A. Shakeel

CLUSTER PRODUCTION IN 14.5A GeV/c Si-NUCLEUS COLLISIONS

Characteristics of clusters of relativistic charged secondaries produced in 14.5A GeV/c Si-nucleus collisions are investigated by examining the behaviour of the rapidity gap distribution. The findings reveal that the maximum number of relativistic charged particles constituting a cluster is four. Further, the size of the cluster is observed to remain essentially independent of the mass of the struck nucleus. A comparison of the result of the present study with those reported earlier for hadron-hadron and hadron-nucleus collisions indicates that similar mechanisms may operate in the production of secondary particles in both hadronic and nuclear collisions at high energies.

Cluster Size in 400 GeV Proton-Nucleon Interactions

An experimental study has been undertaken to determine the cluster size in p-N interactions at 400 GeV. The maximum number of charged particles constituting a cluster has been observed to be four. Comparison of this finding with those obtained for 50 GeV π - -nucleus, 400 GeV p-nucleus and 1000 GeV p-N reactions earlier, leads to the conclusion that the cluster size is independent of the identity and energy of the incident hadron which indicates that the dynamics of the cluster formation and hence the mechanism of hadronization in the final stage is probably the same in both types of reactions at high energies.

On the Characteristics of Clusters Produced in 400 GeV p-N Interactions

For examining the characteristics of clusters produced in 400 GeV p-N interactions, experimental data have been analysed in terms of the predictions of various theoretical models dealing with the interactions of peripheral nature. The results reveal that the leading particle effect is more pronounced in low multiplicity events. Furthermore, about 90% of the disintegrations having multiplicities in the interval \(6{\leqslant}n_{\text{ch}}{\leqslant}10\) possess at least one cluster. Finally, on the basis of the study of short(long)-short(long) correlations, it is concluded that there might be several clusters present in an event and the cluster on an average decay into a minimum of three charged poins.

Multiparticle production in 24, 50 and 400 GeV/c particle-nucleus interactions

SummarySome interesting aspects of multiparticle production in 24 and 400 GeV/c p-nucleus and 50 GeV/c π--nucleus collisions have been studied. The correlations of fast target protons with evaporated and shower particles produced in these interactions have been thoroughly investigated. The results reveal that the average number of shower particles produced in these interactions is in marked disagreement with the values predicted by the simple independent-particle and hydrodynamical models. Finally, on invoking the additive quark model, the mean normalized multiplicitiesR4 andR5 are observed to be independent of the nature of the projectile indicating a new kind of scaling in hadron-nucleus interactions.RiassuntoSono stati studiati alcuni aspetti interessanti della produzione di molte particelle in collisioni p-nucleo a 24 e 400 GeV/c e π--nucleo a 50 GeV/c. Sono state studiate esaurientemente le correlazioni dei protoni veloci del bersaglio con particelle evaporate e dello sciame prodotte in queste interazioni. I risultati rivelano che il numero medio di particelle prodotte in queste interazioni è in marcato disaccordo con i valori previsti dal modello semplice delle particelle indipendenti e da quello idrodinamico. In fine, chiamando in causa il modello additivo dei quark si osserva che le molteplicità medie normalizzateR4 eR5 sono indipendenti della natura del proiettile indicando un nuovo tipo di variazione di scala nelle interazioni adrone-nucleo.РезюмеИсследуются некоторые интересные аспекты множественного рождения частиц при соударениях протонов, имеющих импульсы 24 и 400 ГэВ/с, с ядрами и π- мезонов, имеющих импульс 50 ГэВ/с, с ядрами. 0 Изучаются корреляции быстрых протонов мишени с испарительными и ливневыми частицами, образованными в этих взаимодействиях. Полученные результаты показывают, что среднее число ливневых частиц, образованных в этих взаимодействиях существенно отличается от величин, предсказанных с помощью простой модели независимых частиц и с помощью гидродинамической модели. Используя аддитивнчю кварковую модель, показывается, что средние нормированные множественностиR4 иR5 не завизят от природы налетающих частиц, что указывает на новый тип скейлинга в адрон-ядерных взаимодействиях.

Scaling of Multiplicity Distribution of Charged Shower Particles in Proton-Nucleus Interactions at 400 GeV

Data on multiplicity distribution of charged shower particles produced in 400 GeV p-Em interactions have been analysed by using a single scaling function. On comparing the findings of the present work with those obtained earlier by other workers using different projectiles in the energy range ~ (19-405) GeV, it is observed that the scaled multiplicity distribution is independent of the nature and energy of the incident particle. It has further been noted that the multiplicity distribution is independent of Nh and hence v.

MULTIFRACTAL STRUCTURE IN MULTIPLICITY DISTRIBUTION OF PARTICLES PRODUCED IN RELATIVISTIC NUCLEAR COLLISIONS

Analysis of the experimental data on 14.5A GeV/c 28Si-nucleus interactions yields a linear relationship between ln〈nq〉 and ln〈n〉, for q = 2, 3, 4 and 5 and also between

Characteristics of hadron-nucleus interactions with and without emission of hadrons in the backward hemisphere

\frac{\langle n\ln n\rangle}{\langle n\rangle}

Determination of cluster size in particle-nucleus interactions at 50 and 400 GeV

and ln〈n〉, where n is the multiplicity in a given psedorapiodity bin. Generalized dimensions, Dq are also determined from the slopes of the linear variations of ln〈nq〉 with ln〈n〉. These results are supported reasonably well by the predictions of the Lund Model of nuclear collisions, FRITIOF.

Pseudorapidity distribution and cluster formation in 50 and 400 GeV/c hadron–nucleus interactions

SummaryAn attempt has been made to study the emission of hadrons produced in the backward hemisphere in nuclear emulsion at 340 GeV pion-nucleus and 400 GeV proton-nucleus collisions. Some characteristics of grey particles emitted in the forward and backward hemispheres have been investigated. The dispersion of relativistic particles depends linearly on the average multiplicity. The observed difference between the behaviour of angular distribution of grey (shower) particles in hadron-nucleus interactions with and without the emission of shower (grey) particles has also been discussed.RiassuntoSi fa un tentativo per studiare l’emissione di adroni prodotti nell’emisfero all’indietro in emulsione nucleare in collisioni protone-nucleo a 400 GeV e nucleo-pione a 340 GeV. Si sono ricercate alcune caratteristiche di particelle grigie emesse negli emisferi in avanti e all’indietro. La dispersione di particelle relativistiche dipende linearmente dalla molteplicità media. Si è anche discussa la differenza osservata tra il comportamento della distribuzione angolare di particelle grigie (dello sciame) nelle interazioni adrone-nucleo con e senza l’emissione di particelle dello sciame (grigie).РезюмеИсследуется эмиссия адронов, образованных в задней полусфере в ядерных эмульсиях при соударениях пионов с ядрами при энергии 340 ГэВ и протонов с ядрами при энергии 400 ГэВ. Излучаются некоторые характеристики серых частиц, испущенных в переднюю и заднюю полусферы. Дисперсия релятивистских частиц зависит линейно от средней множественности. Также обсуждается наблюденное различие между поведением угловых распределений серых (ливневых) частиц в адрон-ядерных взаимодействиях с и без испускания ливневых (серых) частиц.