THE ENERGY AND CENTRALITY DEPENDENCES OF THE PSEUDORAPIDITY DISTRIBUTIONS OF THE CHARGED PARTICLES IN Au+Au COLLISIONS

2012 ◽  
Vol 21 (01) ◽  
pp. 1250002 ◽  
Author(s):  
ZHIJIN JIANG ◽  
YUFEN SUN ◽  
QINGGUANG LI
Keyword(s):  
Theoretical Model ◽  
Impact Parameter ◽  
Beam Energy ◽  
Charged Particles ◽  
Nucleon Nucleon ◽  
Experimental Measurements ◽  
Phobos Collaboration ◽  
Free Parameters ◽  
Pseudorapidity Distributions ◽  
Theoretical Results

We present the pseudorapidity distributions of the charged particles in nucleus–nucleus collisions as the function of beam energy and impact parameter through weighted superposition of the pseudorapidity distributions in the effective binary nucleon–nucleon collisions. We then analyze with the theoretical model the experimental measurements carried out by BNL-RHIC-PHOBOS Collaboration in Au + Au collisions at [Formula: see text], 130, 62.4 and 19.6 GeV. The model has only two free parameters and the theoretical results favor the experimental measurements well.

scholarly journals The Evolution-Dominated Hydrodynamic Model and the Pseudorapidity Distributions in High Energy Physics

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Z. J. Jiang ◽  
H. L. Zhang ◽  
J. Wang ◽  
K. Ma
Keyword(s):  
Hydrodynamic Model ◽  
High Energy Physics ◽  
Charged Particles ◽  
Heavy Ion ◽  
High Energy ◽  
Ion Collisions ◽  
Phobos Collaboration ◽  
Pseudorapidity Distributions ◽  
Theoretical Results ◽  
Energy Physics

By taking into account the effects of leading particles, we discuss the pseudorapidity distributions of the charged particles produced in high energy heavy ion collisions in the context of evolution-dominated hydrodynamic model. The leading particles are supposed to have a Gaussian rapidity distribution normalized to the number of participants. A comparison is made between the theoretical results and the experimental measurements performed by BRAHMS and PHOBOS Collaboration at BNL-RHIC in Au-Au and Cu-Cu collisions atsNN=200 GeV and by ALICE Collaboration at CERN-LHC in Pb-Pb collisions atsNN=2.76 TeV.

THE HYDRODYNAMIC DESCRIPTION OF THE ENERGY AND CENTRALITY DEPENDENCES OF THE PSEUDORAPIDITY DISTRIBUTIONS OF THE PRODUCED CHARGED PARTICLES IN Au+Au COLLISIONS

2013 ◽  
Vol 22 (09) ◽  
pp. 1350069 ◽  
Author(s):  
ZHIJIN JIANG ◽  
QINGGUANG LI ◽  
GUANXIANG JIANG
Keyword(s):  
Hydrodynamic Model ◽  
Charged Particles ◽  
Heavy Ion ◽  
High Energy ◽  
Hydrodynamic Description ◽  
Gaussian Form ◽  
Ion Collisions ◽  
Phobos Collaboration ◽  
Rapidity Distributions ◽  
Pseudorapidity Distributions

By using the revised Landau hydrodynamic model and taking into account the effect of leading particles, we discuss the pseudorapidity distributions of produced charged particles in high energy heavy-ion collisions. The charged particles resulted from the freeze-out of the matter produced in collisions possess the Gaussian-like rapidity distributions. The leading particles are assumed having the rapidity distributions of the Gaussian form with the normalization constant being equal to the number of participants, which can be figured out in theory. It is found that the results from the revised Landau hydrodynamic model together with the contributions from leading particles are well consistent with the experimental data carried out by BNL-RHIC-PHOBOS Collaboration in different centrality Au + Au collisions at energies of [Formula: see text], 130 and 62.4 GeV , respectively.

scholarly journals A combined model for pseudo-rapidity distributions in Cu–Cu collisions at BNL-RHIC energies

2016 ◽  
Vol 25 (04) ◽  
pp. 1650025 ◽  
Author(s):  
Z. J. Jiang ◽  
J. Wang ◽  
Y. Huang
Keyword(s):  
Experimental Data ◽  
Proper Time ◽  
Charged Particles ◽  
Dense Matter ◽  
Rapidity Distribution ◽  
Experimental Measurements ◽  
Combined Model ◽  
Model Predictions ◽  
Phobos Collaboration ◽  
Rapidity Distributions

The charged particles produced in nucleus–nucleus collisions come from leading particles and those frozen out from the hot and dense matter created in collisions. The leading particles are conventionally supposed having Gaussian rapidity distributions normalized to the number of participants. The hot and dense matter is assumed to expand according to the unified hydrodynamics, a hydro model which unifies the features of Landau and Hwa–Bjorken model, and freeze out into charged particles from a time-like hypersurface with a proper time of [Formula: see text]. The rapidity distribution of this part of charged particles can be derived analytically. The combined contribution from both leading particles and unified hydrodynamics is then compared against the experimental data performed by BNL-RHIC-PHOBOS Collaboration in different centrality Cu–Cu collisions at [Formula: see text] and 62.4[Formula: see text]GeV, respectively. The model predictions are consistent with experimental measurements.

