A pathway towards decentralized studies of radioactive post-lead elements and their applications in beyond standard model physics

TL;DR

This paper introduces a new method for efficiently producing radioactive molecules, like radium monofluoride, enabling decentralized fundamental physics research without large nuclear facilities.

Contribution

It presents a novel scheme for harvesting radioactive ions and studying their reactions, facilitating research on radioactive molecules in labs lacking nuclear reactors.

Findings

Ra$^+$ reaction rate aligns with other alkaline earth elements.

Ra$^{2+}$ + SF$_6$ reaction achieves near-unity conversion efficiency.

Scheme enables decentralized research on short-lived radioactive molecules.

Abstract

Molecules have proven to be sensitive tools for studying physics beyond the standard model, with heavy and deformed nuclei offering decisive sensitivity to parity- and time-reversal-violating effects. However, almost all elements beyond lead, occupying the 6p~to~5f atomic orbitals, lack stable isotopes, hence molecules containing them are referred to as radioactive molecules. Among those, radium monofluoride has seen particular interest, but to date, research on radioactive molecules has mainly been limited to large-scale nuclear facilities. Here, we present a scheme that allows efficient and fast harvest of radioactive ions (including short-lived Ra), and show ion gas-phase reaction studies of singly and doubly charged Ra, Po, and Pb ions with SF$_6$ gas inside an ion trap. Our results show that the chemical reaction rate of Ra$^+$ is in line with trends of other alkaline earth elements, further support by quantum chemical computations. The reaction Ra$^{2+}$ + SF$_6$ $\rightarrow$ RaF${^+}$ + SF$_5^{+}$ achieves an almost unity conversion efficiency, making it particularly suitable for the application for studies in physics beyond the standard model. The scheme enables future decentralized research avenues with short-lived radioactive molecules for fundamental physics research at laboratories without the need for local nuclear reactors or accelerators.