  Three-body recombination is a phenomenon common in atomic and molecular
collisions, producing heating in the system. However, we find the cooling
effect of the three-body recombination of a 6Li Fermi gas near its s-wave
narrow Feshbach resonance. Such counter-intuitive behavior is explained as
follows, the threshold energy of the quasi-bounded Feshbach molecule acts as
the knife of cooling, expelling the scattering atoms with selected kinetic
energy from the trap. When the threshold energy happens to be larger than
3/2kBT, each lost atom in the three-body recombination process has more than
3kBT energy which results in cooling. The best cooling is found with the
threshold energy set at about 3kBT, consistent with a theoretical model. The
three-body recombination induced cooling raises potential applications for
cooling complex atomic systems.
