scholarly journals Exploring the Partonic Phase at Finite Chemical Potential in and out-of Equilibrium

Particles ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 178-192 ◽  
Author(s):  
O. Soloveva ◽  
P. Moreau ◽  
L. Oliva ◽  
V. Voronyuk ◽  
V. Kireyeu ◽  
...  
Keyword(s):  
Cross Sections ◽  
Chemical Potential ◽  
Transport Coefficients ◽  
Gluon Plasma ◽  
Entropy Density ◽  
Baryon Chemical Potential ◽  
Equilibrium Study ◽  
200 Gev ◽  
Quasiparticle Model ◽  
Scattering Cross Sections

We study the influence of the baryon chemical potential μ B on the properties of the Quark–Gluon–Plasma (QGP) in and out-of equilibrium. The description of the QGP in equilibrium is based on the effective propagators and couplings from the Dynamical QuasiParticle Model (DQPM) that is matched to reproduce the equation-of-state of the partonic system above the deconfinement temperature T c from lattice Quantum Chromodynamics (QCD). We study the transport coefficients such as the ratio of shear viscosity η and bulk viscosity ζ over entropy density s, i.e., η / s and ζ / s in the ( T , μ ) plane and compare to other model results available at μ B = 0 . The out-of equilibrium study of the QGP is performed within the Parton–Hadron–String Dynamics (PHSD) transport approach extended in the partonic sector by explicitly calculating the total and differential partonic scattering cross sections based on the DQPM and the evaluated at actual temperature T and baryon chemical potential μ B in each individual space-time cell where partonic scattering takes place. The traces of their μ B dependences are investigated in different observables for symmetric Au + Au and asymmetric Cu + Au collisions such as rapidity and m T -distributions and directed and elliptic flow coefficients v 1 , v 2 in the energy range 7.7 GeV ≤ s N N ≤ 200 GeV.

scholarly journals QCD at finite chemical potential in and out-of equilibrium

2021 ◽  
Author(s):  
Olga Soloveva ◽  
Pierre Moreau ◽  
Elena Bratkovskaya
Keyword(s):  
Heavy Ion Collisions ◽  
Chemical Potential ◽  
Transport Coefficients ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Entropy Density ◽  
Baryon Chemical Potential ◽  
Ion Collisions ◽  
Strongly Interacting ◽  
Quasiparticle Model

Abstract We review the transport properties of the strongly interacting quark-gluon plasma (QGP) created in heavy-ion collisions at ultrarelativistic energies, i.e. out-of equilibrium, and compare them to the equilibrium properties. The description of the strongly interacting (non-perturbative) QGP in equilibrium is based on the effective propagators and couplings from the Dynamical QuasiParticle Model (DQPM) that is matched to reproduce the equation-of-state of the partonic system above the deconfinement temperature $T_c$ from lattice QCD. We study the transport coefficients such as the ratio of shear viscosity and bulk viscosity over entropy density, diffusion coefficients, electric conductivity etc. versus temperature and baryon chemical potential. Based on a microscopic transport description of heavy-ion collisions we, furthermore, discuss which observables are sensitive to the QGP formation and its properties.

scholarly journals STRONGLY INTERACTING MATTER AT FINITE CHEMICAL POTENTIAL: HYBRID MODEL APPROACH

2013 ◽  
Vol 28 (14) ◽  
pp. 1350051 ◽  
Author(s):  
P. K. SRIVASTAVA ◽  
C. P. SINGH
Keyword(s):  
Hybrid Model ◽  
Chemical Potential ◽  
Gluon Plasma ◽  
Model Description ◽  
Baryon Chemical Potential ◽  
Qcd Phase Diagram ◽  
Strongly Interacting ◽  
Hadron Gas ◽  
Quasiparticle Model ◽  
Model Approach

Search for a proper and realistic equation of state (EOS) for strongly interacting matter used in the study of the QCD phase diagram still appears as a challenging problem. Recently, we constructed a hybrid model description for the quark–gluon plasma (QGP) as well as hadron gas (HG) phases where we used an excluded volume model for HG and a thermodynamically consistent quasiparticle model for the QGP phase. The hybrid model suitably describes the recent lattice results of various thermodynamical as well as transport properties of the QCD matter at zero baryon chemical potential (μB). In this paper, we extend our investigations further in obtaining the properties of QCD matter at finite value of μB and compare our results with the most recent results of lattice QCD calculation.

scholarly journals Strangeness at high μB: Recent data from FOPI and HADES

2018 ◽  
Vol 171 ◽  
pp. 02001
Author(s):  
Yvonne Leifels
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Particle Production ◽  
Chemical Potential ◽  
Good Description ◽  
Branching Ratio ◽  
Heavy Ion ◽  
Nuclear Medium ◽  
Strangeness Production ◽  
Baryon Chemical Potential

Strangeness production in heavy-ion reactions at incident energies at or below the threshold in NN collisions gives access to the characteristics of bulk nuclear matter and the properties of strange particles inside the hot and dense nuclear medium, like potentials and interaction cross sections. At these energies strangeness is produced in multi-step processes potentially via excitation of intermediate heavy resonances. The amount of experimental data on strangeness production at these energies has increased substantially during the last years due to the FOPI and the HADES experiments at SIS18 at GSI. Experimental data on K+ and K0 production support the assumption that particles with an s quark feel a moderate repulsive potential in the nuclear medium. The situation is not that clear in the case of K-. Here, spectra and flow of K- mesons is influenced by the contribution of ø mesons which are decaying into K+K- pairs with a branching ratio of 48.9 %. Depending on incident energy upto 30 % of all K- mesons measured in heavyion collisions are originating from ø-decays. Strangeness production yields - except the yield of Ξ- are described by thermal hadronisation models. Experimental data not only measured for heavy-ion collisions but also in proton induced reactions are described with sets of temperature T and baryon chemical potential μb which are close to a universal freeze-out curve which is fitting also experimental data obtained at lower baryon chemical potential. Despite the good description of most particle production yields, the question how this is achieved is still not settled and should be the focus of further investigations.

