We have observed and located more than 60 magnetic field-induced Feshbach
resonances in ultracold collisions of ground-state $^{133}$Cs atoms. These
resonances are associated with molecular states with up to four units of
rotational angular momentum, and are detected through variations in the
elastic, inelastic, and radiative collision cross sections. These observations
allow us to greatly improve upon the interaction potentials between two cesium
atoms and to reproduce the positions of most resonances to accuracies better
than 0.5%. Based on the relevant coupling scheme between the electron spin,
nuclear spin, and orbital angular momenta of the nuclei, quantum numbers and
energy structure of the molecular states beneath the dissociation continuum are
revealed. Finally, we predict the relevant collision properties for cesium
Bose-Einstein condensation experiments.
