Jets as Probes of Ultra-Relativistic Heavy-Ion Collisions

喷流作为超相对论重离子碰撞的探测器

• 批准号: 1207918
• 负责人: Abhijit Majumder
• 金额: $ 32.9万
• 依托单位: Wayne State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1207918&HistoricalAwards=false
• 关键词: Jets; Probes; Ultra; Relativistic; Heavy

For several microseconds after the big bang the entire universe passed through a phase called the Quark-Gluon Plasma (QGP). More than a million times hotter than the sun, the QGP is a form of matter governed by quantum chromodynamics (QCD) where the individual quarks and gluons localized within nucleons are expected to scatter out over distances and times many times larger than a femtometer (fm). Only in the last ten years has it become possible to create and study this form of matter in the laboratory using the fleetingly short-lived nuclear sized droplets of plasma created in the aftermath of a heavy-ion collision. The very short lifetime (10 fm/c, where c is the speed of light) and small size (10 fm) have made the study of this matter a theoretical and experimental challenge. The modification of hard QCD jets (bundles of strongly interacting particles) as they pass through this exotic form of matter presents the best tool to date to study the various properties of the QGP. The goal of the research supported by this grant is to continue to formulate both a systematic and sophisticated approach to the theoretical study of these modified jets. Considerable effort will be directed towards a deeper understanding of the factorization of the hard jet cascade from the soft rescattering experienced by the patrons in the jet, as they propagate through the QGP. Yet another goal will be to numerically simulate the partonic cascade process within the dense medium to better understand the event-by-event characteristics of such modified showers. A third goal will be a rigorous analysis of the data within the framework of perturbative QCD based jet modification to isolate the transport properties of the plasma and place stringent error bars on the extracted transport coefficients of jets in a QGP.This research, at the intersection of particle and nuclear physics, will greatly enhance our understanding of perturbative and non-perturbative QCD in the complicated environments of a dynamically expanding quark gluon plasma. It will introduce state of the art numerical tools to simulate such processes. It will lead to the training of graduate students in both the sophisticated analytical approaches used as well as the numerical simulation tools used in such efforts. The project also includes an outreach effort to convey the latest results from such analyses as well as from other new cutting edge fields to the general public.

在大爆炸后的几微秒内，整个宇宙经历了一个称为夸克-胶子等离子体（QGP）的阶段。 QGP比太阳热一百多万倍，是一种由量子色动力学（QCD）控制的物质形式，其中位于核子内的单个夸克和胶子预计会散射出比femmeter（fm）大许多倍的距离。 只有在过去的十年里，才有可能在实验室中使用重离子碰撞后产生的短暂的核大小的等离子体液滴来创造和研究这种形式的物质。 非常短的寿命（10 fm/c，其中c是光速）和小尺寸（10 fm）使这一问题的研究成为理论和实验挑战。 当硬QCD喷流（强相互作用粒子束）穿过这种奇异形式的物质时，它们的修改是迄今为止研究QGP各种性质的最佳工具。 这项资助支持的研究的目标是继续制定一个系统和复杂的方法来理论研究这些修改后的喷气机。 相当大的努力将被导向更深入地了解的硬射流级联的因式分解的软rescattering经历的顾客在射流中，因为他们通过QGP传播。 另一个目标将是数值模拟稠密介质内的部分子级联过程，以更好地理解这种修改后的簇射的逐事件特性。 第三个目标将是在基于微扰QCD的喷流修正框架内对数据进行严格分析，以隔离等离子体的输运性质，并在QGP中提取的喷流输运系数上设置严格的误差条。这项研究在粒子物理和核物理的交叉点上，将大大提高我们对动态膨胀夸克胶子等离子体复杂环境中微扰和非微扰QCD的理解。它将介绍最先进的数值工具来模拟这样的过程。 它将导致培训研究生在这两个复杂的分析方法，以及在这种努力中使用的数值模拟工具。该项目还包括一项外联工作，向公众传达这些分析以及其他新的前沿领域的最新结果。