CENTRAL CARBON–CARBON COLLISIONS AT 4.2 A GeV/c AND NEAREST-NEIGHBOR SPACING DISTRIBUTIONS

2012 ◽  
Vol 27 (16) ◽  
pp. 1250090 ◽  
Author(s):  
Z. WAZIR ◽  
M. FAKHAR-E-ALAM ◽  
S. A. KHAN ◽  
M. A. RAFIH AMER
Keyword(s):  
Nearest Neighbor ◽  
Matrix Theory ◽  
Relativistic Quantum ◽  
Charged Particles ◽  
Simulated Data ◽  
Quantum Molecular Dynamics ◽  
Primary Level ◽  
Central Collisions ◽  
Urqmd Model ◽  
Central Carbon

The obtained experimental results due to nearest-neighbor spacing distributions were compared with simulated data using random matrix theory (RMT) with aid of the ultra relativistic quantum molecular dynamics (UrQMD) model. The present assessment reveals the primary level of multiplicity of secondary charged particles which might be linked with the onset of region of central collisions based on mentioned results. The author tried to demonstrate the importance of the nearest-neighbor distributions for various multiplicities to detect the region of central collisions.

Intermittency and erraticity of charged particles produced in 28Si-Ag/Br interaction at 14.5 A GeV

2011 ◽  
Vol 89 (9) ◽  
pp. 949-960 ◽  
Author(s):  
Provash Mali ◽  
Amitabha Mukhopadhyay ◽  
Gurmukh Singh
Keyword(s):  
Experimental Data ◽  
Incident Energy ◽  
Particle Density ◽  
Relativistic Quantum ◽  
Charged Particles ◽  
Statistical Simulation ◽  
High Energy ◽  
Quantum Molecular Dynamics ◽  
Urqmd Model ◽  
Charged Particle Density

In this paper, we present the intermittency and the erraticity analyses of the distributions of charged particles produced in 28Si-Ag/Br interaction at incident energy 14.5 A GeV. The experimental results are compared with a Monte Carlo simulation using ultra-relativistic quantum molecular dynamics (UrQMD) model. The experimental data show the presence of a nonstatistical component in the produced charged-particle density. Neither the UrQMD simulation nor the purely statistical simulation was found to match the experimental data. The present set of results are compared to those obtained in similar measurements from earlier high-energy nucleus–nucleus experiments.

Observation of universality for high pT distribution at LHC energies

2018 ◽  
Vol 27 (04) ◽  
pp. 1850036 ◽  
Author(s):  
U. Tabassam ◽  
Y. Ali ◽  
S. Ullah ◽  
M. Ajaz ◽  
Q. Ali ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Relativistic Quantum ◽  
Charged Particles ◽  
Simulated Data ◽  
Heavy Ion ◽  
Quantum Molecular Dynamics ◽  
Boundary Values ◽  
Momentum Range ◽  
Jet Interaction ◽  
Atlas Data

We have studied the distributions of the yield of primary charged particles produced in the asymmetric [Formula: see text]–[Formula: see text] collisions at [Formula: see text] for the three pseudorapidity regions: [Formula: see text] and [Formula: see text] and the transverse momentum range of [Formula: see text]. Heavy ion jet interaction generator (HIJING) and Ultra relativistic quantum molecular dynamics (UrQMD) models are used to produce simulated data and the results are compared with the CMS and ATLAS data. The comparison of models and data shows the existence of high [Formula: see text] area with boundary values that depend upon pseudorapidity ([Formula: see text]). At high [Formula: see text] values, the behavior of the distributions shows some universality, which does not depend upon the models. The reason of the universality could be the string dynamics for the parton hadronization at high [Formula: see text] values.

Forward–backward multiplicity correlation and event-by-event multiplicity fluctuation in nucleus–nucleus collisions at 200A GeV

2021 ◽  
pp. 2150021
Author(s):  
Sanjib Kumar Manna ◽  
Amitabha Mukhopadhyay ◽  
Provash Mali
Keyword(s):  
Transport Model ◽  
Relativistic Quantum ◽  
Cluster Formation ◽  
Simulated Data ◽  
Correlation Effect ◽  
Quantum Molecular Dynamics ◽  
Particle Correlation ◽  
Statistical Measures ◽  
Singly Charged ◽  
Bose Einstein

Correlation among singly charged particles emitted in the forward and backward pseudo-rapidity cones is measured in [Formula: see text]O-Ag/Br and [Formula: see text]S-Ag/Br interactions at an incident energy of [Formula: see text] GeV/nucleon. Event-by-event fluctuations in the charged particle multiplicities and their pseudo-rapidity values are also investigated in terms of some known statistical measures. Evidences of short-ranged particle correlation and cluster formation in the pseudo-rapidity space are found from our analysis. A microscopic transport model based on the Ultra-relativistic Quantum Molecular Dynamics could not match the experimental results. The differences between experimental observation and corresponding simulation could neither be accounted for even when a Bose–Einstein type of correlation effect is implemented into the simulated data.

