Relativistic Heavy Ion Collision Studies at the LHC and RHIC

LHC 和 RHIC 的相对论重离子碰撞研究

• 批准号: 1307188
• 负责人: Thomas Humanic
• 金额: $ 126万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1307188&HistoricalAwards=false
• 关键词: Relativistic; Heavy; Ion; Collision; Studies

This award is primarily to carry out experiments with relativistic heavy ion collisions. The principal investigators are T. J. Humanic and M. A. Lisa, of the Department of Physics at The Ohio State University. Our goals for the high-energy program are threefold. Firstly, we will study the space-time properties of the extremely dense matter created at in collisions between heavy nuclei at the highest achievable energies. It is believed that this matter is a quark-gluon plasma (QGP), characterized by colored degrees of freedom at the microscopic scale. The second activity is to study the bulk phase structure of Quantum Chromodynamics (QCD), believed to be the correct theory of the Strong interaction between partons. This will be achieved by varying the conditions of the collision to lower energies, to probe the transition(s) between confined and deconfined matter. In particular, we plan to perform a novel analysis as a function of the collision energy, measuring coordinate-space anisotropies and dynamics. Thirdly, we will take the tools developed to study bulk physics in heavy ion collisions, and apply them to hadronic(p+p) collisions at similar energies. We will look particularly for collective behaviour(flow) in hadronic collisions. If our initial reports of such flow in ultrarelativistic p+p collisions are confirmed at higher energies, this raises important issues about the nature of flow, and the nature of the initial self-interacting state, itself. In the present grant ultrarelativistic heavy ion collisions will be studied with Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), and with Pb-Pb collisions at the Large Hadron Collider (LHC) at CERN in Geneva. RHIC started delivering Au-Au collisions in Summer 2000, and the LHC, which is the highest energy heavy ion accelerator now in operation, began delivering Pb-Pb collisions at the end of 2010. In order to look for signatures that a phase transition to Quark Matter has taken place, one must study the properties of the particles produced in the collisions, such as particle momenta and multiplicities of each type that can be detected (e.g. pions, kaons, protons, and more exotic particles). This will be done at both RHIC and the LHC using the large acceptance detectors available in the STAR and ALICE experiments, respectively, which can sample most of the interesting particles per collision. The information obtained in this way can be used to determine, for example, the physical size of the interaction region (using two-particle interferometry), the temperatures reached in the collisions (from particle momentum distributions) and exotic particle production such as strange baryons.Besides the intellectual merit described above, there are broader impacts to society of this proposal in the areas of education, technology and computing. Since undergraduate students, graduate students and postdoctoral researchers will play key roles in this project, training will be provided to these groups in how to carry out research in large collaborations and in general problem solving skills. Since this research requires large-scale computing in order to acquire and analyze data on the teraflop and terabyte scale, new methods in information science, such as computing grid systems, will be developed, which can enhance the computing power of society as a whole.

该奖项主要用于开展相对论重离子碰撞实验。主要研究者是T. J. Humanic和M. A.俄亥俄州州立大学物理系的丽莎说。我们的高能计划有三个目标。 首先，我们将研究在最高可达到的能量下，重核碰撞产生的极致密物质的时空特性。人们认为这种物质是夸克-胶子等离子体（QGP），其特征是在微观尺度上的有色自由度。第二项活动是研究量子色动力学（QCD）的体相结构，QCD被认为是部分子之间强相互作用的正确理论。这将通过将碰撞条件改变为较低能量来实现，以探测受限和非受限物质之间的过渡。特别是，我们计划执行一个新的分析作为碰撞能量的函数，测量坐标空间各向异性和动力学。第三，我们将把研究重离子碰撞体物理的工具应用于类似能量的强子（p+p）碰撞。我们将特别关注强子碰撞中的集体行为（流）。如果我们最初关于超相对论p+p碰撞中的这种流的报道在更高能量下得到证实，这就提出了关于流的性质以及初始自相互作用态本身的性质的重要问题。在本研究计划中，将在布鲁克海文国家实验室（BNL）的相对论重离子对撞机（RHIC）上研究超相对论重离子碰撞，并在日内瓦的欧洲核子研究中心（CERN）的大型强子对撞机（LHC）上研究Pb-Pb碰撞。RHIC于2000年夏天开始提供金-金碰撞，而LHC是目前运行的最高能量重离子加速器，于2010年底开始提供铅-铅碰撞。为了寻找夸克物质相变发生的特征，必须研究碰撞中产生的粒子的性质，例如可以检测到的每种类型的粒子动量和多重性（例如π介子，K介子，质子和更多的奇异粒子）。这将分别在RHIC和LHC中使用星星和ALICE实验中可用的大型接收探测器来完成，它们可以在每次碰撞中对大多数感兴趣的粒子进行采样。以这种方式获得的信息可用于确定例如相互作用区域的物理大小（使用双粒子干涉测量法）、碰撞中达到的温度（根据粒子动量分布）和奇异粒子（如奇异重子）的产生。除了上述智力价值外，这一建议在教育、技术和计算领域对社会有更广泛的影响。由于本科生、研究生和博士后研究人员将在本项目中发挥关键作用，因此将向这些群体提供如何在大型合作中开展研究和解决一般问题的技能方面的培训。由于这项研究需要大规模计算，以获得和分析数据的万亿次和万亿字节的规模，在信息科学的新方法，如计算网格系统，将开发，这可以提高计算能力的社会作为一个整体。