The most recent comprehensive evaluation of nuclear charge radii was published in 2013 by Angeli and Marinova, whose work has since been cited over 1300 times—highlighting the growing demand for precise nuclear charge radii. These values often represent the dominant source of uncertainty in precision tests of fundamental theories and searches for physics beyond the Standard Model.
Our group is collaborating closely with Prof. Angeli and the International Atomic Energy Agency (IAEA) to develop an updated set of nuclear charge radii and a flexible database framework that enables re-evaluation in light of future theoretical advancements. This will support consistent comparison across the primary experimental methods, including muonic atoms, elastic electron scattering, Kα isotope shifts, and optical isotope shifts, as well as novel emerging techniques. Our approach treats the global set of charge radius data as a network and breaks down the minimization process into computationally efficient steps.
On the experimental side, we have developed a new technique that uses extreme ultraviolet spectroscopy of highly charged ions to provide additional constraints on the nuclear charge radius surface. In particular, Na-like and Mg-like ions are of special interest due to the enhanced overlap of their ground-state wavefunctions with the nucleus, making them especially sensitive probes. We have demonstrated the method using the electron beam ion trap (EBIT) at the National Institute of Standards and Technology (NIST) and are currently preparing to conduct measurements with ions of rare isotopes at the TRIUMF facility in Canada.
This talk will present both of these efforts, highlighting ongoing projects at Clemson University, NIST, and in international collaborations, including work with partners in Japan.