Studies of shapes and stability in exotic nuclei

原子核的形状是它最基本的特性之一。原子核最简单的形状是球形。由中子和质子组成的闭合壳层的原子核是球形的。离开封闭的壳层，原子核可以变成非球形或变形。最常见的变形形状是橄榄球（长形）形状或南瓜（扁形）形状，这两种形状都被称为四极体变形。一些原子核可以呈现出反射不对称的梨形，称为八极形变，而另一些原子核可以呈现出旋转陀螺的形状，称为六极形变。在粒子的量子力学系统中，形状的出现是组成粒子之间相互作用的直接结果。因此，核的形状研究可以探测核子-核子相互作用，特别是中子-质子相互作用，这还有待完全了解。核形状还可以影响粒子和团簇衰变的特性，这是目前核结构物理的前沿课题，特别是在稳定极限区域。专注于核变形测量的实验研究将允许将测量的形状与理论计算预测的形状进行比较，以检验模型的有效性。总的来说，原子核的形状对核物理的几个领域和其他一些领域，如天体物理环境中元素的起源，无疑具有重要的影响。因此，提出的形状、中子-质子相互作用和粒子衰变的实验研究是当前核物理研究的前沿。

The shape of an atomic nucleus is one of its most fundamental properties. The simplest shape that a nucleus can have is a sphere. Nuclei that have closed shells of neutrons and protons are spherical. Away from closed shells, nuclei can become non-spherical, or deformed. The most common deformed shapes are rugby-ball (prolate) shapes or pumpkin (oblate) shapes, both of which are termed quadrupole deformation. Some nuclei can take on a reflection-asymmetric pear shape, termed as octupole deformation while some others can take a shape of a spinning top, termed as hexadecapole deformation. In a quantum-mechanical system of particles, the emergence of a shape is a direct consequence of the interaction between the constituent particles. Therefore, shape studies of nuclei can probe nucleon-nucleon interactions and, in particular, neutron-proton interactions, which are yet to be fully understood. The nuclear shape can also affect the characteristics of particle and cluster decays, which are currently topics at the forefront of nuclear-structure physics, particularly in the regions at the limits of stability. Experimental studies that are focused on the measurement of nuclear deformations will allow a comparison of the measured shapes with those predicted by theoretical calculations to test the validity of models. In general, the shapes of nuclei indisputably have an important impact on several areas of nuclear physics and some other areas such as the origin of elements in astrophysical environments. Consequently, the proposed experimental studies of shapes, neutron-proton interactions and particle decays are at the forefront of current nuclear-physics research.