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.

scholarly journals Pseudorapidity distributions of charged particles produced in p–p collisions at center-of-mass energies from 23.6 GeV to 900 GeV

2014 ◽  
Vol 29 (27) ◽  
pp. 1450130 ◽  
Author(s):  
Z. J. Jiang ◽  
H. L. Zhang
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Hydrodynamic Model ◽  
Energy Region ◽  
Center Of Mass ◽  
Charged Particles ◽  
The Other ◽  
Fragmentation Region ◽  
Available Energy ◽  
Pseudorapidity Distributions

In p–p collisions there are two leading particles, one in the projectile and the other in the target fragmentation region. In this paper we show that, just like in nucleus–nucleus collisions, the revised Landau hydrodynamic model alone does not provide a good enough description of the measured pseudorapidity distributions of charged particles produced in p–p collisions. Only after the leading particles are taken into account can the experimental data be properly matched with the theoretical model in the entire available energy region from [Formula: see text] to 900 GeV.

Thermocouple Response Characteristics in Deflagrating Low-Conductivity Materials

1971 ◽  
Vol 93 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Nam P. Suh ◽  
C. L. Tsai
Keyword(s):  
Theoretical Model ◽  
Gas Phase ◽  
Wire Diameter ◽  
Solid Propellants ◽  
Optimum Ratio ◽  
Response Characteristics ◽  
Bead Diameter ◽  
Double Base ◽  
Theoretical Results ◽  
Good Agreement

The transient thermocouple response characteristics in deflagrating low-conductivity materials with high temperature gradients were investigated theoretically and experimentally. The theoretical model considers the thermocouple bead and lead wires separately, and the two resulting partial differential equations are solved simultaneously by a finite difference technique. The experimental results are obtained by embedding various size thermocouple wires in double-base solid propellants and consequently measuring the temperature profiles and the surface temperatures. The theoretical model is used to predict the experimentally measured temperatures. There is good agreement. The experimentally measured values are smaller than the correct surface temperature, corresponding to the model prediction for zero wire diameter, by at least 20 percent even when 1/2-mil thermocouple wire is used. Both the experimental and theoretical results show a plateau when the thermocouple bead emerges from the solid into the gas phase. The theoretical results also show that there is an optimum ratio of. the thermocouple bead diameter to the wire diameter, which is found to be close to three

Determination of hyperon properties through the variational method considering the hyperfine interaction

2019 ◽  
Vol 28 (10) ◽  
pp. 1950087 ◽  
Author(s):  
S. M. Moosavi Nejad ◽  
A. Armat
Keyword(s):  
Experimental Data ◽  
Wave Function ◽  
Ground State ◽  
Radiative Decay ◽  
Magnetic Moments ◽  
Wave Functions ◽  
Decay Widths ◽  
Free Parameters ◽  
Theoretical Results

Performing a fit procedure on the hyperon masses, we first determine the free parameters in the Cornell-like hypercentral potential between the constituent quarks of hyperons in their ground state. To this end, using the variational principle, we apply the hyperspherical Hamiltonian including the Cornell-like hypercentral potential and the perturbation potentials due to the spin–spin, spin–isospin and isospin–isospin interactions between constituent quarks. In the following, we compute the hyperon magnetic moments as well as radiative decay widths of spin-3/2 hyperons using the spin-flavor wave function of hyperons. Our analysis shows acceptable consistencies between theoretical results and available experimental data. This leads to reliable wave functions for hyperons at their ground state.

The multiplicity characteristics of 7Li-Em interactions as a function of noninteracting projectile nucleons

2020 ◽  
Vol 29 (08) ◽  
pp. 2050063
Author(s):  
M. Mohery ◽  
E. M. Sultan ◽  
N. N. Abdallah ◽  
M. H. Farghaly
Keyword(s):  
Impact Parameter ◽  
Charged Particles ◽  
Heavy Ion ◽  
The Other ◽  
Total Charge ◽  
Secondary Particles ◽  
Ion Interactions ◽  
Charged Secondary ◽  
The Impact ◽  
Relativistic Particles

In this work, the interactions of 7Li nuclei with emulsion at 3 A GeV/c were studied. Multiplicity of the charged secondary particles as well as the charge of the outgoing projectile fragments were measured, while correlations among them are discussed. The values of the total charge of the noninteracting projectile nucleons and the average number of interacting projectile nucleons are estimated. The dependence of the secondary particles on the number of heavily-ionized tracks is analyzed. The results show that interactions of 7Li nuclei with emulsion nuclei exhibit a number of regularities, which had been noted in experiments with lighter nuclei. The absorption of relativistic particles, while increasing the degree of target destruction, is observed. The average multiplicities of the secondary charged particles depend on the impact parameter, as their values increase, while decreasing the impact parameter. The number of secondary charged particles in the heavy-ion interactions depends on the degree of disintegration of the target nuclei. This dependence is not observed in the case of the interaction of hadron with emulsion. The experimental data of the interaction of 7Li are systematically compared with the other interactions at different energies. The results agree with the corresponding results at nearly the same energy.

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