Shining Light on Radioactive Molecules

Short-lived radioactive molecules constructed with octupole deformed nuclei represent a new frontier for high precision experiments. Such molecules are predicted to have sensitivity to parity and time-reversal violating effects that are up to three orders of magnitude larger than the current generation of stable molecules. Advances in molecular trapping techniques make it feasible to consider experiments that study molecules with coherence times of up to 10s. Such an arrangement with radioactive molecules would extend eEDM searches by more than 4 orders of magnitude, probing PeV energy scales and providing a complementary search domain to proposed future accelerator projects with table top instrumentation. Consecutive STFC consolidated grants have supported the developed a uniquely sensitive instrument (CRIS) that can perform high resolution spectroscopy on short-lived radioactive molecules with lifetimes down to milliseconds. This project will further enhance the capability of this technology and enable the first spectroscopy measurements on a range of radioactive molecules. This will allow the identification of the most sensitive molecular systems, critical to prepare future high precision experiments. This project will also lead to new opportunities with radioactive molecules for the purpose of studying the atomic nucleus. We have already demonstrated in the case of RaF that diatomic molecules can have enhanced sensitivity to the nuclear charge radius and distribution of magnetisation. This project and investment will enable the development of radioactive molecules as new sensors for future experiments to better understand the fundamental forces that govern the nucleus and search for new physics beyond the standard model of particle physics.