Abstract
The chemical and thermal equilibration in the central zone of heavy-ion collisions at energies around FAIR is studied within two microscopic models. Two systems are utilized for the analysis: (i) central cubic cell of fixed volume V = 125 fm 3 and (ii) expanding central area of uniformly distributed energy density. It is found that kinetic, thermal, and chemical equilibration of the expanding hadronic matter are nearly approached in both systems for the period of 10–18 fm/ c . The expansion proceeds almost isentropically. The extracted equation of state (EOS) in P − ɛ plane has a linear dependence P = aɛ , where a ≡ c 2 s slightly increases with the collision energy from 0.12 to 0.145. Linear dependencies for the EOS are found also in T − μ B and T − μ S planes. The characteristic kinks observed in the last two phase diagrams are linked to inelastic freeze-out in the expanding fireball.
Highlights
Ultra-relativistic heavy ion collisions offer a unique opportunity to study the nuclear phase diagram at high temperatures and densities, and to search for a new state of matter, predicted by Quantum Chromodynamics (QCD), namely, a quark-gluon plasma (QGP) of deconfined quarks and gluons
Lattice QCD calculations show that as the temperature of the system crosses some critical value Tc, the energy density rapidly increases and reaches the black body limit for T > Tc, indicating that the system has turned into the QGP phase
Since the initial state of HIC’s is produced far from equilibrium, its relaxation to local equilibrium should be studied within e.g. kinetic theory and/or non-equilibrium microscopic models of hadronic matter
Summary
Ultra-relativistic heavy ion collisions offer a unique opportunity to study the nuclear phase diagram at high temperatures and densities, and to search for a new state of matter, predicted by Quantum Chromodynamics (QCD), namely, a quark-gluon plasma (QGP) of deconfined quarks and gluons. Central gold-gold collisions with zero impact parameter b = 0 were simulated at bombarding energies Elab = 11.6, 20, 30, 40, 80 and 160 AGeV, respectively These reactions can probe the domain of temperatures and baryon chemical potentials where, according to the lattice QCD calculations, the tricritical point of nuclear phase diagram is located [4].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
