CAREER: Spectral Properties of Hot and Dense QCD Matter

【摘要】热致密QCD物质的光谱特性（Ralf Rapp）我们周围99%以上的物质集中在原子核中，原子核是由质子和中子组成的。这些（和其他“强子”）的基本组成部分被认为是（几乎）无质量的“夸克”和“胶子”。然而，夸克和胶子从来没有被单独观察到过，它们之间强烈的相互作用是产生强子质量的原因。这些现象的起源是现代核物理学的主要问题之一。在温度和密度的极端条件下，强子预计会溶解成一种新的物质状态，即“夸克-胶子等离子体”，这种物质可能在早期宇宙诞生几微秒后就存在了。Rapp博士研究计划的关键目标之一是研究强子在高温和致密物质中如何改变其光谱特性（如质量和衰减宽度），以及这与夸克-胶子等离子体的相变有何关系。他的计算将应用于布鲁克海文国家实验室的相对论重离子对撞机的实验中，在那里，金原子核以高能碰撞，在短时间内重现夸克-胶子等离子体。为了应对识别这种瞬态特征的挑战，rappdr将评估不稳定粒子的衰变产物，从而获得其光谱特性的修饰。他将在杰斐逊实验室对原子核的电子散射实验进行类似的研究，也将对可能存在于非致密恒星物体（即所谓的中子星）中的冷密夸克物质进行类似的研究。此外，拉普博士将为研究生和本科生建立一个强有力的教育计划，包括继续参与由美国国家科学基金会资助的回旋加速器研究所的u网站。他将努力通过德克萨斯农工大学面向大学城周边地区高中生的“周六上午物理”项目，扩大大众对现代核科学的兴趣和教育，该项目特别适合加强少数民族的参与，并提高物理学本科的预期入学率。

AbstractCAREER: Spectral Properties of Hot and Dense QCD Matter (Ralf Rapp) More than 99% of the mass of matter around us is concentrated in atomicnuclei, which are made of protons and neutrons. The elementary buildingblocks of these (and other ``hadrons") are believed to be (almost)massless ``quarks" and ``gluons". However, quarks and gluons have neverbeen observed in isolation, and their strong interaction is responsiblefor generating the masses of the hadrons. The origin of these phenomenais among the main questions in modern nuclear physics. Under extremeconditions of temperature and density, hadrons are expected to dissolveinto a new state of matter, the ``Quark-Gluon Plasma", which probablyexisted in the early universe a few microseconds after its birth. One ofthe key objectives in Dr. Rapp's research plan is to investigate howhadrons change their spectral properties (such as masses and decaywidths) in hot and dense matter, and how this relates to phase changesinto a Quark-Gluon Plasma. His calculations will be applied toexperiments at the Relativistic Heavy-Ion Collider at BrookhavenNational Laboratory, where gold nuclei are collided at high energy torecreate, for a short moment, the Quark-Gluon Plasma. To meet thechallenge of identifying signatures of this transient state, Dr. Rappwill evaluate decay products of unstable particles allowing access tomodifications of their spectral properties. He will pursue similarapproaches to electron scattering experiments off nuclei at JeffersonLaboratory, as well as to cold dense quark matter which could prevail incompact stellar objects, so-called neutrons stars. In addition, Dr.Rapp will build a vigorous educational program for graduate andundergraduate students, including continued engagement in the NSF-fundedREU site at the Cyclotron Institute. He will endeavor to broaden thegeneral interest and education in modern nuclear science via a``Saturday Morning Physics" program at Texas A&M University for highschool students from a greater area around College Station, which isparticularly suitable to enhance the involvement of minority groups, andto improve prospective undergraduate enrollment in physics.