Interorbital interactions in an SU(2) ⊗ SU(6)-symmetric Fermi-Fermi mixture

We characterize interisotope interorbital interactions between atoms in the S01 ground state and the P03 metastable state in interacting Fermi-Fermi mixtures of Yb171 and Yb173. We perform high-precision clock spectroscopy to measure interaction-induced energy shifts in a deep three-dimensional optical lattice and determine the corresponding scattering lengths. We find the elastic interaction of the interisotope mixtures Ybe173-Ybg171 and Ybg173-Ybe171 to be weakly attractive and very similar, while the corresponding two-body decay coefficients differ by more than two orders of magnitude. By comparing different spin mixtures we experimentally demonstrate the SU(2) - SU(6) symmetry of the elastic interactions. Furthermore, we measure the interorbital spin-exchange interaction in Yb171 and confirm its previously observed antiferromagnetic nature.