High-resolution spectroscopy of RaF - The search for New Physics beyond the Standard Model
The key role in understanding Nature is to validate our fundamental physical theories by experimental proofs. The Standard Model (SM) is a theoretical framework combining three out of the four fundamental interactions and arranging all known fundamental particles. However it cannot adequately explain everything, like the matter-antimatter asymmetry of our universe (baryogenesis), which suggests the necessary existence of New Physics (NP) beyond the SM.
Typically, the idea of NP is tested by highly accelerated colliding particles, but nowadays, also table-top experiments evolve in sensitivity and precision to enable noticing deviations of observables from their SM predictions. The basic idea in most performed experiments is to measure the energy level structure of an atom or molecule very accurately by observing the transition frequencies.
Radium-containing molecules are the perfect testing environment for investigations of the SM and beyond . In preparation to observe the small energy shift induced by NP, the underlying molecular motions have to be understood. Here, we report on our  spectroscopic investigation of the radioactive molecule RaF  at the ISOLDE radioactive ion-beam facility at CERN, leading to understand of its complex molecular motions and showing potential for efficient laser cooling, which will enable ultra-high-precision studies.