High-resolution spectroscopy of exotic nuclei to study NN and 3N interactions

奇异核的高分辨率光谱研究 NN 和 3N 相互作用

• 批准号: 2431945
• 金额: --
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2431945
• 关键词: resolution; spectroscopy; exotic; nuclei; study

The atomic nucleus is a quantum many-body system, where protons and neutrons are subject to complex NN interactions that include central, spin-orbit, tensor and many-body (e.g. 3N) contributions. The modification of nuclear structure in exotic nuclei is driven by specific components of these NN interactions and by studying experimentally very exotic nuclei, we can identify which component is responsible for distinct features of exotic nuclei. The study of these phenomena requires measurement of key spectroscopic information on excited states of exotic nuclei, and the new HiCARI campaign at RIKEN provides an exciting opportunity to do so in nuclei at the extremes of nuclear stability. In particular, we will study the lifetime of the 2+ excited state of the very neutron-rich 20C nuclide, where tensor and two-body spin-orbit forces are responsible for the erosion of the Z=6 spin-orbit shell gap. At the same time, lifetimes of excited states are very sensitive to 3N forces and such measurements at the dripline will give us a unique insight on how 3N correlations drive the shell evolution at the extremes of isospin. We will perform detailed spectroscopy of 78Ni, whose doubly magic nature has been confirmed [Nature 569, 53 (2019)]; these results, however, show a potential deformed state lying close to the spherical one, signaling a modification of nuclear structure beyond 78Ni. We will measure for the first time lifetimes in neutron-rich Ca isotopes, a critical testing ground for phenomenology and ab initio calculations, where we will be able to shed light into 3N force effects. We will measure lifetimes of excited states in the heaviest accessible N=Z nuclei 88Ru and 86Tc to shed light on the role of a special type of neutron-proton pairing correlation (isoscalar) predicted to exist in these exotic systems and which is predicted to impact on these measurements.

原子核是一个量子多体系统，其中质子和中子受到复杂的神经网络相互作用，包括中心、自旋轨道、张量和多体（例如 3N）的贡献。奇异核中核结构的修饰是由这些神经网络相互作用的特定成分驱动的，通过实验研究非常奇异的核，我们可以确定哪个成分负责奇异核的独特特征。对这些现象的研究需要测量奇异核激发态的关键光谱信息，而 RIKEN 的新 HiCARI 活动提供了一个令人兴奋的机会，可以在极端核稳定性的核中进行测量。特别是，我们将研究中子含量非常丰富的 20C 核素的 2+ 激发态的寿命，其中张量和二体自旋轨道力导致 Z=6 自旋轨道壳层间隙的侵蚀。同时，激发态的寿命对 3N 力非常敏感，滴水线处的此类测量将为我们提供关于 3N 相关性如何驱动同位旋极端情况下壳层演化的独特见解。我们将对 78Ni 进行详细的光谱分析，其双重神奇性质已被证实 [Nature 569, 53 (2019)]；然而，这些结果显示出一种接近球形状态的潜在变形状态，这表明 78Ni 之外的核结构发生了改变。我们将首次测量富中子 Ca 同位素的寿命，这是现象学和从头计算的关键试验场，在这里我们将能够揭示 3N 力效应。我们将测量最重的 N=Z 核 88Ru 和 86Tc 中激发态的寿命，以阐明预计存在于这些奇异系统中的特殊类型的中子-质子配对相关性（等标量）的作用，并预计会影响在这些测量上。