Relativistic Heavy Ion Collision Studies with the RHIC STAR Experiment

这个项目的主要物理目标有两个：1)通过加热/压缩正常核物质到足够高的温度/密度，在理论上创造一种称为“夸克物质”的新状态，以及同样重要的是，2)唯一地确定这种向夸克物质的转变是否真的发生了。夸克物质由“自由”夸克和胶子组成，这些基本粒子被束缚成质子和中子，构成正常的核物质。据预测，宇宙在大爆炸后的百万分之一秒内完全处于夸克物质状态。我们将用来制造夸克物质的方法是将重原子核(例如铅和金上的金)以接近光速的速度运动的光束相撞。这些光束将由位于长岛布鲁克海文国家实验室和日内瓦欧洲核子研究组织实验室的新的最先进的粒子加速器产生。为了确定在这些高能重离子碰撞中是否真的产生了夸克物质，将出现大型粒子探测器来探测产生的次级粒子(主要是pi和k介子以及一系列更奇异的粒子)。理论预测，夸克物质形成的独特特征可以从从这些次级粒子获得的信息中提取出来。俄亥俄州立大学小组在这些实验中的主要作用之一是领导分析来自俄亥俄州立大学参与开发的一种新型粒子探测器的数据，该探测器被称为“硅漂移探测器”，并有望提取独特的夸克物质特征。5

The main physics goals of this project are two-fold: 1) to create in thelaboratory a new state of matter called "Quark Matter" by heating/compressing normal nuclear matter to a sufficiently high temperature/density, and, equally important, 2) to uniquely determine whether such atransformation to Quark Matter has actually taken place. Quark Matter iscomposed of "free" quarks and gluons, the fundamental particles whichare bound into protons and neutrons which make up normal nuclear matter. Itis predicted that the Universe was entirely in the Quark Matter stateseveral millionths of a second after the Big Bang. The method which we will useto make Quark Matter will be to collide beams of heavy nuclei (e.g. leadon lead and gold on gold) moving at speeds near the speed of light.These beams will be generated by new state-of-the-art particle acceleratorslocated at Brookhaven National Laboratory on Long Island and at the CERNlaboratory in Geneva. To determine whether Quark Matter has actuallybeen created in these high energy heavy ion collisions, large particledetectors will be present to detect the secondary particles which are produced(mostly pi and K mesons and a range of more exotic particles). Theoriespredict that unique signatures for Quark Matter formation can beextracted from information obtained from these secondary particles. One of themain roles of the Ohio State University group in these experiments is to leadthe analysis of the data from a new type of particle detector which OSUhas taken part in developing called a "Silicon Drift Detector" and,hopefully, to extract unique Quark Matter signatures.5