Measurement of the three-body-recombination coefficient of ultracold lithium and strontium atoms

We report on the observation of a conspicuous loss in an ultracold mixture of $^{7}\mathrm{Li}$ and $^{88}\mathrm{Sr}$ atoms confined in a far-off-resonance optical dipole trap. We attribute the trap loss to the three-body inelastic Li-Sr-Sr collision and extract the corresponding three-body-recombination coefficient ${K}_{3}$ at $T\ensuremath{\sim}18.5,45,70,600\phantom{\rule{0.28em}{0ex}}\textmu{}\mathrm{K}$. The measured three-body-recombination coefficient is about two to three orders of magnitude larger than the typical values convenient for realizing quantum degenerate gases, and essentially rules out the prospect of realizing $^{7}\mathrm{Li}$ and $^{88}\mathrm{Sr}$ mixtures of high phase space density. The measured three-body-recombination rates agree with the unitarity limit at high temperatures. Our results also confirm that the three-body-recombination loss is dominated by the light-heavy-heavy process, in agreement with the prediction for a system with a large mass-imbalanced and negligible intraspecies interaction.