ENTROPY SCALING IN ION–ION COLLISIONS AT AGS AND SPS ENERGIES

2013 ◽  
Vol 22 (12) ◽  
pp. 1350088 ◽  
Author(s):  
SHAKEEL AHMAD ◽  
ANUJ CHANDRA ◽  
M. ZAFAR ◽  
M. IRFAN ◽  
A. AHMAD
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Phase Space ◽  
Beam Energy ◽  
Center Of Mass ◽  
Total Entropy ◽  
Ion Collisions ◽  
Full Phase Space ◽  
Mass Frame

Analysis of the experimental data on nucleus–nucleus collisions at AGS and SPS energies reveals that entropy produced in a limited and full phase-space increases with increasing beam energy and mass of the colliding nuclei. The analysis of the data and corresponding mixed event samples, carried out by considering the particles emitted in the forward and backward hemispheres separately, indicates the presence of clusterization and correlations amongst the produced particles. It is also observed that the total entropy produced in a limited pseudorapidity bin, when normalized to the maximum rapidity in the center of mass frame, is essentially independent of projectile and target masses as well as beam energy, indicating thereby presence of a kind of entropy scaling. The observed scaling is also nicely reproduced by the Monte Carlo models, AMPT and FRITIOF. Furthermore, results of the analysis of the mixed events reveal that the observed entropy scaling is a distinguishable feature of the data rather than a manifestation of the statistics.

scholarly journals Event-by-event fluctuations clusterization and entropy production in AA collisions at AGS and SPS energies

2019 ◽  
Vol 28 (03) ◽  
pp. 1950018
Author(s):  
Bushra Ali ◽  
Shaista Khan ◽  
Anuj Chandra ◽  
Shakeel Ahmad
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Beam Energy ◽  
Charged Particles ◽  
Nucleon Nucleon ◽  
Final States ◽  
Full Phase Space ◽  
Independent Particle ◽  
Multi Phase ◽  
Phase Transport

Event-by-event (ebe) fluctuations in mean pseudorapidity values of relativistic charged particles in full phase space are studied by analyzing experimental data on [Formula: see text] collisions at 14.5A, 60A and 200A GeV/c and [Formula: see text] collisions at 200A GeV/c. The findings are compared with the prediction of A Multi-Phase Transport (AMPT) model and those obtained from the analysis of correlation free Monte-Carlo events. Fluctuations in mean pseudorapidity distributions are noted to be in excess to that expected from the statistically independent particle emission. The observed dependence of the fluctuation strength measure parameter, [Formula: see text] on the beam energy and number of participating target nucleons indicate that nucleus–nucleus collisions cannot be treated as simple superposition of multiple nucleon–nucleon interactions. Presence of clusters or jet-like phenomena in multihadron final states are searched for on ebe basis by using the concept of Jaynes Shannon entropy. The findings indicate the presence of cluster-like objects in the experimental data with their size and frequency increasing with increasing beam energy. These observations in turn suggest that the clustering or jet-like algorithm adopted in the present study may be used as a tool for triggering different classes of events.

Production cross-section of heavy flavored hadrons in pp collision at s = 7 TeV

2019 ◽  
Vol 34 (19) ◽  
pp. 1950150 ◽  
Author(s):  
Muhammad Ajaz ◽  
Irfan Khan ◽  
M. K. Suleymanov
Keyword(s):  
Experimental Data ◽  
Transverse Momentum ◽  
Differential Cross Section ◽  
Cross Section ◽  
Momentum Distribution ◽  
Cross Sections ◽  
Production Cross ◽  
Center Of Mass ◽  
Transverse Momentum Distribution ◽  
Mass Frame

The transverse momentum distribution of the differential production cross-sections of heavy flavored charm hadrons [Formula: see text], [Formula: see text] in pp collisions at 7 TeV are simulated. Predictions of DPMJETIII.17-1, HIJING1.383 and Sibyll2.3c are compared to the differential cross-section measurements of the LHCb experimental data presented in the region of [Formula: see text] and [Formula: see text], where the pp center of mass frame is used to measure the transverse momentum and rapidity. The models reproduce only some regions of [Formula: see text] and/or bins of [Formula: see text] but none of them predict completely all the [Formula: see text] bins over the entire [Formula: see text] range.

scholarly journals Charged-Particle Multiplicity Moments as Described by Shifted Gompertz Distribution in e+e−, pp¯, and pp Collisions at High Energies

2020 ◽  
Vol 2020 ◽  
pp. 1-24
Author(s):  
Aayushi Singla ◽  
M. Kaur
Keyword(s):  
Charged Particle ◽  
Phase Space ◽  
Center Of Mass ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Distribution Analysis ◽  
Factorial Moments ◽  
Hadronic Interactions ◽  
Gompertz Distribution ◽  
Full Phase Space

In continuation of our earlier work, in which we analysed the charged particle multiplicities in leptonic and hadronic interactions at different center-of-mass energies in full phase space as well as in restricted phase space using the shifted Gompertz distribution, a detailed analysis of the normalized moments and normalized factorial moments is reported here. A two-component model in which a probability distribution function is obtained from the superposition of two shifted Gompertz distributions, as introduced in our earlier work, has also been used for the analysis. This is the first analysis of the moments with the shifted Gompertz distribution. Analysis has also been performed to predict the moments of multiplicity distribution for the e+e− collisions at s=500 GeV at a future collider.

