Transverse momentum spectra and elliptic flow in ideal hydrodynamics and geometric scaling

TL;DR

This paper uses ideal hydrodynamics to simulate Au+Au collisions at 200 GeV, analyzing transverse momentum spectra and elliptic flow, and finds that initial energy density scaling varies with collision centrality.

Contribution

It demonstrates how initial energy density scaling with collision geometry affects the simulation's agreement with experimental data in heavy-ion collisions.

Findings

Central collisions require energy density scaling with binary collision density.

Less central collisions match data when scaling with participant density.

Viscous effects are minimal in central collisions.

Abstract

In an ideal hydrodynamic model, with an equation of state where the confinement-deconfinement transition is a cross-over at $T_{co}=196 MeV$, we have simulated $\sqrt{s}$=200 GeV Au+Au collisions. Simultaneous description of the experimental charged particle's $p_T$ spectra and elliptic flow require that in central (0-10%) Au+Au collisions, initial energy density scales with the binary collision number density. In less central collisions, experimental data demand scaling with the participant density. Simulation studies also indicate that in central collisions viscous effects are minimal.