RUI: Disentangling Quark and Gluon Energy Loss with Heavy Flavor Jets in the ALICE Experiment at the CERN LHC

我们所知道的宇宙是从一个非常热的，致密的基本粒子的原始汤演变而来的，这些基本粒子是在被称为大爆炸的大灾难中创造的。 随着宇宙的膨胀和冷却，这些基本粒子，称为夸克和胶子，凝聚成质子和中子，最终结合成原子核，捕获电子形成原子。 我们所能观察到的几乎所有东西都是由这种基本材料制成的。 利用大型粒子加速器，科学家们正在实验室中通过以非常高的能量碰撞金或铅原子来重现宇宙诞生时的条件，以研究这些粒子之间的性质和相互作用。 这些研究将为我们揭示宇宙中基本力的深层本质提供线索。从这些实验中得出的最重要的发现之一是，在这些碰撞中产生的致密物质对其中产生的高能夸克和胶子是不透明的。这些“部分子”在离开碰撞区时会遭受巨大的能量损失，将大部分初始能量沉积在介质中。能量损失的强度与介质的密度直接相关，并根据部分子的类型而变化。看来部分子越重，它遭受的能量损失就越多。 高能部分子分裂成一束叫做“喷流”的粒子。 如果喷流包含一个高能电子，那么它很有可能起源于一个重夸克。这些电子喷注的能量损失可以用来研究它所穿过的夸克胶子等离子体介质的性质。 这项研究的目的是通过分离含有电子的喷流，并将它们的能量损失模式与不含电子的喷流进行比较，来解开夸克和胶子的能量损失。位于瑞士的欧洲核子研究中心大型强子对撞机（LHC）以实验室中创造的最高能量碰撞原子核。这个RUI项目将利用ALICE实验，以重夸克喷注的能量损失为探针，探索夸克-胶子等离子体的性质。从事这项实验的本科生将接受高能核物理前沿最先进的数据收集、还原和分析技术的培训。他们将能够在各种各样的职业中应用这些技能，无论他们是否选择攻读基础科学的高级学位。他们的贡献还将帮助我们对物质基本组成部分之间的基本相互作用有新的理解，从而更深入地了解我们所居住的宇宙。

The Universe as we know it evolved from a very hot, dense primordial soup of fundamental particles that were created in the cataclysm known as the Big Bang. As the Universe expanded and cooled, these fundamental particles, called quarks and gluons, condensed into protons and neutrons, which eventually combined into nuclei that captured electrons to form atoms. Nearly everything we can observe is made from this fundamental material. Using large particle accelerators, scientists are recreating the conditions at the birth of the Universe in the laboratory by colliding gold or lead atoms at very high energies to study the properties and interactions among these particles. These investigations will provide us with clues to the deeper nature of the fundamental forces in the Universe.One of the most important discoveries to come from such experiments is that the dense matter created in these collisions is opaque to very high energy quarks and gluons produced in them. These "partons" suffer tremendous energy loss as they make their way out of the collision zone, depositing a large fraction of their initial energy in the medium. The strength of the energy loss is directly related to the density of the medium and varies according to the type of parton. It appears that the heavier the parton, the more energy loss it suffers. Energetic partons fragment into a spray of particles called a "jet". If a jet contains a high energy electron, there is a very high probability that it originated from a heavy quark. The energy loss of these electron-jets can be used to investigate the properties of the quark gluon plasma medium through which it passed. The goal of this research is to disentangle the energy loss of quarks and gluons by isolating jets containing electrons and comparing their energy loss patterns to those without electrons.The CERN Large Hadron Collider (LHC) in Switzerland collides nuclei at the highest energies ever created in a laboratory. This RUI project will utilize the ALICE experiment to explore the properties of the quark-gluon plasma using the energy loss of heavy quark jets as a probe. Undergraduate students working on this experiment will be trained in the most advanced data collection, reduction and analysis techniques at the cutting edge of high energy nuclear physics. They will be able to apply these skills in a wide variety of careers, whether they choose to pursue an advanced degree in basic science or not. Their contributions will also help us develop new understanding of the fundamental interactions among the basic building blocks of matter, leading to a deeper understanding of the Universe we inhabit.