| DATE: |
2004-05-24 13:30 - |
| PLACE: |
Kenkyu-Honkan 3F RM321 |
| TITLE: |
Toward a unified dynamical description of heavy ion collisions at RHIC - From Color Glass Condensate to QGP |
| CONTACT: |
Tango |
| SPEAKER: |
Dr. Yasushi Nara (Department of Physics, University of Arizona) |
| LANGUAGE: |
Japanese |
| ABSTRACT: |
High density QCD matter seems to be created in nuclear collisions at the RHIC energies. A lot of work has been done to analyze copious experimental data. High energy heavy ion collisions involve many aspects according to the relevant scales or time. Paticularly, the following three subjects have been turned out to be important in understanding the whole stage of nuclear collisions. (1) A saturation-based model is successful in describing the centrality, energy and rapidity dependences of multiplicity. In this model, gluons are produced from the Color Glass Condensate (CGC) state.(2) Large elliptic flow observed in midrapidity region is consistent with hydrodynamic description. (3) Observed suppression of high $p_T$ hadrons can be well explained by the scenario of parton energy loss. All these three physics are closely related with each other. In particular, high parton density is required in all cases. (Nuclear wave functions at small x are obtained from high density QCD. Hydrodynamic description needs high density matter to justify the assumption of the local thermal equilibrium state. Large parton energy loss indicates that large parton density is produced.) We combine the above three pictures into one dynamical model called CGC+hydro+jet: Initial condition for hydrodynamic simulations is calculated from CGC, space-time evolution of thermalized matter is described by hydrodynamics and parton energy loss for semihard components is considered. We will show by explicit simulations that this dynamical model works very well for the description the bulk properties of RHIC data. |
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