scholarly journals Scaling Properties of Multiplicity Fluctuations in the AMPT Model

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Rohni Sharma ◽  
Ramni Gupta
Keyword(s):  
Phase Transition ◽  
Charged Particles ◽  
Scaling Behavior ◽  
Spatial Distributions ◽  
Scaling Exponents ◽  
Ginzburg Landau ◽  
Multiphase Transport ◽  
Factorial Moments ◽  
Scaling Properties ◽  
Second Order Phase Transition

From the events generated from the MC code of a multiphase transport (AMPT) model with string melting, the properties of multiplicity fluctuations of charged particles in Pb–Pb collisions at sNN = 2.76 TeV are studied. Normalized factorial moments, Fq, of spatial distributions of the particles have been determined in the framework of intermittency. Those moments are found in some kinematic regions to exhibit scaling behavior at small bin sizes, but not in most regions. However, in relating Fq to F2 scaling behavior is found in nearly all regions. The corresponding scaling exponents, ν, determined in the low transverse momentum (pT) region ≤ 1.0 GeV/c are observed to be independent of the pT bin position and width. The value of ν is found to be larger than 1.304, which is the value that characterizes the Ginzburg-Landau type second-order phase transition. Thus there is no known signature for phase transition in the AMPT model. This study demonstrates that, for the system under investigation, the method of analysis is effective in extracting features that are relevant to the question of whether the dynamical processes leading phase transition are there or not.

INFLUENCE OF LONG-RANGE CORRELATION ON THE SCALING PROPERTIES OF THE NORMALIZED FACTORIAL CORRELATORS IN RELATIVISTIC HEAVY-ION COLLISIONS

2013 ◽  
Vol 22 (08) ◽  
pp. 1350059 ◽  
Author(s):  
X. Z. BAI ◽  
C. B. YANG
Keyword(s):  
Phase Transition ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collisions ◽  
Ginzburg Landau ◽  
Scaling Properties ◽  
Ion Collisions ◽  
Range Correlation ◽  
Dynamical Fluctuations ◽  
Second Order Phase Transition

The effect of multiplicity correlation between two bins to the dynamical fluctuations is investigated for a second-order phase transition from quark–gluon plasma (QGP) to hadrons, within the Ginzburg–Landau description for the transition. Normalized factorial correlators are used to characterize the dynamical fluctuations. A scaling behavior among the correlators is found, and an approximate universal exponent is obtained with very weak dependence on the details of the phase transition.

PHASE DIAGRAMS AND SCALING REGIMES FOR A CONTINUUM MODEL OF THE GROWTH OF THIN COMPOSITE FILMS

2005 ◽  
Vol 16 (05) ◽  
pp. 727-743 ◽  
Author(s):  
EHSAN NEDAAEE OSKOEE ◽  
MUHAMMAD SAHIMI
Keyword(s):  
Phase Diagrams ◽  
Composite Films ◽  
Kpz Equation ◽  
Scaling Exponents ◽  
Ginzburg Landau ◽  
Scaling Properties ◽  
Solid Films ◽  
Morphological Transitions ◽  
Tdgl Equation ◽  
Composite Solid

We present the results of extensive numerical integration in (1 +1) dimensions of a set of continuum equations which was recently proposed for describing the growth of thin composite solid films composed of two types of particles. In this model, the Kardar–Parisi–Zhang (KPZ) equation, which describes the growth of the films, is coupled to the time-dependent Ginzburg–Landau (TDGL) equation for the order parameter. We study the effect of the model's parameters on the universality of the scaling exponents that characterize the power-law behavior of the various properties of interest, and the transitions in the films' morphology that result from varying the parameters. We find that the scaling properties of the model are nonuniversal. Phase diagrams that identify the various scaling regimes, as well as the morphological transitions, are obtained. Thus, neither the dynamics of the domains' growth is governed by the TDGL equation, nor is the scaling of the films' surface structure described by the KPZ equation.

SCALING BEHAVIOR OF MULTIPLICITY DIFFERENCE CORRELATORS IN FIRST-ORDER QGP PHASE TRANSITION

2000 ◽  
Vol 15 (22) ◽  
pp. 3577-3585
Author(s):  
W. B. YAN ◽  
C. B. YANG ◽  
X. CAI
Keyword(s):  
Phase Transition ◽  
Quark Gluon Plasma ◽  
Gluon Plasma ◽  
Scaling Behavior ◽  
Ginzburg Landau ◽  
Landau Model ◽  
First Order ◽  
Plasma Phase

Within the extended Ginzburg–Landau model, multiplicity difference correlators in first-order quark–gluon plasma phase transition are investigated for two well-separated bins with nonidentical mean multiplicities. For very small bin width, a kind of scaling behavior and a universal exponent index γ, which are independent of the parameters of model, are found.

DYNAMICS OF FRACTALITY AND PHASE TRANSITION IN MULTIPARTICLE PRODUCTION IN RELATIVISTIC NUCLEUS–NUCLEUS COLLISIONS

2013 ◽  
Vol 22 (05) ◽  
pp. 1350033 ◽  
Author(s):  
ARSHAD KAMAL ◽  
N. AHMAD ◽  
M. M. KHAN ◽  
M. I. HAQUE ◽  
M. ZAFAR ◽  
...  
Keyword(s):  
Phase Transition ◽  
Critical Value ◽  
Data Sets ◽  
Scaling Exponent ◽  
Factorial Moments ◽  
Universal Scaling ◽  
Average Value ◽  
Thermal Phase ◽  
Scaled Factorial Moments ◽  
Second Order Phase Transition

This paper reports the results of an investigation regarding occurrence of second-order phase transition in 14.5A GeV /c28 Si -nucleus interactions using the method of scaled factorial moments. Incidentally, the value of the universal scaling exponent, ν, for our experimental data is found to be 1.224±0.068, which is quite close to its critical value 1.304. An attempt is also made to search for the evidence of phase transition in terms of Levy index, μ, using scaled factorial moments as well as Takagi moments for both experimental and FRITIOF generated data sets. Average value of μ, calculated from Fq moments, turns out to be more than unity but is less than unity when estimated in terms of Takagi moments for both the data sets. Thus the analyses carried out in terms of Fq and Takagi moments reveal the occurrence of nonthermal and thermal phase transitions, respectively.

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