DIELECTRON PRODUCTION IN Ar+KCl AT 1.756 AGeV WITH HADES

2009 ◽  
Vol 24 (02n03) ◽  
pp. 603-606
Author(s):  
◽  
FILIP KŘÍŽEK
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Data Analysis ◽  
Thermal Model ◽  
Beam Energy ◽  
Monte Carlo Event ◽  
Event Generator ◽  
Monte Carlo Event Generator ◽  
Hades Collaboration ◽  
Experimental Data Analysis

The HADES collaboration studied dielectron production in C + C , p + p , and d + p reactions, with the main goal to investigate properties of vectors mesons through their dielectron decay. Production of e+e- pairs in Ar + KCl collisions at a beam energy of 1.756 A GeV was measured recently by the collaboration and preliminary results of the experimental data analysis will be reported. Pair spectra will be compared with a prediction of a thermal model based on the Monte Carlo event generator Pluto.

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.

scholarly journals Efimov States From Triple α Resonances

2019 ◽  
Vol 26 ◽  
pp. 1
Author(s):  
S. Zhang ◽  
M. Huang ◽  
H. Zheng ◽  
G. Zhang ◽  
Z. Kohley ◽  
...  
Keyword(s):  
Experimental Data ◽  
Excitation Energy ◽  
Ground State ◽  
Beam Energy ◽  
Heavy Ion ◽  
Relative Energy ◽  
Energy Distributions ◽  
Form Complex ◽  
Ion Collisions ◽  
Efimov States

The Efimov trimers in excited 12C nuclei, which no observation exists yet, are discussed by means of analyzing the experimental data of 70(64)Zn(64Ni) +70(64)Zn(64Ni )reactions at beam energy of E/A=35 MeV/nucleon. In heavy ion collisions, the αs interact with each other and can form complex systems such as 8Be and 12C. For the 3α systems, multi resonance processes give rise to excited levels of 12C. The interaction between any two of the 3α particles provides events with one, two or three 8Be. Their interfering levels are clearly seen in the minimum relative energy distributions. Events of three couple αrelative energies consistent with the ground state of 8Be are observed with the decreasing of the instrumental error at the reconstructed 7.458 MeV excitation energy of 12C, which was suggested as the (Thomas) Efimov state.

J/ψ PRODUCTION IN A GLAUBER MONTE CARLO FRAMEWORK

2010 ◽  
Vol 25 (05) ◽  
pp. 1009-1018 ◽  
Author(s):  
HONG-MIN WANG ◽  
ZHAO-YU HOU ◽  
BEN-AI ZHANG ◽  
XIAN-JING SUN
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Center Of Mass ◽  
Nuclear Modification Factor ◽  
Center Of Mass Energy ◽  
Modification Factor ◽  
Energy Formula ◽  
Theoretical Results ◽  
Monte Carlo Framework ◽  
Good Agreement

By means of a Glauber Monte Carlo framework, the J/ψ production at RHIC energies is studied with the EKS98, EPS09 and HKN07 shadowing parameters. With a χ2 analysis of the experimental data given by PHENIX, a significant dependence of the absorption cross-section, σ abs , on the J/ψ-nucleon center-of-mass energy, [Formula: see text], is revealed with the HKN07 shadowing, but an unconspicuous dependence is shown with the EKS98 and EPS09 shadowing. In this paper, the nuclear modification factor Rd Au vs y, pT and N coll are also calculated and the theoretical results are in good agreement with the experimental data.

Velocity Distribution of Secondary π Mesons Produced in Interactions of 70 GeV/c Protons with the Nuclei (CNO) and (Ag, Br)

1975 ◽  
Vol 53 (9) ◽  
pp. 935-936
Author(s):  
B. K. Bandyopadhyay ◽  
I. K. Daftari
Keyword(s):  
Experimental Data ◽  
Velocity Distribution ◽  
Center Of Mass ◽  
Type Function ◽  
Gaussian Type ◽  
Nuclear Interactions ◽  
Mass Frame ◽  
Usual Criterion ◽  
Gaussian Type Function

One hundred nuclear interactions produced by 70 GeV/c protons with photoemulsion nuclei have been analyzed. The velocity distribution of the secondary π mesons produced in these interactions was studied. A Gaussian type function is observed to simulate the experimental data which confirms the usual criterion of isotropy in the center of mass frame.

EP-1464: Flattening Filter Free phase space files: Comparison between Monte Carlo simulations and experimental data

2014 ◽  
Vol 111 ◽  
pp. S147
Author(s):  
M.F. Belosi ◽  
A. Fogliata ◽  
L. Brualla ◽  
J. Sempau ◽  
M. Rodriguez ◽  
...  
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Phase Space ◽  
Monte Carlo Simulations ◽  
Flattening Filter Free ◽  
Flattening Filter

MONTE CARLO SIMULATIONS OF dd REACTION PARAMETERS STUDY AT ULTRA-LOW ENERGY RANGE USING PLASMA HALL ACCELERATOR AND DEUTERIZED TARGETS

2012 ◽  
Vol 21 (11) ◽  
pp. 1250089 ◽  
Author(s):  
M. FILIPOWICZ ◽  
V. M. BYSTRITSKY ◽  
G. N. DUDKIN ◽  
F. M. PENK'OV ◽  
A. V. PHILIPPOV
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Energy Spectrum ◽  
Energy Range ◽  
Beam Energy ◽  
Low Energy ◽  
Reaction Parameters ◽  
Energy Beam ◽  
Analyze Data

This paper presents results of the application Monte Carlo method to analyze data from the interaction of deuteron beams with metallic targets saturated with deuterium. The SRIM software was used to generate energy spectrum of ions passing the target. These spectra were used to calculate the neutron yields from dd reactions in energy range 7–12 keV of incident deuteron beams. The calculated outputs were compared with the experimental data for the determination of the electron screening potential for dd reactions. The calculations were performed using two different values of the beam energy spread (FWHM) equal 1% and 16%. It was shown that plasma beams with a relatively high spread (16%) were almost as good a tool as the traditional accelerator with mono-energy beam related to the study of the reaction within an ultra-low energy region.

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