不同味夸克产生的喷注硬度特性的比较研究

用蒙特卡洛模拟方法研究了e e对撞Zo强子衰变事件中胶子喷注和夸克喷注的硬度特性.发现夸克喷注和胶子喷注的硬度特性存在较大的差异;不同味的夸克喷注的平均多重数、平均横动量和平均快度随硬度的分布特性也存在明显的差异,而不同味的夸克发射的胶子产生的喷注的硬度特性是一致的;胶子喷注与夸克喷注的平均横动量、平均多重数与硬度之间存在较强的正关联,而平均快度与硬度之间存在较强的负关联.     

夸克-胶子等离子体的临界温度研究

基于MIT袋模型,在纵向能量近似下,求解了高能重离子碰撞核子的部分子波函数,进而得到了核子的袋压强,并确定了高能重离子碰撞过程中产生夸克-胶子等离子体的临界温度。此外,还利用有限温度QCD求和规则,讨论了手征对称性恢复和双轻子产生的问题。     

RHIC上核子-核子碰撞实验集锦

1IntroductionLattice QuantumChromoDynamics(QCD)predicts that at hightemperature and/or high baryon densityquarks and gluons are deconfined and a newstate of matter,the Quark-Gluon Plasma(QGP)is formed.Thenature of the transition from hadrons to the QGP ha…     

高能核-核碰撞中带电粒子的赝快度分布

用柱模型研究了高能核-核碰撞中产生的带电粒子的赝快度分布，蒙特卡罗方法计算的结果表明，柱模型对实验给出的赝快度分布中的涨落现象给出了较好的解释．模型计算结果与200AGeV的质子，^16O和^32S与溴化银中心碰撞，14．6A和3．7A GeV的携Si与溴化银中心碰撞，以及158A GeV的208Pb-^208Pb中心碰撞的实验数据符合。     

10.7AGeV^197Au诱发乳胶核反应射弹碎片平均自由程研究

本文对10.7 AGeV197Au诱发乳胶核反应射弹碎片平均自由程进行了研究,结果表明射弹碎片的平均自由程在实验误差范围内与距射弹作用点的距离D无关,射弹碎片的平均自由程不存在反常现象.对于α射弹碎片平均自由程,实验发现在实验误差范围内与距射弹作用点的距离D、碰撞参数b、射弹α碎片多重数无明显的依赖关系,以上结论也可以通过I Otterlund等人提出的检验方法得到进一步证实.     

A model to predict mid-air and near-mid-air collisions

The probability of mid-air and near-mid-air collisions in terminal areas depends on a variety of factors such as visibility, number of air traffic controllers, communication channels, terrain, mix of aircraft and aircraft speeds, local densities of air traffic in specific subregions surrounding airports, as well as other measures of congestion. We develop, with the use of influence diagrams, a probabilistic model to analyze and predict mid-air and near-mid-air collisions. The probability of near-mid-air and mid-air collisions in the model is influenced by weather, traffic density, detection and collision avoidance maneuvres. Low-hazard near-mid-air collisions (LNMACs) can escalate to critical near-mid-air collisions (CNMACs) and eventually to a mid-air collision (MAC) with the probability of escalation reduced through the use of a collision-avoidance system. The predictive probability of a collision in the model is the product of three factorsdensity, effectiveness of the collision-avoidance system, and the conditional probability that independently of the collision-avoidance system a CNMAC escalates, by chance alone, to a MAC. The paper obtains several conclusions based on sensitivity analysis of the model. Under the assumption that new designs of collision-avoidance systems will result in much higher detection probabilities than presently available, it is important that both aircraft use the system if there is to be a significant improvement in collision avoidance. For maximum benefit, these collision-avoidance systems should not reduce the probabilities of avoidance given that a near-mid-air collision has been detected.