The Precision Frontier at FRIB: Masses, Radii, Moments, and Fundamental Interactions

原子核的潜在作用力和成分是什么？这个问题的答案是通过物质的基本核属性来揭示的，如质量、电荷半径和原子衰变为其他原子。FRIB的精密测量小组将进行实验，以确定原子质量、核半径，并扩大对原子核奇异衰变的搜索。这些测量旨在提取原子核的基本性质，这些原子核具有很大的中子与质子比，这只能在极端天体物理事件期间发生在自然界中。这项研究对核结构物理、核天体物理和解释多信使天体物理信号具有重要意义。这里提出的工作还将通过改进对多信使天体物理事件中观察到的信号的解释的测量，为NSF的大想法“宇宙之窗”做出重大贡献。精密测量小组将利用稀有同位素束设施(FRIB)前所未有的能力来创造不寻常的同位素束流，并测量它们的性质。该项目有三个主要推动力。首先，测量原子质量。这些测量对于理解极端天体物理环境中的核合成以及作为处于稳定边缘的核结构的探测器具有直接重要性。此外，通过足够精确的测量，PI可以测试核物理和粒子物理中的基本对称性。第二，原子核半径和电磁矩。对镜像核性质的测量将有助于我们理解核态方程，这对于理解双星中子星的合并特别重要。此外，基态测量在各种系统中验证了核结构理论。第三，异域互动。对奇异原子核、极化原子核和正电子的测量将测试基本对称性。此外，这些测量还检验了基本核理论的极端。测量将在FRIB停止光束线上进行，例如，使用彭宁陷阱和本地激光设备。这些工具也将提供给FRIB设施的其他用户。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。

What are the underlying forces and constituents of atomic nuclei? An answer to this question is revealed through the basic nuclear properties of matter such as the mass, charge radius, and decay of atoms into other atoms. The Precision Measurements group at FRIB will perform experiments to determine atomic masses, nuclear radii, and extend the search for exotic decays of nuclei. The measurements are designed to extract the fundamental properties of nuclei, with large neutron to proton ratios, which can only occur in Nature during extreme astrophysical events. The research has implications for nuclear structure physics, nuclear astrophysics and the interpretation of multi-messenger astrophysical signals. The work proposed here will also provide significant contributions to the NSF Big Idea “Windows on the Universe” through measurements that improve the interpretation of signals observed in multi-messenger astrophysical events.The Precision Measurements group will take advantage of the unprecedented capabilities of the Facility for Rare Isotope Beams (FRIB) to create beams of unusual isotopes and to measure their properties. There are three main thrusts in the project. First, measuring atomic masses. These measurements are of direct importance for understanding nucleosynthesis in extreme astrophysical environments and as probes of nuclear structure at the edge of stability. In addition, with adequately precise measurements, the PIs can test fundamental symmetries in Nuclear and Particle Physics. Second, nuclear radii and electromagnetic moments. Measurements of the properties of mirror nuclei will contribute to our understanding of the nuclear equation of state, which is particularly relevant for the understanding the merging of binary neutron stars. In addition, ground-state measurements in a variety of systems test nuclear-structure theory. Third, exotic interactions. Measurements with exotic nuclei, polarized nuclei, and positronium will test fundamental symmetries. In addition, these measurements test the extremes of basic nuclear theory.The measurements will be performed on the FRIB stopped-beam line using, for example, a Penning Trap and local laser facilities. These tools will also be made available to other users of the FRIB facility.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.