Collisions between tunable halo dimers: exploring an elementary   four-body process with identical bosons
  We study inelastic collisions in a pure, trapped sample of Feshbach molecules made of bosonic cesium atoms in the quantum halo regime. We measure the relaxation rate coefficient for decay to lower-lying molecular states and study the dependence on scattering length and temperature. We identify a pronounced loss minimum with varying scattering length along with a further suppression of loss with decreasing temperature. Our observations provide insight into the physics of a few-body quantum system that consists of four identical bosons at large values of the two-body scattering length. 
F. Ferlaino, S. Knoop, M. Mark, M. Berninger, H. Sch\"obel, H.-C.   N\"agerl, and R. Grimm