QGP SIGNALS AND THE DUAL PARTON MODEL: IS THERMAL EQUILIBRIUM REACHED IN HEAVY ION COLLISIONS?

2005 ◽  
Vol 20 (19) ◽  
pp. 4399-4404
Author(s):  
A. CAPELLA
Keyword(s):  
Thermal Equilibrium ◽  
Final State Interaction ◽  
String Model ◽  
Parton Model ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
State Interaction ◽  
Final State ◽  
Ion Collisions ◽  
Dual Parton Model

Some of the so-called signals of Quark Gluon Plasma (QGP) formation are examined in the framework of a string model, the Dual Parton Model, supplemented with final state interaction. The aim is to determine the strength and duration time of the final state interaction required to describe the data, in order to gain some insight on whether or not the system reaches thermal equilibrium.

scholarly journals Coulomb Final State Interaction in Heavy Ion Collisions for Lévy Sources

Universe ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. 133 ◽  
Author(s):  
Máté Csanád ◽  
Sándor Lökös ◽  
Márton Nagy
Keyword(s):  
Coulomb Interaction ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
Final State Interaction ◽  
Heavy Ion ◽  
High Energy ◽  
State Interaction ◽  
Final State ◽  
Ion Collisions ◽  
Final State Interactions

Investigation of momentum space correlations of particles produced in high energy reactions requires taking final state interactions into account, a crucial point of any such analysis. Coulomb interaction between charged particles is the most important such effect. In small systems like those created in e + e - - or p + p collisions, the so-called Gamow factor (valid for a point-like particle source) gives an acceptable description of the Coulomb interaction. However, in larger systems such as central or mid-central heavy ion collisions, more involved approaches are needed. In this paper we investigate the Coulomb final state interaction for Lévy-type source functions that were recently shown to be of much interest for a refined description of the space-time picture of particle production in heavy-ion collisions.

scholarly journals Fluctuating shapes of fireballs in heavy-ion collisions

2019 ◽  
Vol 204 ◽  
pp. 03011
Author(s):  
Boris Tomášik ◽  
Jakub Cimerman ◽  
Renata Kopečná ◽  
Martin Schulc
Keyword(s):  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Event Shape ◽  
Final State ◽  
Ion Collisions ◽  
Final State Hadron ◽  
Novel Method ◽  
Energy And Momentum

We argue that the energy and momentum deposition from hard partons into quark-gluon plasma induces an important contribution to the final state hadron anisotropies. We also advocate a novel method of Event Shape Sorting which allows one to analyse the azimuthal anisotropies of the fireball dynamics in more detail. The application of the method in femtoscopy is demonstrated.

scholarly journals Monte-Carlo simulation of the 1st order hadron-QGP phase transition in heavy ion collisions using a parton model

2020 ◽  
Vol 56 (1) ◽  
pp. 84-91
Author(s):  
Yu. A. Rusak ◽  
L. F. Babichev
Keyword(s):  
Phase Transition ◽  
Monte Carlo ◽  
Heavy Ion Collisions ◽  
Parton Model ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Heavy Nuclei ◽  
Total N ◽  
Ion Collisions ◽  
Probabilistic Process

Quark gluon plasma (QGP) is a special state of nuclear matter where quarks and gluons behave like free particles. Recently, a number of investigations of this state with high temperature and/or density have been conducted using collisions of relativistic and ultra-relativistic heavy nuclei. It is accepted that depending on the temperature and density, 1st or the 2nd order phase transitions take place in hadron matter during the formation of QGP. Herein, we have modeled heavy ion collisions using a HIJING Monte-Carlo generator, taking into account the description of the 1st order phase transition as a probabilistic process. We analyzed the behavior of the fluctuations of the total (N = N+ – N–) and resultant (Q = N+ – N–) electric charges of the system. Different phases were introduced using the BDMPS (Baier – Dokshitzer – Mueller – Piegne – Schiff) model of parton energy loss during crossing through a dense nuclear medium.

PARTICLE IDENTIFICATION IN THE DYNAMICAL STRING-PARTON MODEL OF RELATIVISTIC HEAVY-ION COLLISIONS

1999 ◽  
Vol 08 (04) ◽  
pp. 299-309 ◽  
Author(s):  
D. E. MALOV ◽  
A. S. UMAR ◽  
D. J. ERNST ◽  
D. J. DEAN
Keyword(s):  
Heavy Ion Collisions ◽  
Parton Model ◽  
Heavy Ion ◽  
Particle Identification ◽  
Relativistic Heavy Ion Collisions ◽  
Mass Window ◽  
Final State ◽  
Ion Collisions ◽  
Physical Mass ◽  
The Masses

The dynamical string-parton model for relativistic heavy-ion collisions is generalized to include particle identification of the final-state hadrons by phenomenologically quantizing the masses of the classical strings which result from string breaking. General features of the Nambu-Gotō strings are used to motivate a model that identifies a mass window near the physical mass of a meson, and does not allow the string to decay further if its mass falls within the window. Data from e+e- collisions in the region [Formula: see text] to 30 GeV are well reproduced by this model.

