Ab initio Prediction of the 163Ho Electron Capture Spectrum

163Ho 电子捕获谱的从头预测

• 批准号: 400329440
• 负责人: Professor Dr. Maurits Haverkort
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/400329440?language=en
• 关键词: Ab; initio; Prediction; 163Ho; Electron

Within this workgroup, we will ab initio predict the calorimetric electron capture spectra of 163Ho. From the particle physics point of view, the weak interaction of an electron with a proton leading to the creation of a neutron and an electron neutrino is theoretically straightforward. In a neutral atom, when this same interaction occurs, more complex processes will accompany the electron capture by the nucleus. Electrons in an atom are not independent identities and due to strong Coulomb forces, all electrons react once one electron is captured. The calorimetrically measured spectrum of Ho is thus not given by just 7 Lorentzian shaped peaks originating from capture events from the 3s to 6s and 3p1/2 to 5p1/2 shell respectively, but several additional shake-up and shake-off structures with an involved multiplet structure emerge. The theoretical description of the full spectrum requires one to have knowledge about the Green’s function propagators describing the time evolution of a Dy atom with the electron multi-configurational many body wave-function corresponding to the ground-state of Ho with one additional core hole. The time evolution involves fluorescence and Auger decays into bound and continuum states. These decays produce the tails of the spectrum and ultimately create the end-point of the spectrum that is influenced most by the mass of the neutrino.Using a combination of numerical methods as used in quantum chemistry (configuration interaction) and solid state physics (Green’s functions and renormalization group) we aim to achieve a numerical accuracy able to predict the mulitplet governed spectra of the core level decay with unprecedented precision. In order to achieve this we will include all possible local multiplets (shake-up and shake-down) as well as Auger and fluorescence yield decay of the excitations. We furthermore will consider the interaction of the local Ho 4f states with the electronic continuum of the host metal. We will develop the needed numerical methods to handle the many body correlations of both the ground-state as well as the excited states with sub-electron volt accuracy. We will furthermore provide an error estimate of the calculations indicating the maximal difference between the physical reality and calculated spectra.These calculations will firstly provide a detailed understanding of the electron capture resonances and their structure. Secondly, these calculations will provide information how much the end-point region is influenced by mulitplet excitations, extended fine-structure in the spectra due to multiple scattering events of Auger electrons in the host material and selection rules in the decay process related to the alignment of the magnetic moment of the 163Ho 4f shell and the 163Ho nucleus. The final aim is to provide a detailed understanding of the 163Ho electron capture spectrum needed for the accurate determination of the neutrino mass.

在这个工作组中，我们将从头开始预测 163Ho 的量热电子捕获光谱。从粒子物理学的角度来看，电子与质子的弱相互作用导致中子和电子中微子的产生在理论上是简单的。在中性原子中，当发生同样的相互作用时，更复杂的过程将伴随着原子核的电子捕获。原子中的电子不是独立的个体，由于强大的库仑力，一旦一个电子被捕获，所有电子都会发生反应。因此，Ho 的量热测量光谱不仅仅由分别源自 3s 到 6s 和 3p1/2 到 5p1/2 壳的捕获事件的 7 个洛伦兹形峰给出，而是出现了几个具有相关多重结构的附加振动和振动结构。全光谱的理论描述要求人们了解格林函数传播子，该传播子描述了镝原子的时间演化，其电子多构型多体波函数对应于具有一个附加核心空穴的 Ho 基态。时间演化涉及荧光和俄歇衰变成束缚态和连续态。这些衰变产生光谱的尾部，并最终形成受中微子质量影响最大的光谱终点。结合使用量子化学（构型相互作用）和固态物理学（格林函数和重整化群）中使用的数值方法，我们的目标是实现能够以前所未有的方式预测核心能级衰变的多重态控制光谱的数值精度。 精确。为了实现这一目标，我们将包括所有可能的局部多重态（震动和震动）以及激发的俄歇和荧光产量衰减。我们还将考虑局部 Ho 4f 态与主体金属的电子连续体的相互作用。我们将开发所需的数值方法，以亚电子伏特精度处理基态和激发态的许多体相关性。我们还将提供计算的误差估计，表明物理现实与计算光谱之间的最大差异。这些计算将首先提供对电子捕获共振及其结构的详细理解。其次，这些计算将提供终点区域受多线激发影响的程度、由于主体材料中俄歇电子的多次散射事件导致的光谱扩展精细结构以及与 163Ho 4f 壳层和 163Ho 核的磁矩对准相关的衰变过程中的选择规则的影响。最终目标是详细了解准确测定中微子质量所需的 163Ho 电子捕获谱。