scholarly journals Entropy and Multifractality in Relativistic Ion-Ion Collisions

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Shaista Khan ◽  
Shakeel Ahmad
Keyword(s):  
Information Entropy ◽  
Particle Production ◽  
Monte Carlo Model ◽  
Theoretical Models ◽  
Ion Collisions ◽  
Full Phase Space ◽  
Wide Range ◽  
Multiplicity Distributions ◽  
Generalized Dimensions ◽  
Multiparticle Systems

Entropy production in multiparticle systems is investigated by analyzing the experimental data on ion-ion collisions at AGS and SPS energies and comparing the findings with those reported earlier for hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. It is observed that the entropy produced in limited and full phase space, when normalized to maximum rapidity, exhibits a kind of scaling which is nicely supported by Monte Carlo model HIJING. Using Rényi’s order q information entropy, multifractal characteristics of particle production are examined in terms of generalized dimensions, Dq. Nearly the same values of multifractal specific heat, c, observed in hadronic and ion-ion collisions over a wide range of incident energies suggest that the quantity c might be used as a universal characteristic of multiparticle production in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. The analysis is extended to the study of spectrum of scaling indices. The findings reveal that Rényi’s order q information entropy could be another way to investigate the fluctuations in multiplicity distributions in terms of spectral function f(α), which has been argued to be a convenient function for comparison sake not only among different experiments but also between the data and theoretical models.

scholarly journals Multifractal characteristics of multiparticle production in heavy-ion collisions at SPS energies

2018 ◽  
Vol 27 (01) ◽  
pp. 1850004 ◽  
Author(s):  
Shaista Khan ◽  
Shakeel Ahmad
Keyword(s):  
Experimental Data ◽  
Phase Space ◽  
Information Entropy ◽  
Particle Production ◽  
Monte Carlo Model ◽  
Heavy Ion ◽  
High Energy ◽  
Detector Resolution ◽  
Ion Collisions ◽  
Multiplicity Distributions

Entropy, dimensions and other multifractal characteristics of multiplicity distributions of relativistic charged hadrons produced in ion–ion collisions at SPS energies are investigated. The analysis of the experimental data is carried out in terms of phase space bin-size dependence of multiplicity distributions following the Takagi’s approach. Yet another method is also followed to study the multifractality which, is not related to the bin-width and (or) the detector resolution, rather involves multiplicity distribution of charged particles in full phase space in terms of information entropy and its generalization, Rényi’s order-[Formula: see text] information entropy. The findings reveal the presence of multifractal structure — a remarkable property of the fluctuations. Nearly constant values of multifractal specific heat “[Formula: see text]” estimated by the two different methods of analysis followed indicate that the parameter “[Formula: see text]” may be used as a universal characteristic of the particle production in high energy collisions. The results obtained from the analysis of the experimental data agree well with the predictions of Monte Carlo model AMPT.

On moments of the multiplicity events of slow target fragments in relativistic Sulfur-ion collisions

2014 ◽  
Vol 23 (08) ◽  
pp. 1450040 ◽  
Author(s):  
A. Abdelsalam ◽  
S. Kamel ◽  
N. Rashed ◽  
N. Sabry
Keyword(s):  
Energy Dependence ◽  
Heavy Ion ◽  
Universal Function ◽  
Relativistic Heavy Ion Collisions ◽  
Strongly Correlated ◽  
Ion Collisions ◽  
Full Phase Space ◽  
Scaling Hypothesis ◽  
Multiplicity Distributions ◽  
Mean Variance

A detailed study on the multiplicity characteristics of the slow target fragments emitted in relativistic heavy-ion collisions has been carried out at E Lab = 3.7 A and 200A GeV using 32 S projectile. The beam energy dependence of the black particles produced in the full phase space of 32 S -emulsion (32 S -Em) interactions on the target size in terms of their moments (mean, variance, skewness and kurtosis) is investigated. The various order moments of target fragments emitted in the interactions of 32 S beams with the heavy ( AgBr ) target nuclei are estimated in the forward (FHS) and backward (BHS) hemispheres. The investigated values of ratio of variance to mean at both energies show that the multiplicity distributions (MDs) are not Poissonian and the strongly correlated emission of target fragments are in the forward directions. The degree of anisotropic fragment emission and nature of correlation among the emitted fragments are investigated. The energy dependence of entropy is examined in both hemispheres. The entropy values normalized to average multiplicity are found to be energy independent. Scaling of MD of black particles produced in these interactions has been studied to verify the validity of scaling hypothesis via two scaling (Koba–Nielsen–Olesen (KNO)-scaling and Hegyi-scaling) functions. A simplified universal function has been used in each scaling to display the experimental data.

