Equilibrium and non-equilibrium effects in relativistic heavy ion collisions.
The hypothesis of local equilibrium (LE) in relativistic heavy ion collisions at energies from AGS to RHIC is checked in the microscopic transport model. We find that kinetic, thermal, and chemical equilibration of the expanding hadronic matter is nearly reached in central collisions at AGS energy for t ≥ 10 fm/c in a central cell. At these times the equation of state may be approximated by a simple dependence P ≅ (0.12 - 0.15) ε. Increasing deviations of the yields and the energy spectra of hadrons from statistical model values are observed for increasing bombarding energies. The origin of these deviations is traced to the irreversible multiparticle decays of strings and many-body (N ≥ 3) decays of resonances. The violations of LE indicate that the matter in the cell reaches a steady state instead of idealized equilibrium. The entropy density in the cell is only about 6% smaller than that of the equilibrium state.
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Related Subject Headings
- Nuclear & Particles Physics
- 5107 Particle and high energy physics
- 5106 Nuclear and plasma physics
- 5101 Astronomical sciences
- 0206 Quantum Physics
- 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
- 0201 Astronomical and Space Sciences
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Nuclear & Particles Physics
- 5107 Particle and high energy physics
- 5106 Nuclear and plasma physics
- 5101 Astronomical sciences
- 0206 Quantum Physics
- 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
- 0201 Astronomical and Space Sciences