We use Monte Carlo simulation to study new features of a mass-aggregation m
odel which undergoes a dynamical phase transition. The model is characteriz
ed by an aggregate phase where the mass distribution decays as a power law,
in addition to the delta function peak at infinite mass. The self-organize
d criticality state is observed. The avalanches in the critical state manif
est a power law distribution, that reveals the existence of avalanches for
all scales. (C) 2001 Elsevier Science B.V. All rights reserved.