dorsal/arxiv
View SchemaReaction dynamics in Pb+Pb at the CERN/SPS: from partonic degrees of freedom to freeze-out
| Authors | S. A. Bass, H. Weber, C. Ernst, M. Bleicher, M. Belkacem, L. Bravina, S. Soff, H. Stoecker, W. Greiner, C. Spieles |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9810077 |
| URL | https://arxiv.org/abs/nucl-th/9810077 |
| DOI | 10.1016/S0146-6410(99)00086-1 |
| Journal | Prog.Part.Nucl.Phys. 42 (1999) 313-322 |
Abstract
We analyze the reaction dynamics of central Pb+Pb collisions at 160 GeV/nucleon. First we estimate the energy density pile-up at mid-rapidity and calculate its excitation function: The energy density is decomposed into hadronic and partonic contributions. A detailed analysis of the collision dynamics in the framework of a microscopic transport model shows the importance of partonic degrees of freedom and rescattering of leading (di)quarks in the early phase of the reaction for E > 30 GeV/nucleon. The energy density reaches up to 4 GeV/fm^3, 95% of which are contained in partonic degrees of freedom. It is shown that cells of hadronic matter, after the early reaction phase, can be viewed as nearly chemically equilibrated. This matter never exceeds energy densities of 0.4 GeV/fm^3, i.e. a density above which the notion of separated hadrons loses its meaning. The final reaction stage is analyzed in terms of hadron ratios, freeze-out distributions and a source analysis for final state pions.
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"abstract": "We analyze the reaction dynamics of central Pb+Pb collisions at 160\nGeV/nucleon. First we estimate the energy density pile-up at mid-rapidity and\ncalculate its excitation function: The energy density is decomposed into\nhadronic and partonic contributions. A detailed analysis of the collision\ndynamics in the framework of a microscopic transport model shows the importance\nof partonic degrees of freedom and rescattering of leading (di)quarks in the\nearly phase of the reaction for E \u003e 30 GeV/nucleon. The energy density reaches\nup to 4 GeV/fm^3, 95% of which are contained in partonic degrees of freedom. It\nis shown that cells of hadronic matter, after the early reaction phase, can be\nviewed as nearly chemically equilibrated. This matter never exceeds energy\ndensities of 0.4 GeV/fm^3, i.e. a density above which the notion of separated\nhadrons loses its meaning. The final reaction stage is analyzed in terms of\nhadron ratios, freeze-out distributions and a source analysis for final state\npions.",
"arxiv_id": "nucl-th/9810077",
"authors": [
"S. A. Bass",
"H. Weber",
"C. Ernst",
"M. Bleicher",
"M. Belkacem",
"L. Bravina",
"S. Soff",
"H. Stoecker",
"W. Greiner",
"C. Spieles"
],
"categories": [
"nucl-th"
],
"doi": "10.1016/S0146-6410(99)00086-1",
"journal_ref": "Prog.Part.Nucl.Phys. 42 (1999) 313-322",
"title": "Reaction dynamics in Pb+Pb at the CERN/SPS: from partonic degrees of freedom to freeze-out",
"url": "https://arxiv.org/abs/nucl-th/9810077"
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