Physics Colloquium - Precision Studies of Radioactive Molecules for Nuclear Science

Despite its wide-ranging success, the Standard Model fails to explain multiple critical aspects of reality including the overwhelming dominance of matter over antimatter in the universe. The discovery of additional sources of CP-violation are thought to be needed to explain this matter-antimatter asymmetry
which has remained an open question in nuclear science for decades.

Molecules containing heavy, deformed radioactive nuclei are premier candidates for next-generation experiments aiming to study the fundamental symmetries of nature in unprecedented detail [Arr24]. In these molecules, large increases in sensitivity resulting from the rare octupole deformation of certain
radioactive nuclei can be combined with molecular structure enhancement factors to provide an unparalleled sensing capability to symmetry-violating nuclear properties.

Advances in experimental techniques have recently enabled the first laser spectroscopy study of molecules containing radioactive nuclei [Gar20, Udr21], despite their more complicated structures compounding their small production rates. This Colloquium will present recent results from subsequent experiments studying radium monofluoride at ISOLDE-CERN [Udr24]. A highlight of which includes the first observation of the distribution of nuclear magnetization in the structure of a molecule [Wil25].

[Arr24] Arrowsmith-Kron, G. et al., Rep. Prog. Phys 87 084301 (2024)
[Gar20] Garcia Ruiz, R. et al., Nature 581 396 (2020)
[Udr21] Udrescu, S. et al., Phys. Rev. Lett 127 033001 (2021)
[Udr 24] Udrescu, S. et al., Nat. Phys. 20 202-207 (2024)
[Wil25] Wilkins, S. et al., arXiv 2311 04121 (2025)