The observation of three-body narrow resonances in ultra-cold collisions

Summary form only given, as follows. We report on the observation of narrow resonances associated with cold cesium collisions. A loss of laser cooled atoms in a trap is induced with a laser tuned to the blue of the 6S-6P transition. Several sharp resonances, with /spl sim/kHz intrinsic linewidths, are observed as a function of an applied magnetic field. The resonances appear near magnetically tunable Feshbach resonances. We identify the collision resonances as three-body processes. We have observed both mixed resonances where the collision partners are in different states and resonances consisting of identical atoms. These resonances are promising candidates of Efimov-like states. Efimov predicted that three-body, S-wave bound states could exist near a scattering resonance regardless of whether the pair-wise interaction is attractive or repulsive. These states were first predicted to occur in nuclear scattering, but have never been seen.