dorsal/arxiv
View SchemaPerfect Fluidity of the Quark Gluon Plasma Core as Seen through its Dissipative Hadronic Corona
| Authors | Tetsufumi Hirano, Miklos Gyulassy |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/0506049 |
| URL | https://arxiv.org/abs/nucl-th/0506049 |
| DOI | 10.1016/j.nuclphysa.2006.02.005 |
| Journal | Nucl.Phys.A769:71-94,2006 |
Abstract
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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"abstract": "The agreement of hydrodynamic predictions of differential elliptic flow and\nradial flow patterns with Au+Au data is one of the main lines of evidence\nsuggesting the nearly perfect fluid properties of the strongly coupled Quark\nGluon Plasma, sQGP, produced at RHIC. We study the sensitivity of this\nconclusion to different hydrodynamic assumptions on chemical and thermal\nfreezeout after the sQGP hadronizes. We show that if chemical freezeout occurs\nat the hadronization time, the differential elliptic flow for pions increase\nwith proper time in the late hadronic phase until thermal freezeout and leads\nto a discrepancy with the data. In contrast, if both chemical and thermal\nequilibrium are maintained past the hadronization, then the mean pT per pion\nincreases in a way that accidentally preserves v2(pT) from the sQGP phase in\nagreement with the data, but at the cost of the agreement with the hadronic\nyields. In order that all the data on hadronic ratios, radial flow, and\ndifferential elliptic flow be reproduced, the sQGP must expand with a minimal\nviscosity, \\eta_Q, that is however even greater than the viscosity, \\eta_H, of\nits hadronic corona. However, because of the large entropy density difference\nof the two phases of QCD matter, the larger viscosity in the sQGP phase leads\nto nearly perfect fluid flow while the smaller entropy density of the hadronic\ncorona strongly hinders the applicability of Euler hydrodynamics. The ``perfect\nfluid\u0027\u0027 property of the sQGP is thus not due to a sudden reduction of the\nviscosity at the critical temperature Tc, but to a sudden increase of the\nentropy density of QCD matter and is therefore an important signature of\ndeconfinement.",
"arxiv_id": "nucl-th/0506049",
"authors": [
"Tetsufumi Hirano",
"Miklos Gyulassy"
],
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"doi": "10.1016/j.nuclphysa.2006.02.005",
"journal_ref": "Nucl.Phys.A769:71-94,2006",
"title": "Perfect Fluidity of the Quark Gluon Plasma Core as Seen through its Dissipative Hadronic Corona",
"url": "https://arxiv.org/abs/nucl-th/0506049"
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