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

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.

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Li-Na Gao ◽  
Ya-Hui Chen ◽  
Hua-Rong Wei ◽  
Fu-Hu Liu

In framework of combing the participant-spectator model and the Landau hydrodynamic model, the pseudorapidity distributions of charged particles produced in heavy-ion (or nucleus-nucleus) collisions at RHIC and LHC energies are described by a modified Landau hydrodynamic model, where the Landau hydrodynamic model is applied to the target/projectile spectators and the target/projectile participants, respectively. The modeling results are in agreement with the PHOBOS and ALICE experimental data. Then, the values of square speed of sound (cs2) for the participants and spectators can be obtained from the widths of charged particle pseudorapidity distributions. Some features ofcs2for different centralities and center-of-mass energies are obtained too.


2013 ◽  
Vol 22 (09) ◽  
pp. 1350069 ◽  
Author(s):  
ZHIJIN JIANG ◽  
QINGGUANG LI ◽  
GUANXIANG JIANG

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.


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Fu-Hu Liu ◽  
Ya-Qin Gao ◽  
Tian Tian ◽  
Bao-Chun Li

The transverse momentum and pseudorapidity distributions of charged particles produced in Pb-Pb collisions with different centrality intervals at center-of-mass energy per nucleon pairsNN=2.76 TeV have been analyzed by using the improved multisource thermal model in which the whole interacting system and then the sources are described by the Tsallis statistics. The modelling results are in agreement with experimental data of the ALICE Collaboration. The rapidity distributions of charged particles are obtained according to the extracted parameter values. The shapes of interacting events (the dispersion plots of charged particles) are given in the momentum, rapidity, velocity, and coordinate spaces. Meanwhile, the event shapes in different spaces consisted by different transverse quantities and longitudinal quantities are presented.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ya-Qin Gao ◽  
Tian Tian ◽  
Li-Na Gao ◽  
Fu-Hu Liu

Pseudorapidity distributions of charged particles produced in proton-proton (p-p) or proton-antiproton (p-p-) collisions over an energy range from 0.053 to 7 TeV are studied by using the four-component Landau hydrodynamic model. The results calculated by the model are in agreement with the experimental data of the UA5, PHOBOS, UA1, P238, CDF, ALICE, and CMS Collaborations which present orderly from low to high energies. According to the distribution widths of different components, the values and some features of square speed of sound parametercs2for “participant” and “spectator” quark components are obtained. It is shown that the speed of sound for “participant” quark components agrees approximately with that for “spectator” quark components in the error ranges. The present work is useful for studying nucleus-nucleus collisions in the related energy range.


2012 ◽  
Vol 21 (01) ◽  
pp. 1250002 ◽  
Author(s):  
ZHIJIN JIANG ◽  
YUFEN SUN ◽  
QINGGUANG LI

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.


2013 ◽  
Vol 53 (A) ◽  
pp. 707-711 ◽  
Author(s):  
Anatoly A. Petrukhin

The cosmic ray energy region 10<sup>15</sup> ÷ 10<sup>17</sup>TeV corresponds to LHC energies 1 ÷ 14TeV in the center-of-mass system. The results obtained in cosmic rays (CR) in this energy interval can therefore be used for developing new approaches to the analysis of experimental data, for interpreting the results, and for planning new experiments. The main problem in cosmic ray investigations is the remarkable excess of muons, which increases with energy and cannot be explained by means of contemporary theoretical models. Some possible new explanations of this effect and other unusual phenomena observed in CR, and ways of searching for them in the LHC experiments are discussed.


Author(s):  
A. C. Balbahadur ◽  
R. G. Kirk

Abstract An approximate model for thermal bending caused by viscous lubricant shearing in overhung rotors has been developed. This model has been tested against a published theoretical model and an experimental study. It was found that the current model agreed well with both the other theoretical model and the experimental data.


2015 ◽  
Vol 24 (06) ◽  
pp. 1550048 ◽  
Author(s):  
M. Mohery ◽  
E. M. Sultan ◽  
Shadiah S. Baz

In the present paper, some results on the correlations of the nucleus–nucleus interactions, at high energy, between different particle multiplicities are reported. The correlations between the multiplicities of the different charged particles emitted in the interactions of 22 Ne and 28 Si nuclei with emulsion at (4.1–4.5)A GeV/c have been studied. The correlations of the compound multiplicity nc, defined as the sum of both numbers of the shower particles ns and grey particles ng, have been investigated. The experimental data have been compared with the corresponding theoretical ones, calculated according to the modified cascade evaporation model (MCEM). An agreement has already been fairly obtained between the experimental values and the calculated ones. The dependence of the average compound multiplicity, on the numbers of shower, grey, black and heavy particles is obvious and the values of the slope have been found to be independent of the projectile nucleus. On the other hand, the variation of the average shower, grey, black and heavy particles is found to increase linearly with the compound particles. A strong correlation has been observed between the number of produced shower particles and the number of compound particles. Moreover, the value of the average compound multiplicity is found to increase with the increase of the projectile mass. Finally, an attempt has also been made to study the scaling of the compound multiplicity distribution showing that the compound multiplicity distribution is nearly consistent with the KNO scaling behavior.


Author(s):  
P. Krammer

This paper describes a new theoretical model which computes two main excitation mechanisms, one based on the potential flow theory and the other explainable by the motion of blades through the wakes of preceding blades. The computation of the potential flow field is based on the assumption of a plane, unsteady, incompressible flow. Fluctuations of circulation caused by an alternating velocity field are taken into account by free vortex paths. Blade surfaces are modeled by a vortex distribution. Viscous wakes are simulated by means of contrarotating vortex rows. Results of the theoretical approach are compared with experimental data measured in axial turbomachines.


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