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Nuclear Structure and Reactions from Effective Field Theory

有效场论的核结构和反应

基本信息

批准号：
1913620
负责人：
Gautam Rupak
金额：
$ 27万
依托单位：
Mississippi State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1913620&HistoricalAwards=false
关键词：
Nuclear Structure Reactions Effective Field

项目摘要

The fundamental interactions in nuclear physics are described by the theory of Quantum Chromodynamics (QCD). At low energies, QCD is a strongly interacting theory that cannot be solved from first principles in a pencil-and-paper calculation. The effective field theory (EFT) formulation provides a complementary framework where nuclear properties at low energy can be systematically calculated. As such, EFT calculations can provide accurate input for astrophysical models of element synthesis that cannot be obtained in direct experimental measurements. In this project, the PI and his collaborators will use numerical methods defined on a space-time lattice to calculate properties of medium-light atomic nuclei (mass number up to around 40) using EFT. The PI will use Bayesian statistics to quantitatively compare competing EFT formulations. The latter is useful in constructing an accurate and systematic theory for low energy nuclear physics. Broader impacts of the research include training of graduate students in numerical and analytical work for an academic or industry career benefiting society.The current project builds on the lattice EFT pinhole algorithm that was previously introduced by the PI. This algorithm allows for the calculation of the charge and matter distribution (in the center-of-mass coordinate) in Monte Carlo simulations that is necessary to couple external electro-weak currents to atomic nuclei. The PI aims to calculate electromagnetic moments of light nuclei. The same method will be used to calculate neutrino-nucleus coherent scattering that is sensitive to the neutron matter distribution. This cross section serves as a background in dark matter search experiments. The PI will study also low energy nuclear reactions involving halo nuclei using Bayesian statistics. Halo nuclei are characterized as weakly bound quantum systems and play an important role in element synthesis in the Big Bang and stellar burning. Bayesian analysis provides a natural framework to incorporate EFT assumptions about naturalness of sizes of couplings in parameter estimation. It also allows quantitative comparison of competing theories and aids in model selection. This project will support the science programs at planned major U.S. investments in rare isotope beam experiments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

量子色动力学（QCD）理论描述了核物理中的基本相互作用。在低能量下，QCD是一种强相互作用理论，无法从纸上计算的第一原理中解决。有效场论（EFT）公式提供了一个补充框架，在低能量下的核性质可以系统地计算。因此，EFT计算可以为元素合成的天体物理模型提供准确的输入，这在直接实验测量中无法获得。在这个项目中，PI和他的合作者将使用定义在时空晶格上的数值方法，使用EFT计算中轻原子核（质量数高达40左右）的性质。PI将使用贝叶斯统计学定量比较竞争EFT制剂。后者对于建立准确而系统的低能核物理理论是有用的。该研究的更广泛影响包括培训研究生从事数值和分析工作，以造福社会的学术或工业职业。目前的项目建立在PI先前介绍的晶格EFT针孔算法的基础上。该算法允许在Monte Carlo模拟中计算电荷和物质分布（在质心坐标中），这对于将外部电弱电流耦合到原子核是必要的。PI旨在计算轻核的电磁矩。同样的方法将被用来计算中微子-核相干散射，这是敏感的中子物质的分布。这个横截面作为暗物质搜索实验的背景。 PI还将使用贝叶斯统计研究涉及晕核的低能核反应。晕核是一种弱束缚的量子系统，在大爆炸和恒星燃烧的元素合成中起着重要作用。贝叶斯分析提供了一个自然的框架，将EFT假设的自然度的耦合参数估计的大小。它还允许竞争理论的定量比较和模型选择的援助。该项目将支持美国计划在稀有同位素束实验方面进行重大投资的科学计划。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。