"Chemical" composition of the Quark Gluon Plasma

Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus–Nucleus Collisions 2012

Scardina, Francesco^1,2 ; Colonna, Maria^2 ; Plumari, Salvatore^1,2 ; Greco, Vincenzo^1,2

Department of Physics and Astronomy, University of Catania, Via S. Sofia 64, I-95125 Catania, Italy^1

Laboratorio Nazionale Del Sud, INFN-LNS, Via S. Sofia 63, I-95125 Catania, Italy^2

关键词: Equilibrium ratios;    Hadronization;    Initial state;    Mean field dynamics;    Quark-gluon plasma;    Quasi particles;    Transport theory;    Ultrarelativistic heavy ion collision;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/446/1/012018/pdf
DOI  :  10.1088/1742-6596/446/1/012018

来源: IOP

【 摘 要 】

In this article we discuss the issue of the quark to gluon ratio in the Quark Gluon Plasma (QGP). Our model to describe the QGP evolution is based on transport theory including the mean field dynamics described by a quasi-particle model.The last is able to take into account for the lattice QCD thermodynamics and implies a "chemical" equilibrium ratio between quarks and gluons strongly increasing as T approaches to the temperature of the phase transition Tc. We present first the tests performed in a fixed box to check that our code is able to reproduce the equilibrium ratio and then the results obtained for the simulations of ultra-Relativistic Heavy Ion Collisions (uRHIC's) at RHIC and LHC energies. We observe a rapid evolution from a gluon dominated initial state to a quark dominated plasma and we see that near Tcalmost 80% of the particles composing the plasma are quarks. This has potentially a strong impact on several quantitative aspects of QGP probes and furnishes a justification to the coalescence hadronization model.