scholarly journals Measuring the isotropization time of quark-gluon plasma from direct photons at energies available at the BNL Relativistic Heavy Ion Collider (RHIC)

2009 ◽  
Vol 79 (5) ◽  
Author(s):  
Lusaka Bhattacharya ◽  
Pradip Roy
Keyword(s):  
Quark Gluon Plasma ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collider ◽  
Direct Photons

scholarly journals On Pseudorapidity Distribution and Speed of Sound in High Energy Heavy Ion Collisions Based on a New Revised Landau Hydrodynamic Model

2015 ◽  
Vol 2015 ◽  
pp. 1-23 ◽  
Author(s):  
Li-Na Gao ◽  
Fu-Hu Liu
Keyword(s):  
Speed Of Sound ◽  
Hydrodynamic Model ◽  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Relativistic Heavy Ion Collider ◽  
Central Source ◽  
Ion Collisions

We propose a new revised Landau hydrodynamic model to study systematically the pseudorapidity distributions of charged particles produced in heavy ion collisions over an energy range from a few GeV to a few TeV per nucleon pair. The interacting system is divided into three sources, namely, the central, target, and projectile sources, respectively. The large central source is described by the Landau hydrodynamic model and further revised by the contributions of the small target/projectile sources. The modeling results are in agreement with the available experimental data at relativistic heavy ion collider, large hadron collider, and other energies for different centralities. The value of square speed of sound parameter in different collisions has been extracted by us from the widths of rapidity distributions. Our results show that, in heavy ion collisions at energies of the two colliders, the central source undergoes a phase transition from hadronic gas to quark-gluon plasma liquid phase; meanwhile, the target/projectile sources remain in the state of hadronic gas. The present work confirms that the quark-gluon plasma is of liquid type rather than being of a gas type.

scholarly journals STUDY OF VECTOR MESON FRAGMENTATION USING A BROKEN SU(3) MODEL

2012 ◽  
Vol 27 (19) ◽  
pp. 1250103 ◽  
Author(s):  
D. INDUMATHI ◽  
H. SAVEETHA
Keyword(s):  
Quark Gluon Plasma ◽  
Light Quark ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Dglap Evolution ◽  
Relativistic Heavy Ion Collider ◽  
Breaking Parameter ◽  
Fragmentation Functions ◽  
Scaled Energy ◽  
Gluon Fragmentation

Inclusive hadro-production in e+e- annihilation processes is examined to study the fragmentation process. A broken SU(3) model is used to determine the quark and gluon fragmentation functions of octet vector mesons, ρ and K*, in a simple way with an SU(3) breaking parameter λ. These are expressed in terms of just two light quark fragmentation functions, V(x, Q2) and γ(x, Q2) and the gluon fragmentation function Dg(x, Q2). These functions are parametrized at the low input scale of [Formula: see text], evolved through LO DGLAP evolution including charm and bottom flavor at appropriate thresholds, and fitted by comparison with data at the Z-pole. The model is extended with the introduction of a few additional parameters to include a study of singlet–octet mixing and hence ω and ϕ fragmentation. The model gives good fits to the available data for x ≳0.01, where x is the scaled energy of the hadron. The model is then applied successfully to ω, ϕ production in pp collisions at the relativistic heavy ion collider, RHIC, these data form an important baseline for the study of Quark Gluon Plasma in heavy nucleus collisions at RHIC, and also in future at the LHC.

THERMAL RADIATION FROM AN EVOLVING VISCOUS QUARK GLUON PLASMA

2013 ◽  
Vol 22 (01) ◽  
pp. 1350004 ◽  
Author(s):  
SUKANYA MITRA ◽  
PAYAL MOHANTY ◽  
SOURAV SARKAR ◽  
JAN-E ALAM
Keyword(s):  
Quark Gluon Plasma ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Viscous Effects ◽  
Relativistic Heavy Ion Collider ◽  
Nuclear Collisions ◽  
Evolution Dynamics ◽  
Small Change ◽  
Photon Spectra ◽  
Space Time Evolution

The effects of viscosity on the space-time evolution of quark gluon plasma produced in nuclear collisions at relativistic heavy ion collider energies have been studied. The entropy generated due to the viscous motion of the fluid has been taken into account in constraining the initial temperature by the final multiplicity (measured at the freeze-out point). The viscous effects on the photon spectra has been introduced consistently through the evolution dynamics and phase space factors of all the participating partons/hadrons in the production process. In contrast to some of the recent calculations the present work includes the contribution from the hadronic phase. A small change in the transverse momentum (pT) distribution of photons is observed due to viscous effects.

DILEPTONS AND PHOTONS IN HIGH ENERGY HEAVY ION REACTIONS: A REVIEW

1991 ◽  
Vol 06 (04) ◽  
pp. 517-558 ◽  
Author(s):  
SIBAJI RAHA ◽  
BIKASH SINHA
Keyword(s):  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Direct Photons ◽  
Ion Collisions ◽  
State Of Matter ◽  
Ultrarelativistic Heavy Ion Collisions ◽  
New State Of Matter

We review the production of dilepton pairs, direct photons and diphoton pairs in ultrarelativistic heavy ion collisions, with special attention to the applicability of these particles as the signal for a new state of matter—the quark-gluon plasma.

scholarly journals Equation of state and initial temperature of quark gluon plasma at RHIC

Open Physics ◽  
2012 ◽  
Vol 10 (4) ◽  
Author(s):  
Máté Csanád ◽  
Imre Májer
Keyword(s):  
Time Evolution ◽  
Quark Gluon Plasma ◽  
Initial Temperature ◽  
Equations Of State ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Azimuthal Asymmetry ◽  
Relativistic Heavy Ion Collider ◽  
Final State ◽  
Dimensional Solution

AbstractIn gold-gold collisions of the Relativistic Heavy Ion Collider a perfect fluid of strongly interacting quark gluon plasma (sQGP) is created. The time evolution of this fluid can be described by hydrodynamical models. After an expansion, hadrons are created during the freeze-out period. Their distribution reveals information about the final state. To investigate the time evolution one needs to analyze penetrating probes: e.g. direct photon observations. In this paper we analyze a 1+3 dimensional solution of relativistic hydrodynamics. We calculate momentum distribution, azimuthal asymmetry and momentum correlations of direct photons. Based on earlier fits to hadronic spectra, we compare photon calculations to measurements to determine the equations of state and the initial temperature of sQGP. We find that the initial temperature in the center of the fireball is 507±12 MeV, while for the sound speed we get c s=0.36±0.02. We also estimate a systematic error of these results. We find that the measured azimuthal asymmetry is also compatible with this model. We also predict a photon source that is significantly larger in the out direction than in the side direction.

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