SOME CHARACTERISTICS OF THE COMPOUND MULTIPLICITY IN HIGH-ENERGY NUCLEUS–NUCLEUS INTERACTIONS

2011 ◽  
Vol 20 (08) ◽  
pp. 1735-1754 ◽  
Author(s):  
M. MOHERY ◽  
M. ARAFA
Keyword(s):  
Experimental Data ◽  
Impact Parameter ◽  
Mass Number ◽  
Multiplicity Distribution ◽  
High Energy ◽  
Projectile Nucleus ◽  
Target Mass ◽  
Compound Multiplicity ◽  
Multiplicity Distributions ◽  
The Impact

The present paper deals with the interactions of 22 Ne and 28 Si nuclei at (4.1–4.5)A GeV /c with emulsion. Some characteristics of the compound multiplicity nc given by the sum of the number of shower particles ns and grey particles ng have been investigated. The present experimental data are compared with the corresponding ones calculated according to modified cascade evaporation model (MCEM). The results reveal that the compound multiplicity distributions for these two reactions are consistent with the corresponding ones of MCEM data. It can also be seen that the peak of these distributions shifts towards a higher value of nc with increasing projectile mass. It may further be seen that the compound multiplicity distributions becomes broader with increasing target size and its width increases with the size of the projectile nucleus. In addition, it has been found that the MCEM can describe the compound multiplicity characteristics of the different projectile, target and the correlation between different emitted particles. The values of average compound multiplicity increase with increasing mass of the projectile. Furthermore, it is observed that while the value of 〈nc〉 depends on the mass number of the projectile Ap and the target mass number At, the value of the ratio 〈nc〉/D(nc) seems to be independent of Ap and At. The impact parameter is found to affect the shape of the compound multiplicity distribution. Finally, the dependence of the average compound multiplicity on the numbers of grey and black particles, and the sum of them, is obvious. The values of the slope have been found to be independent of the projectile nucleus.

scholarly journals TACHYON DYNAMICS OF THE BLACK DISC LIMIT IN THE HARD SMALL x PROCESSES IN QCD

2006 ◽  
Vol 21 (07) ◽  
pp. 549-558 ◽  
Author(s):  
B. BLOK ◽  
L. FRANKFURT
Keyword(s):  
Cross Section ◽  
Impact Parameter ◽  
High Energy ◽  
Black Disk ◽  
Black Disc ◽  
Energy Behavior ◽  
Small X ◽  
The Cross ◽  
The Impact ◽  
Black Disc Limit

We investigate the effective field theory (EFT) which gives the approximate description of the scattering of two hard small dipoles in the small x processes in QCD near the black disc limit (BDL). We argue that the perturbative QCD approaches predict the existence of tachyon and visualize it in the approximation where α′P=0. We demonstrate that the high energy behavior of the cross-section depends strongly on the diffusion law in the impact parameter plane. On the other hand, almost threshold behavior of the cross section of the hard processes and multiplicities, i.e. fast increase of cross sections (color inflation), melting of ladders into color network and softening of the longitudinal distributions of hadrons are qualitatively insensitive to the value of diffusion in the impact parameter space. We evaluate α′P near the black disk limit and find significant α′P as the consequence of the probability conservation.

scholarly journals Dependence of the multiplicities of secondary particles on the impact parameter in collisions of high-energy neon and iron nuclei with photoemulsion nuclei

1993 ◽  
Vol 551 (4) ◽  
pp. 723-733 ◽  
Author(s):  
V.E. Dudkin ◽  
E.E. Kovalev ◽  
N.A. Nefedov ◽  
V.A. Antonchik ◽  
S.D. Bogdanov ◽  
...  
Keyword(s):  
Impact Parameter ◽  
High Energy ◽  
Secondary Particles ◽  
The Impact

Nonstatistical fluctuations of target fragments emitted in high-energy nucleus–nucleus collisions

2002 ◽  
Vol 80 (2) ◽  
pp. 119-128
Author(s):  
N N Abd-Allah
Keyword(s):  
Excitation Energy ◽  
Impact Parameter ◽  
Target Nucleus ◽  
Incident Energy ◽  
Nuclear Emulsion ◽  
Residual Nucleus ◽  
High Energy ◽  
Critical Value ◽  
Nucleus Interaction ◽  
The Impact

