Speaker
Dr
Harri Niemi
(Frankfurt Institute for Advanced Studies)
Description
We investigate the effects of a temperature-dependent shear
viscosity-to-entropy density ratio $\eta/s$ on the elliptic
flow of hadrons in ultrarelativistic heavy-ion collisions [1].
We use relativistic dissipative fluid dynamics to model the
space-time evolution of the hot and dense system formed in
such collisions. The final hadron spectra are calculated using
the Cooper-Frye freeze-out procedure.
By studying different parametrizations for the temperature
dependence of $\eta/s$, we found that the viscous suppression
of the elliptic flow coefficient in $\sqrt{s_{NN}} = 200$ GeV
Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC)
is dominated by the viscosity in the hadronic phase and in the
phase transition region. However, the elliptic flow at RHIC is
largely insensitive to the viscosity of the
quark-gluon plasma (QGP).
On the other hand, we found that sensitivity of the elliptic
flow to the high-temperature $\eta/s$ increases with increasing
multiplicity and simultaneously the sensitivity to the hadronic
viscosity decreases. At the highest LHC energy, the elliptic
flow becomes sensitive to the QGP viscosity and insensitive to
the hadronic viscosity.
The change of the sensitivity from hadronic to QGP viscosity
from RHIC to LHC can provide access to determining the
temperature dependence of $\eta/s$ from elliptic flow data.
[1] H. Niemi, G. S. Denicol, P. Huovinen, E. Molnar, D. H. Rischke,
[arXiv:1101.2442 [nucl-th]].
Author
Dr
Harri Niemi
(Frankfurt Institute for Advanced Studies)
Co-authors
Prof.
Dirk Rischke
(Frankfurt Institute for Advanced Studies; Institute für Theoretische Physik, Johann Wolfgang Goethe-Universität)
Dr
Etele Molnár
(Institute für Theoretische Physik, Johann Wolfgang Goethe-Universität; MTA-KFKI, Research Institute of Particle and Nuclear Physics)
Mr
Gabriel Denicol
(Institute für Theoretische Physik, Johann Wolfgang Goethe-Universität)
Dr
Pasi Huovinen
(Institute für Theoretische Physik, Johann Wolfgang Goethe-Universität)