We have studied the properties of the relativistic helium fragments emitted from the projectile in the interactions of 24Mg ions accelerated at an energy of 3.7 A GeV with emulsion nuclei. The total, partial nuclear cross-sections and production rates of helium fragmentation channels in relativistic nucleus-nucleus collisions and their dependence on the mass and energy of the incident projectile nucleus are investigated. The yields of multiple helium projectile fragments disrupted from the interactions of 24Mg projectile nuclei with hydrogen H, light CNO and heavy AgBr groups of target emulsion nuclei are discussed and they indicate that the breakup mechanism of the projectile seems to be independent of the target mass. Limiting fragmentation behavior of fast-moving helium fragments is observed in both the projectile and target nuclei. The multiplicity distributions of helium projectile fragments emitted in the interactions of 24Mg projectile nuclei with the different target nuclei of the emulsion are well described by the KNO scaling presentation. The mean multiplicities of the different charged secondary particles, normally defined shower, grey and black ( 〈ns〉, 〈ng〉 and 〈nb〉) emitted in the interactions of 3.7 A GeV 24Mg with the different groups of emulsion nuclei at different ranges of projectile fragments are decreasing when the number of He fragments stripped from projectile increases. These values of 〈ni〉 ( i = s, g, b and h particles) in the events where the emission of fast helium fragments were accompanied by heavy fragments having Z ⩾ 3 seem to be constant as the He multiplicity increases, and exhibit a behavior independent of the He multiplicity.

http://becquerel.jinr.ru/text/Papers/2pnu0felnml3fpmk.pdf

Fast helium production in interactions of 3.7 A GeV 24Mg with emulsion nuclei

In this work, the electromagnetic dissociation (EMD) of sulphur projectile induced by two widely differing energies in nuclear emulsions is investigated. Although the percentages of EMD events of the total numbers of studied interactions are relatively small, i.e. 5.7 and 14.4% for 3.7 and 200A GeV interactions respectively, one could extract some results out of them. The emission of a proton through the 32S(γ, p)31P channel is found to be a dominant process (43.8%) at 200A GeV whereas the single alpha emission through the 32S(γ, α)28Si channel is the dominant one (34.0%) at 3.7A GeV. Multiplicity distributions of hydrogen and helium isotopes as well as the measured probabilities for the different modes of fragmentation are studied. The comparison of the present results, from electromagnetic and peripheral nuclear interactions, indicates the effective role of the different reaction mechanisms at ultra-relativistic energy (200A GeV). The experimental inclusive cross sections of different fragmentation modes produced in the EMD of 32S ions at 200A GeV were found to be in satisfactory agreement with the predictions of the combined approach of Pshenichnov et al.

https://iopscience.iop.org/article/10.1088/0954-3899/28/2/305/pdf

Sulphur dissociation in nuclear emulsion at 3.7 and 200A GeV

Analysis of target fragmentation induced by relativistic 24Mg

This paper presents the results of the study of interaction of the relativistic 16 O nucleus with the momentum 4.5 A GeV/c with the photo emulsion. The average multiplicities of the different emitted hadrons (shower and grey) in the forward (FHS) and backward (BHS) hemisphere, compared with other data from the interaction of 1 P, 4 He, 6 Li, 12 C, 22 Ne and 28 Si at nearly the same momentum, have been studied as a function of projectile mass number, the number of interacting projectile nucleons, impact parameter and number of shower particles emitted in the backward hemisphere. The multiplicity distribution of the shower particles emitted in the forward and backward hemisphere directions using the KNO representation are represented and described by an exponential form for BHS shower particles. Another objective of this paper is to examine whether the mechanism of particle production in the BHS is significantly different from the operating in the production of particles in the FHS which can help to solve some questions connected with the role of collective phenomena in the backward emission of particles from the nuclear targets.

Study of backward, forward shower and grey particles production from the interactions of 16O with emulsion nuclei at 4.5 AGeV/c

In the present work, we calculate the total reaction cross sections for the reactions of the following projectiles: P, 12C, 14N, 16O, 22Ne, 24Mg, 28Si, and 32S with emulsion nuclei, at incident ene...

The mass-number dependence studies for the multiplicity of shower particles produced in interactions of different projectiles with emulsion nuclei at 3.7 GeV/n in the framework of the modified Glauber models I and II

Projectile multifragment breakup of 16O, 2C and 7Li at energies 3.0–4.5 A-GeV is studied by means of the Weizsacker-Williams method. The fragmentation channels of the 16O projectile at 4.5 A-GeV are investigated and compared with that of 16O at 200 A-GeV. The events characterized by Nh=0 and the events due to both Coulomb and diffraction dissociation have been selected and analyzed as a function of impact parameter. Also, the dependence of the electromagnetic dissociation cross-section on incident energy and the charge of projectile and target is found.

Coulomb dissociation of incident 16O at 4.5 GeV/c

The charged-particle multiplicities produced in inelastic interactions of16O ions at 3.7 and 60A GeV with emulsion nuclei are investigated and compared with theoretical predictions. Results from the interaction with CNO and AgBr target nuclei are analysed in terms of negative binomial (NB) distribution. Data from other nucleus-emulsion collision experiments have been used to fit an empirically proposed relationship for the average value of total charged multiplicity as a function of the geometrically determined number of interacting nucleons.

Some characteristics of produced particles in16O-emulsion collisions at different relativistic energies

The interaction of 400 GeV/c protons and 340 GeV/c π- with nucleons in nuclear emulsion has been investigated. The interaction mean free paths (m.f.p.) and the corresponding reaction cross-sections (σin) have been found, the multiplicity distributions for the events with Nh = 0 (clean events) are measured and studied as well as the angular and pseudorapidity distributions. Finally the coherent multiparticle production cross-sections (σcoh) were estimated and compared with other data, where it was found to be increasing slowly with increasing incident momentum for protons while it increases rapidly with increasing π--momentum.

S. M. Abd El-Halim

Papers

Coulomb dissociation of incident 16O at 4.5 GeV/c

Some characteristics of produced particles in16O-emulsion collisions at different relativistic energies

Some Analysis of Hadron-Nucleon Collisions at High Energy Inelastic Interactions in Photo-Emulsion

Fast deuteron and deuteron-like pairs produced in proton interactions with emulsion nuclei at 8.4 GeV/c