We present theoretical calculations of thermally averaged elastic cross sections and spin-relaxation rate coefficients in the temperature range 0.1 to $300\mu \mathrm{K}$ for magnetically trapped, doubly polarized cesium atoms. The calculations reproduce the recent experimental results of Arndt et al. (1997) and Söding et al. (1998) for cases where the $a^3{\Sigma }_u$ ground state potential of $\mathrm{Cs}{}_2$ possesses a large scattering length ( $|A_3|>35\mathrm{}\mathrm{nm}$) and the magnitude of the second-order spin-orbit interaction is scaled to reproduce room temperature scattering data.

• Received 23 April 1998

DOI:https://doi.org/10.1103/PhysRevLett.81.1389