scholarly journals Dilepton creation based on an analytic hydrodynamic solution

Open Physics ◽  
2014 ◽  
Vol 12 (2) ◽  
Author(s):  
Máté Csanád ◽  
Levente Krizsán
Keyword(s):  
Time Evolution ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Direct Photon ◽  
Relativistic Hydrodynamics ◽  
Final State ◽  
Mass Distributions ◽  
Ion Collisions ◽  
Hydrodynamic Solution

AbstractHigh-energy collisions of various nuclei, so called “Little Bangs” are observed in various experiments of heavy ion colliders. The time evolution of the strongly interacting quark-gluon plasma created in heavy ion collisions can be described by hydrodynamical models. After expansion and cooling, the hadrons are created in a freeze-out. Their distribution describes the final state of this medium. To investigate the time evolution one needs to analyze penetrating probes, such as direct photon or dilepton observables, as these particles are created throughout the evolution of the medium. In this paper we analyze an 1+3 dimensional analytic solution of relativistic hydrodynamics, and we calculate dilepton transverse momentum and invariant mass distributions. We investigate the dependence of dilepton production on time evolution parameters, such as emission duration and equation of state. Using parameters from earlier fits of this model to photon and hadron spectra, we compare our calculations to measurements as well. The most important feature of this work is that dilepton observables are calculated from an exact, analytic, 1+3D solution of relativistic hydrodynamics that is also compatible with hadronic and direct photon observables.

scholarly journals Time evolution of the anisotropies of the hydrodynamically expanding SQGP

2016 ◽  
Vol 31 (28n29) ◽  
pp. 1645016
Author(s):  
A. Bagoly ◽  
M. Csanád
Keyword(s):  
Time Evolution ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Initial Distribution ◽  
Hadronic Matter ◽  
Initial State ◽  
Ion Collisions ◽  
Hydrodynamic Evolution ◽  
Plane Anisotropy

In high energy heavy ion collisions of RHIC and LHC, a strongly interacting quark gluon plasma (sQGP) is created. This medium undergoes a hydrodynamic evolution, before it freezes out to form a hadronic matter. The initial state of the sQGP is determined by the initial distribution of the participating nucleons and their interactions. Due to the finite number of nucleons, the initial distribution fluctuates on an event-by-event basis. The transverse plane anisotropy of the initial state can be translated into a series of anisotropy coefficients or eccentricities: second, third, fourth-order anisotropy etc. These anisotropies then evolve in time, and result in measurable momentum-space anisotropies, to be measured with respect to their respective symmetry planes. In this paper we investigate the time evolution of the anisotropies. With a numerical hydrodynamic code, we analyze how the speed of sound and viscosity influence this evolution.

scholarly journals Signatures of QGP at RHIC and the LHC

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
T. Niida ◽  
Y. Miake
Keyword(s):  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
Theoretical Studies ◽  
Debye Screening ◽  
Direct Photons ◽  
Ion Collisions ◽  
Experimental And Theoretical Studies

AbstractThe progress over the 30 years since the first high-energy heavy-ion collisions at the BNL-AGS and CERN-SPS has been truly remarkable. Rigorous experimental and theoretical studies have revealed a new state of the matter in heavy-ion collisions, the quark-gluon plasma (QGP). Many signatures supporting the formation of the QGP have been reported. Among them are jet quenching, the non-viscous flow, direct photons, and Debye screening effects. In this article, selected signatures of the QGP observed at RHIC and the LHC are reviewed.

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 Probing jet medium interactions via Z(H) + jet momentum imbalances

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Lin Chen ◽  
Shu-Yi Wei ◽  
Han-Zhong Zhang
Keyword(s):  
Transport Coefficient ◽  
Good Description ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
Quenching Effect ◽  
Nuclear Collisions ◽  
Ion Collisions ◽  
Pqcd Approach

