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

Abstract

We present an 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, ultrarelativistic quantum molecular dynamics, to account for hadronic final-state interactions. We present first results for nuclear collisions of the Facility for Antiproton and Ion Research--Nuclotron-based Ion Collider Facility energy scan program (Au+Au collisions, $\sqrt{{s}_{NN}}=4\ensuremath{-}11\phantom{\rule{0.16em}{0ex}}\mathrm{GeV}$). We address the directed flow of protons and pions as well as the proton rapidity distribution for two model equations of state, one with a first-order phase transition and 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.