Comparison study of the pT distributions of the charged particles in p–Pb interactions at LHC energies

2017 ◽  
Vol 32 (31) ◽  
pp. 1750167 ◽  
Author(s):  
Y. Ali ◽  
U. Tabassam ◽  
M. Suleymanov ◽  
A. S. Bhatti
Keyword(s):  
Transverse Momentum ◽  
Transport Model ◽  
Relativistic Quantum ◽  
Charged Particles ◽  
Medium Effect ◽  
Quantum Molecular Dynamics ◽  
Essential Difference ◽  
Momentum Range ◽  
Cronin Effect ◽  
Model Predictions

Transverse momentum [Formula: see text] distributions of primary charged particles were compared to simulations using the Ultra Relativistic Quantum Molecular Dynamics (UrQMD) transport model and the HIJING 1.0 model in minimum bias p–Pb collisions at [Formula: see text] in the pseudorapidity [Formula: see text] regions: [Formula: see text], [Formula: see text] and [Formula: see text] and in the transverse momentum range [Formula: see text]. The simulated distributions were then compared with the ALICE data and it was observed that UrQMD predicts systematically higher yields than HIJING 1.0. Both codes cannot describe the experimental data in the range of [Formula: see text], though in the region of [Formula: see text] the model predictions are very close to the experimental results for particles with [Formula: see text], [Formula: see text]. The ratio of the yield at forward pseudorapidity to that at [Formula: see text] was also studied. It was observed that the predictions of the models depend on [Formula: see text]. In the experiment there is no essential difference of yields for particles from the intervals of [Formula: see text], [Formula: see text] and [Formula: see text]. The differences are significant for the models where the ratios are systematically less than 1. This means that the results are not connected to a medium effect but reflect the Cronin effect. We are led to conclude that the codes cannot take into account satisfactorily the leading effect due to the asymmetric p–Pb fragmentation.

Observation of universality for high pT distribution at LHC energies

2018 ◽  
Vol 27 (04) ◽  
pp. 1850036 ◽  
Author(s):  
U. Tabassam ◽  
Y. Ali ◽  
S. Ullah ◽  
M. Ajaz ◽  
Q. Ali ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Relativistic Quantum ◽  
Charged Particles ◽  
Simulated Data ◽  
Heavy Ion ◽  
Quantum Molecular Dynamics ◽  
Boundary Values ◽  
Momentum Range ◽  
Jet Interaction ◽  
Atlas Data

We have studied the distributions of the yield of primary charged particles produced in the asymmetric [Formula: see text]–[Formula: see text] collisions at [Formula: see text] for the three pseudorapidity regions: [Formula: see text] and [Formula: see text] and the transverse momentum range of [Formula: see text]. Heavy ion jet interaction generator (HIJING) and Ultra relativistic quantum molecular dynamics (UrQMD) models are used to produce simulated data and the results are compared with the CMS and ATLAS data. The comparison of models and data shows the existence of high [Formula: see text] area with boundary values that depend upon pseudorapidity ([Formula: see text]). At high [Formula: see text] values, the behavior of the distributions shows some universality, which does not depend upon the models. The reason of the universality could be the string dynamics for the parton hadronization at high [Formula: see text] values.

scholarly journals Probing chemical freeze-out criteria in relativistic nuclear collisions with coarse grained transport simulations

2020 ◽  
Vol 56 (10) ◽  
Author(s):  
Tom Reichert ◽  
Gabriele Inghirami ◽  
Marcus Bleicher
Keyword(s):  
Chemical Potential ◽  
Transport Model ◽  
Relativistic Quantum ◽  
Coarse Graining ◽  
Coarse Grained ◽  
Quantum Molecular Dynamics ◽  
Novel Approach ◽  
Relativistic Nuclear Collisions ◽  
Chemical Freeze ◽  
Freeze Out

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.

