Extracting hadronic viscosity from microscopic transport models
Ultrarelativistic heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC) are thought to have created a Quark-Gluon Plasma, characterized by a very small shear viscosity to entropy density ratio η/s, close to the lower bound predicted for that quantity by string theory. However, due to the dynamics of the collision, the produced matter passes through a phase characterized by an expanding and rapidly cooling hadron gas with strongly increasing η/s. Such a rise in η/s would not be compatible with the success of (viscous) hydrodynamics, which requires a very small value of η/s throughout the full evolution of the reaction in order to successfully describe the collective flow seen in the experiments. Here we show that the inclusion of a pion-chemical potential, which is bound to arise due to the separation of chemical and kinetic freeze-out during the collision evolution, will reduce the value of η/s, and argue that introduction of other chemical potentials could ensure the successful application of (viscous) hydrodynamics to collisions at RHIC. © 2009 Springer-Verlag / Società Italiana di Fisica.
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- Nuclear & Particles Physics
- 5107 Particle and high energy physics
- 5102 Atomic, molecular and optical physics
- 5101 Astronomical sciences
- 0206 Quantum Physics
- 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Nuclear & Particles Physics
- 5107 Particle and high energy physics
- 5102 Atomic, molecular and optical physics
- 5101 Astronomical sciences
- 0206 Quantum Physics
- 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics