Viscosity in the excluded volume hadron gas model
- Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine)
- Helmholtz Research School, University of Frankfurt, Frankfurt (Germany)
The shear viscosity {eta} in the van der Waals excluded volume hadron-resonance gas model is considered. For the shear viscosity the result of a nonrelativistic gas of hard-core particles is extended to a mixture of particles with different masses but equal values of hard-core radius r. The relativistic corrections to hadron average momenta in thermal equilibrium are also taken into account. The ratio of the viscosity {eta} to the entropy density s is studied. It monotonically decreases along the chemical freeze-out line in nucleus-nucleus collisions with increasing collision energy. As a function of hard-core radius r, a broad minimum of the ratio {eta}/s{approx_equal}0.3 near r{approx_equal}0.5 fm is found at high collision energies. For the charge-neutral system at T=T{sub c}=180 MeV, a minimum of the ratio {eta}/s congruent with 0.24 is reached for r congruent with 0.53 fm. To justify a hydrodynamic approach to nucleus-nucleus collisions within the hadron phase the restriction from below, r{>=}0.2 fm, on the hard-core hadron radius should be fulfilled in the excluded volume hadron-resonance gas.
- OSTI ID:
- 21068147
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 77, Issue 2; Other Information: DOI: 10.1103/PhysRevC.77.024911; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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