Comparison study of the pT distributions of the charged particles in p–Pb interactions at LHC energies

2017 ◽  
Vol 32 (31) ◽  
pp. 1750167 ◽  
Author(s):  
Y. Ali ◽  
U. Tabassam ◽  
M. Suleymanov ◽  
A. S. Bhatti
Keyword(s):  
Transverse Momentum ◽  
Transport Model ◽  
Relativistic Quantum ◽  
Charged Particles ◽  
Medium Effect ◽  
Quantum Molecular Dynamics ◽  
Essential Difference ◽  
Momentum Range ◽  
Cronin Effect ◽  
Model Predictions

Transverse momentum [Formula: see text] distributions of primary charged particles were compared to simulations using the Ultra Relativistic Quantum Molecular Dynamics (UrQMD) transport model and the HIJING 1.0 model in minimum bias p–Pb collisions at [Formula: see text] in the pseudorapidity [Formula: see text] regions: [Formula: see text], [Formula: see text] and [Formula: see text] and in the transverse momentum range [Formula: see text]. The simulated distributions were then compared with the ALICE data and it was observed that UrQMD predicts systematically higher yields than HIJING 1.0. Both codes cannot describe the experimental data in the range of [Formula: see text], though in the region of [Formula: see text] the model predictions are very close to the experimental results for particles with [Formula: see text], [Formula: see text]. The ratio of the yield at forward pseudorapidity to that at [Formula: see text] was also studied. It was observed that the predictions of the models depend on [Formula: see text]. In the experiment there is no essential difference of yields for particles from the intervals of [Formula: see text], [Formula: see text] and [Formula: see text]. The differences are significant for the models where the ratios are systematically less than 1. This means that the results are not connected to a medium effect but reflect the Cronin effect. We are led to conclude that the codes cannot take into account satisfactorily the leading effect due to the asymmetric p–Pb fragmentation.

scholarly journals Intermittency Approach in the Nuclear Collisions of 28Si + AgBr at 14.6A GeV - Nuclear Emulsion Experiment a Particle Detector

2017 ◽  
Vol 7 (2) ◽  
pp. 127
Author(s):  
Mohammad Ayaz Ahmad
Keyword(s):  
Charged Particles ◽  
Factorial Moment ◽  
Simulated Data ◽  
Particle Detector ◽  
Factorial Moments ◽  
Nuclear Collisions ◽  
Statistical Fluctuations ◽  
Urqmd Model ◽  
Scaled Factorial Moments ◽  
Good Agreement

A new method has been applied for the study of intermittency in the collisions of 28Si + AgBr at 14.6 A GeV for the produced relativistic charged particles by using the method of mixed factorial moment (MFM). In this paper an analysis has been made for the presence of fractal behavior with three different approaches of Scaled factorial Moments (SFMs) named as- horizontal, vertical and mixed (horizontal and vertical together). The non-statistical fluctuations of relativistic charged particles have been calculated on events with different degree of centrality. These results have been compared with the results of simulated data obtained from UrQMD model and we find a good agreement between experimental data and simulated data.

scholarly journals Centrality Dependence of Multiplicity Fluctuations in Ion-Ion Collisions from the Beam Energy Scan at FAIR

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Anuj Chandra ◽  
Bushra Ali ◽  
Shakeel Ahmad
Keyword(s):  
Beam Energy ◽  
Relativistic Quantum ◽  
Heavy Ion ◽  
Quantum Molecular Dynamics ◽  
Ion Collisions ◽  
Statistical Fluctuations ◽  
The Central Limit Theorem ◽  
Urqmd Model ◽  
Multiplicity Distributions ◽  
Beam Energy Scan

Multiplicity distributions and event-by-event multiplicity fluctuations in AuAu collisions at energies in future heavy-ion experiment at the Facility for Anti-proton and Ion Research (FAIR) are investigated. Events corresponding to FAIR energies are simulated in the frame work of Ultra Relativistic Quantum Molecular Dynamics (URQMD) model. It is observed that the mean and the width of multiplicity distributions monotonically increase with beam energy. The trend of variations of dispersion with mean number of participating nucleons for the centrality-bin width of 5% are in accord with the Central Limit Theorem. The multiplicity distributions in various centrality bins as well as for full event samples are observed to obey Koba, Nielsen and Olesen (KNO) scaling. The trends of variations of scaled variance with beam energy are also found to support the KNO scaling predictions for larger collision centrality. The findings also reveal that the statistical fluctuations in 5% centrality-bin width appear to be under control.

