Nuclear Physics Consolidated Grant 21-24 - University of York

约克核物理小组是全球领先的小组之一，最近扩大到14个学术机构，拥有广泛和相互关联的研究项目，包括强子物理，核结构，核天体物理，核理论和应用为重点的工作。核物理是约克大学物理系的主要研究领域之一，该组约占学术人员的25%，并在其持续发展中得到了该系和大学的大力支持。该小组在欧洲、北美和日本的领先设施中进行理论核物理学和实验核物理学的研究。这笔综合赠款将支持该小组在2021-2024年期间的活动。为了解释我们研究的背景，我们必须描述一下我们正在研究的系统——原子核。构成我们可见宇宙的每个原子都包含一个原子核，由轻（上、下）夸克组成，在多体量子力学系统中，轻（上、下）夸克表现为质子和中子的熟悉的三夸克组（一起称为核子）。关于这些核子如何在原子核中排列自己还有许多悬而未决的问题：当核子在剧烈碰撞中重叠时会发生什么？核子之间的强作用力对于不同的组合（pn和pp）是相同的吗？三核子力的作用是什么？重核有“中子皮”吗？这些都是我们的研究将通过理论发展和一个雄心勃勃的实验计划在世界范围内广泛的设施来解决的主题。我们今天观察到的原子核范围，从轻元素到重元素，都是由恒星内部的核反应和密集恒星物体（如中子星）的剧烈碰撞产生的。我们的研究通过在地球上，在实验室里重现这些反应，解决了我们对恒星中形成这些原子核的核反应知识的基本空白。我们也在探索中子星的基础核科学。关于中子星有很多东西要学，甚至还没有确定里面是什么！我们的小组将领导研究一种令人兴奋的可能性，即一种新的物质形式，一种包含六个夸克的六夸克，可能发挥关键作用。在更小的距离尺度上，我们还将挑战原子核质量从何而来的问题。我们知道这是由质子和中子的质量决定的。然而，其中只有2%来自组成核子的三个夸克的质量。通过世界领先的实验设施探索这个模糊的量子世界，将为质量的起源提供更多的线索。

The York Nuclear Physics Group is firmly positioned as one of the leading groups worldwide having recently expanded to a full complement of 14 academics with broad and connected research programmes encompassing hadron physics, nuclear structure, nuclear astrophysics, nuclear theory and applications-focussed work. Nuclear physics is one of the principal areas of research in the Department of Physics at York, where the group represents about 25% of the academic staff, and enjoys the strong support of the Department and the University in its continued development. The group carries out research in theoretical nuclear physics, as well as experimental nuclear physics which it conducts at leading facilities in Europe, North America and Japan. This consolidated grant will support the group's activities in the period 2021-2024. To explain the context of our research, we have to describe the system we are working on - the atomic nucleus. The atoms forming our visible universe each contain an atomic nucleus, comprised of light (up, down) quarks which manifest as the familiar three-quark groupings of protons and neutrons (together known as nucleons) in a many-body quantum mechanical system. There are many open questions regarding how these nucleons arrange themselves in the nucleus: What happens when the nucleons overlap in violent collisions? Are the strong forces between nucleons the same for different combinations (pn and pp)? What is the role of three-nucleon forces? Do heavy nuclei have a "neutron skin"? These are all topics that our research will address through theoretical developments and an ambitious experimental programme at a wide range of facilities worldwide. The range of nuclei we observe today, from light to heavy elements, was created by nuclear reactions within stars and by the violent collisions of dense stellar objects such as neutron stars. Our research addresses fundamental gaps in our knowledge of the nuclear reactions forming these nuclei in stars by reproducing these reactions here on earth, in the laboratory. We are also probing the underlying nuclear science of neutron stars. There is a lot to learn about neutron stars, it is not even established what is inside! Our group will lead investigations into the exciting possibility that a new form of matter, a hexaquark containing six quarks, could play a pivotal role. At even smaller distance scales, we will also challenge the question of where the mass of the nucleus comes from. We know this arises from the masses of the constituent protons and neutrons. However only ~2% of this comes from the mass of the three quarks making up the nucleon. Exploring this murky quantum world through experiments at world-leading facilities will cast more light on the origins of mass.