arXiv subjects
Publications and source records attributed to Mohamed Abdel-Aziz.
We use the Ultra-relativistic Quantum Molecular Dynamic model (UrQMD v2.2) to study forward-backward fluctuations and compare our results with the data published by the PHOBOS experiment. The extracted effective cluster multiplicities show a clear centrality dependence within the present hadron-string transport approach. This behavior is not reproduced with models not taking into account final state rescattering.
We use the ultra-relativistic quantum molecular dynamic UrQMD version 2.2 to study forward backward fluctuations and compare our results with the published data by the PHOBOS.
Elliptic flow measurements at RHIC suggest that quark gluon plasma flows with very little viscosity compared to weak coupling expectations, challenging theorists to explain why this fluid is so nearly ``perfect''. It is therefore vital to find quantitative experimental information on the viscosity of the plasma. We propose that measurements of transverse momentum fluctuations can be used to determine the shear viscosity. We use current data to estimate the viscosity-to-entropy ratio in the range from 0.08 to 0.3, and discuss how future measurements can reduce this uncertainty.
We study forward-backward charge fluctuations to probe the correlations among produced particles in ultra relativistic heavy ion collisions. We develop a model that describes the forward-backward dynamical fluctuations and apply it to interpret the recent PHOBOS data. Within the present model, the dynamical fluctuations are related to the particle production mechanism via cluster decay and to long range correlations between the forward and backward rapidity hemispheres. We argue that with a tight centrality cut, PHOBOS may see a strong decrease of the dynamical fluctuations. Within the present model, this deterioration of the correlation among the produced hadrons can be interpreted as a sign for the production of a hot, dense and interacting medium.
The onset of equilibration in nuclear collisions can lead to related trends in the centrality dependence of the average transverse momentum, pt fluctuations and net charge fluctuations. We extend the transport description of S. Gavin (Phys. Rev. Lett. 92, 162301 (2004)) to include radial flow.