Equilibrium and nonequilibrium effects in nucleus nucleus collisions

  • Abstract: Local thermal and chemical equilibration is studied for central AqA collisions at 10.7 160 AGeV in the Ultrarelativis- . tic Quantum Molecular Dynamics model UrQMD . The UrQMD model exhibits strong deviations from local equilibrium at the high density hadron string phase formed during the early stage of the collision. Equilibration of the hadron resonance matter is established in the central cell of volume Vs125 fm3 at later stages, tG10 fmrc, of the resulting quasi-isentropic expansion. The thermodynamical functions in the cell and their time evolution are presented. Deviations of the UrQMD quasi-equilibrium state from the statistical mechanics equilibrium are found. They increase with energy per baryon and lead to a strong enhancement of the pion number density as compared to statistical mechanics estimates at SPS energies. PACS: 25.75.-q; 24.10.Lx; 24.10.Pa; 64.30.qt

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Author:Larissa BravinaORCiDGND, Mark I. GorensteinORCiDGND, Eugene E. ZabrodinORCiD, Steffen A. BassORCiDGND, Mohamed Belkacem, Marcus BleicherORCiDGND, Mathias Brandstetter, Markus Hofmann, Sven SoffORCiD, Christian Spieles, H. Weber, Horst StöckerORCiDGND, Walter GreinerGND
Parent Title (German):Physics letter B
Publisher:North-Holland Publ.
Place of publication:Amsterdam
Document Type:Article
Year of Completion:1999
Year of first Publication:1999
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2005/12/07
Tag:Kollisionen schwerer Ionen; Nichtgleichgewicht; QMD Modell; Zustandsgleichung; lokales thermodynamisches Gleichgewicht
Equation of state; Heavy ion collisions; Local thermodynamical equilibrium; Non-equilibrium effects; QMD model
Page Number:7
First Page:660
Last Page:666
Institutes:Physik / Physik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):License LogoDeutsches Urheberrecht