A study of inelastic hadron–nucleus interactions at 50 and 400 GeV

1984 ◽  
Vol 62 (3) ◽  
pp. 218-225 ◽  
Author(s):  
H. Ahrar ◽  
S. Ahmad ◽  
M. Zafar ◽  
M. Irfan ◽  
M. Shafi
Keyword(s):  
Quark Model ◽  
Charged Particles ◽  
Target Size ◽  
Projectile Fragmentation ◽  
Particle Multiplicity ◽  
Nuclear Mass ◽  
Target Fragmentation ◽  
Pseudorapidity Distributions ◽  
Grey Particle

Some results on multiplicity, mean normalized multiplicity, and pseudorapidity distributions of shower particles produced in pion–nucleus and proton–nucleus collisions at 50 and 400 GeV are presented and discussed. From the study of the pseudorapidity distributions, it is found that the projectile fragmentation is mass independent and the target fragmentation depends upon the target size. The effect of nuclear mass on the forward–backward asymmetry is also examined by using the grey particle multiplicity data. Upon using the additive quark model, a new kind of nuclear scaling is observed between RA4, in terms of created charged particles and [Formula: see text].

A study of particle–nucleus collisions at 24, 50, and 400 GeV/c

1982 ◽  
Vol 60 (10) ◽  
pp. 1523-1533 ◽  
Author(s):  
H. Khushnood ◽  
M. Irfan ◽  
M. Zafar ◽  
A. Ahmad ◽  
A. R. Khan ◽  
...  
Keyword(s):  
Quark Model ◽  
Target Nucleus ◽  
Incident Energy ◽  
Mass Number ◽  
Projectile Fragmentation ◽  
Fragmentation Region ◽  
Target Fragmentation ◽  
The Mean ◽  
Pseudorapidity Distributions

An attempt has been made to investigate multiplicity, dispersion, and pseudorapidity distributions of shower particles produced in 24, 50, and 400 GeV/c hadron–nucleus collisions. The study of pseudorapidity reveals that with the increase in the mass number of the target nucleus, the excess of particles appears in the target fragmentation region, shifting the maxima of the distributions towards smaller values of rapidity. Further, with the increase in the incident energy, the excess of particles appears in the projectile fragmentation region. Finally, on using the additive quark model, the mean normalized multiplicity has been observed to be independent of the energy and nature of the projectile, suggesting a new kind of scaling in hadron–nucleus collisions.

Leading particle and nuclear-mass effects on multiparticle production in 50 GeV/c π− interactions in nuclear emulsion

1981 ◽  
Vol 59 (6) ◽  
pp. 812-819 ◽  
Author(s):  
S. C. Varma ◽  
V. Kumar ◽  
A. P. Sharma
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Nuclear Emulsion ◽  
Hadronic Matter ◽  
Multiparticle Production ◽  
Particle Multiplicity ◽  
Nuclear Mass ◽  
Space Time Structure ◽  
Leading Particle ◽  
Grey Particle

An experimental study is carried out on the effects of nuclear mass on leading particle multiplicity and multiparticle production with the help of an emulsion stack exposed to 50 GeV/c π− beam under a strong pulsed magnetic field. The study of the effect of nuclear mass on the forward–backward asymmetry in a π−–A collision is also carried out using the grey particle multiplicity data. The results support the concept of "formation length" of radiation. An attempt is made to explain the space–time structure of hadronic matter in terms of the additive quark model of multiparticle production.

Sensibility of grey particle production system to energy and centrality in 60A and 200A GeV 16O–Nucleus interactions

2016 ◽  
Vol 25 (06) ◽  
pp. 1650034 ◽  
Author(s):  
A. Abdelsalam ◽  
M. S. El–Nagdy ◽  
B. M. Badawy ◽  
W. Osman ◽  
M. Fayed
Keyword(s):  
Production System ◽  
Particle Production ◽  
Target Size ◽  
Particle Multiplicity ◽  
Distribution Shape ◽  
Wide Range ◽  
Black Particle ◽  
Limiting Fragmentation ◽  
Light Target ◽  
Grey Particle

The grey particle production following 60 A and 200[Formula: see text]A GeV [Formula: see text]O interactions with emulsion nuclei is investigated at different centralities. The evaporated target fragment multiplicity is voted as a centrality parameter. The target size effect is examined over a wide range, where the C, N and O nuclei present the light target group while the Br and Ag nuclei are the heavy group. In the framework of the nuclear limiting fragmentation hypothesis, the grey particle multiplicity characteristics depend only on the target size and centrality while the projectile size and energy are not effective. The grey particle is suggested to be a multisource production system. The emission direction in the 4[Formula: see text] space depends upon the production source. Either the exponential decay or the Poisson’s peaking curves are the usual characteristic shapes of the grey particle multiplicity distributions. The decay shape is suggested to be a characteristic feature of the source singularity while the peaking shape is a multisource super-position. The sensibility to the centrality varies from a source to other. The distribution shape is identified at each centrality region according to the associated source contribution. In general, the multiplicity characteristics seem to be limited w.r.t. the collision system centrality using light target nuclei. The selection of the black particle multiplicity as a centrality parameter is successful through the collision with the heavy target nuclei. In the collision with the light target nuclei it may be qualitatively better to vote another centrality parameter.