scholarly journals Photon Multiplicity Distributions at Heavy Ion Au+Au, Pb+Au, Pb+Pb Interactions

2016 ◽  
Vol 2 (1) ◽  
pp. 2-6
Author(s):  
Mohammad Kheare Abu Shayeb
Keyword(s):  
Heavy Ion Collisions ◽  
Particle Production ◽  
Dominant Role ◽  
Heavy Ion ◽  
Ion Collisions ◽  
Ion Interactions ◽  
Polynomial Fit ◽  
Multiplicity Distributions ◽  
Photon Multiplicity

The experimental distributions for Heavy ion interaction, Au+Au, Pb+Au, Pb+Pb have been fitted to polynomial fit of 4th order to look at minor differences in multiplicity distributions for different targets at heavy ion collisions experiment. The multiplicity distributions found similar; except for small differences which may be of statistical in nature.  This analysis supports the hypothesis that geometrical aspects play a dominant role in particle production in heavy ion interactions.

scholarly journals INFLUENCE OF STATISTICAL FLUCTUATIONS ON K/π RATIOS IN RELATIVISTIC HEAVY ION COLLISIONS

2001 ◽  
Vol 16 (07) ◽  
pp. 1227-1235 ◽  
Author(s):  
C. B. YANG ◽  
X. CAI
Keyword(s):  
Negative Binomial ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Relative Variance ◽  
Ion Collisions ◽  
Statistical Fluctuations ◽  
Binomial Distributions ◽  
The Mean ◽  
Multiplicity Distributions ◽  
Statistical Background

The influence of pure statistical fluctuations on K/π ratio is investigated in an event-by-event way. Poisson and the modified negative binomial distributions are used as the multiplicity distributions since they both have statistical background. It is shown that the distributions of the ratio in these cases are Gaussian, and the mean and relative variance are given analytically.

Dynamics and Performance of a Harmonically Excited Vertical Impact Damper

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Sanjiv Ramachandran ◽  
George Lesieutre
Keyword(s):  
Loss Factor ◽  
Vertical Direction ◽  
Theoretical Models ◽  
Coefficient Of Restitution ◽  
Numerical Continuation ◽  
Particle Impact ◽  
Impact Damper ◽  
High Loss ◽  
Wide Range ◽  
And Performance

Particle impact dampers (PIDs) have been shown to be effective in vibration damping. However, our understanding of such dampers is still limited, based on the theoretical models existing today. Predicting the performance of the PID is an important problem, which needs to be investigated more thoroughly. This research seeks to understand the dynamics of a PID as well as those parameters which govern its behavior. The system investigated is a particle impact damper with a ceiling, under the influence of gravity. The base is harmonically excited in the vertical direction. A two-dimensional discrete map is obtained, wherein the variables at one impact uniquely dictate the variables at the next impact. This map is solved using a numerical continuation procedure. Periodic impact motions and “irregular” motions are observed. The effects of various parameters such as the gap clearance, coefficient of restitution, and the base acceleration are analyzed. The dependence of the effective damping loss factor on these parameters is also studied. The loss factor results indicate peak damping for certain combinations of parameters. These combinations of parameters correspond to a region in parameter space where two-impacts-per-cycle motions are observed over a wide range of nondimensional base accelerations. The value of the nondimensional acceleration at which the onset of two-impacts-per-cycle solutions occurs depends on the nondimensional gap clearance and the coefficient of restitution. The range of nondimensional gap clearances over which two-impacts-per-cycle solutions are observed increases as the coefficient of restitution increases. In the regime of two-impacts-per-cycle solutions, the value of nondimensional base acceleration corresponding to onset of these solutions initially decreases and then increases with increasing nondimensional gap clearance. As the two-impacts-per-cycle solutions are associated with high loss factors that are relatively insensitive to changing conditions, they are of great interest to the designer.

