Observation of interspecies 6 Li- 133 Cs Feshbach resonances

We report on the observation of 19 interspecies Feshbach resonances in an optically trapped ultracold Bose-Fermi mixture of ${}^{133}\text{Cs}$ and ${}^{6}\text{Li}$ in the two energetically lowest spin states. We assign the resonances to $s$- and $p$-wave molecular channels by a coupled-channels calculation, resulting in an accurate determination of LiCs ground-state potentials. Fits of the resonance position based on the undressed asymptotic bound state model do not provide the same level of accuracy as the coupled-channels calculation. Several broad $s$-wave resonances provide prospects to create fermionic LiCs molecules with a large dipole moment via Feshbach association followed by stimulated Raman passage. Two of the $s$-wave resonances overlap with a zero crossing of the Cs scattering length, which offers prospects for the investigation of polarons in an ultracold Li-Cs mixture.