  The dynamics of a few ultra-cold bosons tunneling from a one-dimensional
potential well into open space is studied. In such a system several decay
channels can be distinguished, each corresponding to a different number of
bosons escaping simultaneously. We show that as the interparticle interaction
strength is changed, the system undergoes transitions between distinct regimes
characterized by the dominance of different decay channels. These transitions
are reflected in the behavior of the decay rate of the system, which is
measurable experimentally. By means of a simple theoretical description we show
that the transitions occur at the points where a new decay channel becomes
energetically viable. The results provide insight into the behavior of decaying
few-body systems and may have potential interest to experiments.
