Chemical freezeout in relativistic A+A collisions: is it close to the QGP?

Abstract

Preliminary experimental data for particle number ratios in the collisions of Au+Au at the BNL AGS (11$A$ GeV/$c$) and Pb+Pb at the CERN SPS (160$A$ GeV/$c$) are analyzed in a thermodynamically consistent hadron gas model with excluded volume. Large values of temperature, T=140--185 MeV, and baryonic chemical potential, ${\mu }_b=590$--270 MeV, close to the boundary of the quark-gluon plasma phase are found from fitting the data. This seems to indicate that the energy density at the chemical freezeout is tremendous which would be indeed the case for the point-like hadrons. However, a self-consistent treatment of the van der Waals excluded volume reveals much smaller energy densities which are very far below a lowest limit estimate of the quark-gluon plasma energy density.

arXiv commentRevTeX, 11 pages, 3 figures

References in corpus (7)

• Thermal Equilibration and Expansion in Nucleus-Nucleus Collision at the AGS
• Thermal and Hadrochemical Equilibration in Nucleus-Nucleus Collisions at the SPS
• Thermal Hadron Production in High Energy Heavy Ion Collisions
• Excluded volume hadron gas model for particle number ratios in A+A collisions
• Evidence for a high entropy phase in nuclear collisions
• Hadron production in relativistic nuclear collisions: thermal hadron source or hadronizing quark-gluon plasma?
• Strangeness and Pion Production as Signals of QCD Phase Transition

Cited by in corpus (12)

• The analysis of particle multiplicities in Pb+Pb collisions at 158A GeV/c within hadron gas models
• Viscosity in the excluded volume hadron gas model
• Dissipative properties of hot and dense hadronic matter in excluded volume hadron resonance gas model
• Hadron Resonance Gas Equation of State from Lattice QCD
• Van der Waals Excluded Volume Model of Multicomponent Hadron Gas
• Equation of state of resonance-rich matter in the central cell in heavy-ion collisions at $\sqrt{s}$=200 AGeV
• Particle number fluctuations in nuclear collisions within excluded volume hadron gas model
• Medium modification of hadron masses and the thermodynamics of hadron resonance gas model
• Second Cluster Integral and Excluded Volume Effects for the Pion Gas
• Neutron star structure in a quark model with excluded volume correction
• Diffusion matrix associated with the diffusion processes of multiple conserved charges in a hot and dense hadronic matter
• The Parton-Hadron Phase Transition in Central Nuclear Collisions at the CERN SPS