的作用进行了研究.研究表明:关联度是描述集合侧向流性质的一个重要参量.少数关联度较大的粒子(或碎片)可以产生集合侧向流效应,但高阶集合流关联却不受其支配,而是关联度不同的多数粒子(或碎片)集体贡献的结果.     

高能碰撞多粒子末态间歇现象与关联积分的研究

用理论分析和Monte Carlo模拟表明:研究间歇现象时用关联积分代替阶乘矩的统计会改变快度bin减小时的反常标度行为. 指出,关联函数积分与阶乘矩可能分别反映不同的物理内容.提出了一种随机移动分bin起点的统计阶乘矩方法以消除分bin造成的人为因素.证明了,“钉子”事件对间歇指数有重要贡献.     

On the Emission of Target Black Fragments in High Energy Nucleus-Nucleus Collisions

The mechanism of friction-evaporation process for target spectator contact layer in high energy nucleus-nucleus collisions is presented.The distribution of multiplicity,azimuthal and spatial angles,transverse and total momenta,as well as kinetic energy of target black fragments are calculated and compared with the experimental results of 200GeV/N ¹⁶O-Em interactions.     

高能核子-核子和核-核碰撞中电荷起伏的测量

利用强子-强子碰撞的模型PYTHIA以及核-核碰撞的模型RQMD比较了各种电荷起伏测量量的快度依赖性，结果发现，这些测量量对快度的依赖性依赖于模型. 但是，电荷关联能很好地测量整体电荷守恒以及短程快度关联性质. 因此，被认为是一个好的反应电荷起伏的测量量.     

高能核-核碰撞中蒸发碎片的研究

在高能核－核碰撞中,基于简单的模型计算,描述了来自弹核和靶核旁观体的蒸发碎片的多重数分布与角分布． Based on the simple modelling calculation,the multiplicity and angular distribution of evaporated fragments from both projectile and target spectators in high energy nucleus-nucleus collisions are described.     

高能轻子－核碰撞中簇射粒子的研究

在高能轻子－核碰撞中，基于二源发射图象描述了簇射粒子多重数和赝快度分布，计算结果与３－２１０ＧｅＶ的中微子－核乳胶碰撞的实验数据符合．     

高能重离子碰撞中的横向非对称流

对末态粒子方位角分布的研究可以获得反应中有关横向非对称流的信息.研究了碰撞中侧向流与椭圆流间的方位角关联,给出了一种定量测量反应中椭圆流大小的方法,该方法的计算结果可以有效地消除估计反应平面离散的影响.     

高能核—核碰撞中产生质子的快度分布

用三火球模型分析了核--核以AGS(the Alternating Gradient Synchrotron)和SPS(the Super Proton Synchrotron)能量碰撞中产生质子的快度分布. Monte Carlo方法计算的结果分别与金--金以6, 8和10.8A GeV的能量并以不同中心性碰撞、铅-铅以158A GeV/c的动量碰撞、以及硫-硫以200A GeV/c的动量碰撞的实验数据符合.     

High Energy Unequal-nuclei Collisions and Relaxation Time in Fokker Plank Equation

In this paper,the time evolution of high energy heavy ion collisions is described by Fokker-Planck Equation.The rapidity distribution of the final state particles is analysed with this model for ¹⁶O and ³²S particles beams of 200AGeV.The relaxation time for various systems are determined.Results comparable to the usual empirical data are obtained.     

中能重离子碰撞中的涨落和中间质量碎片发射的机制

在ＱＭＤ模型的基础上，系统研究了４０Ｃａ＋４０Ｃａ中心碰撞系统的中间质量碎片随能量和时间的演化以及它们的动力学起源．集中讨论了反应机制的跃迁，动力学过程中密度涨落和平均中间质量碎片的关系以及碎裂的时间尺度．发现中间质量碎片随能量的上升和下降伴随着涨落的上升和下降．并预言对所研究的反应，当入射能量为６５ＭｅＶ／ｕ时，彻底解体可能发生．碎裂的时间尺度大约为１４０ｆｍ／ｃ，且随能量的增大，此时间尺度不再减小，达到饱和．     

高能p-A碰撞的碰撞几何、能量损失和横能分布

采用一种仔细考虑了作用截面、表面弥散和形变效应的核碰撞几何,同时考虑到在每一次碰撞中领头质子损失能量,得到了高能ｐ－Ａｌ碰撞的横能分布,计算结果与２００ＧｅＶ／ｃｐ－Ａｌ、Ｃｕ及Ｕ碰撞的实验数据符合.In this paper, the nuclear collision geometry which was considered carefully in the interaction cross sections, surface effects and nuclear deformations is adopted. The energy loss of leading proton in each collision is considered. The transverse energy distributions in high energy p A collisions are obtained. The calculated results are in agreement with the experiment data of 200 GeV/ c p Al, Cu and U collisions.     

Multiplicity Distributions for Different Rapidity Windows in High Energy Collisions

On the assumption that ,under the constraints of energy conservation and transverse-momentum cutoff,the rapidities of produced particles by the fireball are distributed with equal probability,multiplicity distributions for different rapidity windows are calculated by using the multisource model.The calculated results fit the experimental data well.     

The Excited Nucleon Model for High Energy N-N Collisions

Based on the quark model, we propose a new version for a detailed analysis of the energy exchange relation in multiparticle production of high energy hadron-hadron collisions. The multiplicities of various final state hadrons are calculated in the N-N collisions for a wide energy range (s=12 ～ 485 GeV²). The result predicts an energy dependence of various multiplicities and agrees with the experimental data quite well. It can be taken as a more reliable foundation to study the increase of the K/π ratio in pA and A-A collisions.     

The Systematical Investigation of Intermittency in High Energy Heavy Ion Collisions

The intermittency of multiparticle production processes in high energies oxygen,silicon and sulphur induced emulsion and sulphur gold interactions are investigated systematically.It is found that in the pseudorapidity region 1～0.1,the EMU01 data exhabits the intermittent behaviour.The intermittent indexes are found to decreases with increasing the incident energy and mean multiplicity and to increase with increasing target mass.It seems also to increase as the projectile mass increases.     

高能重离子碰撞中的集体流与空间-动量关联

高能重离子碰撞中,末态粒子的侧向流与椭圆流间存在方位角集体关联,该关联对反应中集体流的性质反映敏感.碰撞时,系统在坐标空间的演化与动量空间的演化过程相互影响,表现出明显的空间-动量关联.不同事件中椭圆流形式的差别与此空间-动量关联有关,反映了系统演化过程的涨落.     

The Intranuclear Cascade and the Target Fragmentation in High Energy hA Collisions

A model for describing the target fragmentation in high energy hadron-nucleus collisions on the bases of intranuclear cascade is suggested.The analysis of the correlation between grey and black particles shows that the phenomena of saturation about mean number of grey and/or black particles observed in experiments result from the limitation of charge number in the nucleus.     

高能重离子碰撞多粒子产生的热力学模型研究

评述了高能重离子碰撞中多粒子产生的热力学模型,并根据该模型的最新发展,研究了有关高能核－核碰撞中簇射粒子的赝快度分布问题． The thermodynamic models for multiparticle production in high energy heavy ion collisions are reviewed.According to the recent developments of the thermodynamic models,the pseudorapidity distributions of shower particles produced in high energy nucleus nucleus collions are investigated.