Ab initio theory for major questions in subatomic physics

亚原子物理学主要问题的从头算理论

• 批准号: SAPIN-2018-00027
• 负责人: Holt, Jason
• 金额: $ 2.55万
• 依托单位: TRIUMF
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=653792
• 关键词: Ab; initio; theory; major; questions

Perhaps the most complicated quantum systems in the universe, the many facets of atomic nuclei are intertwined with some of the most profound questions in nature. Long considered a phenomenological discipline, modern nuclear theory now aims to confront these questions from the ground up: as a first-principles discipline capable of providing reliable predictions with quantified uncertainties. To do this we must first develop a consistent description of the forces which bind protons and neutrons into nuclei, as well as methods which solve the nuclear many-body problem starting only from those interactions.******My previous Discovery Grant was crucial for establishing the valence-space in-medium similarity renormalization group (VS-IMSRG) as a powerful ab initio many-body tool. With the accuracy of large-space methods, but the versatility of the shell model, the VS-IMSRG is currently unique in its capability to calculate essentially all properties of all nuclei up to the mass 100 region. The central focus of this Discovery Grant will be a strong push to improve accuracy, estimate model uncertainty, and expand the physics reach to capitalize quickly on this progress. With sufficient support we will contribute directly to understanding five of the seven "Big Questions in Subatomic Physics", as laid out in the Canadian Subatomic Physics Long Range Plan.******The range of the VS-IMSRG is broad, and applications to exotic nuclei present some of the most exciting possibilities to understand how the structure of nuclei emerges from nuclear forces. We will address major nuclear structure issues across the chart such as the limits of existence of nuclei (the proton and neutron driplines) in the light and medium-mass regions. Furthermore, we will predict the evolution of new magic numbers in unexplored regions to guide future experimental efforts. In the long term we will contribute first-principles data for r-process nucleosynthesis simulations modeling the formation of heavy elements in the universe.******In addition we will address some of the most important questions related to nuclear-weak physics. The most prominent of these is the nuclear matrix element for neutrinoless double beta decay, which is necessary to extract the absolute neutrino mass scale from a potential experimental discovery. Ab initio calculations are underway for the light candidates 48Ca 76Ge and 82Se and will reach 130Te and 136Xe. Similarly for understanding the nature of dark matter, WIMP-nucleus cross sections are needed to interpret results of large-scale direct-detection searches. We will provide the first ab initio calculations of WIMP-nucleus elastic-scattering structure factors, where calculations for light candidates are underway, and will be extended to 129,131Xe. Finally for understanding physics at the electroweak scale, we will provide ab initio input to extract Gv and the up-down component of the CKM quark-mixing matrix.

也许是宇宙中最复杂的量子系统，原子核的许多方面与自然界中一些最深刻的问题交织在一起。长期以来，现代核理论一直被认为是一种现象学纪律，目的是从头开始面对这些问题：作为一门原理学科，能够通过量化的不确定性提供可靠的预测。为此，我们首先必须对将质子和中子结合到核的力进行一致的描述，以及仅从这些相互作用开始的核多体问题的方法。凭借大空间方法的准确性，但是壳模型的多功能性，VS-IMSRG目前在其计算所有核的所有特性的能力上是独一无二的，直到质量100区域。这项发现赠款的主要重点将是提高准确性，估计模型不确定性并扩大物理范围以快速利用这一进展的强大推动力。在足够的支持下，我们将直接为理解“亚原理中的七个大问题”中的五个，如加拿大亚原子物理远距离计划中所述。我们将解决整个图表中的主要核结构问题，例如在光和中质质量区域中核（质子和中子滴）的存在的限制。此外，我们将预测未探索区域中新的魔术数量的演变，以指导未来的实验努力。 从长远来看，我们将为R-Process核合成模拟建模的R-Process核合成模拟的第一原理数据，以建模宇宙中重元素的形成。******此外，我们还将解决与核卫星物理学有关的一些最重要的问题。其中最突出的是中微子双β衰减的核基质元素，这对于从潜在的实验发现中提取绝对中微子质量尺度是必不可少的。从头开始计算48CA 76GE和82SE，将达到130te和136 Xe。类似地，为了理解暗物质的性质，需要wimp核横截面来解释大规模直接检测搜索的结果。我们将提供WIMP-Nucleus弹性散发结构因子的第一个从头算法，其中正在进行轻候选物的计算，并将扩展到129,131 Xe。最后，为了理解电动量表的物理，我们将提供从头算输入，以提取GV和CKM夸克混合矩阵的上向下组件。