Nuclear Physics Consolidated Grant 2013 (Equipment Bid)

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：“当物理定律被推向极端时，它们是如何工作的？”宇宙的基本组成和结构是什么，它们如何相互作用？宇宙是如何开始的，又是如何演化的？核物质和强子物质的本质是什么？“我们研究的目的是研究原子核和核物质的性质，以回答这些问题。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。通过在高能核反应中从原子核中猛烈地移除一个核子并测量其性质，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（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。核物质的热力学性质及其相变可以用它的状态方程来描述.在密度和温度的极端条件下（大约是太阳中心温度的10万倍！），相变应该发生，夸克和胶子（质子和中子的组成）应该存在于一种新的物质状态中，称为夸克-胶子等离子体。通过在高能量下将原子核碰撞在一起，我们将研究这种新的物质状态的性质以及核物质如何随着同位旋不对称性和密度的变化而表现。这些信息不仅对核物理学很重要，而且对了解中子星和其他致密天体也很重要，这项研究方案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相，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家改进和测试他们试图预测原子核和核物质性质的计算，这些计算通常会得到非常不同的结果。这个问题的解决将有助于我们描述复杂的多体核系统，并更好地理解大爆炸后几分之一秒内宇宙的状况。

The majority of the visible mass of the universe is made up of atomic nuclei that lie at the centre of atoms. Nuclear physics seeks to answer fundamental questions such as: "How do the laws of physics work when driven to the extremes? What are the fundamental constituents and fabric of the universe and how do they interact? How did the universe begin and how is it evolving? What is the nature of nuclear and hadronic matter?" The aim of our research is to study the properties of atomic nuclei and nuclear matter in order 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. By violently removing a nucleon from a 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), nuclear matter can undergo a transition from one phase to another. Thermodynamic properties nuclear matter and its phase transitions can be described by its equation of state. In extreme conditions of density and temperature (about 100 thousands times more than the temperature at the heart of the sun!), a phase transition should occur and quarks and gluons (of which the protons and neutrons are made of) should exist in a new state of matter called the Quark-Gluon Plasma. By colliding nuclei together at high energies, we will study properties of this new state of matter and 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 nuclear matter, often with widely differing results. The resolution of this problem will help us to describe complex many-body nuclear systems and better understand conditions in our universe a few fractions of a second after the big bang.