Very-high-energy light charged-particle production near 0° in heavy-ion collisions, 9≤E/A≤40 MeV

1990 ◽  
Vol 42 (4) ◽  
pp. 1519-1529 ◽  
Author(s):  
S. Shaheen ◽  
F. D. Becchetti ◽  
D. A. Roberts ◽  
J. W. Jänecke ◽  
R. L. Stern ◽  
...  
Keyword(s):  
Charged Particle ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
Heavy Ion ◽  
High Energy ◽  
Light Charged Particle ◽  
Ion Collisions ◽  
Charged Particle Production ◽  
Very High Energy ◽  
Very High

scholarly journals Particle Production in Ultrarelativistic Heavy-Ion Collisions: A Statistical-Thermal Model Review

2013 ◽  
Vol 2013 ◽  
pp. 1-27 ◽  
Author(s):  
S. K. Tiwari ◽  
C. P. Singh
Keyword(s):  
Thermal Model ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Transverse Mass ◽  
Current Status ◽  
Thermal Models ◽  
Ion Collisions ◽  
Ultrarelativistic Heavy Ion Collisions

The current status of various thermal and statistical descriptions of particle production in the ultrarelativistic heavy-ion collisions experiments is presented in detail. We discuss the formulation of various types of thermal models of a hot and dense hadron gas (HG) and the methods incorporated in the implementing of the interactions between hadrons. It includes our new excluded-volume model which is thermodynamically consistent. The results of the above models together with the experimental results for various ratios of the produced hadrons are compared. We derive some new universal conditions emerging at the chemical freeze-out of HG fireball showing independence with respect to the energy as well as the structure of the nuclei used in the collision. Further, we calculate various transport properties of HG such as the ratio of shear viscosity-to-entropy using our thermal model and compare with the results of other models. We also show the rapidity as well as transverse mass spectra of various hadrons in the thermal HG model in order to outline the presence of flow in the fluid formed in the collision. The purpose of this review article is to organize and summarize the experimental data obtained in various experiments with heavy-ion collisions and then to examine and analyze them using thermal models so that a firm conclusion regarding the formation of quark-gluon plasma (QGP) can be obtained.

scholarly journals Two components in charged particle production in heavy-ion collisions

2016 ◽  
Vol 903 ◽  
pp. 204-210 ◽  
Author(s):  
A.A. Bylinkin ◽  
N.S. Chernyavskaya ◽  
A.A. Rostovtsev
Keyword(s):  
Charged Particle ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
Heavy Ion ◽  
Ion Collisions ◽  
Charged Particle Production

Viscosity Effect on Thermocapillary Rupture of Falling Liquid Films

2010 ◽  
Author(s):  
Dmitry Zaitsev ◽  
Andrey Semenov ◽  
Oleg Kabov
Keyword(s):  
Heat Flux ◽  
Film Thickness ◽  
Inclination Angle ◽  
Theoretical Models ◽  
Liquid Films ◽  
Liquid Viscosity ◽  
Inclined Plate ◽  
Film Rupture ◽  
Generalize Data ◽  
Wide Range

Rupture of a subcooled liquid film flowing over an inclined plate with a 150×150 mm heater is studied for a wide range of liquid viscosity (dynamic viscosity μ = (0.91–17.2)x10−3 Pa·s) and plate inclination angle with respect to the horizon (Θ = 3–90 deg). The main governing parameters of the experiment and their respective values are: Reynolds number Re = 0.15–54, heat flux q = 0–224 W/cm2. The effect of the heat flux on the film flow leads to the formation of periodically flowing rivulets and thin film between them. As the heat flux grows the film thickness between rivulets gradually decreases, and, upon reaching a certain threshold heat flux, qidp, the film ruptures in the area between the rivulets. The threshold heat flux increases with the flow rate of liquid and with the liquid viscosity, while the plate inclination angle has little effect on qidp. Criterion Kp, which is traditionally used in the literature to predict thermocapillary film rupture, was found to poorly generalize data for high viscous liquids (ethylene glycol, and aqueous solutions of glycerol) and also data for Θ≤45 deg. The criterion Kp was modified by taking into account characteristic critical film thickness for film rupture under isothermal conditions (no heating), deduced from existing theoretical models. The modified criterion has allowed to successfully generalize data for whole ranges of μ, Re, Θ and q, studied.

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