Chemical freeze-out conditions and fluctuations of conserved charges in heavy-ion collisions within a quantum van der Waals model

Abstract

The chemical freeze-out parameters in central nucleus-nucleus collisions are extracted consistently from hadron-yield data within the quantum van der Waals (QvdW) hadron resonance gas model. The beam energy dependencies for skewness and kurtosis of net baryon, net electric, and net strangeness charges are predicted. The QvdW interactions in asymmetric matter, $Q/B\ensuremath{\ne}0.5$, between (anti)baryons yield a noncongruent liquid-gas phase transition, together with a nuclear critical point (CP) with critical temperature of ${T}_{c}=19.5$ MeV. The nuclear CP shows that the collision energy dependence of the skewness and the kurtosis both deviate significantly from the ideal hadron resonance gas baseline predictions even far away, in the $(T,{\ensuremath{\mu}}_{B})$ plane, from the CP. These predictions can readily be tested by the STAR and NA61/SHINE Collaborations at the RHIC BNL and the SPS CERN, respectively, and by HADES at GSI. The results presented here offer a broad opportunity for the search for signals of phase transition in dense hadronic matter at the future NICA and FAIR high-intensity facilities.