Quark-to-gluon composition of the quark-gluon plasma in relativistic heavy-ion collisions

Abstract

We study the evolution of the quark-gluon composition of the plasma created in ultra-Relativistic Heavy-Ion Collisions (uRHIC's) employing a partonic transport theory that includes both elastic and inelastic collisions plus a mean fields dynamics associated to the widely used quasi-particle model. The latter, able to describe lattice QCD thermodynamics, implies a "chemical" equilibrium ratio between quarks and gluons strongly increasing as $T\to T_c$, the phase transition temperature. Accordingly we see in realistic simulations of uRHIC's a rapid evolution from a gluon dominated initial state to a quark dominated plasma close to $T_c$. The quark to gluon ratio can be modified by about a factor of $\sim 20$ in the bulk of the system and appears to be large also in the high $p_T$ region. We discuss how this aspect, often overflown, can be important for a quantitative study of several key issues in the QGP physics: shear viscosity, jet quenching, quarkonia suppression. Furthermore a bulk plasma made by more than $80\%$ of quarks plus antiquarks provides a theoretical basis for hadronization via quark coalescence.

6 pages, 4 figures, version published in Phys.Lett. B724 (2013) 296

References in corpus (10)

• Viscosity Information from Relativistic Nuclear Collisions: How Perfect is the Fluid Observed at RHIC?
• The QCD equation of state with dynamical quarks
• 200 A GeV Au+Au collisions serve a nearly perfect quark-gluon liquid
• Pinch Technique: Theory and Applications
• Coalescence Models For Hadron Formation From Quark Gluon Plasma
• Scalings of Elliptic Flow for a Fluid at Finite Shear Viscosity
• NNLO hard-thermal-loop thermodynamics for QCD
• Are there hadronic bound states above the QCD transition temperature?
• Gluodissociation and Screening of Upsilon States in PbPb Collisions at sqrt (s_NN) = 2.76 TeV
• Flavor Diagonal and Off-Diagonal Susceptibilities in a Quasiparticle Model of the Quark-Gluon Plasma

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