Elliptic flow in heavy-ion collisions at NICA energies

Abstract.

The transverse-momentum-integrated elliptic flow of charged particles at midrapidity, $v_{2}$ (charged), and that of identified hadrons from Au+Au collisions are analyzed in the range of incident energies relevant to the Nuclotron-based Ion Collider Facility (NICA). Simulations are performed within a three-fluid model employing three different equations of state (EoSs): a purely hadronic EoS and two versions of the EoS involving the deconfinement transition--a first-order phase transition and a smooth crossover one. The present simulations demonstrate low sensitivity of $v_{2}$ (charged) to the EoS. All considered scenarios equally well reproduce recent STAR data on $v_{2}$ (charged) for mid-central Au+Au collisions and properly describe its change of sign at the incident energy decrease below $\sqrt{s_{NN}} \approx 3.5$ GeV. The predicted integrated elliptic flow of various species exhibits a stronger dependence on the EoS. A noticeable sensitivity to the EoS is found for anti-protons and, to a lesser extent, for $K^{-}$ mesons. Presently there are no experimental data that could verify these predictions. Future experiments at NICA could corroborate these findings.