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直截了当的。在中性原子中，当同样的相互作用发生时，原子核捕获电子的过程会伴随着更复杂的过程。原子中的电子不是独立的恒等式，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的量热测量光谱不是由分别来自3s到6s和3p1/2到5p1/2壳层的捕获事件产生的7个洛伦兹形峰给出的，而是出现了一些额外的振荡和振荡结构，其中涉及多重结构。全谱的理论描述要求人们了解描述Dy原子的时间演化的格林函数传播子，其电子多构型多体波函数对应于带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。这些衰减产生了光谱的尾部，并最终产生了受中微子质量影响最大的光谱端点。利用量子化学（组态相互作用）和固体物理（格林函数和重整化群）中使用的数值方法的组合，我们的目标是实现能够以前所未有的精度预测核心能级衰变的多态控制光谱的数值精度。为了实现这一点，我们将包括所有可能的局部多重态（震荡和震荡）以及激发的俄歇和荧光产率衰减。我们进一步将考虑局部Ho 4f态与宿主金属的电子连续体的相互作用。我们将发展所需的数值方法来处理基态和激发态的许多体相关，具有亚电子伏特精度。我们将进一步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了解。其次，这些计算将提供端点区域受多重激发的影响程度，由于宿主材料中俄格电子的多次散射事件而导致的光谱中的扩展精细结构以及与163Ho 4f壳层和163Ho核的磁矩排列相关的衰变过程中的选择规则。最终目的是提供对精确测定中微子质量所需的163Ho电子捕获谱的详细了解。