TWO-PARTICLE CORRELATION IN HEAVY-ION COLLISIONS AT CSR ENERGY

2007 ◽  
Vol 16 (07n08) ◽  
pp. 2200-2204
Author(s):  
JINGBO ZHANG ◽  
QICHUN FENG ◽  
LEI HUO ◽  
WEINING ZHANG
Keyword(s):  
Imaging Technique ◽  
Final State Interaction ◽  
Relativistic Quantum ◽  
Heavy Ion ◽  
Quantum Molecular Dynamics ◽  
Dynamics Model ◽  
Final State ◽  
Particle Correlation ◽  
Ion Collisions ◽  
The Relationship

The predictions of the two-particle correlation by using the relativistic quantum molecular dynamics model are presented for the heavy-ion reactions at HIRFL-CSR energy. The two-proton correlation function with the final state interaction is calculated with the Lednicky code for the U + U collisions at beam energy 520 A MeV. Applying the imaging technique, the relationship between the freeze-out spatial distributions and the results of correlation femtoscopy is investigated. We find that one can reliably reconstruct the source functions from the two-particle correlation functions with ignoring the degree of space-momentum correlations at this energy. The results are useful to the designing the hadron detector at CSR.

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.

String fusion in the dual parton model and the production of antihyperons in heavy-ion collisions

1993 ◽  
Vol 47 (9) ◽  
pp. 4142-4145 ◽  
Author(s):  
H. -J. Möhring ◽  
J. Ranft ◽  
C. Merino ◽  
C. Pajares
Keyword(s):  
Heavy Ion Collisions ◽  
Parton Model ◽  
Heavy Ion ◽  
Ion Collisions ◽  
Dual Parton Model

scholarly journals Correlations of High-pT Hadrons and Jets in ALICE

Universe ◽  
2019 ◽  
Vol 5 (5) ◽  
pp. 124
Author(s):  
Filip Krizek
Keyword(s):  
Energy Transport ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Jet Quenching ◽  
Relativistic Heavy Ion Collisions ◽  
High Transverse Momentum ◽  
Subtraction Method ◽  
Final State ◽  
Ion Collisions ◽  
Quenching Phenomenon

There are two prominent experimental signatures of quark–gluon plasma creation in ultra-relativistic heavy-ion collisions: the jet quenching phenomenon and the azimuthal-momentum space-anisotropy of final-state particle emission. Recently, the latter signature was also observed in lighter collision systems such as p–Pb or pp. This raises a natural question of whether in these systems, the observed collectivity is also accompanied by jet quenching. In this paper, we overview ALICE measurements of the jet quenching phenomenon studied using semi-inclusive distributions of track-based jets recoiling from a high-transverse momentum ( p T ) hadron trigger in Pb–Pb and p–Pb collisions at LHC energies. The constructed coincidence observable, the per trigger normalized yield of associated recoil jets, is corrected for the complex uncorrelated jet background, including multi-partonic interactions, using a data-driven statistical subtraction method. In the p–Pb data, the observable was measured in events with different underlying event activity and was utilized to set an upper limit on the average medium-induced out-of-cone energy transport for jets with resolution parameter R = 0.4 . The associated jet momentum shift was found to be less than 0.4 GeV/c at 90% confidence.

scholarly journals Characterising Charm Jet Properties with Azimuthal Correlations of D Mesons and Charged Particles with ALICE at the LHC

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 35
Author(s):  
Shyam Kumar for the ALICE Collaboration
Keyword(s):  
Heavy Ion Collisions ◽  
Charm Quark ◽  
Charged Particles ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collisions ◽  
Pp Collisions ◽  
Final State ◽  
Essential Information ◽  
Ion Collisions

Charm quarks are produced via hard parton scattering in ultra-relativistic heavy-ion collisions, hence are ideal probes to study a possible de-confined state of matter, known as Quark Gluon Plasma (QGP). The angular correlation of a meson containing a charm quark with other charged particles in heavy-ion collisions can help in studying the properties of QGP. Similar studies in pp collisions can give insight about the charm production mechanism while in p-Pb collisions could provide essential information to disentangle final-state QGP-induced modifications from effects caused by cold nuclear matter. In this proceedings, the results are presented for p-Pb collisions at s NN = 5.02 TeV and pp collisions at s = 13 TeV, so far the highest available energy at the LHC. The results are compared with Monte Carlo (MC) simulations using PYTHIA and POWHEG event generators and with pp collision results at s = 7 TeV.

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