scholarly journals Study of the influence of initial-state fluctuations on hydrodynamic simulations

2020 ◽  
Vol 245 ◽  
pp. 06005
Author(s):  
Marcin Słodkowski ◽  
Patryk Gawryszewski ◽  
Dominik Setniewski
Keyword(s):  
Initial Conditions ◽  
Graphics Processing Unit ◽  
Heavy Ion ◽  
Processing Unit ◽  
Initial State ◽  
Final State ◽  
Hydrodynamic Simulation ◽  
Hydrodynamic Simulations ◽  
Cartesian Coordinate ◽  
Ion Collision

In this work, we are focusing on assessing the contribution of the initial-state fluctuations of heavy ion collision in the hydrodynamic simulations. We are trying to answer the question of whether the hydrodynamic simulation retains the same level of fluctuation in the final-state as for the initial stage. In another scenario, the hydrodynamic simulations of the fluctuation drowns in the final distribution of expanding matter. For this purpose, we prepared sufficient relativistic hydrodynamic program to study A+A interaction which allows analysing initial-state fluctuations in the bulk nuclear matter. For such an assumption, it is better to use high spatial resolution. Therefore, we applied the (3+1) dimensional Cartesian coordinate system. We implemented our program using parallel computing on graphics cards processors - Graphics Processing Unit (GPU). Simulations were carried out with various levels of fluctuation in initial conditions using the average method of events coming from UrQMD models. Energy density distributions were analysed and the contribution of fluctuations in initial conditions was assessed in the hydrodynamic simulation.

scholarly journals Simulations of Energy Losses in the Bulk Nuclear Medium Using Hydrodynamics on the Graphics Cards (GPU)

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Marcin Słodkowski ◽  
Patryk Gawryszewski ◽  
Patryk Marcinkowski ◽  
Dominik Setniewski ◽  
Joanna Porter-Sobieraj
Keyword(s):  
Nuclear Matter ◽  
Initial Conditions ◽  
Graphics Processing Unit ◽  
Nuclear Medium ◽  
Energy Losses ◽  
Processing Unit ◽  
Hydrodynamic Simulation ◽  
Cartesian Coordinate ◽  
Graphics Processing ◽  
Event Simulations

We are developing a software for energy loss simulation which is affected by jets in the nuclear matter described by relativistic hydrodynamics. Our program uses a Cartesian coordinate system in order to provide high spatial resolution for the analysis of jets propagation in nuclear matter. In this work, we use 7th order WENO numerical algorithm which is resistant to numerical oscillations and diffusions. For simulating energy losses in the bulk nuclear medium, we develop efficient hydrodynamic simulation program for parallel computing using Graphics Processing Unit (GPU) and Compute Unified Device Architecture (CUDA). It allows us to prepare event-by-event simulations in high computing precision in order to study jet modifications in the medium and event-by-event simulations of fluctuating initial conditions. In our simulation, we start the hydrodynamic simulation from generation initial condition based on the UrQMD model in order to simulate comparable nucleus-nucleus interaction in the RHIC and LHC energies. The main part of this simulation is the computation of hydrodynamic system evolution. We present obtained energy density distributions which can be compared to experimental results.

scholarly journals Correlations in the Initial Conditions of Heavy-Ion Collisions

2020 ◽  
Vol 235 ◽  
pp. 08002 ◽  
Author(s):  
Douglas Wertepny ◽  
Jacquelyn Noronha-Hostler ◽  
Matthew Sievert ◽  
Skandaprasad Rao ◽  
Noah Paladino
Keyword(s):  
Initial Conditions ◽  
Heavy Ion ◽  
Color Glass ◽  
Heavy Nuclei ◽  
Initial State ◽  
Final State ◽  
Microscopic Mechanism ◽  
Ion Collisions ◽  
The Impact ◽  
Initial Geometry

Ultracentral collisions of heavy nuclei, in which the impact parameter is nearly zero, are especially sensitive to the details of the initial state model and the microscopic mechanism for collective flow. In a hydrodynamic “flow” picture, the final state momentum correlations are a direct response to the fluctuating initial geometry, although models of the initial geometry differ widely. Alternatively, dynamical mechanisms based in the color glass condensate (CGC) formalism can naturally lead to many-body correlations with very different systematics. Here we present a calculation of event-by-event elliptic flow in both the hydrodynamic and CGC paradigms and show that they can be qualitatively distinguished in ultracentral collisions of deformed nuclei. Specifically, the multiplicity dependence in such collisions is qualitatively opposite, with the CGC correlations increasing with multiplicity while the hydrodynamic correlations decrease. The consistency of the latter with experimental data on UU collisions appears to rule out a CGC-mediated explanation. We find that these qualitative features also persist in small deformed systems and can therefore be a valuable test of the microscopic physics in that regime. The authors acknowledge support from the US-DOE Nuclear Science Grant No. DE-SC0019175, and the Alfred P. Sloan Foundation, and the Zuckerman STEM Leadership Program.

scholarly journals A Fourier-cumulant analysis for multiharmonic flow fluctuation

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Seyed Farid Taghavi
Keyword(s):  
Heavy Ion ◽  
Third Order ◽  
Final State ◽  
Hydrodynamic Simulation ◽  
Final Particle ◽  
Particle Correlation ◽  
Flow Fluctuations ◽  
Hydrodynamic Response ◽  
Cumulant Analysis ◽  
Ion Collision

AbstractThe Fourier analysis of the final particle distribution followed by cumulant study of the Fourier coefficient event-by-event fluctuation is one of the main approaches for testing the collective evolution in the heavy-ion collision. Using a multidimensional generating function, we propose a method to extract any possible cumulant of multiharmonic flow fluctuations and classify them in terms of the order of cumulants and harmonics involved in them. In particular, we show that there are 33 distinct cumulants with order 2, 3, 4, 5 and harmonics 2, 3, 4, 5. We compute the normalized version of these cumulants from hydrodynamic simulation for Pb–Pb collisions based on $$_\mathtt{R}$$ R ++. We compare the simulation with those normalized cumulants that the LHC has measured and predict the unmeasured ones. Comparing the initial and final state fluctuation normalized cumulants, we compute the linear and nonlinear hydrodynamic response couplings. We finally introduce the genuine three-particle correlation function containing information of all third-order cumulants.

