  In Efimov physics, a three-body parameter (3BP), previously regarded as
nonuniversal, uniquely defines bound and scattering properties of three
particles. A universal 3BP, however, have been recently shown in experiments
and theory in ultracold homonuclear gases. Our present study further predicts a
universal 3BP for heteronuclear atomic systems near broad Feshbach resonances,
and provides physical interpretations for its origin. We show that for a system
composed of two light and one heavy atoms, the physical origin of the universal
3BP is similar to the homonuclear case while for systems composed by one light
and two heavy atoms the universality of the 3BP is now mostly controlled by the
heavy-heavy interatomic properties. This new universality is explained by the
universal properties of the van der Waals interactions in a simple
Born-Oppenheimer (BO) picture. Finally, we show the numerically determined 3BPs
for some combinations of alkali atoms used in ultracold experiments.
