H. Khushnood

Study of disintegrations caused by 4.5 GeV carbon nuclei in nuclear emulsion

SummaryAn attempt has been made to investigate the characteristics of secondary particles produced in 4.5 GeV/c12C-nucleus reactions. The correlations of fast target protons with evaporated and shower particles emitted in12C-nucleus interactions have been thoroughly studied. The results reveal that /D increases withNg and is in fine agreement with the predictions of the simple independent particle model. Furthermore, the ratioD/ decreases withNg. This result is in marked disagreement with the predictions of collective tube model and supports the models which include repeated collisions. Finally our results are almost similar to those obtained in high-energy particle-nucleus collisions.

Some Results on Angular Characteristics of Relativistic Charged Particles Produced in 12C-emulsion Interactions at 4.5 A GeV/c

An attempt has been made to study the angular characteristic of relativistic charged particles produced in 4.5 A GeV/c 12C-emulsion collisions. The dependence of these characteristics on the multiplicity of the relativistic particles, Ns, has also been investigated. The results reveal that the angular distributions of relativistic particles do not depend on Ns, except at small angles where contribution of singly charged particles fragments enhances the number of relativistic charged particles. It is also observed that the maximum of pseudorapidity, η and distributions, shifts towards the lower value of η with increasing multiplicity of Ns. The study of the rapidity dispersion of relativistic charged particles reveals that the clusterization effect occurs significantly among the final state relativistic particles produced in heavy ion interactions.

INTERESTING FEATURES OF PARTICLES PRODUCED IN 4.5 A GeV/c28Si-EMULSION INTERACTIONS

Results on some interesting features of secondary particles produced in collisions of 4.5 A GeV/c 28Si with emulsion nuclei are discussed. Mean multiplicities of grey, black, shower and heavily ionizing particles obtained in this study are compared with their corresponding values obtained for different projectile nuclei. The variations of D(Ns) and with and D(Nc) and with are also investigated. Finally, integral Nc distribution is plotted and fitted with a best-fitting analytical expression.

Angular characteristics of charged shower particles in 4.5A GeV12C-nucleus interactions

SummaryA study of angular characteristics of charged shower particles in terms of pseudorapidity, η, has been carried out by analyzing the experimental data obtained in 4.5 A GeV12C-emulsion interactions. It is observed that the maxima of rapidity width,R(η), distribution shifts towards the smaller values ofR(η) with decreasing impact parameter. It is observed that the average pseudorapidity, and the dispersion,D(η) decrease with an increase in the value of different multiplicities of secondary particles. It is also found that andD(η) strongly depend on the impact parameter. The results also reveal that the values of andD(η) remain almost the same beyond grey particle multiplicity, Ng > 11 and heavy ionizing particles, Nh > 28.

Peripheral collisions caused by 4.5A GeV/c carbon and silicon nuclei

SummaryIn order to study some interesting characteristics of peripheral collisions caused by 4.5A GeV/c carbon and silicon ions in nuclear-emulsion targets, experimental data have been analysed; multiplicity and angular distributions of relativistic charged particles have also been investigated. Results indicate that the characteristics of peripheral collisions depend on the projectile mass. Also positive evidence regarding occurrence of two-particle correlation in these collisions has been obtained.

Production of Secondary Charged Particles in 12C-Nucleus Reactions at 4.5 GeV per Nucleon.

The dependence of the normalized mean multiplicity, R A and reduced multiplicity R S on the enrgy of the projectile in the energy range ∼(2–200) A GeV, has been investigated. Furthermore, the dependence of R A and R S on the mass of the projectile and target nucleus in 4.5 A GeV 12 C-nucleus interactions have also been studied. The variations of R A and R S are found to increase linearly with increasing value of the multiplicity of charged secondaries produced in 4.5 A GeV/c 12 C-nucleus collisions. The results reveal that the normalised and reduced multiplicities of relativistic charged particles depend strongly on the projectile mass. The results reveal that the nature of the dependence of R A on various parameters are identical with those obtained in high energy hadron-nucleus interactions. Finally, the values of the normalised moments of the multiplicity distributions of charged shower particles for different groups of emulsion nuclei were found to be nearly the same.

Dependence of Cluster Size on Shower Particle Multiplicity

Characteristics of clusters and the dependence of their size on the multiplicity of charged shower particles are investigated by analysing the experimental data involving 50 GeV negative pion and 400 GeV proton interactions with emulsion nuclei. The results reveal that the maximum number of particles constituting a cluster is four for the disintegrations with \(n_{s}{\geqslant}10\), where n s is the number of charged particles having \(\beta{\geqslant}0.7\), whilst this number is observed to be three for the events having n s <10. The findings also suggest that cluster size is independent of the nature and energy of the impinging hadron.

Multiplicity correlations in the forward and backward hemispheres in12C-nucleus interactions at 4.5A GeV/c

SummaryAn attempt has been made to investigate the characteristics of secondary charged shower particles produced in the forward and backward hemispheres in 4.5A GeV/c12C-emulsion interactions. The results reveal that the impact parameter has a strong bearing onm-distributions. The ratioNsF/NsB is found to increase with increasing projectile masses. The value of the leading particle multiplicity is estimated to be (0.45±0.04) in the case of12C-nucleus reactions at 4.5A GeV/c. Finally, the forward-backward multiplicity correlations are observed to be linear. However, the value of the slope parameter is found to depend strongly on the mass of the projectile.