MESON PRODUCTION AT SPS ENERGIES

2007 ◽  
Vol 22 (02n03) ◽  
pp. 659-662 ◽  
Author(s):  
ANDRZEJ RYBICKI
Keyword(s):  
Production Process ◽  
Comparative Studies ◽  
Initial Conditions ◽  
Meson Production ◽  
Heavy Ion ◽  
Coulomb Interactions ◽  
Final State ◽  
Ion Collisions ◽  
New Information ◽  
Particle Spectra

Comparative studies of hadron-induced interactions and heavy ion collisions have been performed at beam energies of 158 GeV/nucleon, corresponding to [Formula: see text]. They indicate that the heavy ion reaction is a mixture of various processes, including multiple nucleon collisions, isospin effects, and final state Coulomb interactions. The latter interactions result in surprising phenomena, like the presence of large and strongly varying structures in the shape of double-differential particle spectra. These phenomena depend on the initial conditions of the reaction and therefore can provide new information on the space and time evolution of the non-perturbative meson production process.

scholarly journals HYDRODYNAMIC MODELING OF HEAVY-ION COLLISIONS

2013 ◽  
Vol 28 (11) ◽  
pp. 1340011 ◽  
Author(s):  
CHARLES GALE ◽  
SANGYONG JEON ◽  
BJÖRN SCHENKE
Keyword(s):  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Initial State ◽  
Hydrodynamic Description ◽  
Hydrodynamic Simulations ◽  
Fundamental Properties ◽  
Ion Collisions ◽  
Viscous Hydrodynamic ◽  
Recent Developments ◽  
Successes And Challenges

We review progress in the hydrodynamic description of heavy-ion collisions, focusing on recent developments in modeling the fluctuating initial state and event-by-event viscous hydrodynamic simulations. We discuss how hydrodynamics can be used to extract information on fundamental properties of quantum chromodynamics from experimental data, and review successes and challenges of the hydrodynamic framework.

scholarly journals Anisotropic flow of identified particles in Pb–Pb collisions at √SNN = 5.02 TeV

2018 ◽  
Vol 171 ◽  
pp. 17002
Author(s):  
Redmer Alexander Bertens
Keyword(s):  
Initial Conditions ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Mass Energy ◽  
Initial State ◽  
Anisotropic Flow ◽  
Center Of Mass Energy ◽  
Ion Collisions ◽  
Hydrodynamic Calculations

Anisotropic flow is sensitive to the shear (η/s) and bulk (ζ/s) viscosity of the quark-gluon plasma created in heavy-ion collisions, as well as the initial state of such collisions and hadronization mechanisms. In these proceedings, elliptic (υ2) and higher harmonic (υ3, υ4) flow coefficients of π±, K±, p(p) and the ϕ-meson, are presented for Pb—Pb collisions at the highest-ever center-of-mass energy of [see formula in PDF] = 5.02 TeV. Comparisons to hydrodynamic calculations (IP-Glasma, MUSIC, UrQMD) are shown to constrain the initial conditions and viscosity of the medium.

Free energy of a baryon at finite temperatures and its implications to the heavy-ion collisions

2015 ◽  
Vol 30 (26) ◽  
pp. 1550130
Author(s):  
Minati Biswal ◽  
Sanatan Digal ◽  
P. S. Saumia
Keyword(s):  
Free Energy ◽  
Transition Temperature ◽  
Chemical Potential ◽  
Canonical Formalism ◽  
Heavy Ion ◽  
Polyakov Loop ◽  
Heavy Ion Collision ◽  
Hydrodynamic Simulations ◽  
Ion Collisions ◽  
Ion Collision

We study the free energy per baryon using canonical formalism in the Polyakov loop Nambu–Jona-Lasinio model with imaginary chemical potential. We find that the free energy decreases rapidly with temperature around the transition temperature. This result coupled with the heavy-ion collision geometry leads to the creation of a free energy well for the baryons. We study the time evolution of this free energy well using hydrodynamic simulations and discuss the implications of this free energy well on the dynamics of the baryons.

scholarly journals Collectivity in small systems - Initial state vs. final state effects

2018 ◽  
Vol 172 ◽  
pp. 05007 ◽  
Author(s):  
Moritz Greif ◽  
Carsten Greiner ◽  
Björn Schenke ◽  
Sören Schlichting ◽  
Zhe Xu
Keyword(s):  
Theoretical Calculations ◽  
Heavy Ion ◽  
Theoretical Description ◽  
Nonequilibrium Dynamics ◽  
Unified Framework ◽  
Initial State ◽  
Final State ◽  
Azimuthal Correlations ◽  
Weakly Coupled ◽  
First Results

Observations of long rang azimuthal correlations in small collision systems (p+p/A) have triggered an enormous excitement in the heavy-ion community. However, it is presently unclear to what extent the experimentally observed correlations should be attributed to initial state momentum correlations and/or the final state response to the initial state geometry. We discuss how a consistent theoretical description of the nonequilibrium dynamics is important to address both effects within a unified framework and present first results from weakly coupled non-equilibrium simulations in [1] to quantify the relative importance of initial state and final state effects based on theoretical calculations.

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