Three-atom recombination through a narrow Feshbach resonance in $^6$Li

We experimentally measure, and theoretically analyze the three-atom recombination rate, $L_3$, around a narrow $s$ wave magnetic Feshbach resonance of $^6$Li-$^6$Li around 543.3 Gauss. By examining both the magnetic field dependence and especially the temperature dependence of $L_3$ over a wide range of a few $\mu$K to 200 $\mu$K, we show that three-atom recombination through a narrow resonance follows a universal behavior as determined by the long-range van der Waals potential, and can be described by a set of rate equations in which three-body recombination proceeds via successive pairwise interactions. We expect the underlying physical picture to be applicable not only to the narrow $s$ wave resonances, but also to resonances in other partial waves, and not only at ultracold temperatures, but also at higher temperatures. It points to some future directions towards a more complete understanding of three-body physics in general and molecule formation in particular.