COLLECTIVE BALLISTIC MOTION EXPLAINS LARGE AGGREGATION EXPONENTS IN ADHESIVE ACTIVE MATTER

Inspired by motile cells during tissue formation, we identify a mechanism by which active systems of self-aligning adhesive particles undergo ballistic aggregation via a flocking transition. This kinetic regime emerges when the cluster persistence length grows faster with mass than the intercluster distance does. We also characterize and explain the emergence of distinct non-collective kinetic regimes, including long-lived transients relevant to biological systems. Our results provide a unified framework consistent with the broad range of aggregation exponents experimentally observed in cellular systems and uncover physical principles which may enable timely tissue organization.