Species-Resolved Scaling of Azimuthal Anisotropy: Constraining Attenuation, Collective Expansion, and Hadronic Dynamics in Hydrodynamic Simulations

Abstract

Species-resolved azimuthal anisotropy scaling functions are constructed from identified particle $v_2$ and $v_3$ obtained from event-by-event iEBE-VISHNU simulations for Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ and $5.02$~TeV. The scaling functions exhibit a robust collapse across transverse momentum, centrality, particle species, and beam energy, indicating a common and tightly constrained scaling structure. High scaling fidelity yields quantitative agreement with the data-defined reference through an energy-dependent attenuation baseline ${\beta }_0$ in central to mid-central collisions and a centrality-dependent modification of the effective attenuation in more peripheral collisions, with only a weak dependence on $\sqrt{s_{NN}}$. The multiplicity dependence of the extracted scaling parameters reflects the interplay of EOS-driven collective expansion, finite system lifetime, and hadronic re-scattering. These results demonstrate that the scaling framework provides a quantitative, constraint-driven probe of the hydrodynamic response, enabling the disentanglement and constraint of the coupled contributions to azimuthal anisotropy.

Comments: 7 pages, three figures, submitted for publication