AbstractDifferent types of high energy hard probes are used to extract the jet transport properties of the Quark-Gluon Plasma created in heavy-ion collisions, of which the heavy boson tagged jets are undoubtedly the most sophisticated due to its clean decay signature and production mechanism. In this study, we used the resummation improved pQCD approach with high order correction in the hard factor to calculate the momentum ratio $$x_J$$ x J distributions of Z and Higgs (H) tagged jets. We found that the formalism can provide a good description of the 5.02 TeV pp data. Using the BDMPS energy loss formalism, along with the OSU 2 + 1D hydro to simulate the effect of the medium, we extracted the value of the jet transport coefficient to be around $${\hat{q}}_0=4\sim 8~\text {GeV}^2/\text {fm}$$ q ^ 0 = 4 ∼ 8 GeV 2 / fm by comparing with the Z + jet PbPb experimental data. The H + jet $$x_J$$ x J distribution were calculated in a similar manner in contrast and found to have a stronger Sudakov effect as compared with the Z + jet distribution. This study uses a clean color-neutral boson as trigger to study the jet quenching effect and serves as a complimentary method in the extraction of the QGP’s transport coefficient in high energy nuclear collisions.

scholarly journals PROBING THE STATES OF MATTER IN QCD

2013 ◽  
Vol 28 (27) ◽  
pp. 1330043 ◽  
Author(s):  
HELMUT SATZ
Keyword(s):  
Critical Temperature ◽  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Ideal Resonance ◽  
Ion Collisions ◽  
Quantum Numbers ◽  
Quark Deconfinement

The ultimate aim of high energy heavy ion collisions is to study quark deconfinement and the quark–gluon plasma predicted by quantum chromodynamics. This requires the identification of observables calculable in QCD and measurable in heavy ion collisions. I concentrate on three such phenomena, related to specific features of strongly interacting matter. The observed pattern of hadrosynthesis corresponds to that of an ideal resonance gas in equilibrium at the pseudo-critical temperature determined in QCD. The critical behavior of QCD is encoded in the fluctuation patterns of conserved quantum numbers, which are presently being measured. The temperature of the quark–gluon plasma can be determined by the dissociation patterns of the different quarkonium states, now under study at the LHC for both charmonia and bottomonia.

Collective flow and correlation with higher harmonic event planes

Open Physics ◽  
2012 ◽  
Vol 10 (6) ◽  
Author(s):  
ShinIchi Esumi
Keyword(s):  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
System Response ◽  
Azimuthal Correlation ◽  
Particle Correlation ◽  
Ion Collisions ◽  
Higher Harmonic

AbstractAzimuthal event anisotropy and particle correlation have been used to analyze the collectivity of the system created in the high-energy heavy-ion collisions in order to study the properties of Quark Gluon Plasma (QGP). Higher harmonic event anisotropy is recently recognized to carry the information of initial participant geometrical fluctuation because of the finite number of participating nucleons in heavy-ion collisions. The system response after the collective expansion can be observed as higher harmonic event anisotropy, the n-th harmonic order dependence can be used to further constrain the hydro-dynamical properties of the system. The multi-particle azimuthal correlation with respect to the higher harmonic event plane can be used as a tool to understand the origin of the higher harmonic event anisotropy and its relation to the medium response from the jet-quenching as soft-hard interplay. Recent results on the higher harmonic event anisotropy measurements and an attempt of two-particle correlation analysis with respect to the higher harmonic event planes are discussed.

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 The First fm/c of Heavy-Ion Collisions

2019 ◽  
Vol 69 (1) ◽  
pp. 447-476 ◽  
Author(s):  
S. Schlichting ◽  
D. Teaney
Keyword(s):  
Heavy Ion Collisions ◽  
Early Time ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Nonequilibrium Dynamics ◽  
Local Thermal Equilibrium ◽  
Time Dynamics ◽  
Ion Collisions ◽  
The Many

We present an introductory review of the early-time dynamics of high-energy heavy-ion collisions and the kinetics of high-temperature quantum chromodynamic matter. The equilibration mechanisms in the quark–gluon plasma uniquely reflect the nonabelian and ultrarelativistic character of the many-body system. Starting with a brief exposé of the key theoretical and experimental questions, we provide an overview of the theoretical tools employed in weak coupling studies of the early-time nonequilibrium dynamics. We highlight theoretical progress in understanding different thermalization mechanisms in weakly coupled nonabelian plasmas, and discuss their relevance in describing the approach to local thermal equilibrium during the first fm/ c of a heavy-ion collision. We also briefly discuss some important connections to the phenomenology of heavy-ion collisions.

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