Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Perfect Fluidity of the Quark Gluon Plasma Core as Seen through its
  Dissipative Hadronic Corona   The agreement of hydrodynamic predictions of differential elliptic flow and
radial flow patterns with Au+Au data is one of the main lines of evidence
suggesting the nearly perfect fluid properties of the strongly coupled Quark
Gluon Plasma, sQGP, produced at RHIC. We study the sensitivity of this
conclusion to different hydrodynamic assumptions on chemical and thermal
freezeout after the sQGP hadronizes. We show that if chemical freezeout occurs
at the hadronization time, the differential elliptic flow for pions increase
with proper time in the late hadronic phase until thermal freezeout and leads
to a discrepancy with the data. In contrast, if both chemical and thermal
equilibrium are maintained past the hadronization, then the mean pT per pion
increases in a way that accidentally preserves v2(pT) from the sQGP phase in
agreement with the data, but at the cost of the agreement with the hadronic
yields. In order that all the data on hadronic ratios, radial flow, and
differential elliptic flow be reproduced, the sQGP must expand with a minimal
viscosity, \eta_Q, that is however even greater than the viscosity, \eta_H, of
its hadronic corona. However, because of the large entropy density difference
of the two phases of QCD matter, the larger viscosity in the sQGP phase leads
to nearly perfect fluid flow while the smaller entropy density of the hadronic
corona strongly hinders the applicability of Euler hydrodynamics. The ``perfect
fluid'' property of the sQGP is thus not due to a sudden reduction of the
viscosity at the critical temperature Tc, but to a sudden increase of the
entropy density of QCD matter and is therefore an important signature of
deconfinement.

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The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
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The categories of this paper are: eess
7
The categories of this paper are: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
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The categories of this paper are: bayes-an
3
The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga