Research in Theoretical Nuclear and Neutrino Physics

探索可见物质的起源、演化和结构是现代科学正在进行的探索。最轻的元素是在大爆炸后的第一分钟内形成的，这一时期被称为大爆炸核合成(BBN)。BBN时代和恒星不断演化，直到它们成为超新星，产生了元素，直到铁。大多数比铁更重的元素被认为是通过捕获种子核上的中子而产生的。快速中子捕获过程(r过程)的可能地点包括超新星爆炸后形成的热中子星表面蒸发的物质，两颗中子星的合并(最近首次观察到)，以及伽马射线爆发中的吸积盘。不管元素形成过程的确切细节如何，人们都需要大量的中子而不是质子。上面列出的所有环境也都含有非常大量的中微子，这些中微子控制着中子与质子的比例。这个项目将利用核物理和天体物理学的工具以及实验和观测数据来探索中微子性质和元素形成之间的相互作用。这个项目将通过求解描述中微子集体振荡的多体方程来描述r过程站点中的中微子输运。中微子集体振荡是中微子-中微子相互作用在足够高的中微子密度的天体物理环境中引发的紧急非线性演化现象。我们的目标是将我们的理论和计算努力与对化学元素丰度的光学观测结合在一起，以解释这些元素在宇宙中形成的位置。PI和他的学生将探索中微子的性质，如质量、混合和偶极矩，并计算它们的俘获截面，以促进这一目标。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Exploring the origin, evolution and the structure of the visible matter is an ongoing quest of modern science. The lightest elements are formed during the first minutes after the Big Bang, the epoch known as the Big Bang Nucleosynthesis (BBN). The BBN epoch and the proceeding evolution of the stars until they go supernova produce elements up to iron. Most of the elements heavier than iron are thought to be produced by the capture of neutrons on seed nuclei. Possible sites of the rapid neutron capture process (r-process) include matter evaporated from the surface of a hot neutron star formed following a supernova explosion, the merging of two neutron stars (recently observed for the first time), and accretion disks in gamma-ray bursts. Irrespective of the precise details of the elements-formation process, one needs an abundance of neutrons over protons. All environments listed above also contain a very large number of neutrinos, which control the ratio of neutrons to protons. This project will explore the interplay between neutrino properties and the formation of elements using tools from nuclear physics and astrophysics, as well as experimental and observational data.This project will contribute to the description of neutrino transport in the r-process sites by solving the many-body equations describing collective oscillations of neutrinos, which are emergent nonlinear flavor evolution phenomena instigated by neutrino-neutrino interactions in astrophysical environments with sufficiently high neutrino densities. The goal is to bring together our theoretical and computational efforts with the optical observations of the abundances of chemical elements to explain where in the cosmos these elements are formed. The PI and his students will explore properties of neutrinos such as masses, mixings, and dipole moments and calculate their capture cross sections to facilitate this goal.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.