Event simulation based on three-fluid hydrodynamics for collisions at energies available at the Dubna Nuclotron-based Ion Collider Facility and at the Facility for Antiproton and Ion Research in Darmstadt

TL;DR

This paper introduces a new event generator based on three-fluid hydrodynamics for simulating nuclear collisions at FAIR/NICA energies, capable of modeling hadron-to-quark matter transitions in baryon stopping regimes.

Contribution

The novel simulation program integrates three-fluid hydrodynamics with a microscopic transport model, enabling the study of phase transitions at energies previously inaccessible to such detailed modeling.

Findings

Proton and pion directed flow analyzed at 4-11 GeV.

Proton rapidity distribution studied with different equations of state.

Model can simulate hadron-to-quark matter transition in baryon stopping regime.

Abstract

We present a new event generator based on the three-fluid hydrodynamics approach for the early stage of the collision, followed by a particlization at the hydrodynamic decoupling surface to join to a microscopic transport model, UrQMD, to account for hadronic final state interactions. We present first results for nuclear collisions of the FAIR/NICA energy scan program (Au+Au collisions, $\sqrt{s_{NN}}=4-11$ GeV). We address the directed flow of protons and pions as well as the proton rapidity distribution for two model EoS, one with a first order phase transition the other with a crossover type softening at high densities. The new simulation program has the unique feature that it can describe a hadron-to-quark matter transition which proceeds in the baryon stopping regime that is not accessible to previous simulation programs designed for higher energies.