Transverse momentum and nuclear modification factor distributions of charged particles in p + Pb and p+p collisions at s NN = 5.02 TeV

2019 ◽  
Vol 34 (16) ◽  
pp. 1950120 ◽  
Author(s):  
Q. Ali ◽  
Y. Ali ◽  
M. Haseeb ◽  
M. Ajaz
Keyword(s):  
Experimental Data ◽  
Transverse Momentum ◽  
Charged Particles ◽  
Momentum Range ◽  
Nuclear Modification Factor ◽  
Nuclear Modification ◽  
Model Distribution ◽  
Momentum Distributions ◽  
Modification Factor ◽  
Good Agreement

Transverse momentum distributions and nuclear modification factor of integrated charged particles yield produced in p[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] = 5.02 TeV are investigated in mid-rapidity regions of [Formula: see text] at one event multiplicity class 0–5% in the transverse momentum range of [Formula: see text]20 GeV/c. Simulations with EPOS-1.99, EPOS-LHC and QGSJETII-04 are compared with the ALICE data. All three models are in good agreement with each other up to [Formula: see text]3 GeV/c for transverse momentum distributions but after that QGSJETII-04 overpredicts the experimental data. EPOS-LHC seems to describe the experimental data quite well as compared to the other two models. The ratios of the kaons to pions and protons to pions are also presented where again EPOS-LHC provides good agreement with the ALICE data. In case of the nuclear modification factor, for (anti) pions and (anti) kaons, the model distribution is around 1, whereas it is greater than 1 in case of (anti) protons which shows Cronin enhancement.

scholarly journals PRODUCTION AND RESCATTERING OF STRANGE BARYONS AT ENERGIES AVAILABLE AT THE CERN SUPER PROTON SYNCHROTRON IN A TRANSPORT MODEL WITH HADRON POTENTIALS

2012 ◽  
Vol 27 (03) ◽  
pp. 1250004 ◽  
Author(s):  
QINGFENG LI ◽  
ZHUXIA LI
Keyword(s):  
Transport Model ◽  
Relativistic Quantum ◽  
Mean Field ◽  
Field Potential ◽  
Heavy Ion ◽  
Transverse Mass ◽  
Proton Synchrotron ◽  
Quantum Molecular Dynamics ◽  
Super Proton Synchrotron ◽  
Strange Baryons

A mean-field potential version of the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model is used to investigate the production of strange (anti-)baryons, especially the Λs and [Formula: see text]s, from heavy ion collisions at SPS energies. It is found that, with the consideration of both formed and pre-formed hadron potentials in UrQMD, the transverse mass and longitudinal rapidity distributions of experimental data of both Λs and [Formula: see text]s can be quantitatively explained fairly well. Our investigation also shows the equal importance of both the production mechanism and the rescattering process of hadrons for the final yield of strange baryons.

Forward–backward multiplicity correlation and event-by-event multiplicity fluctuation in nucleus–nucleus collisions at 200A GeV

2021 ◽  
pp. 2150021
Author(s):  
Sanjib Kumar Manna ◽  
Amitabha Mukhopadhyay ◽  
Provash Mali
Keyword(s):  
Transport Model ◽  
Relativistic Quantum ◽  
Cluster Formation ◽  
Simulated Data ◽  
Correlation Effect ◽  
Quantum Molecular Dynamics ◽  
Particle Correlation ◽  
Statistical Measures ◽  
Singly Charged ◽  
Bose Einstein

Correlation among singly charged particles emitted in the forward and backward pseudo-rapidity cones is measured in [Formula: see text]O-Ag/Br and [Formula: see text]S-Ag/Br interactions at an incident energy of [Formula: see text] GeV/nucleon. Event-by-event fluctuations in the charged particle multiplicities and their pseudo-rapidity values are also investigated in terms of some known statistical measures. Evidences of short-ranged particle correlation and cluster formation in the pseudo-rapidity space are found from our analysis. A microscopic transport model based on the Ultra-relativistic Quantum Molecular Dynamics could not match the experimental results. The differences between experimental observation and corresponding simulation could neither be accounted for even when a Bose–Einstein type of correlation effect is implemented into the simulated data.

