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.

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 比太阳热一百万倍以上，是一种受量子色动力学 (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分散到比飞米 (fm ）。 直到最近十年，才有可能在实验室中利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）使得这种物质的研究成为理论和实验的挑战。 当硬 QCD 射流（强相互作用粒子束）穿过这种奇异的物质形式时，对其进行修改是迄今为止研究 QGP 各种特性的最佳工具。 这笔赠款支持的研究目标是继续制定系统且复杂的方法来对这些改进的喷气机进行理论研究。 相当大的努力将用于更深入地理解硬喷射级联的因式分解，该分解来自喷射流中的顾客在通过 QGP 传播时所经历的软再散射。 另一个目标是对致密介质内的部分子级联过程进行数值模拟，以更好地了解这种改进的流星雨的逐个事件特征。 第三个目标是在基于扰动 QCD 的射流修改框架内对数据进行严格分析，以隔离等离子体的传输特性，并对 QGP 中提取的射流传输系数设置严格的误差线。这项研究，在交叉点粒子和核物理的研究将极大地增强我们对动态膨胀夸克胶子等离子体的复杂环境中微扰和非微扰 QCD 的理解。它将引入最先进的数值工具来模拟此类过程。 它将对研究生进行复杂分析方法以及此类工作中使用的数值模拟工具的培训。该项目还包括一项外展工作，旨在向公众传达此类分析以及其他新前沿领域的最新结果。