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Equation of state of resonance-rich matter in the central cell in heavy-ion collisions at $\sqrt{s}$=200 AGeV

L. V. Bravina·E. E. Zabrodin·S. A. Bass·M. Bleicher·M. Brandstetter·A. Faessler·C. Fuchs·W. Greiner·S. Soff·H. Stoecker
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Abstract

The equilibration of hot and dense nuclear matter produced in the central cell of central Au+Au collisions at RHIC ($\sqrt{s}=200$ AGeV) energies is studied within a microscopic transport model. The pressure in the cell becomes isotropic at $t\approx 5$ fm/$c$ after beginning of the collision. Within the next 15 fm/$c$ the expansion of matter in the cell proceeds almost isentropically with the entropy per baryon ratio $S/A \approx 150$, and the equation of state in the $(P,ε)$ plane has a very simple form, $P=0.15ε$. Comparison with the statistical model of an ideal hadron gas indicates that the time $t \approx 20$ fm/c may be too short to reach the fully equilibrated state. Particularly, the creation of long-lived resonance-rich matter in the cell decelerates the relaxation to chemical equilibrium. This resonance-abundant state can be detected experimentally after the thermal freeze-out of particles.

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L. V. Bravina, E. E. Zabrodin, S. A. Bass, M. Bleicher, M. Brandstetter, A. Faessler, C. Fuchs, W. Greiner, S. Soff, H. Stoecker. 2000-10-16. Equation of state of resonance-rich matter in the central cell in heavy-ion collisions at $\sqrt{s}$=200 AGeV. https://doi.org/10.1103/physrevc.63.064902

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