scholarly journals Intermittency Approach in the Nuclear Collisions of 28Si + AgBr at 14.6A GeV - Nuclear Emulsion Experiment a Particle Detector

2017 ◽  
Vol 3 (2) ◽  
pp. 127
Author(s):  
Mohammad Ayaz Ahmad
Keyword(s):  
Charged Particles ◽  
Factorial Moment ◽  
Simulated Data ◽  
Particle Detector ◽  
Factorial Moments ◽  
Nuclear Collisions ◽  
Statistical Fluctuations ◽  
Urqmd Model ◽  
Scaled Factorial Moments ◽  
Good Agreement

A new method has been applied for the study of intermittency in the collisions of 28Si + AgBr at 14.6 A GeV for the produced relativistic charged particles by using the method of mixed factorial moment (MFM). In this paper an analysis has been made for the presence of fractal behavior with three different approaches of Scaled factorial Moments (SFMs) named as- horizontal, vertical and mixed (horizontal and vertical together). The non-statistical fluctuations of relativistic charged particles have been calculated on events with different degree of centrality. These results have been compared with the results of simulated data obtained from UrQMD model and we find a good agreement between experimental data and simulated data.

scholarly journals Probing chemical freeze-out criteria in relativistic nuclear collisions with coarse grained transport simulations

2020 ◽  
Vol 56 (10) ◽  
Author(s):  
Tom Reichert ◽  
Gabriele Inghirami ◽  
Marcus Bleicher
Keyword(s):  
Chemical Potential ◽  
Transport Model ◽  
Relativistic Quantum ◽  
Coarse Graining ◽  
Coarse Grained ◽  
Quantum Molecular Dynamics ◽  
Novel Approach ◽  
Relativistic Nuclear Collisions ◽  
Chemical Freeze ◽  
Freeze Out

AbstractWe introduce a novel approach based on elastic and inelastic scattering rates to extract the hyper-surface of the chemical freeze-out from a hadronic transport model in the energy range from E$$_\mathrm {lab}=1.23$$ lab = 1.23  AGeV to $$\sqrt{s_\mathrm {NN}}=62.4$$ s NN = 62.4  GeV. For this study, the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model combined with a coarse-graining method is employed. The chemical freeze-out distribution is reconstructed from the pions through several decay and re-formation chains involving resonances and taking into account inelastic, pseudo-elastic and string excitation reactions. The extracted average temperature and baryon chemical potential are then compared to statistical model analysis. Finally we investigate various freeze-out criteria suggested in the literature. We confirm within this microscopic dynamical simulation, that the chemical freeze-out at all energies coincides with $$\langle E\rangle /\langle N\rangle \approx 1$$ ⟨ E ⟩ / ⟨ N ⟩ ≈ 1  GeV, while other criteria, like $$s/T^3=7$$ s / T 3 = 7 and $$n_\mathrm {B}+n_{\bar{\mathrm {B}}}\approx 0.12$$ n B + n B ¯ ≈ 0.12 fm$$^{-3}$$ - 3 are limited to higher collision energies.

scholarly journals Comparing Standard Distribution and Its Tsallis Form of Transverse Momenta in High Energy Collisions

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Rui-Fang Si ◽  
Hui-Ling Li ◽  
Fu-Hu Liu
Keyword(s):  
Hadron Collider ◽  
Simulated Data ◽  
Heavy Ion ◽  
High Energy ◽  
Central Nucleus ◽  
Quantum Molecular Dynamics ◽  
Relativistic Heavy Ion Collider ◽  
Two Component ◽  
Standard Distribution ◽  
Effective Temperatures

The experimental (simulated) transverse momentum spectra of negatively charged pions produced at midrapidity in central nucleus-nucleus collisions at the Heavy-Ion Synchrotron (SIS), Relativistic Heavy-Ion Collider (RHIC), and Large Hadron Collider (LHC) energies obtained by different collaborations are selected by us to investigate, where a few simulated data are taken from the results of FOPI Collaboration which uses the IQMD transport code based on Quantum Molecular Dynamics. A two-component standard distribution and the Tsallis form of standard distribution are used to fit these data in the framework of a multisource thermal model. The excitation functions of main parameters in the two distributions are analyzed. In particular, the effective temperatures extracted from the two-component standard distribution and the Tsallis form of standard distribution are obtained, and the relation between the two types of effective temperatures is studied.

Relativistic quantum molecular dynamics and the collision 40Ca−40Ca at Elab/A = 1.05 GeV

1991 ◽  
Vol 268 (2) ◽  
pp. 161-166 ◽  
Author(s):  
Tomoyuki Maruyama ◽  
Guoqiang Li ◽  
Amand Faessler
Keyword(s):  
Molecular Dynamics ◽  
Relativistic Quantum ◽  
Quantum Molecular Dynamics
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