scholarly journals Search for Long-Range Correlations in Relativistic Heavy-Ion Collisions at SPS Energies

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shakeel Ahmad ◽  
Anisa Khatun ◽  
Shaista Khan ◽  
A. Ahmad ◽  
M. Irfan
Keyword(s):  
Long Range ◽  
Short Range ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Long Range Correlations ◽  
Ion Collisions ◽  
Extended Range ◽  
Multi Phase ◽  
Phase Transport ◽  
Nuclear Geometry

Long-range correlations are searched for by analysing the experimental data on16O-AgBr and32S-AgBr collisions at 200 A GeV/c and the results are compared with the predictions of a multi phase transport (AMPT) model. The findings reveal that the observed forward-backward (F-B) multiplicity correlations are mainly of short range in nature. The range of F-B correlations are observed to extend with increasing projectile mass. The observed extended range of F-B correlations might be due to overall multiplicity fluctuations arising because of nuclear geometry. The findings are not sufficient for making any definite conclusions regarding the presence of long-range correlations.

System scan of the multiplicity correlation between forward and backward rapidities in the relativistic heavy-ion collisions by using a multi-phase transport model

2021 ◽  
Author(s):  
Yi-An Li ◽  
Dong-Fang Wang ◽  
Song Zhang ◽  
Yugang Ma
Keyword(s):  
Long Range ◽  
Transport Model ◽  
Longitudinal Direction ◽  
Heavy Ion ◽  
Light Nuclei ◽  
Relativistic Heavy Ion Collisions ◽  
Source Information ◽  
Long Range Correlations ◽  
Multi Phase ◽  
Phase Transport

Abstract A systematic study on forward-backward (FB) multiplicity correlations from large systems to small ones through a multi-phase transport model (AMPT) has been performed and the phenomenon that correlation strength increases with the centrality can be explained by taking the distribution of events as the superposition of a series of Gaussian distributions. It is also found that correlations in the η - Φ plane can imply the shape of event. Furthermore, long range correlations originate from the fluctuations associated with the source information. FB correlations allow us to decouple long range correlations from short range correlations, and may provide a chance to investigate the $\alpha$-clustering structure in initial colliding light nuclei as well. It seems the tetrahedron $^{16}$O + $^{16}$O collision gives a more uniform and symmetrical fireball, after that emits the final particles more isotropically or independently in the longitudinal direction, indicating that the forward-backward multiplicity correlation could be used to identify the pattern of $\alpha$-clustered $^{16}$O in future experiments.

SHORT- AND LONG-RANGE MULTIPLICITY CORRELATIONS IN RELATIVISTIC HEAVY-ION COLLISIONS

2013 ◽  
Vol 22 (09) ◽  
pp. 1350066 ◽  
Author(s):  
SHAKEEL AHMAD ◽  
ANUJ CHANDRA ◽  
M. ZAFAR ◽  
M. IRFAN ◽  
A. AHMAD
Keyword(s):  
Long Range ◽  
Monte Carlo Model ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Long Range Correlations ◽  
Ion Collisions ◽  
Range Type ◽  
Central Rapidity Region ◽  
Central Rapidity ◽  
Charge Correlations

Forward–backward (FB) charge correlations are investigated by analyzing experimental data on 16 O – AgBr interactions at 14.5A, 60A and 200A GeV . Findings are compared with the predictions of Monte Carlo model, heavy-ion jet interaction generater (HIJING). The results reveal that the observed correlations are mainly of short-range type, which arise due to the decay of clusters and/or resonances produced in the central rapidity region. The range of FB correlations are observed to extend with increasing beam energy. However, there is no evidence for the presence of long-range correlations even at the highest incident energy considered.

scholarly journals Transverse momentum dependent decorrelation in Pb–Pb collisions at LHC

2020 ◽  
Vol 29 (08) ◽  
pp. 2050057
Author(s):  
De-Xian Wei
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Transverse Momentum Dependent ◽  
Model Simulations ◽  
Ion Collisions ◽  
Difference Formula ◽  
Multi Phase ◽  
Phase Transport ◽  
Different Order

Based on A Multi-Phase Transport (AMPT) model simulations, the transverse momentum dependent decorrelation has been studied in Pb–Pb collisions at [Formula: see text] and 5.02 TeV, respectively. It has been found that the mix-order factorization ratio [Formula: see text] value deviates significantly from unity in noncentral collisions. Such effect becomes stronger with an increase in the [Formula: see text] difference [Formula: see text]. These decorrelations are not only between the same order harmonic but also between the different order harmonic, which as a result of the initial fluctuations appear between the different phase spaces. It has also been found that the correlations involving higher powers of the flow vector yield stronger decorrelation, [Formula: see text], except for the weighted factorization ratio [Formula: see text]. The breaking phenomenon of these factorization ratios indicated that it provides a possible observation for studying the initial fluctuation properties of heavy-ion collisions.