Analysis of target-fragmented "black" particles in nuclear emulsion from high-energy relativistic interactions initiated by 28Si at 4.5 A GeV/c is investigated. The number of slowly emitted particles from the struck target nucleus is considered as a measure of the degree of excitation of the residual nucleus. This number shows a constant critical value, with the degree of the impact parameter or the degree of excitation. The target evaporation particles of nucleus–nucleus interaction reveal the existence of nonstatistical fluctuations in the azimuthal plane of the interaction. The asymmetry or nonstatistical fluctuations, while found to be independent of projectile mass or incident energy, are dependent on the excitation energy of the target nucleus. A multiparticle correlation is observed between created particles as well as target fragments. This assumes production of clusters. These clusters seem to be formed during the decoloring process. PACS No.: 25.70Mn

scholarly journals Short- and long-range rapidity correlations in the model with a lattice in transverse plane

2018 ◽  
Vol 191 ◽  
pp. 04011 ◽  
Author(s):  
Vladimir Vechernin
Keyword(s):  
Long Range ◽  
Impact Parameter ◽  
String Model ◽  
High Energy ◽  
Transverse Plane ◽  
Observation Window ◽  
Hadronic Interactions ◽  
Fundamental String ◽  
Different Types ◽  
The Impact

In the framework of the quark-gluon string model we consider the various fluctuation and correlation observables used in the analysis of the multiparticle production in hadronic interactions at high energy. We express these observables through the fundamental string characteristics and analyze their resulting properties: the dependence on the width of observation window(s), the range of the correlation in rapidity, the intensive or strongly intensive behavior. To take into account the influence of a string fusion processes on the string characteristics and on the behavior of the observables. we use the version of string model with a lattice (grid) in the impact parameter plane. In particular we show that the observable between multiplicities in two acceptance windows separated in rapidity, which is a strongly intensive in the case with independent identical strings, loses this property, when we take into account the string fusion and the formation of strings of a few different types takes place in a collision.

On the possibility of gluon number fluctuations in diffractive deep inelastic scattering data with impact parameter

2016 ◽  
Vol 31 (33) ◽  
pp. 1650186
Author(s):  
Z. Hu ◽  
W. Xiang ◽  
S. Cai
Keyword(s):  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Impact Parameter ◽  
Scattering Amplitude ◽  
Global Analysis ◽  
High Energy ◽  
Scattering Data ◽  
Deep Inelastic Scattering Data ◽  
Saturation Exponent ◽  
The Impact

A global analysis of the latest diffractive deep inelastic scattering (DIS) data with gluon number fluctuations and impact parameter is performed. The impact parameter is introduced into the scattering amplitude by saturation scale with a Gaussian b-dependence. The results show that the description of the diffractive DIS data is improved once the gluon number fluctuations and impact parameter are included, with [Formula: see text]/d.o.f = 0.878, [Formula: see text]/d.o.f = 0.928 and [Formula: see text]/d.o.f = 0.897 in different sets of free parameters. Moreover, we find that the impact parameter ([Formula: see text] 0.1) is possibly compressed by the gluon number fluctuations, which leads to the value of saturation exponent returning to [Formula: see text] 0.2. This outcome is compatible with the prediction that the saturation exponent is dominated by the fluctuations at sufficiently high energy, which may indicate the possibility of gluon number fluctuations in diffractive DIS data.

Calculation of many-beam dynamic electron diffraction without high-energy approximation

1996 ◽  
Vol 54 ◽  
pp. 128-129
Author(s):  
B. R. Ahn ◽  
N. J. Kim
Keyword(s):  
Electron Diffraction ◽  
Flat Surface ◽  
Dynamic Theory ◽  
High Energy ◽  
Perfect Crystal ◽  
Zone Axis ◽  
Beam Dynamic ◽  
Diffraction Angle ◽  
Energy Approximation ◽  
The Many

High energy approximation in dynamic theory of electron diffraction involves some intrinsic problems. First, the loss of theoretical strictness makes it difficult to comprehend the phenomena of electron diffraction. Secondly, it is difficult to believe that the approximation is reasonable especially in the following cases: 1) when accelerating voltage is not sufficiently high, 2) when the specimen is thick, 3) when the angle between the surface normal of the specimen and zone axis is large, and 4) when diffracted beam with large diffraction angle is included in the calculation. However, until now the method to calculate the many beam dynamic electron diffraction without the high energy approximation has not been proposed. For this reason, the authors propose a method to eliminate the high energy approximation in the calculation of many beam dynamic electron diffraction. In this method, a perfect crystal with flat surface was assumed. The method was applied to the calculation of [111] zone axis CBED patterns of Si.

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