Nuclear, Particle, and Weak Interaction Physics of the Big Bang and Stellar Collapse

该项目支持的研究将深入了解原子核和基本粒子以及辐射在极端温度和密度条件下的行为。PI将利用这些见解提供有关基本粒子，特别是神秘中微子的性质以及元素在自然界中如何合成的重要线索，例如，最重的元素存在于坍缩恒星或碰撞中子星的炽热内部，最轻的元素存在于宇宙早期的最初几秒钟。 反过来，这些考虑可以让我们深入了解新的物理学。在这个项目中要做的计算将涉及磨练人类的基本自然理论，即，量子力学，成为一种能够模拟宇宙提供的极端环境中中微子行为的工具。该项目的另一个主要成果是培训研究生和本科生级别的年轻核物理学家。该项目支持的研究将致力于探索中微子和原子核的基础物理学，一方面利用核物理学和中微子物理学令人兴奋的新发展的交叉点，另一方面利用多信使天文学和精密宇宙学的新数据和见解的爆炸。这项事业的一个关键问题将是研究中微子如何在致密物质中相互作用，以及这些相互作用如何导致中微子改变它们的味道（例如，电子型中微子变为τ型，反之亦然）。这是一个非常非线性的问题，因为中微子的味道/自旋决定了中微子如何相互作用，而它们如何相互作用又决定了味道/自旋如何变化。为此，PI他和他的研究生和本科生将致力于：（1）理解和模拟量子动力学方程，这些方程控制着一般介质中的中微子味和自旋演化;（2）对早期宇宙和致密物体环境中的中微子味/自旋演化进行大规模数值模拟，并评估这种中微子味物理学对这些地点的原子核合成前景的反馈，以及该物理学对多信使观测和暗区物理学的意义;（3）了解高温环境下的核结构、中微子-核相互作用、核配分函数和核弱强度分布。多信使天体物理学时代”，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。

The research supported in this project will provide insights into how atomic nuclei and elementary particles and radiation behave in extreme conditions of temperature and density. The PI will leverage these insights to provide important clues about the nature of elementary particles, the mysterious neutrinos in particular, and about how the elements are synthesized in nature, e.g., the heaviest elements in the fiery interiors of collapsing stars or colliding neutron stars, and the lightest in the first seconds in the early universe. In turn, these considerations can give us insight into new physics. The calculations to be done in this project will involve honing humanity's fundamental theory of nature, i.e., Quantum Mechanics, into a tool capable of modeling the behavior of neutrinos in the extreme environments provided by the cosmos. Another key product of this Project will be the training of young nuclear physicists, at both the graduate and undergraduate levels. The research supported in this Project will be directed toward probing the fundamental physics of neutrinos and nuclei by exploiting the intersection of exciting new developments in nuclear physics and neutrino physics on the one hand, with the explosion of new data and insights from the advent of multi-messenger astronomy and precision cosmology on the other. A key issue in this enterprise will be studying how neutrinos interact in dense matter and how these interactions may cause neutrinos to change their flavors (e.g., electron type neutrinos changing to tau type and vice versa). This is a fiercely nonlinear problem because neutrino flavor/spin determines how neutrinos interact, and how they interact determines how flavors/spin change. To these ends, the P.I. and his graduate and undergraduate students will work toward: (1) Understanding and modeling the quantum kinetic equations which govern neutrino flavor and spin evolution in a general medium; (2) Constructing large-scale numerical simulations of neutrino flavor/spin evolution in the early universe and compact object environments and assessing the feedback of this neutrino flavor physics on the prospects for the synthesis of nuclei in these sites, and the implications of this physics for multi-messenger observations and dark sector physics; (3) Understanding nuclear structure, neutrino-nucleus interactions, nuclear partition functions, and nuclear weak strength distributions in high temperature environments.This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments.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.