ALICE Upgrade 2 (Silicon Physicist post)

ALICE 升级 2（硅物理学家岗位）

• 批准号: ST/P005438/1
• 负责人: Marielle Chartier
• 金额: $ 21.13万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FP005438%2F1
• 关键词: ALICE; Upgrade; Silicon; Physicist; post

Quantum-ChromoDynamics (QCD) is the theory of the strong force and understanding its properties has been the focus ofintense World-wide research over the past half century. QCD forms a major part of the Standard Model and itsunderstanding is crucial in producing an overall theory to describe the properties of matter and the fundamental forces ofnature including a grand unification theory to explain how the Universe evolved from the Big Bang.The principal purpose of our research is to use ultra-relativistic heavy-ion interactions to study QCD at extreme energydensities. Theoretical models predict that under very extreme conditions of high energy densities the quarks, which areconfined in normal nuclear matter, will be freed and nuclear matter will undergo a phase transition into a hot, dense plasmaof free quarks and gluons known as a Quark-Gluon Plasma (QGP). It is thought that such a state of matter would haveexisted until about 10^-5 seconds after the Big Bang, after which time the Universe would have cooled sufficiently forprotons and neutrons to form.The physics aim of this research is to study the strong force under these extreme conditions and, in particular, explore theproperties of this exotic state of matter. By studying the QGP, we hope to address the fundamental questions of quarkconfinement and how quarks gain a large effective mass in hadrons due to the strong force (accounting for 99% of atomicmass).In order to create the conditions required to produce a QGP we must collide heavy nuclei together at the highest possibleenergies, creating tiny hot (~10^13K) and dense fireballs. As the resulting QGP will only last for about 10-22 seconds,before condensing in to thousands of elementary particles, we must also use the most sophisticated detectors to analysethese collisions.The LHC collides lead ions at centre-of-mass energies of 2.76 TeV in ALICE. We also collide protons together as this formsan excellent reference data set. Moreover, the excellent particle identification and tracking make ALICE an ideal detectorto study the global aspects of proton-proton collisions in their own right.This field of research employs about two thousand physicists around the world and ALICE is the most sophisticatedexperiment ever built in the field, studying heavy-ion collisions at centre-of-mass energies over an order of magnitudegreater than its nearest rival. It hence represents the pinnacle of research in this field.The ALICE collaboration is now preparing for the second LHC Upgrade scheduled to start in 2018. These upgrades arerequired to cope with the anticipated increase in lead beam luminosity which will increase beam intensities by an order ofmagnitude. The main motivation for the luminosity upgrade is to achieve a precise, quantitative understand of theproperties of the QGP by focusing on rare probes both at low and high transverse momenta as well as on multidimensionalanalysis of such probes with respect to centrality, event plane, multi-particle correlations, etc.

量子色动学（QCD）是研究强相互作用的理论，半个世纪来，对它的性质的认识一直是世界范围内研究的热点。QCD是标准模型的一个重要组成部分，它的理解对于建立一个完整的理论来描述物质的性质和自然界的基本力是至关重要的，包括大统一理论来解释宇宙是如何从大爆炸演化而来的.我们研究的主要目的是利用超相对论重离子相互作用来研究极端能量密度下的QCD.理论模型预测，在非常极端的高能量密度条件下，被限制在正常核物质中的夸克将被释放，核物质将经历相变，成为一个由自由夸克和胶子组成的热的、致密的等离子体，称为夸克-胶子等离子体（QGP）。人们认为，这样的物质状态会一直存在到大爆炸后的10^-5秒左右，在此之后，宇宙会冷却到足以形成质子和中子。这项研究的物理目的是研究在这些极端条件下的强力，特别是探索这种奇异物质状态的性质。通过对QGP的研究，我们希望解决夸克禁闭的基本问题，以及强子中夸克如何由于强相互作用而获得大的有效质量（占原子质量的99%）。为了创造产生QGP所需的条件，我们必须使重核在尽可能高的能量下碰撞在一起，产生微小的热（~10^13K）和密集的火球。由于产生的QGP只会持续大约10-22秒，然后凝聚成数千个基本粒子，我们还必须使用最先进的探测器来分析这些碰撞。LHC在ALICE中碰撞质心能量为2.76 TeV的铅离子。我们还将质子碰撞在一起，这形成了一个很好的参考数据集。此外，出色的粒子识别和跟踪使ALICE成为研究质子-质子碰撞全球方面的理想探测器。这一研究领域雇用了全世界约2000名物理学家，ALICE是该领域有史以来最成熟的实验，研究质量中心能量超过其最接近的竞争对手的数量级的重离子碰撞。ALICE合作项目目前正在为计划于2018年启动的第二次LHC升级做准备。这些升级是为了科普预期的铅束亮度的增加，这将增加一个数量级的光束强度。光度升级的主要动机是通过关注低和高横动量的稀有探针以及对这些探针的中心性、事件平面、多粒子关联等的多维分析来实现对QGP性质的精确、定量的理解。

项目成果

Data-driven precision determination of the material budget in ALICE

• DOI: 10.1088/1748-0221/18/11/p11032
• 发表时间: 2023-03
• 期刊: Journal of Instrumentation
• 影响因子: 1.3
• 作者: S. Acharya;D. Adamová;A. Adler;G. Aglieri Rinella;M. Agnello;N. Agrawal;Z. Ahammed;S. Ahmad