Lattice based equation of state and transverse momentum spectra of identified particles in ideal and viscous hydrodynamics

TL;DR

This study uses lattice-based equations of state in hydrodynamics to analyze transverse momentum spectra of identified particles in Au+Au collisions, highlighting the effects of viscosity on the spectra's accuracy.

Contribution

It introduces a lattice-based EOS in hydrodynamic modeling and compares ideal and viscous fluid evolution to experimental data in heavy-ion collisions.

Findings

Ideal and minimally viscous fluids reproduce pion, kaon, and phi spectra well.

Viscous fluids with higher viscosity poorly fit the data.

Proton production is underestimated by a factor of about 2.

Abstract

Assuming that in Au+Au collisions, a baryon free fluid is produced, transverse momentum spectra of identified particles ($\pi$, $K$, $p$ and $\phi$), in evolution of ideal and viscous fluid is studied. Hydrodynamic evolution is governed by a lattice based equation of state (EOS), where the confinement-deconfinement transition is a cross-over at $T_{co}$=196 MeV. Ideal or viscous fluid was initialised to reproduce $\phi$ meson multiplicity in 0-5% Au+Au collisions. Ideal or minimally viscous ($\eta/s$=0.08) fluid evolution reasonably well explain the transverse momentum spectra of pion's, kaon's, and $\phi$ meson's in central and mid-central Au+Au collisions. Description to the data is much poorer in viscous fluid evolution with $\eta/s \geq$0.12. The model however under estimate proton production by a factor $\sim$ 2.