Research in Theoretical Nuclear and Neutrino Physics

这个核物理、天文学和粒子物理交界处的项目的主要目标是探索基础物理中的一个突出问题，即中微子在化学元素的起源和形成中的作用。第二个目标是探索磁场对元素形成的影响。这是非常及时的，因为科学家现在可以使用多种工具，如最先进的地面望远镜和空间天文台，并辅之以中微子、宇宙射线和引力波观测。这些多信使信号将使我们能够对预测进行基准测试。此外，这项研究活动有助于在威斯康星大学麦迪逊分校和首席研究员(PI)合作的其他机构培训一支高技能的劳动力队伍。该项目将支持对中微子集体振荡的研究，这是中微子-中微子相互作用在具有足够高中微子密度的天体物理环境中引发的新出现的非线性风味演化现象。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，比如铁。目前，还不能确切地知道快中子俘获过程(r过程)发生在哪里。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，两颗中子星合并成一个黑洞，以及伽马射线爆发中的吸积盘。所有这些环境都含有数量非常多的中微子。中微子，因为它们可以将质子转化为中子，反之亦然，决定了所有这些环境中的中子与质子的比率。考虑到集体中微子振荡可以显著影响这一比率和由此产生的核合成产额，PI和他的学生将批判性地检验当前计算中使用的平均场近似的有效性。量子信息科学的工具，如纠缠熵，为这种分析提供了便利。PI还将比较对核合成成果的不同近似预测。该项目推进了未来NSF投资的十大想法之一的“宇宙之窗：多信使天体物理时代”的目标。该奖项反映了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。

The primary goal of this project at the interface of nuclear physics, astronomy, and particle physics is to explore one of the outstanding questions in fundamental physics, namely the role of neutrinos in the origin and formation of chemical elements. A second goal is to explore the impact of magnetic fields on element formation. This is very timely since scientists now have access to a multitude of tools such as state-of-the-art terrestrial telescopes as well as space observatories, supplemented with neutrino, cosmic-ray, and gravitational wave observations. These multi-messenger signals will enable us to benchmark and test predictions. Additionally this research activity contributes to the training of a highly skilled workforce, both at the University of Wisconsin, Madison and at the other institutions with which the principal investigator (PI)collaborates.This project will support a study of the collective oscillations of neutrinos, which are emergent nonlinear flavor evolution phenomena instigated by neutrino-neutrino interactions in astrophysical environments with sufficiently high neutrino densities. Most of the elements heavier than iron are thought to be produced by the capture of neutrons on seed nuclei such as iron. Presently, it is not known with any certainty where the rapid neutron capture process (r-process) occurs. Possible sites of the r-process include matter evaporated from the surface of a hot neutron star formed following a supernova explosion, the merging of two neutron stars into a black hole, and accretion disks in gamma-ray bursts. All these environments contain a very large number of neutrinos. Neutrinos, since they can convert protons into neutrons and vice versa, determine the neutron-to-proton ratio in all those environments. Given that collective neutrino oscillations can significantly impact this ratio and the resulting yields of nucleosynthesis, the PI and his students will critically examine the validity of mean-field approximations utilized in current calculations. Tools from quantum information science, such as the entanglement entropy, facilitate this analysis. The PI will also compare predictions of different approximations for nucleosynthesis yields.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.