scholarly journals Diffusion of Conserved Charges in Relativistic Heavy Ion Collisions

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 31
Author(s):  
Jan A. Fotakis ◽  
Moritz Greif ◽  
Gabriel S. Denicol ◽  
Carsten Greiner
Keyword(s):  
Diffusion Coefficients ◽  
Coefficient Matrix ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Navier Stokes ◽  
Diffusion Matrix ◽  
Conserved Charges ◽  
Ion Collisions ◽  
Hadron Gas ◽  
Dilute System

We discuss the diffusion currents occurring in a dilute system and show that the charge currents do not only depend on gradients in the corresponding charge density, but also on the other conserved charges in the system—the diffusion currents are therefore coupled. Gradients in one charge thus generate dissipative currents in a different charge. In this approach, we model the Navier-Stokes term of the generated currents to consist of a diffusion coefficient matrix, in which the diagonal entries are the usual diffusion coefficients and the off-diagonal entries correspond to the coupling of different diffusion currents. We evaluate the complete diffusion matrix for a specific hadron gas and for a simplified quark-gluon gas, including baryon, electric and strangeness charge. Our findings are that the off-diagonal entries can range within the same magnitude as the diagonal ones.

scholarly journals Relaxation to equilibrium and EOS in ultra-relativistic heavy-ion collisions

2018 ◽  
Vol 191 ◽  
pp. 05005
Author(s):  
E. Zabrodin ◽  
L. Bravina
Keyword(s):  
Linear Dependence ◽  
Heavy Ion Collisions ◽  
Thermal Contact ◽  
Central Zone ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Hydrodynamic Description ◽  
Ion Collisions ◽  
Relaxation To Equilibrium ◽  
Hadron Gas

We study relaxation to equilibrium of hot and dense hadron-string matter produced in the central zone of central heavy-ion collisions at energies 11:6AGeV ≤ Elab ≤ 160AGeV. Two microscopic transport models, UrQMD and QGSM, are employed. The analysis is performed for the central cubic cell with volume V = 125 fm3. To check how close the system is to the equilibrium, its hadron yields and hadron energy spectra are compared with those of the statistical model of ideal hadron gas. For all collision energies it was found that the matter in the cell was approaching the equilibrium state, which lasted about 10 - 20 fm/c. After that the matter became very dilute and the thermal contact between the hadrons was lost. Equation of state is well fitted to linear dependence P/ε = a = c2s, where the square of the sonic velocity c2s increases from 0.12 at Elab = 11:6AGeV to 0.145 at Elab = 160AGeV. These results are valid also for very early times of the system evolution when the matter is still out of equilibrium. Together with the isentropic expansion, the linear dependence of P on ε supports the application of hydrodynamic description to early stages of heavy-ion collisions.

INFLUENCE OF THE EQUATION OF STATE ON THE MOMENTUM ANISOTROPY IN HADRODYNAMIC EVOLUTION OF RELATIVISTIC HEAVY ION COLLISIONS

2007 ◽  
Vol 16 (09) ◽  
pp. 2974-2978
Author(s):  
DETLEF ZSCHIESCHE ◽  
EDUARDO FRAGA ◽  
TAKESHI KODAMA ◽  
TOMOI KOIDE ◽  
BERNARDO TAVARES ◽  
...  
Keyword(s):  
Heavy Ion Collisions ◽  
Equations Of State ◽  
Three Dimensional ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Simulation Code ◽  
Ion Collisions ◽  
First Order Phase Transition ◽  
Hydrodynamical Simulation ◽  
Hadron Gas

We investigate the collective momentum anisotropy in relativistic heavy ion collisions in the BNL-RHIC energy regime with a three-dimensional hydrodynamical simulation code (SPHERIO) for different equations of state. We compare the widely used hadron gas-QGP bag model yielding a strong first order phase transition to other equations of state, which yield a smooth crossover as suggested by lattice QCD calculations.

scholarly journals Relaxation to equilibrium in relativistic heavy ion collisions

2018 ◽  
Vol 182 ◽  
pp. 02019
Author(s):  
L. Bravina ◽  
E. Zabrodin
Keyword(s):  
Heavy Ion Collisions ◽  
Thermal Contact ◽  
Central Area ◽  
Dense Matter ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Transport Models ◽  
Ion Collisions ◽  
Relaxation To Equilibrium ◽  
Hadron Gas

Relaxation to equilibrium of hot and dense matter produced in central area of relativistic heavy ion collisions at energies ranging from several AGeV to hundreds AGeV is studied within two Monte Carlo transport models. The analysis was performed for three different areas: (i) fixed cubic cell with volume V = 125 fm3, (ii) fixed asymmetric cell with volume V = 4 x 4 x 1 = 16 fm3, and (iii) expanding cell. In the last case the cell volume follows the growth of the area with uniformly distributed energy. To check whether or not the system is equilibrated, its hadron yields and their energy spectra are compared with those of the statistical model of ideal hadron gas. For all cells and for all collision energies it was found that the matter in the cell was approaching the equilibrium state. The higher the collision energy, the shorter the time of equilibration. The equilibration phase lasts about 10 - 20 fm/c, after that the matter becomes very dilute and the thermal contact between hadrons is lost. Equation of state is well fitted to linear dependence P/ɛ = a = c2s , where the square of the sonic velocity c2s increases from 0.12 at Elab = 11.6AGeV to 0.145 at Elab = 160AGeV. The characteristic kinks observed in the T - μB phase diagrams are linked to inelastic freeze-out in the expanding fireball.

scholarly journals Diffusion of Conserved Charges in Relativistic Heavy Ion Collisions

2018 ◽  
Vol 120 (24) ◽  
Author(s):  
Moritz Greif ◽  
Jan. A. Fotakis ◽  
Gabriel S. Denicol ◽  
Carsten Greiner
Keyword(s):  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Conserved Charges ◽  
Ion Collisions
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