Comparative study for target fragmentation in 4He and 6Li interactions with emulsion nuclei at Elab = 3.7A GeV

2019 ◽  
Vol 97 (6) ◽  
pp. 662-669 ◽  
Author(s):  
W. Osman ◽  
M. Fayed
Keyword(s):  
Comparative Study ◽  
Exponential Decay ◽  
System Size ◽  
Target Size ◽  
Particle Distributions ◽  
Target Fragmentation ◽  
Black Particle ◽  
Exponential Decay Law ◽  
Limiting Fragmentation ◽  
Grey Particle

The multiplicity characteristics of the grey and black particles are studied in 3.7A GeV 4He and 6Li interactions with emulsion nuclei. The dependence on the system size is examined. The data are classified according the emission direction in the 4π space. The forward or backward emitted grey particle multiplicities distributions are approximated by exponential decay law. The black particle distributions also have the decay shapes, except for the CNO target nuclei; they are shoulder-shaped curves. The production probabilities and average multiplicities increase linearly with the target size. Multiplicity correlations are carried out. Regarding the nuclear limiting fragmentation hypothesis, the grey and black particle productions are independent of the projectile size.

scholarly journals Multiplicity dependence of (multi-)strange hadron production in proton-proton collisions at $$\sqrt{s}$$ = 13 TeV

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
S. P. Adhya ◽  
A. Adler ◽  
...  
Keyword(s):  
Charged Particle ◽  
Charged Particles ◽  
General Purpose ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Production Rates ◽  
Proton Proton ◽  
Proton Collisions ◽  
Strange Hadron ◽  
Proton Proton Collisions

Abstract The production rates and the transverse momentum distribution of strange hadrons at mid-rapidity ($$\left| y\right| < 0.5$$y<0.5) are measured in proton-proton collisions at $$\sqrt{s}$$s = 13 TeV as a function of the charged particle multiplicity, using the ALICE detector at the LHC. The production rates of $$\mathrm{K}^{0}_{S}$$KS0, $$\Lambda $$Λ, $$\Xi $$Ξ, and $$\Omega $$Ω increase with the multiplicity faster than what is reported for inclusive charged particles. The increase is found to be more pronounced for hadrons with a larger strangeness content. Possible auto-correlations between the charged particles and the strange hadrons are evaluated by measuring the event-activity with charged particle multiplicity estimators covering different pseudorapidity regions. When comparing to lower energy results, the yields of strange hadrons are found to depend only on the mid-rapidity charged particle multiplicity. Several features of the data are reproduced qualitatively by general purpose QCD Monte Carlo models that take into account the effect of densely-packed QCD strings in high multiplicity collisions. However, none of the tested models reproduce the data quantitatively. This work corroborates and extends the ALICE findings on strangeness production in proton-proton collisions at 7 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.

Modeling charged-particle multiplicity distributions at LHC

2020 ◽  
Vol 35 (36) ◽  
pp. 2050302
Author(s):  
Amr Radi
Keyword(s):  
High Energy Physics ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Charged Particles ◽  
High Energy ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
8 Tev

With many applications in high-energy physics, Deep Learning or Deep Neural Network (DNN) has become noticeable and practical in recent years. In this article, a new technique is presented for modeling the charged particles multiplicity distribution [Formula: see text] of Proton-Proton [Formula: see text] collisions using an efficient DNN model. The charged particles multiplicity n, the total center of mass energy [Formula: see text], and the pseudorapidity [Formula: see text] used as input in DNN model and the desired output is [Formula: see text]. DNN was trained to build a function, which studies the relationship between [Formula: see text]. The DNN model showed a high degree of consistency in matching the data distributions. The DNN model is used to predict with [Formula: see text] not included in the training set. The expected [Formula: see text] had effectively merged the experimental data and the values expected indicate a strong agreement with Large Hadron Collider (LHC) for ATLAS measurement at [Formula: see text], 7 and 8 TeV.

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