  The dynamical properties of a one-dimensional system of two and three bosons
escaping from an open potential well are studied in terms of the momentum
distributions of particles. In the case of a two-boson system, it is shown that
the single- and two-particle momentum distributions undergo a specific
transition as the interaction strength is tuned through the point where
tunneling switches from the pair tunneling to the sequential one.
Characteristic features in the momentum spectra can be used to quantitatively
determine the participation of specific decay processes. A corresponding
analysis is also performed for the three-boson system, showing a scheme for
generalizations to higher particle numbers. For completeness, the
time-dependent Tan's contact of the system is also examined and its dynamics is
found to undergo a similar transition. The results provide insight into the
dynamics of decaying few-body systems and offer potential interest for
experimental research.
