scholarly journals Chemical Evolution of Strongly Interacting Quark-Gluon Plasma

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Ying-Hua Pan ◽  
Wei-Ning Zhang

At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (~1 fm/c). However, the quark-gluon plasma (QGP) system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperatureT=400 MeV toT=150 MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations.

2016 ◽  
Vol 31 (07) ◽  
pp. 1630010 ◽  
Author(s):  
Leonard S. Kisslinger ◽  
Debasish Das

This is a review of the Quantum Chromodynamics Cosmological Phase Transitions, the quark–gluon plasma, the production of heavy quark states via [Formula: see text]–[Formula: see text] collisions and Relativistic Heavy Ion Collisions (RHIC) using the mixed hybrid theory for the [Formula: see text] and [Formula: see text] states; and the possible detection of the quark–gluon plasma via heavy quark production using RHIC. Recent research on fragmentation for the production of [Formula: see text] mesons is reviewed, as is future theoretical and experimental research on the Collins and Sivers fragmentation functions for pions produced in polarized [Formula: see text]–[Formula: see text] collisions.


2007 ◽  
Vol 16 (07n08) ◽  
pp. 1930-1936 ◽  
Author(s):  
WEI LIU ◽  
CHE MING KO ◽  
BEN-WEI ZHANG

A gluon or quark jet traversing through a quark-gluon plasma can be converted into a quark or gluon jet through scatterings with thermal partons. Their conversion rates due to two-body elastic and inelastic scattering as well as scatterings involving gluon radiation are evaluated in the lowest order in Quantum Chromodynamics (QCD). Including both energy loss and conversions of quark and gluon jets in the expanding quark-gluon plasma produced in relativistic heavy ion collisions, we find a net conversion of quark jets to gluon jets. This reduces the difference between the nuclear modification factors for quark and gluon jets in central heavy ion collisions and thus enhances the p/π+ and [Formula: see text] ratios at high transverse momentum. Using the larger QCD coupling constant from lattice QCD calculations than that given by the perturbative QCD further enhances the net quark to gluon jet conversion rate, leading to a closer similarity between these ratios at high transverse momentum in central Au + Au collisions at [Formula: see text] and in p + p collisions at same energy as observed in experiments.


2012 ◽  
Vol 27 (02) ◽  
pp. 1250009 ◽  
Author(s):  
VINEET AGOTIYA ◽  
LATA DEVI ◽  
UTTAM KAKADE ◽  
BINOY KRISHNA PATRA

We have developed an equation of state for strongly interacting quark–gluon plasma (QGP) in the framework of strongly coupled plasma with appropriate modifications to take account of color and flavor degrees of freedom and the interactions among themselves. For this purpose we used the effective potential to improve the plasma parameter (Γ) by correcting the full Cornell potential with a dielectric function embodying the effects of the deconfined medium and not its Coulomb part alone and obtain the equation of state in terms of Γ. Our results on thermodynamic observables viz. pressure, energy density, speed of sound etc. nicely fit to the results of lattice equation of state for gluon, massless as well massive flavored plasma. We have then employed our equation of state to estimate the quarkonium suppression in an expanding QGP produced in the relativistic heavy-ion collisions. We have found that our predictions matches with the recent PHENIX data on the centrality dependence of J/ψ suppression in Au+Au collisions at BNL RHIC within the limit of other uncertainties. We have also predicted for the ϒ suppression in Pb+Pb collisions at LHC energy which could be tested in the ALICE experiments at CERN LHC.


2014 ◽  
Vol 23 (08) ◽  
pp. 1450036 ◽  
Author(s):  
Ying-Hua Pan ◽  
Wei-Ning Zhang

Experiment and lattice simulation show that the quark–gluon plasma (QGP) system displays strong interaction between constituents at temperature a few times the critical temperature Tc. This QGP picture can be explained by assuming that the QGP matter above Tc is rich in different kinds of bound states, namely resonance-like QGP (RQGP). The chemical composition of the QGP system produced in ultra-relativistic heavy-ion collisions can be investigated through a general charge balance function which describes two-wave quark production during expansion afterward. In this paper, we investigate the signals of this RQGP through general charge balance functions. We find that the quasiparticles in QGP contribute a little to the balance functions because of their heavy masses. The balance functions reduce to the situation discussed before where only one-wave charge production is involved if only the quasiparticles in QGP are considered. However, the baryonic bound states in QGP have a significant effect on the balance function [Formula: see text], causing a dip in the [Formula: see text] balance function at small Δy. The existence of the binary and baryonic bound states amplify the negative dip of the balance function BpK-(Δy) at Δy ∽ 1.


2007 ◽  
Vol 16 (09) ◽  
pp. 2952-2955
Author(s):  
◽  
MAURO R. COSENTINO

Heavy Quarkonium states modifications in relativistic heavy ion collisions have been of great interest since the proposal by Matsui and Satz of J/ψ suppression as a signature of Quark-Gluon Plasma (QGP) formation. Recent studies suggest that the excited states χc, ψ(2 S ) and ϒ(3 S ) melt sequentially1,2 and the amount of observed suppression depends on the state and medium conditions. Therefore, this suppression pattern may be used as a probe of the medium temperature. In this work we present preliminary results on the charmonium and bottomnium measurements performed by the STAR experiment at RHIC for p + p and Cu + Cu collisions at [Formula: see text].


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