Birmingham Nuclear Physics Group Consolidated Grant

伯明翰核物理小组综合拨款

基本信息

批准号：
ST/L005751/1
负责人：
Peter Jones
金额：
$ 160.63万
依托单位：
University of Birmingham
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2014
资助国家：
英国
起止时间：
2014 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FL005751%2F1
关键词：
Birmingham Nuclear Physics Group Consolidated

项目摘要

The atomic nucleus has recently seen its centenary. Over this time understanding of nuclei and their structure has evolved considerably. However, and perhaps surprisingly it is still not possible to calculate their structure with sufficient accuracy. The fundamental limitation is not only that the nucleus is a many body object, and the complexity that is a natural consequence, but the interaction is fundamentally yet to be understood. It is this interaction which generates all sorts of complex nuclear structures from clustering to halos, from spherical to deformed, from stable to unstable. In order to make more progress one has to understand how the nuclear strong interaction emerges from that at the sub nucleonic level, where quarks and gluons are the appropriate degrees of freedom. Growing the nuclear force from the Quantum Chromodynamic (QCD) level is the dominion of chiral effective field theory. This is one of a range of approaches which it is hoped will lead to understanding nuclei from first principles (ab initio). The Birmingham Nuclear Physics group's research spans the territory from the QCD to nucleonic and seeks to answer some of the central challenges of the subject. Through the collisions of nuclei at the highest possible energies yet created in the laboratory the group is exploring the quark-gluon plasma (QGP). This is a state of matter created when the energy in the collision is so high that the nucleons (protons and neutrons) melt into the quarks and gluons. This is believed to be precisely the phase of matter an instant after the big bang. These conditions are created in the laboratory for a fleeting moment and the challenge is to probe the matter in this phase before it dissociates. The Birmingham group are part of the ALICE collaboration at the LHC in CERN and have developed the sophisticated trigger, which selects key events in the millions of collisions in which the QGP is formed. Through our scientific leadership we have been able to get a feeling for the properties of the QGP. The challenge for the present grant is to go beyond the rather rudimentary understanding to provide a precise characterisation of its properties. This involves detailed measurements of particles as they are emitted from the QGP, for example measuring their survival probability as they cross the plasma. The aim to to reach a detailed understanding of this state of hadronic matter.The second strand reaches from the quark scale to the scale of nuclei. The ab initio calculations of nuclei are challenging and for many of them the limits lie close to mass 12. As a result much of the focus has fallen on carbon-12. The Birmingham group has led the development of the experimental understand of this nucleus and one particular quantum state - the Hoyle-state. This rather exotic state is not only believed to be constructed from three alpha-particles, but to be associated with the synthesis of carbon in stars. If the state did not exist nor would organic (carbon-based) life. Understanding its structure is fundamental to human existence. Not only has the group made a significant contribution to this understanding, but we are exploring the alpha-cluster correlations in a whole sequence of light nuclei. It is understanding these correlations which is key to testing the ab initio models and our understanding of the nuclear force. The group will perform a series of precision measurements to provide stringent tests of the best nuclear models to-date.The present application is a potentially high impact contribution to the development of our understanding of nuclear and hadronic matter.

原子核最近迎来了百年诞辰。在此期间，对原子核及其结构的理解有了很大的发展。然而，也许令人惊讶的是，仍然不可能以足够的精度计算它们的结构。根本的限制不仅在于原子核是一个多体物体，其复杂性是自然结果，而且其相互作用从根本上尚待理解。正是这种相互作用产生了各种复杂的核结构，从簇到晕，从球形到变形，从稳定到不稳定。为了取得更多进展，我们必须了解核强相互作用是如何从亚核子层面产生的，其中夸克和胶子是适当的自由度。从量子色动力学（QCD）水平增长核力是手性有效场理论的领域。这是希望能够从第一原理（从头开始）理解原子核的一系列方法之一。伯明翰核物理小组的研究跨越了从量子色动力学到核子学的领域，并试图回答该学科的一些核心挑战。通过在实验室中产生的最高能量的原子核碰撞，该小组正在探索夸克胶子等离子体（QGP）。这是当碰撞中的能量如此高以至于核子（质子和中子）熔化成夸克和胶子时产生的物质状态。据信，这正是大爆炸后瞬间的物质状态。这些条件是在实验室中短暂创造的，挑战是在物质解离之前对其进行探测。伯明翰小组是 CERN 大型强子对撞机 ALICE 合作的一部分，并开发了复杂的触发器，该触发器可以在形成 QGP 的数百万次碰撞中选择关键事件。通过我们的科学领导力，我们已经能够感受到 QGP 的特性。目前的资助面临的挑战是超越相当基本的理解，提供对其属性的精确描述。这涉及对从 QGP 发射的粒子进行详细测量，例如测量它们穿过等离子体时的生存概率。目的是详细了解强子物质的这种状态。第二条链从夸克尺度延伸到原子核尺度。原子核的从头计算具有挑战性，对于许多原子核来说，其极限接近于质量 12。因此，大部分焦点都落在了碳 12 上。伯明翰小组领导了对这种原子核和一种特定量子态——霍伊尔态的实验理解的发展。这种相当奇特的状态不仅被认为是由三个α粒子构成的，而且与恒星中碳的合成有关。如果国家不存在，有机（碳基）生命也不存在。了解其结构是人类生存的基础。该小组不仅对这种理解做出了重大贡献，而且我们正在探索整个轻核序列中的α簇相关性。理解这些相关性是测试从头算模型和我们对核力理解的关键。该小组将进行一系列精确测量，以对迄今为止最好的核模型进行严格的测试。目前的应用对于我们对核和强子物质的理解的发展具有潜在的重大影响。