Giant Feshbach resonances in $^{6}$Li+$^{85}$Rb mixtures*

We report on the observation of Feshbach resonances in an ultracold mixture of $^{6}$Li and $^{85}$Rb. While the Feshbach resonances in $^{6}$Li+$^{87}$Rb and $^{7}$Li+$^{87}$Rb mixtures are known to be relatively sparse and narrow, those in $^{6}$Li+$^{85}$Rb mixtures are, by contrast, numerous and wide. The experimental data are interpreted using a full coupled channels calculation which provides the energy of the least bound molecular states responsible for the observed resonances. This analysis fully characterizes the ground-state scattering properties in any combination of spin states.