Efimov Trimer Formation via Ultracold Four-body Recombination
  We discuss the collisional formation of Efimov trimers via ultracold four-body recombination. In particular, we consider the reaction A+A+A+B->A3+B with A and B ultracold atoms. We obtain expressions for the four-body recombination rate and show that it reflects the three-body Efimov physics either as a function of collision energy or as a function of the two-body s-wave scattering length between A atoms. In addition, we briefly discuss issues important for experimentally observing this interesting and relatively unexplored process. 
Yujun Wang (Department of Physics, Kansas State University) and B. D.   Esry (Department of Physics, Kansas State University)