Towards laser cooling molecules with octupole-deformed nuclei for fundamental physics

Radium-containing molecules offer unique opportunities to explore fundamental physics, such as the cause of the matter/antimatter asymmetry, the search for symmetry violation in the strong interaction, and the potential existence of new particles and forces. Octupole-deformed radium nuclei amplify parity (P) and time-reversal (T) violating nuclear properties by more than three orders of magnitude compared to spherical nuclei. Recent spectroscopy results have demonstrated that certain radioactive molecules, such as RaF and RaOH, possess a relatively simple structure that is favorable for laser cooling, enabling long interrogation times. This combination opens the door to sensitive molecular searches for P,T violating nuclear effects, such as the nuclear Schiff moment. We are building an experiment to demonstrate laser cooling of radium-containing molecules, in collaboration with MIT, Harvard, Caltech, and the Facility for Rare Isotope Beams (FRIB). Experimental work will begin with the less radioactive isotope, 226-Ra (half-life = 1600 yr), enabling rapid prototyping at university laboratories. We provide an update on the production of a cryogenic molecular beam source for radioactive molecules. We overview progress toward for laser cooling RaF, which has an ideal molecular structure for cooling, and to explore optical cycling in RaOH, where the polyatomic structure offers advantageous parity doublets for precision measurements. This work will establish a path to trapping radium-containing molecules at <mK temperatures, laying the groundwork for eventual measurements of hadronic P,T violation with 225-Ra (half-life = 14.9 d) containing molecules at FRIB.