scholarly journals Heavy-quark probes of the quark-gluon plasma and interpretation of recent data taken at the BNL Relativistic Heavy Ion Collider

2006 ◽  
Vol 73 (3) ◽  
Author(s):  
Hendrik van Hees ◽  
Vincenzo Greco ◽  
Ralf Rapp
2015 ◽  
Vol 2015 ◽  
pp. 1-23 ◽  
Author(s):  
Li-Na Gao ◽  
Fu-Hu Liu

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.


2012 ◽  
Vol 27 (19) ◽  
pp. 1250103 ◽  
Author(s):  
D. INDUMATHI ◽  
H. SAVEETHA

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.


2013 ◽  
Vol 22 (01) ◽  
pp. 1350004 ◽  
Author(s):  
SUKANYA MITRA ◽  
PAYAL MOHANTY ◽  
SOURAV SARKAR ◽  
JAN-E ALAM

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.


Author(s):  
Shuang Li ◽  
Jinfeng Liao

Abstract Heavy quark production provides a unique probe of the quark-gluon plasma transport properties in heavy ion collisions. Experimental observables like the nuclear modification factor $$R_\mathrm{AA}$$RAA and elliptic anisotropy $$v_\mathrm{2}$$v2 of heavy flavor mesons are sensitive to the heavy quark diffusion coefficient. There now exist an extensive set of such measurements, which allow a data-driven extraction of this coefficient. In this work, we make such an attempt within our recently developed heavy quark transport modeling framework (Langevin-transport with Gluon Radiation, LGR). A question of particular interest is the temperature dependence of the diffusion coefficient, for which we test a wide range of possibility and draw constraints by comparing relevant charm meson data with model results. We find that a relatively strong increase of diffusion coefficient from crossover temperature $$T_c$$Tc toward high temperature is preferred by data. We also make predictions for Bottom meson observables for further experimental tests.


2017 ◽  
Vol 32 (15) ◽  
pp. 1730008 ◽  
Author(s):  
Leonard S. Kisslinger

This review of the quantum chromodynamics (QCD), the early universe cosmological phase transition from the quark–gluon plasma (QGP) to our present universe (QCDPT), relativistic heavy ion collisions (RHIC) which can produce the QGP, the possible detection of the QGP produced by the production of mixed hybrid heavy quark mesons. We also review the recent studies of the production of mixed heavy quark hybrids via RHIC and heavy quark meson suppression in p-Pb and Pb–Pb collisions.


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.


Open Physics ◽  
2012 ◽  
Vol 10 (4) ◽  
Author(s):  
Máté Csanád ◽  
Imre Májer

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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