Matching stages of heavy-ion collision models

Journal Article · Tue Jun 15 04:00:00 EDT 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.81.064910· OSTI ID:21388628

Yun, Cheng ^[1]; Csernai, L P ^[1]; Magas, V K ^[2]; Schlei, B R ^[3]; Strottman, D ^[4]

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1. Institute of Physics and Technology, University of Bergen, Allegaten 55, N-5007 Bergen (Norway)
2. Departament d'Estructura i Constituents de la Materia, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain)
3. GSI Helmholtz Centre for Heavy Ion Research GmbH, Planckstrasse 1, D-64291 Darmstadt (Germany)
4. Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main (Germany)

Heavy-ion reactions and other collective dynamical processes are frequently described by different theoretical approaches for the different stages of the process, like initial equilibration stage, intermediate locally equilibrated fluid dynamical stage, and final freeze-out stage. For the last stage, the best known is the Cooper-Frye description used to generate the phase space distribution of emitted, noninteracting particles from a fluid dynamical expansion or explosion, assuming a final ideal gas distribution, or (less frequently) an out-of-equilibrium distribution. In this work we do not want to replace the Cooper-Frye description, but rather clarify the ways of using it and how to choose the parameters of the distribution and, eventually, how to choose the form of the phase space distribution used in the Cooper-Frye formula. Moreover, the Cooper-Frye formula is used in connection with the freeze-out problem, while the discussion of transition between different stages of the collision is applicable to other transitions also. More recently, hadronization and molecular dynamics models have been matched to the end of a fluid dynamical stage to describe hadronization and freeze-out. The stages of the model description can be matched to each other on space-time hypersurfaces (just like through the frequently used freeze-out hypersurface). This work presents a generalized description of how to match the stages of the description of a reaction to each other, extending the methodology used at freeze-out, in simple covariant form which is easily applicable in its simplest version for most applications.

• OSTI ID: 21388628
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 6 Vol. 81; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CALCULATION METHODS
COLLISIONS
DISTRIBUTION
EQUILIBRIUM
EXPANSION
EXPLOSIONS
FLUIDS
FREEZING OUT
HEAVY ION REACTIONS
MATHEMATICAL SPACE
MOLECULAR DYNAMICS METHOD
NUCLEAR REACTIONS
PHASE SPACE
SEPARATION PROCESSES
SIMULATION
SPACE
SPACE-TIME