Quasi-Particle Degrees of Freedom versus the Perfect Fluid as Descriptors of the Quark-Gluon Plasma
| dc.creator | Levy, L. A. Linden | |
| dc.creator | Nagle, J. L. | |
| dc.creator | Rosen, C. | |
| dc.creator | Steinberg, P. | |
| dc.date | 2007-09-19 | |
| dc.date | 2007-12-21 | |
| dc.date.accessioned | 2026-07-07T11:53:11Z | |
| dc.date.available | 2026-07-07T11:53:11Z | |
| dc.description | The hot nuclear matter created at the Relativistic Heavy Ion Collider (RHIC) has been characterized by near-perfect fluid behavior. We demonstrate that this stands in contradiction to the identification of QCD quasi-particles with the thermodynamic degrees of freedom in the early (fluid) stage of heavy ion collisions. The empirical observation of constituent quark ``$n_q$'' scaling of elliptic flow is juxtaposed with the lack of such scaling behavior in hydrodynamic fluid calculations followed by Cooper-Frye freeze-out to hadrons. A ``quasi-particle transport'' time stage after viscous effects break down the hydrodynamic fluid stage, but prior to hadronization, is proposed to reconcile these apparent contradictions. However, without a detailed understanding of the transitions between these stages, the ``$n_q$'' scaling is not a necessary consequence of this prescription. Also, if the duration of this stage is too short, it may not support well defined quasi-particles. By comparing and contrasting the coalescence of quarks into hadrons with the similar process of producing light nuclei from nucleons, it is shown that the observation of ``$n_{q}$'' scaling in the final state does not necessarily imply that the constituent degrees of freedom were the relevant ones in the initial state. | |
| dc.description | 9 pages, 7 figures, Updated text and figures | |
| dc.identifier | https://arxiv.org/abs/0709.3105 | |
| dc.identifier | http://arxiv.org/abs/0709.3105 | |
| dc.identifier | Phys.Rev.C78:044905,2008 | |
| dc.identifier | doi:10.1103/PhysRevC.78.044905 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/204450 | |
| dc.subject | Nuclear Theory | |
| dc.title | Quasi-Particle Degrees of Freedom versus the Perfect Fluid as Descriptors of the Quark-Gluon Plasma | |
| dc.type | text |