Consolidated nuclear physics grant 2011

2011年综合核物理补助金

• 批准号: ST/J000094/1
• 负责人: Peter Butler
• 金额: $ 277.34万
• 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: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FJ000094%2F1
• 关键词: Consolidated; nuclear; physics; grant; 2011

The majority of the visible mass of the universe is made up of atomic nuclei that lie at the centre of the atom. Nuclear physics seeks to answer fundamental questions such as: 'What are the limits of nuclear existence, at the proton drip-line and for the heaviest masses?'; 'How do simple patterns emerge in complex nuclei?'; 'Can nuclei be described in terms of our understanding of the underlying fundamental interactions?'; 'What is the equation-of-state of nuclear matter, including compact matter in neutron stars?'; 'How does the ordering of quantum states change in extremely unstable nuclei?; 'Are there new forms of structure and symmetry at the limits of nuclear existence?'. The aim of this research proposal is to try to answer these questions. No one yet knows how heavy a nucleus can be; in other words, just how many neutrons and protons can be made to bind together. We will study the heaviest nuclei that can be made in the laboratory and determine their properties which will allow better predictions to be made for the 'superheavies'. For lighter nuclei we will explore in the region of the proton and neutron drip lines, which are the borders between bound and unbound nuclei. We will determine more precisely than ever before the location of these drip lines. Nuclei beyond the proton drip line have so much electrical charge that they are highly unstable and try to achieve greater stability through the process of proton emission. We will investigate how nuclear behaviour is affected when protons become unbound. For these exotic systems we will also explore how the nucleus prefers to rearrange its shape, which can be a sphere, rugby ball, pear, etc. and how it stores its energy among the possible degrees of freedom. We will also investigate how the properties of these nuclei develop as we make them spin faster and faster. We will try to determine the precise nature of ultra high spin states in heavy nuclei, just before the nucleus breaks up due to fission. We will study whether a nucleon looks the same when it is inside the nucleus or when it is in free space. By violently removing the nucleon from the nucleus in a nuclear reaction at high energies and measuring its properties, we can investigate to what extent the nucleon 'feels' the influence of its neighbouring nucleons, whether it is correlated with them. Such information tells us about the nuclear force inside the nucleus at different inter-nucleon distances. Nuclear matter can exist in different phases, analogous to the solid, liquid, gas and plasma phases in ordinary substances. By varying the temperature, density, pressure and isospin asymmetry (the relative number of neutrons and protons in the matter), nuclear matter can undergo a transition from one phase to another. The thermodynamic properties of the matter and its phase transitions can be summarised by the equation of state. By colliding nuclei together at high energies, we will study how nuclear matter behaves as the isospin asymmetry and density vary. Such information is not only important for nuclear physics but also to understand neutron stars and other compact astrophysical objects. This programme of research will employ a large variety of experimental methods to probe many aspects of nuclear structure and the phases of strongly interacting matter, mostly using instrumentation that we have constructed at several world-leading accelerator laboratories. The work will require a series of related experiments at a range of facilities in order for us to gain an insight into the answers to the questions posed above. These experiments will help theorists to refine and test their calculations that have attempted to predict the properties of nuclei and the phases of strongly interacting matter, often with widely differing results. The resolution of this problem will help us to describe complex many-body nuclear systems.

宇宙中大部分可见物质是由位于原子中心的原子核组成的。核物理学试图回答一些基本问题，例如：“在质子滴线和最重质量处，核存在的极限是什么？”简单的图案是如何在复杂的原子核中出现的？原子核能用我们对基本相互作用的理解来描述吗？什么是核物质的状态方程，包括中子星中的致密物质？在极不稳定的原子核中，量子态的有序性是如何变化的？在核存在的极限上，是否存在新的结构和对称形式？'.本研究的目的就是试图回答这些问题。目前还没有人知道原子核的重量，换句话说，究竟有多少中子和质子可以结合在一起。我们将研究在实验室中可以制造的最重的原子核，并确定它们的性质，这将使我们能够更好地预测“超物质”。对于较轻的核，我们将在质子和中子滴线区域进行探索，这些区域是束缚核和非束缚核之间的边界。我们将比以往任何时候都更精确地确定这些滴灌线的位置。超过质子滴线的原子核具有如此多的电荷，以至于它们非常不稳定，并试图通过质子发射过程获得更大的稳定性。我们将研究当质子变得不受束缚时，核的行为是如何受到影响的。对于这些奇异的系统，我们还将探索原子核如何倾向于重新排列其形状，可以是球体，橄榄球，梨等，以及它如何在可能的自由度中存储能量。我们还将研究当我们使这些原子核旋转得越来越快时，它们的性质是如何发展的。我们将试图确定重原子核中超高自旋态的精确性质，就在原子核由于裂变而分裂之前。我们将研究核子在原子核内部和在自由空间中的样子是否相同。通过在高能核反应中猛烈地将核子从核中移除并测量其性质，我们可以研究核子在多大程度上“感受”到其邻近核子的影响，以及它是否与它们相关。这样的信息告诉我们在不同核子间距离的原子核内的核力。核物质可以以不同的相态存在，类似于普通物质中的固体、液体、气体和等离子体相。通过改变温度、密度、压力和同位旋不对称性（物质中中子和质子的相对数量），核物质可以经历从一个相到另一个相的转变。物质的热力学性质及其相变可以用状态方程来概括。通过在高能量下将原子核碰撞在一起，我们将研究核物质在同位旋不对称性和密度变化时的行为。这些信息不仅对核物理很重要，而且对了解中子星和其他致密天体也很重要。这项研究计划将采用各种各样的实验方法来探测核结构的许多方面和强相互作用物质的阶段，主要使用我们在几个世界领先的加速器实验室建造的仪器。这项工作将需要在一系列设施中进行一系列相关实验，以便我们深入了解上述问题的答案。这些实验将帮助理论学家完善和测试他们的计算，这些计算试图预测原子核的性质和强相互作用物质的相位，通常会得到不同的结果。这个问题的解决将有助于我们描述复杂的多体核系统。

项目成果

Inclusive photon production at forward rapidities in proton-proton collisions at $$\mathbf {\sqrt{s}}$$ s = 0.9, 2.76 and 7 TeV

$$mathbf {sqrt{s}}$$ s = 0.9、2.76 和 7 TeV 下质子-质子碰撞中正向快速产生的光子

• DOI: 10.1140/epjc/s10052-015-3356-2
• 发表时间: 2015
• 期刊: The European Physical Journal C
• 作者: Abelev B

Freeze-out radii extracted from three-pion cumulants in pp, p-Pb and Pb-Pb collisions at the LHC

• DOI: 10.1016/j.physletb.2014.10.034
• 发表时间: 2014-12-12
• 期刊: PHYSICS LETTERS B
• 影响因子: 4.4
• 作者: Abelev, B.;Adam, J.;Zyzak, M.
• 通讯作者: Zyzak, M.