Prospects for Bose-Einstein condensation in cesium

The recent success of BEC in rubidium, lithium and sodium has led us to reinvestigate the collisional properties of cesium, that define the circumstances for BEC. We analyze a set of cold-collision data, comprising atomic fountain frequency shifts and elastic scattering rates, to determine phase parameters that completely characterize cold collisions between two ground-state atoms. Very interesting in this case are the surprisingly large decay rates of atoms polarized in the highest state of the upper and lower hyperfine manifold(J. Söding, D. Guéry-Odelin, P. Desbiolles, G. Ferrari, and J. Dalibard (unpublished).)^,(J. Söding and J. Dalibard, Priv. Commun.). We show these decay rates can be described consistently with the other data by taking into account an indirect spin-spin interaction, where collisional resonances play an essential role. We discuss circumstances where BEC in cesium might be achievable