Particle production in relativistic collisions of heavy nuclei is analyzed in a wide range of incident energies 2.7 GeV $\le \sqrt{s_{NN}}\le$ 62.4 GeV. The analysis is performed within the three-fluid model employing three different equations of state (EoSs): a purely hadronic EoS, an EoS with the first-order phase transition, and an EoS with a smooth crossover transition. It is found that the hadronic scenario fails to reproduce experimental yields of antibaryons (strange and nonstrange), starting already from lower Super Proton Synchrotron (SPS) energies, i.e., $\sqrt{s_{NN}}>$ 5 GeV. Moreover, at energies above the top SPS one, i.e., $\sqrt{s_{NN}}>$ 17.4 GeV, the midrapidity densities predicted by the hadronic scenario considerably exceed the available Relativistic Heavy-Ion Collider data on all species. At the same time the deconfinement-transition scenarios reasonably agree (to a various extent) with all the data. The present analysis demonstrates certain advantage of the deconfinement-transition EoSs. However, all scenarios fail to reproduce the strangeness enhancement in the incident energy range near 30$A$ GeV (i.e., a horn anomaly in the $K^{+}/{\pi }^{+}$ ratio) and yields of $\varphi$ mesons at 20$A$–40$A$ GeV.

• Received 8 April 2013

DOI:https://doi.org/10.1103/PhysRevC.87.064905