CENTRAL CARBON–CARBON COLLISIONS AT 4.2 A GeV/c AND NEAREST-NEIGHBOR SPACING DISTRIBUTIONS

2012 ◽  
Vol 27 (16) ◽  
pp. 1250090 ◽  
Author(s):  
Z. WAZIR ◽  
M. FAKHAR-E-ALAM ◽  
S. A. KHAN ◽  
M. A. RAFIH AMER
Keyword(s):  
Nearest Neighbor ◽  
Matrix Theory ◽  
Relativistic Quantum ◽  
Charged Particles ◽  
Simulated Data ◽  
Quantum Molecular Dynamics ◽  
Primary Level ◽  
Central Collisions ◽  
Urqmd Model ◽  
Central Carbon

The obtained experimental results due to nearest-neighbor spacing distributions were compared with simulated data using random matrix theory (RMT) with aid of the ultra relativistic quantum molecular dynamics (UrQMD) model. The present assessment reveals the primary level of multiplicity of secondary charged particles which might be linked with the onset of region of central collisions based on mentioned results. The author tried to demonstrate the importance of the nearest-neighbor distributions for various multiplicities to detect the region of central collisions.

MULTIFRACTAL ANALYSIS OF CHARGED PARTICLE DISTRIBUTION IN 28Si-Ag/Br INTERACTION AT 14.5A GeV

Fractals ◽  
2012 ◽  
Vol 20 (03n04) ◽  
pp. 203-215 ◽  
Author(s):  
P. MALI ◽  
A. MUKHOPADHYAY ◽  
G. SINGH
Keyword(s):  
Charged Particle ◽  
Particle Production ◽  
Transport Model ◽  
Particle Density ◽  
Relativistic Quantum ◽  
Quantitative Difference ◽  
Quantum Molecular Dynamics ◽  
Particle Density Distribution ◽  
Charged Particle Density ◽  
Self Similar

The multifractal structure of one dimensional charged particle density distribution in 28 Si-Ag / Br interactions at 14.5 GeV per nucleon is investigated by using two different techniques. The experimental measurements are compared with a microscopic transport model of particle production based on the Ultra-relativistic Quantum Molecular Dynamics (UrQMD). Various parameters related to multifractality, for example the Lévy's index, are obtained. Our analysis shows that multifractal structure is present both in the experiment as well as in the simulation. As far as the self-similar nature of the density fluctuation is concerned, there exists, however, a small but definite quantitative difference between the two.

The production of π±, K±, p and p̄ in p–Pb collisions at sNN = 5.02 TeV

2018 ◽  
Vol 33 (17) ◽  
pp. 1850094 ◽  
Author(s):  
U. Tabassam ◽  
Y. Ali ◽  
M. Suleymanov ◽  
A. S. Bhatti ◽  
M. Ajaz
Keyword(s):  
Transverse Momentum ◽  
Longitudinal Momentum ◽  
Momentum Range ◽  
Text Production ◽  
Cronin Effect ◽  
Protons And Neutrons ◽  
Baryon Resonances ◽  
Rhic Data

In this study, we are reporting comprehensive results on [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] production in the transverse momentum range of [Formula: see text] 4 GeV/c at midrapidity of [Formula: see text] 0.5 GeV/c, in p–Pb collisions at [Formula: see text] = 5.02 TeV. HIJING 1.0 and UrQMD 3.4 event generators are used to perform simulations and the results are compared with the ALICE and RHIC data. It is observed from the comparison that the yields for the baryons are more complex compared to the mesons and the complexity in baryons is due to the striping dynamics (spectators, leading particles of projectiles) of inner nucleus protons and neutrons. Though all the mesons could be produced during the interaction, they have maximum longitudinal momentum [Formula: see text]; baryons and mesons could be produced as a result of decay of massive baryon-resonances. Yields for the [Formula: see text] mesons are greater than the yield for the [Formula: see text] mesons. These are the well-known results from the RHIC data, which stated that the Cronin Effect is mainly due to [Formula: see text] mesons that can be produced as a result of multi-particle inner nucleus cascade. There exists the regions where yields for the [Formula: see text] mesons and baryons are same that may be due to the appearance of parton nature. The code used in simulation includes the parton dynamics earlier than it is included in the experiment.

