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CAREER: Uncertainty Estimates in Low-Energy Nuclear Physics

职业：低能核物理的不确定性估计

基本信息

批准号：
1555030
负责人：
Lucas Platter
金额：
$ 43万
依托单位：
University of Tennessee Knoxville
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-07-01 至 2023-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1555030&HistoricalAwards=false
关键词：
CAREER Uncertainty Estimates Low Energy

项目摘要

Many important reactions in nuclear physics cannot be measured with currently available experimental techniques. For example, the reaction probability of the process in which two protons fuse to a Deuteron (a bound state of a neutron and a proton) is an important process in the sun. However, it cannot be measured experimentally and only theoretical calculations can provide this rate. In the absence of guidance from experiment, it becomes important to quantify theoretical uncertainties. To address these issues, this project will use analytical and numerical methods to calculate reaction rates for astrophysically relevant reaction rates and new parametrizations of the internuclear interaction that will be useful to the larger nuclear physics community. Specifically, the PI and his students will use nuclear interactions constructed using effective field theory. In this theoretical approach, the nuclear interaction model can be systematically improved to improve the accuracy of the calculation. Intrinsic error of this approach will be determined using numerical techniques. This project will allow not only for a better understanding of important nuclear processes occurring in the universe, but also the project will provide a stimulating training ground for students and postdoctoral fellows and outreach community activities.This project aims at improving our understanding of electroweak processes using effective field theory. A number of weak processes in few-nucleon systems will be calculated within the unified framework of 'pionless' effective field theory. Specifically, the well-measured decay half-life time of tritium will be studied theoretically in order to obtain a highly accurate description for proton-proton fusion and weak proton capture on Helium-3. Furthermore, the PI and his student will study the intrinsic error of Hamiltonians and associated electroweak currents generated in 'pionfull' effective field theory. The PI will use novel techniques to analyze uncertainties in matrix elements calculated with the chiral potential and the associated electroweak currents in order to account correctly for the intrinsic error of the Hamiltonian order-by-order. With his collaborators, the PI will then use these results to calculate observables such as half-life times or total decay rates that are currently measured to new accuracy and with correct error estimates. The resulting interactions and currents will be made available to the nuclear theory community.

核物理中的许多重要反应无法用现有的实验技术测量。例如，两个质子融合成一个氘核（中子和质子的束缚态）的过程的反应概率是太阳中的一个重要过程。然而，它不能通过实验测量，只有理论计算才能提供这个速率。在缺乏实验指导的情况下，量化理论上的不确定性变得很重要。为了解决这些问题，该项目将使用分析和数值方法来计算与天体物理学有关的反应速率以及对更大的核物理界有用的核间相互作用的新参数。具体来说，PI和他的学生将使用有效场论构建的核相互作用。在这种理论方法中，可以系统地改进核相互作用模型，以提高计算的准确性。这种方法的固有误差将使用数值技术来确定。该项目不仅有助于更好地了解宇宙中发生的重要核过程，而且还将为学生和博士后研究员以及外联社群活动提供一个激励性的培训基地，该项目旨在利用有效场论提高我们对电弱过程的理解。在“无π介子”有效场论的统一框架下，计算了少核子系统中的一些弱过程。具体而言，将从理论上研究氚的良好测量的衰变半衰期，以获得对氦-3上质子-质子聚变和弱质子捕获的高度准确的描述。此外，PI和他的学生将研究哈密顿量的固有误差和相关的电弱电流产生的“pionfull”有效场理论。PI将使用新的技术来分析与手征势和相关的电弱电流计算的矩阵元素的不确定性，以正确地考虑的固有误差的哈密顿订单订单。与他的合作者一起，PI将使用这些结果来计算可观测值，例如半衰期或总衰变率，这些值目前被测量到新的精度和正确的误差估计。由此产生的相互作用和电流将提供给核理论界。