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arXiv · 1202.0724

Chiral restoration effects on the shear viscosity of a pion gas

Klaus Heckmann·Michael Buballa·Jochen Wambach
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Abstract

We investigate the shear viscosity of a pion gas in relativistic kinetic theory, using the Nambu-Jona-Lasinio model to construct the pion mass and the pi-pi interaction at finite temperature. Whereas at low temperatures the scattering properties and, hence, the viscosity are in agreement with lowest-order chiral perturbation theory, we find strong medium modifications in the crossover region. Here the system is strongly coupled and the scattering lengths diverge, similarly as for ultra-cold Fermi gases at a Feshbach resonance. As a consequence, the ratio eta/s is found to be strongly reduced as compared to calculations without medium-modified masses and scattering amplitudes. However, the quantitative results are very sensitive to the details of the applied approximations.

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Klaus Heckmann, Michael Buballa, Jochen Wambach. 2012-10-29. Chiral restoration effects on the shear viscosity of a pion gas. https://doi.org/10.1140/epja%2Fi2012-12142-2

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