We measure high-resolution Feshbach resonance spectra for ultracold cesium
atoms colliding in different hyperfine and magnetic sublevels. More than 25
Feshbach resonances are observed for magnetic fields below 230 G in the el
astic and inelastic ground state collision cross sections, as well as in th
e cross section for light-assisted collisions. From these spectra a consist
ent set of ground state molecular interaction parameters for cesium is extr
acted, including singlet and triplet scattering lengths of A(s) = (280 +/-
10)alpha (0) and A(t) = (2400 +/- 100)alpha (0), a van der Waals coefficien
t C-6 (6890 +/- 35) a.u., as well as the strength of the indirect spin-spin
coupling. This set of parameters allows for the first time a complete char
acterization of cesium's ultracold-collision properties. (C) 2001 Academie
des sciences/Editions scientifiques et medicales Elsevier SAS.