Criticality in a mass-aggregation model

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.