Target dependence of clan model parameters at Dubna energy-chaotic pion production

Abstract

A detailed study of clan model parameters and their target dependence has been carried out in the light of void probability scaling for heavy (AgBr) and light (CNO) groups of targets present in the nuclear emulsion using 22 Ne (at an incident momentum of 4.1 GeV/c), 28 Si (at an incident momentum of 4.5 GeV/c), 16 O (at an incident momentum of 4.5 GeV/c) and 32 S (at an incident momentum of 4.5 GeV/c) projectiles. The variation of scaled rapgap probability with the single moment combination has been studied for all of the interactions. The experimental points are found to lie approximately on the NBD curve for all of the interactions, indicating a scaling behavior. According to the two-source model of particle production, in the case of 32 S-AgBr interactions at 4.5 GeV/c, the pion production mechanism has been found to be almost chaotic. On the contrary, for all of the other interactions at 4.1-4.5 GeV/c, pion production is predominantly chaotic. Average clan multiplicities (N) for all of the interactions are found to increase with the increase in the pseudo-rapidity interval η. The values of N for the AgBr target are larger than those for the CNO target. The average number of particles per clan (n c ) increases initially with the increase in pseudo-rapidity interval. An approximate saturation of the values of n c is observed for 22 Ne and 16 O projectiles around η = 6. With the increase in projectile size, the saturation of n c seems to be wiped out. It can also be observed from the tables that for a particular target the average number of particles per clan (n c ) increases with the increase in the size of the projectile nucleus. A comparison with the results of the SPS data has also been presented.

Target dependence of clan model parameter in 84 Kr 36 – Emulsion interactions at 1 GeV per nucleon

“…If experimental points can be fitted by NBD model then multi-particle production mechanism is chaotic. If experimental points can be fitted with expectations of minimal model then particle production is coherent [7,8]. However, there is also a possibility that experimental points may lie in region bounded by NBD model and minimal model then particle production mechanism is partly coherent and partly chaotic [7][8][9][10][11]21].…”

Event-by-event pseudo-rapidity fluctuations in high energy nucleus–nucleus interactions

“…We have applied the Ultra Relativistic Quantum Molecular Dynamics (UrQMD) model [62] to compute the number of kaons, hyperons or other mesons produced along with pions at Dubna energy. In our recent publication [63], we have done the same calculation that we are presenting here. Before going into the details of the calculation, we have presented a very brief introduction about the UrQMD code.…”

Projectile fragmentation of relativistic nuclei in peripheral collisions

“…In order to collect the data used for the analysis presented in this paper NIKFI-BR2 emulsion pellicles of dimension 20cm 10 cm  600  m were irradiated by the 16 O (at an incident momentum of 4.5 AGeV/c), 22 Ne (at an incident momentum of 4.1 AGeV/c) and 28 Si beam (at an incident momentum of 4.5 AGeV/c) accelerated from the Synchrophasotron at the Joint Institute of Nuclear Research (JINR), Dubna, Russia [33].…”

“…After finding the primary inelastic interactions induced by the incoming projectiles, the number of black, grey, shower tracks and the number of projectile fragments with charge Z=1,Z=2 and Z>2 were counted for all the events of each interaction using an oil immersion objective of 750X magnification of a special microscope KSM (Kernspurmessmikroskop) made by Karl Zeiss Jena [33].…”