  Recent measurements of Efimov resonances in a number of ultracold atom
species have revealed an unexpected universality, in which three-body
scattering properties are determined by the van der Waals length of the
two-body interaction potential. To investigate whether this universality
extends to heteronuclear mixtures, we measure loss rate coefficients in an
ultracold trapped gas of $^{40}$K and $^{87}$Rb atoms. We find an Efimov-like
resonance in the rate of inelastic collisions between $^{40}$K$^{87}$Rb
Feshbach molecules and $^{87}$Rb atoms. However, we do not observe any
Efimov-related resonances in the rates of inelastic collisions between three
atoms. These observations are compared to previous measurements by the LENS
group of Efimov resonances in a $^{41}$K and $^{87}$Rb mixture as well as to
recent predictions.
