Multifractal analysis of charged particle distributions using horizontal visibility graph and sandbox algorithm

2017 ◽  
Vol 32 (08) ◽  
pp. 1750024 ◽  
Author(s):  
P. Mali ◽  
A. Mukhopadhyay ◽  
S. K. Manna ◽  
P. K. Haldar ◽  
G. Singh

Horizontal visibility graphs (HVGs) and the sandbox (SB) algorithm usually applied for multifractal characterization of complex network systems that are converted from time series measurements, are used to characterize the fluctuations in pseudorapidity densities of singly charged particles produced in high-energy nucleus–nucleus collisions. Besides obtaining the degree distribution associated with event-wise pseudorapidity distributions, the common set of observables, typical of any multifractality measurement, are studied in [Formula: see text]O-Ag/Br and [Formula: see text]S-Ag/Br interactions, each at an incident laboratory energy of 200 GeV/nucleon. For a better understanding, we systematically compare the experiment with a Monte Carlo model simulation based on the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). Our results suggest that the HVG-SB technique is an efficient tool that can characterize multifractality in multiparticle emission data, and in some cases, it is even superior to other methods more commonly used in this regard.

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Provash Mali ◽  
Soumya Sarkar ◽  
Amitabha Mukhopadhyay ◽  
Gurmukh Singh

A continuous wavelet analysis is performed for pattern recognition of charged particle emission data in28Si-Ag/Br interaction at 14.5A GeV and in32S-Ag/Br interaction at 200A GeV. Making use of the event-wise local maxima present in the scalograms, we try to identify the collective behavior in multiparticle production, if there is any. For the first time, the wavelet results are compared with a model prediction based on the ultrarelativistic quantum molecular dynamics (UrQMD), where we adopt a charge reassignment algorithm to modify the UrQMD events to mimic the Bose-Einstein type of correlation among identical mesons—a feature known to be the most dominating factor responsible for local cluster formation. Statistically significant deviations between the experiment and the simulation are interpreted in terms of nontrivial dynamics of multiparticle production.


2014 ◽  
Vol 23 (05) ◽  
pp. 1450027 ◽  
Author(s):  
Provash Mali ◽  
Amitabha Mukhopadhyay ◽  
Soumya Sarkar ◽  
Gurmukh Singh

Presence of unusual azimuthal structures in the particle emission data obtained from the 28 Si – Ag / Br interaction at 14.5A GeV and from the 32 S – Ag / Br interaction at 200A GeV, are investigated in the framework of the Cherenkov gluon emission and/or Mach shock wave formation in nuclear/partonic medium. Nuclear photographic emulsion technique is used to collect the experimental data. The experiment is compared with the predictions of two simulations, namely (i) the Relativistic Quantum Molecular Dynamics (RQMD) and (ii) the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). A charge reassignment algorithm is implemented over the outputs of the simulations to mimic the Bose–Einstein correlation (BEC) effect. Our analysis confirms presence of jet-like structures in both experiments beyond statistical noise. Such structures are more pronounced in the 32 S data than in the 28 Si data.


2011 ◽  
Vol 89 (9) ◽  
pp. 949-960 ◽  
Author(s):  
Provash Mali ◽  
Amitabha Mukhopadhyay ◽  
Gurmukh Singh

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.


2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Swarnapratim Bhattacharyya ◽  
Maria Haiduc ◽  
Alina Tania Neagu ◽  
Elena Firu

A study of multifractality and multifractal specific heat has been carried out for the produced shower particles in nuclear emulsion detector for 16O-AgBr, 28Si-AgBr, and 32S-AgBr interactions at 4.5AGeV/c in the framework of Renyi entropy. Experimental results have been compared with the prediction of Ultra-Relativistic Quantum Molecular Dynamics (UrQMD) model. Our analysis reveals the presence of multifractality in the multiparticle production process in high energy nucleus-nucleus interactions. Degree of multifractality is found to be higher for the experimental data and it increases with the increase of projectile mass. The investigation of quark-hadron phase transition in the multiparticle production in 16O-AgBr, 28Si-AgBr, and 32S-AgBr interactions at 4.5 AGeV/c in the framework of Ginzburg-Landau theory from the concept of multifractality has also been presented. Evidence of constant multifractal specific heat has been obtained for both experimental and UrQMD simulated data.


2002 ◽  
Vol 17 (40) ◽  
pp. 2627-2632 ◽  
Author(s):  
F. BUCCELLA ◽  
L. POPOVA

We deduce the particle distributions in particle collisions with multihadron-production in the framework of mechanical statistics. They are derived as functions of x, [Formula: see text] and the rest mass of different species for a fixed total number of all produced particles, inelasticity and total transverse energy. For PT larger than the mass of each particle, we have [Formula: see text] Values of <PT>π, <PT>K and [Formula: see text] in agreement with experiment are found by taking TH = 180 MeV (the Hagedorn temperature).


2020 ◽  
Vol 56 (10) ◽  
Author(s):  
Tom Reichert ◽  
Gabriele Inghirami ◽  
Marcus Bleicher

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.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Rui-Fang Si ◽  
Hui-Ling Li ◽  
Fu-Hu Liu

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.


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

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