CAREER: Spectral Properties of Hot and Dense QCD Matter

AbstractCAREER：热致密QCD物质的光谱性质（Ralf Rapp）我们周围99%以上的物质质量集中在原子核中，原子核由质子和中子组成。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孤立地观察过，它们的强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。在极端的温度和密度条件下，强子被认为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后的几微秒内就存在了。拉普博士的研究计划中的一个关键目标是研究强子如何改变其在热和致密物质中的光谱特性（如质量和衰变宽度），以及这与夸克-胶子等离子体的相变之间的关系。他的计算结果将被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，金原子核以高能量碰撞，在短时间内重新产生夸克-胶子等离子体。为了应对识别这种瞬态特征的挑战，Rapp博士将评估不稳定粒子的衰变产物，从而允许对其光谱特性进行修改。他将在杰斐逊实验室进行类似的电子散射实验，以及冷的致密夸克物质，这种物质可能会在松散的恒星物体（所谓的中子星）中占主导地位。 此外，拉普博士将为研究生和本科生建立一个充满活力的教育计划，包括继续参与国家科学基金会资助的回旋加速器研究所的REU网站。他将奋进通过德克萨斯A M大学的“星期六早晨物理学”项目来扩大现代核科学的普遍兴趣和教育，该项目面向学院站周围更大区域的高中生，特别适合加强少数群体的参与，并提高未来物理学本科生的入学率。

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.