The η/s of hadrons out of chemical equilibrium

30th Winter Workshop on Nuclear Dynamics

Wiranata, A.^1,2,3 ; Prakash, M.^3 ; Huovinen, P.^4,5 ; Koch, V.^2 ; Wang, X.N.^1,2

Institute of Particle Physics, Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University, Wuhan

430079, China^1

Lawrence Berkeley National Laboratory, Nuclear Science Division, MS 70R0319, Berkeley

CA

94720, United States^2

Department of Physics and Astronomy, Ohio University, Athens

OH

45701, United States^3

Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, Frankfurt am Main

60438, Germany^4

Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität, Max-von-Laue-Strasse 1, Frankfurt am Main

60438, Germany^5

关键词: Baryon number;    Chemical equilibriums;    Entropy density;    Ideal fluids;    Relativistic heavy ion collision;    Time evolutions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/535/1/012017/pdf
DOI  :  10.1088/1742-6596/535/1/012017

来源: IOP

【 摘 要 】

We study how the shear viscosity, η, entropy density, s, and η/s depend on growing hadron chemical potentials resulting from the loss of chemical equilibrium during the evolution of a relativistic heavy-ion collision. Our calculations here are for an interacting pion gas in a system of net baryon number zero. Time evolution of the temperature and pion chemical potential are taken from ideal fluid hydrodynamic calculations of RHIC and LHC collisions. We find that the shear viscosity decreases whereas the entropy density increases with increasing pion chemical potential resulting in values of η/s that are slightly reduced from the case of chemical potentials being zero when chemical equilibrium prevails. Our results indicate that the inclusion of additional mesons and baryons will likely lead to further reduction in the value of η/s.