CAREER: Uncertainty Estimates in Low-Energy Nuclear Physics

核物理学中许多重要的反应不能用现有的实验技术来测量。例如，两个质子聚变成氘核（中子和质子的结合状态）的反应概率是太阳中一个重要的过程。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，量化理论不确定性就变得很重要。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相关的反应速率和新的核间相互作用参数化，这将对更大的核物理学界有用。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用数值技术来确定。这个项目不仅可以让人们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展社区活动提供一个刺激的培训场所。本项目旨在利用有效场论提高我们对电弱过程的理解。将在“无导”有效场论的统一框架内计算少量核子系统中的一些弱过程。具体来说，将从理论上研究氚的衰变半衰期，以获得氦-3上质子-质子聚变和弱质子捕获的高度精确描述。此外，PI和他的学生将研究在“开创性的”有效场论中产生的哈密顿量的固有误差和相关的弱电。PI将使用新的技术来分析用手性势和相关的弱电电流计算的矩阵元素中的不确定性，以便正确地解释哈密顿逐级计算的固有误差。与他的合作者，PI将使用这些结果来计算可观察到的，如半衰期或总衰变率，目前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。

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.