dorsal/arxiv
View SchemaEntropy Production in Collisions of Relativistic Heavy Ions -- a signal for Quark-Gluon Plasma phase transition?
| Authors | M. Reiter, A. Dumitru, J. Brachmann, J. A. Maruhn, H. Stöcker, W. Greiner |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9806010 |
| URL | https://arxiv.org/abs/nucl-th/9806010 |
| DOI | 10.1016/S0375-9474(98)00556-9 |
| Journal | Nucl.Phys. A643 (1998) 99-112 |
Abstract
Entropy production in the compression stage of heavy ion collisions is discussed within three distinct macroscopic models (i.e. generalized RHTA, geometrical overlap model and three-fluid hydrodynamics). We find that within these models \sim 80% or more of the experimentally observed final-state entropy is created in the early stage. It is thus likely followed by a nearly isentropic expansion. We employ an equation of state with a first-order phase transition. For low net baryon density, the entropy density exhibits a jump at the phase boundary. However, the excitation function of the specific entropy per net baryon, S/A, does not reflect this jump. This is due to the fact that for final states (of the compression) in the mixed phase, the baryon density \rho_B increases with \sqrt{s}, but not the temperature T. Calculations within the three-fluid model show that a large fraction of the entropy is produced by nuclear shockwaves in the projectile and target. With increasing beam energy, this fraction of S/A decreases. At \sqrt{s}=20 AGeV it is on the order of the entropy of the newly produced particles around midrapidity. Hadron ratios are calculated for the entropy values produced initially at beam energies from 2 to 200 AGeV.
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"abstract": "Entropy production in the compression stage of heavy ion collisions is\ndiscussed within three distinct macroscopic models (i.e. generalized RHTA,\ngeometrical overlap model and three-fluid hydrodynamics). We find that within\nthese models \\sim 80% or more of the experimentally observed final-state\nentropy is created in the early stage. It is thus likely followed by a nearly\nisentropic expansion. We employ an equation of state with a first-order phase\ntransition. For low net baryon density, the entropy density exhibits a jump at\nthe phase boundary. However, the excitation function of the specific entropy\nper net baryon, S/A, does not reflect this jump. This is due to the fact that\nfor final states (of the compression) in the mixed phase, the baryon density\n\\rho_B increases with \\sqrt{s}, but not the temperature T. Calculations within\nthe three-fluid model show that a large fraction of the entropy is produced by\nnuclear shockwaves in the projectile and target. With increasing beam energy,\nthis fraction of S/A decreases. At \\sqrt{s}=20 AGeV it is on the order of the\nentropy of the newly produced particles around midrapidity. Hadron ratios are\ncalculated for the entropy values produced initially at beam energies from 2 to\n200 AGeV.",
"arxiv_id": "nucl-th/9806010",
"authors": [
"M. Reiter",
"A. Dumitru",
"J. Brachmann",
"J. A. Maruhn",
"H. St\u00f6cker",
"W. Greiner"
],
"categories": [
"nucl-th"
],
"doi": "10.1016/S0375-9474(98)00556-9",
"journal_ref": "Nucl.Phys. A643 (1998) 99-112",
"title": "Entropy Production in Collisions of Relativistic Heavy Ions -- a signal for Quark-Gluon Plasma phase transition?",
"url": "https://arxiv.org/abs/nucl-th/9806010"
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