Bulk Properties of the Matter Produced at Energies of the Beam Energy Scan Program

TL;DR

This paper analyzes STAR experimental data on bulk properties of matter produced in heavy-ion collisions across various energies using a three-fluid dynamics model with different equations of state, highlighting the importance of deconfinement scenarios.

Contribution

It demonstrates that the three-fluid dynamics model with a crossover equation of state best reproduces STAR data without requiring separate freeze-outs.

Findings

Purely hadronic EoS fails to match data.

Deconfinement scenarios provide better data reproduction.

Unified freeze-out suffices across energies.

Abstract

Recent STAR data on the bulk observables in the energy range of the Beam-Energy Scan Program at the Relativistic Heavy-Ion Collider are analyzed within the model of the three-fluid dynamics (3FD). The simulations are performed with different equations of state (EoS). The purely hadronic EoS fails to reproduce the data. A good, though imperfect, overall reproduction of the data is found within the deconfinement scenarios. The crossover EoS turns out to be slightly preferable. For this reproduction a fairly strong baryon stopping in the quark-gluon phase is required. The 3FD model does not need two separate freeze-outs (i.e. kinetic and chemical ones) to describe the STAR data. A unified freeze-out is applied at all energies.