Nuclear Physics Consolidated Grant 2023

核物理学已进入第二个世纪，但它仍然生机勃勃。在过去的100年里，有大量的实验和理论研究，导致了里程碑式的结果和发现，如中子的发现，核的成功模型的发展，以及许多新的衰变模式的识别。核物理学的进步与粒子加速器的发展齐头并进，粒子加速器始于能够加速轻离子的普通静电机器，并导致现代加速器能够加速任何核，直到铀-238，每个核子的能量为10 MeV或更高。现在已经有了可以加速放射性离子的设施，人们正在努力提高放射性束的强度、能量和纯度。尽管核物理学的研究活动非常丰富，而且学科也已经成熟，但人们仍然没有完全理解原子核。仍然有许多悬而未决的问题需要回答，我们将在我们的研究计划中解决这些问题。核物理学的技术和科学发展正在导致基础科学领域之外的应用-与核相关的概念现在用于工业，医学和社会的许多领域，从而导致新的应用研究领域。我们在这个综合资助申请的研究方案涵盖了对原子核的结构，行为和性质的研究，这些原子核远离稳定性以及稳定核中的集体行为，这仍然知之甚少。我们研究计划的主要部分之一是研究原子核的形状。众所周知，具有中子和质子填充壳层的核是球形的，并且具有部分填充壳层的核可以变形。我们的研究计划中的一个主题将研究四极形状的原子核，其中原子核呈现橄榄球形状。这种类型的核变形是普遍的，发生在核图的许多不同区域。更奇特的变形形式是原子核呈现出反射不对称的“梨”形。这种八极形变在原子核图的局部区域最为突出，例如轻锕系元素区域（镭、钍、铀核，A~224）和钡-144附近的镧系元素。在我们的研究计划中，我们将对原子核中的八极形变进行全面研究，重点是锕系和镧系区域，以及N=Z=56附近的富质子核。由于梨形核是寻找原子电偶极矩的最佳候选者，因此在核物理学之外，对这些核的研究受到了极大的关注。在过去的20年里，实验观测和理论计算都表明，奇异核的结构可能不同于那些接近稳定的核。众所周知的幻数序列，对应于核壳层结构中的能隙，被认为会根据质子-中子比而变化，称为I型壳层演化。事实上，II型壳层演化的最新进展表明，当激发核子从一个壳层到另一个壳层时，核中会发生这种变化。在我们的计划中，我们将研究整个核图表中一系列核的壳层演化，包括接近双幻核Sn-100和Pb-208的核。我们研究计划的另一个方面是以多信使方法研究原子核中的高能集体模式。后者为我们研究与核天体物理学相关的反应提供了信息，其中将包括关注恒星中发生的氢燃烧或爆炸天体物理场景中的核结构决定过程，如II型超新星。

Now well into its second century, the science of nuclear physics remains vibrant and active. Over the past 100 years, there has been a wealth of experimental and theoretical research that has led to milestone results and discoveries, such as the discovery of the neutron, the development of successful models of the nucleus, and the identification of numerous novel decay modes. Progress in nuclear physics has gone hand-in-hand with the development of particle accelerators, which started with modest electrostatic machines, capable of accelerating light ions, and resulting in modern day accelerators capable of accelerating any nucleus up to uranium-238, with energies of 10 MeV per nucleon or more. Facilities now exist that can accelerate radioactive ions, and there is effort being put into improving the intensities, energies, and purity of radioactive beams. Despite the wealth of research activity in nuclear physics, and the maturity of the subject, a complete understanding of the atomic nucleus has still not been achieved. There are still many open questions that need to be answered, which we will address in our research programme. Technological and scientific developments in nuclear physics are leading to applications outside of the areas of fundamental science - nuclear-related concepts are now used in many areas of industry, medicine, and society leading to new areas of applied research. Our programme of research in this Consolidated Grant application covers research into the structure, behaviour and properties of atomic nuclei that lie far from stability as well as collective behaviour in stable nuclei, which remains poorly understood. One of the main parts of our programme of research is the study of the shapes of atomic nuclei. It is well established that nuclei with filled shells of neutrons and protons are spherical, and nuclei with partially-filled shells can become deformed. One of the themes within our research programme will study quadrupole shaped nuclei, where the nucleus takes on a rugby-ball shape. This type of nuclear deformation is prevalent and occurs in many different regions of the nuclear chart. A more exotic form of deformation is when the nucleus takes on a reflection-asymmetric "pear" shape. Such octupole deformation is most prominent in localized regions of the nuclear chart, such as the light actinide region (radium, thorium, uranium nuclei with A~224) and lanthanides near barium-144. In our research programme, we will make a comprehensive study of octupole deformation in nuclei, focusing on the actinide and lanthanide regions, as well as the proton-rich nuclei near N=Z=56. There is significant attention on these nuclei from outside of nuclear physics since atoms containing pear-shaped nuclei are excellent candidates in which to search for an atomic electric dipole moment.Over the past 20 years, experimental observations, supported by theoretical calculations, have suggested that the structure of exotic nuclei may be different from those near stability. The well-known sequence of magic numbers, corresponding to energy gaps in nuclear shell structure, are thought to change depending on the proton-neutron ratio, known as type-I shell evolution. Indeed, the recent development of type-II shell evolution suggests such a change happens in a nucleus when exciting nucleons from one shell to another. In our programme, we will study the shell evolution in a range of nuclei across the nuclear chart, including the nuclei close to the doubly-magic nuclei Sn-100 and Pb-208. Another aspect of our research programme is a study of high-energy collective modes in nuclei, in multi-messenger approaches. The latter feeds into our research studying reactions relevant to nuclear astrophysics, which will include a focus on hydrogen burning that occurs in stars or nuclear structure determining processes in explosive astrophysical scenarios, like a type-II supernovae.