Soft heavy-ion physics from hydrodynamics with statistical hadronization - predictions for the Large Hadron Collider

Abstract

Hydrodynamics merged with single-freeze-out statistical hadronization is used to describe the midrapidity hadron production in relativistic heavy-ion collisions at the highest RHIC energies and to make predictions for the LHC. Thermodynamic properties of the quark-gluon plasma are taken from lattice simulations, at low temperatures the hadron-gas equation of state is used, while in the cross-over region an interpolation between the two equations of state is constructed. The initial condition for hydrodynamics is obtained from a Glauber profile for the entropy, with the initial central temperature Ti. The conditions obtained from the hydrodynamic expansion at the freeze-out temperature Tf are used as input for the thermal event generator THERMINATOR. Basic physical observables are obtained: the transverse-momentum spectra, the elliptic flow coefficient v2, and the HBT radii. The femtoscopic observables are evaluated with the help of the two-particle method which accounts for the resonance decays and Coulomb final-state interactions. The problem of a simultaneous description of all discussed observables is addressed, with the conclusion that at the highest RHIC energies our approach gives a quite satisfactory global description of soft hadronic observables. Some discrepancies may be attributed to the absence of the final-state elastic interactions among hadrons. Extrapolating Ti to higher values allows for global predictions for soft hadronic physics at the LHC. We test Ti=400, 450, and 500 MeV, and observe the expected growth of particle multiplicities and the increase of the flow, resulting in smaller slopes of the pT-spectra. The elliptic flow of pions exhibits saturation, with v2 remaining practically constant, while the HBT radii increase moderately with Ti.