Nuclear parameters from high precision atomic physics

High-precision laser spectroscopy of lightest atoms serves as a dual-purpose tool, not only providing a stringent test of atomic bound-state Quantum Electrodynamics (QED) theory but also offering a unique gateway to probe intricate nuclear properties. These include spin, magnetic dipole moment, electric quadrupole moment, and even the more elusive magnetic octupole moment. In addition, laser spectroscopy can be employed to determine finite nuclear size parameters that characterize the electromagnetic distribution, such as the charge radius and Zemach radius, all in a manner independent of nuclear models. This technique proves particularly powerful when studying exotic and radioactive nuclei, such as two-neutron-halo Li-11 and one-proton-halo B-8, where conventional methods often fall short. Experiments typically focus on precise measurements of atomic hyperfine structures and isotope shifts, where nuclear properties manifest as perturbations to the electronic energy levels. These minute shifts can reveal critical information about the underlying nuclear structure and dynamics.

In this presentation, I will review recent progress in the field of high-precision laser spectroscopy as a tool to investigate nuclear properties, and I will highlight our collaborative efforts with the experimental group at the Wuhan Institute of Physics and Mathematics (WIPM). Together, we are focusing on exploring the nuclear properties of Li-6 and Li-7 through detailed spectroscopic measurements of the hyperfine structure in Li+ ions [1,2,3]. These precise measurements enable us to probe subtle nuclear effects, and when compared with state-of-the-art Nonrelativistic Quantum Electrodynamics (NRQED) calculations, they reveal intriguing discrepancies with established values. Notably, we observe deviations in the Zemach radius of the Li-6 nucleus, as well as in the ratio of the nuclear electric quadrupole moments of Li-6 and Li-7. These findings could offer valuable insights into nuclear structure and interactions, providing important feedback to the nuclear physics community.