Elucidating Jet Quenching and Medium Response Mechanisms via Hard Probes in Relativistic Heavy-ion Collisions

在极高的温度和密度下，我们每天经历的正常核物质“熔化”成所谓的夸克-胶子等离子体（QGP）阶段，由“准自由”夸克和胶子组成，这一阶段被认为存在于我们的宇宙在大爆炸中诞生后的前10微秒。 这种QGP可以通过将物质加热到1.7亿电子伏特以上的温度来产生。 在实验上，这是通过在非常高的能量下碰撞两个大的原子核（通常是金或铅）来实现的。 由此产生的炽热而致密的火球预计会在自身压力下膨胀，并冷却下来。 QGP的性质，如温度，压力，化学势，粘度，扩散系数，声速等，可以从火球发射的数千个粒子中推断出来，并通过围绕相互作用区域的大尺度粒子探测器进行探测。 这些研究正在相对论重离子对撞机的PHENIX实验中进行，并计划在大型强子对撞机的ATLAS实验中进行。 该项目的重点是一套独特的测量，可以通过PHENIX探测器建立RHIC产生的高密度物质的属性，以及使用ATLAS探测器在LHC应用其中一些测量技术。 具体来说，我们将通过测量高能单喷流和背靠背喷流对（双喷流）来探测这种物质的性质。 这项研究将改善我们目前对极端条件下物质基本性质的理解，因此对天体物理学和超弦理论等其他领域的研究产生广泛影响。 研究生和本科生的参与预计在整个计划。 PHENIX实验在各级教育中提供了多样化的研究课题，以及一个良好的工作环境，涉及该领域数百名科学家之间的互动，以及编程，硬件，领导力和学术方面的职业发展的独特机会。

At extremely high temperature and density, the normal nuclear matter we experience every day "melts'" into the so called Quark-gluon plasma (QGP) phase consisting of "quasi-free'" quarks and gluons, a phase believed to have existed during the first 10 microseconds after our universe was born in the Big Bang. This QGP can be created by heating matter above a temperature of 170 millon electron volts. Experimentally, this is done by colliding two large nuclei (typically Gold or Lead) at very high energy. The resulting hot and dense fireball is expected to expand under its own pressure, and cool down. Properties of the QGP such as its temperature, pressure, chemical potential, viscosity, diffusion coefficient, speed of sound, etc. can be deduced from thousands of particles emitted from the fireball and detected with large scale particle detectors surrounding the interaction region. Such studies are being carried out in the PHENIX experiment at the Relativistic Heavy-ion Collider (RHIC) and planned for the ATLAS experiment at the Large Hadron Collider (LHC), respectively. This project is focused on a set of exclusive measurements that can establish the properties of the high-density matter created at RHIC via the PHENIX detector, as well as applying some of these measurement techniques at LHC using the ATLAS detector. Specifically, we will probe the properties of this matter via measurements of high-energy single jets and back-to-back jet pairs (di-jets). The research will improve our present understanding of the fundamental nature of the matter under extreme conditions, and therefore has a broad impact on other fields of endeavor such as astrophysics and super-string theories. Participation by graduate students and undergraduate students is expected throughout the program. The PHENIX experiment provide a diverse array of research topics at all levels of education, as well as an excellent working environment involving interactions between hundreds of scientists in the field, and unique opportunities for career development in programming, hardware, leadership and academics.