scholarly journals Entropy Analysis in Relativistic Heavy-Ion Collisions

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Shakeel Ahmad ◽  
A. Ahmad ◽  
Anuj Chandra ◽  
M. Zafar ◽  
M. Irfan
Keyword(s):  
Phase Space ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Strong Correlations ◽  
Entropy Analysis ◽  
Multiphase Transport ◽  
Long Range Correlations ◽  
Ion Collisions ◽  
Full Phase Space ◽  
Multiparticle System

Entropy creation in multiparticle system is investigated by analysing the experimental data on ion-ion collisions at AGS and SPS energies and the results thus obtained are compared with those predicted by multiphase transport and correlation-free Monte Carlo models. Entropies produced in limited- and full-phase space are observed to increase with increasing beam energy. The entropy values, normalized to the maximum rapidity and plotted against pseudorapidity (bin width also normalized to the maximum rapidity), are found to be energy independent, exhibiting a kind of entropy scaling. Such scaling is observed in the full phase space as well as in the regions confined to the forward or backward hemispheres. The findings also reveal that there exist strong correlations amongst the particles produced in the forward and backward hemispheres around the midrapidity. These correlations are found to be of short range in nature, and the contributions from the long-range correlations seem to be absent. PACS numbers: 25.75-q, 25.75.Gz.

CORRELATED NUCLEON EMISSION IN PERIPHERAL RELATIVISTIC HEAVY ION COLLISIONS

1993 ◽  
Vol 08 (13) ◽  
pp. 2287-2296
Author(s):  
L. L. BARZ ◽  
A. F. R. de TOLEDO PIZA
Keyword(s):  
Cross Section ◽  
Born Approximation ◽  
Heavy Ion Collisions ◽  
Short Range ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Final States ◽  
Ion Collisions ◽  
Nucleon Emission ◽  
Short Range Correlations

The effects of short range correlations for two nucleon emission in peripheral relativistic heavy ion collisions are investigated. The cross section is calculated in Born approximation with properly orthogonalized initial and final states.

scholarly journals Baryon spectra and antiparticle-to-particle ratios from the improved AMPT model

2018 ◽  
Vol 171 ◽  
pp. 14004 ◽  
Author(s):  
Yuncun He ◽  
Zi-Wei Lin
Keyword(s):  
Experimental Data ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Current Version ◽  
Ion Collisions ◽  
Particle Ratios ◽  
Quark Coalescence ◽  
Baryon Spectra ◽  
Multi Phase ◽  
Phase Transport

The current version of a multi-phase transport (AMPT) model with string melting can reasonably describe the dN/dy yields, pT spectra and anisotropic flows of pions and kaons at low pT in heavy ion collisions at RHIC and LHC energies, although it failed to reproduce the dN/dy and pT spectra of baryons. In this work, we improve the quark coalescence mechanism in AMPT by removing the forced separate number conservations of mesons, baryons and antibaryons in each event. We find that the improved AMPT model can better describe the yields at midrapidity, the pT spectra and elliptic flow of low-pT baryons in comparison with the experimental data. Antiparticle-to-particle ratios of strange baryons are also significantly improved.

SHORT RANGE CORRELATIONS AND NUCLEON EMISSION IN PERIPHERAL RELATIVISTIC HEAVY ION COLLISIONS

1989 ◽  
Vol 04 (14) ◽  
pp. 1315-1328 ◽  
Author(s):  
C.A. BERTULANI ◽  
L.F. CANTO ◽  
R. DONANGELO ◽  
J.O. RASMUSSEN
Keyword(s):  
Cross Sections ◽  
Heavy Ion Collisions ◽  
Short Range ◽  
Heavy Ion ◽  
Momentum Conservation ◽  
Relativistic Heavy Ion Collisions ◽  
Ion Collisions ◽  
Nucleon Emission ◽  
Short Range Correlations ◽  
Phonon Absorption

We investigate the effects of short range correlations on nucleon emission in peripheral relativistic heavy ion collisions, following an idea originally proposed by Feshbach and Zabek. Expressions for one- and two-nucleon emission cross sections are derived and calculations for typical heavy ion systems are performed. We show that momentum conservation in the phonon absorption process leads to pronounced ridges in the quadruple-differential cross section for two-nucleon emission. We suggest that the presence of such ridges in future exclusive experiments should be considered as a signature of correlated emission of a nucleon pair.

ASPECTS OF THE NUCLEAR GEOMETRY IN ULTRA-RELATIVISTIC HEAVY ION COLLISIONS

1990 ◽  
Vol 05 (15) ◽  
pp. 1159-1166 ◽  
Author(s):  
EVERT STENLUND
Keyword(s):  
Experimental Data ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Ion Collisions ◽  
Nuclear Geometry

In this report I will briefly review experimental observations from ultra-relativistic heavy ion collisions which are directly or indirectly related to the nuclear geometry. Experimental data from the CERN SPS (60 and 200 A Ge V) and from the Brookhaven AGS (14.6 A GeV) will be discussed.

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