Transverse momentum distribution of primary charged particles in the p–Pb interactions using HIJING 1.0

2016 ◽  
Vol 31 (24) ◽  
pp. 1650136 ◽  
Author(s):  
U. Tabassam ◽  
Y. Ali ◽  
M. Suleymanov ◽  
A. S. Bhatti ◽  
J. B. Butt ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Momentum Distribution ◽  
Charged Particles ◽  
Simulated Data ◽  
Transverse Momentum Distribution ◽  
Minimum Bias ◽  
Pseudorapidity Distribution ◽  
Momentum Range ◽  
Comparison Of Results

The shape of the transverse momentum [Formula: see text] distribution of primary charged particles in minimum bias (nonsingle-diffractive) p–Pb collisions at [Formula: see text] is studied in the pseudorapidity regions: [Formula: see text], [Formula: see text] and [Formula: see text] and in the transverse momentum range [Formula: see text] using simulated data produced with the HIJING 1.0 code. These are compared with the ALICE data measured by the ALICE detector at the LHC. In the model, the central and forward [Formula: see text]-regions differ more than in the ALICE data and due to this fact HIJING 1.0 cannot describe well the high [Formula: see text] region in the [Formula: see text] distributions. The comparison of results from simulation implies that the HIJING 1.0 considered narrower pseudorapidity distribution for the charged particles than it is in the ALICE data. It cannot take into account satisfactorily leading effect due to the asymmetric p–Pb fragmentation.

Study of transverse momentum and nuclear modification factors distribution of charged particles produced in pp and Pb–Pb collisions at s NN = 2.76TeV and 5.02TeV

2021 ◽  
pp. 2150068
Author(s):  
A. Arif ◽  
Y. Ali ◽  
M. Haseeb ◽  
Q. Ali ◽  
U. Tabassam ◽  
...  
Keyword(s):  
Experimental Data ◽  
Transverse Momentum ◽  
Charged Particles ◽  
Simulated Data ◽  
Experimental Results ◽  
High Transverse Momentum ◽  
Momentum Range ◽  
Nuclear Modification Factor ◽  
Nuclear Modification ◽  
Nuclear Modification Factors

We have studied transverse momentum distributions of charged particles produced in pp and Pb–Pb collisions at [Formula: see text] TeV and 5.02 TeV in the pseudorapidity interval [Formula: see text] and transverse momentum range [Formula: see text][Formula: see text]GeV/[Formula: see text]. We simulated data using EPOS-LHC, EPOS-1.99 and QGSJETII-04 models. The simulation data is compared with the ALICE experimental data values at [Formula: see text] TeV and 5.02 TeV for pp and most central Pb–Pb collisions. It has been observed that, EPOS-LHC and QGSJETII-04 models explain the experimental results for pp collision at [Formula: see text] TeV and 5.02 TeV. The behavior of nuclear modification factors has been studied. The simulation codes of all three models EPOS-LHC, EPOS-1.99 and QGSJETII-04 overestimate the experimental results at low transverse momentum interval: [Formula: see text] GeV/[Formula: see text], for Pb–Pb collisions at [Formula: see text] TeV and 5.02 TeV. However, only EPOS-LHC model can explain the experimental data at high transverse momentum in the range: [Formula: see text] GeV/[Formula: see text]. EPOS-1.99 and QGSJETII-04 underestimate in the region of Cronin effect and cannot give satisfactory estimates for the [Formula: see text] values for which [Formula: see text] demonstrates stronger suppression because of the collective parton effect. It can be inferred that these effects are not taken into account in EPOS-1.99 and QGSJETII-04 models. These models, however, satisfactorily explain the ALICE experimental data in the ranges of [Formula: see text] for which nuclear modification factor [Formula: see text] shows rising trend.

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