scholarly journals Strangeness chemical potential from the baryons relative to the kaons particle ratios

2017 ◽  
Vol 26 (07) ◽  
pp. 1750046
Author(s):  
Abdel Nasser Tawfik ◽  
Magda Abdel Wahab ◽  
Hayam Yassin ◽  
Eman R. Abo Elyazeed ◽  
Hadeer M. Nasr El Din
Keyword(s):  
Strange Quark ◽  
Collision Energy ◽  
Chemical Potential ◽  
Entropy Density ◽  
Baryon Chemical Potential ◽  
Systematic Analysis ◽  
Particle Ratios ◽  
Alternative Approach ◽  
Strangeness Enhancement ◽  
Thermal Calculations

From a systematic analysis of the energy-dependence of four antibaryon-to-baryon ratios relative to the antikaon-to-kaon ratio, we propose an alternative approach determining the strange-quark chemical potential ([Formula: see text]). It is found that [Formula: see text] generically genuinely equals one-fifth the baryon chemical potential ([Formula: see text]). An additional quantity depending on [Formula: see text] and the freezeout temperature ([Formula: see text]) should be added in order to assure averaged strangeness conversation. This quantity gives a genuine estimation for the possible strangeness enhancement with the increase in the collision energy. At the chemical freezeout conditioned to constant entropy density normalized to temperature cubed, various particle ratios calculated at [Formula: see text] and [Formula: see text] and the resultant [Formula: see text] excellently agree with the statistical-thermal calculations.

Dilepton production as a useful probe of quark gluon plasma with temperature dependent chemical potential quark mass

2016 ◽  
Vol 25 (08) ◽  
pp. 1650049
Author(s):  
Yogesh Kumar ◽  
S. Somorendro Singh
Keyword(s):  
Production Rate ◽  
Quark Gluon Plasma ◽  
Quark Mass ◽  
Chemical Potential ◽  
Gluon Plasma ◽  
Mass Region ◽  
Dilepton Production ◽  
Temperature Dependent ◽  
Quasiparticle Model ◽  
Relevant Range

We extend the previous study of dilepton production using [S. Somorendro Singh and Y. Kumar, Can. J. Phys. 92 (2014) 31] based on a simple quasiparticle model of quark–gluon plasma (QGP). In this model, finite value of quark mass uses temperature dependent chemical potential the so-called Temperature Dependent Chemical Potential Quark Mass (TDCPQM). We calculate dilepton production in the relevant range of mass region. It is observed that the production rate is marginally enhanced from the earlier work. This is due to the effect of TDCPQM and its effect is highly significant in the production of dilepton.

Scattering cross sections for electrons in C2H2F4and its mixtures with Ar from measured transport coefficients

2013 ◽  
Vol 46 (32) ◽  
pp. 325201 ◽  
Author(s):  
Olivera Šašić ◽  
Snježana Dupljanin ◽  
Jaime de Urquijo ◽  
Zoran Lj Petrović
Keyword(s):  
Cross Sections ◽  
Transport Coefficients ◽  
Scattering Cross ◽  
Scattering Cross Sections

scholarly journals A dynamical quasiparticle approach for the QGP bulk and transport properties

2016 ◽  
Vol 25 (07) ◽  
pp. 1642003 ◽  
Author(s):  
Hamza Berrehrah ◽  
Elena Bratkovskaya ◽  
Thorsten Steinert ◽  
Wolfgang Cassing
Keyword(s):  
Cross Sections ◽  
Degrees Of Freedom ◽  
Chemical Potential ◽  
Good Description ◽  
Charm Quark ◽  
Heavy Ion ◽  
Entropy Density ◽  
Self Energy ◽  
Ion Collisions ◽  
Transport Studies

The properties of quantum chromodynamics (QCD) nowadays are accessible by lattice QCD calculations at vanishing quark chemical potential [Formula: see text], but often lack a transparent physical interpretation. In this review, we report about results from an extended dynamical quasiparticle model (DQPM[Formula: see text]) in which the effective parton propagators have a complex self-energy that depends on the temperature [Formula: see text] of the medium as well as on the chemical potential [Formula: see text] and the parton three-momentum [Formula: see text] with respect to the medium at rest. It is demonstrated that this approach allows for a good description of QCD thermodynamics with respect to the entropy density, pressure, etc. above the critical temperature [Formula: see text] 158 MeV. Furthermore, the quark susceptibility [Formula: see text] and the quark number density [Formula: see text] are found to be reproduced simultaneously at zero and finite quark chemical potential. The shear and bulk viscosities [Formula: see text], and the electric conductivity [Formula: see text] from the DQPM[Formula: see text] also turn out in close agreement with lattice results for [Formula: see text] =0. The DQPM[Formula: see text], furthermore, allows to evaluate the momentum [Formula: see text], [Formula: see text] and [Formula: see text] dependencies of the partonic degrees of freedom also for larger [Formula: see text] which are mandatory for transport studies of heavy-ion collisions in the regime 5[Formula: see text]GeV [Formula: see text] 10[Formula: see text]GeV. We finally calculate the charm quark diffusion coefficient [Formula: see text] – evaluated from the differential cross-sections of partons in the medium for light and heavy quarks by employing the propagators and couplings from the DQPM – and compare it to the available lattice data. It is argued that the complete set of observables allows for a transparent interpretation of the properties of hot QCD.

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