Sprecher
Beschreibung
The observation of collective behavior in small collision systems has raised the fundamental question of how small a system can be while still exhibiting fluid-like dynamics. Recent OO collision measurements suggest that the produced medium may already exhibit fluid-like behavior, motivating investigations of even lighter nuclear systems. In this contribution, we investigate the dynamics of He-He collisions and present theoretical predictions for the system opacity, which serves as a quantitative measure of the expected degree of fluid-like behavior within the CoMBolt-RTA framework.
To address this question, we employ CoMBolt-RTA, an extended version of the CoMBolt-ITA kinetic theory model currently under development based on massive quasiparticles. Compared with the previous formulation, the new framework incorporates a more realistic equation of state together with temperature-dependent shear and bulk viscosities, providing a more faithful description of the medium's dynamical evolution. We compare the predicted system opacity in He-He and OO collisions to assess how collectivity changes as the system size is reduced. Our results establish theoretical benchmarks for possible future He-He measurements and provide new insight into the onset of fluid-like behavior in the smallest nuclear collision systems.