Projectile fragmentation of relativistic nuclei in peripheral collisions

摘要

.A study of multiplicity distribution of singly charged, doubly charged, multi-charged projectile fragments and shower particles has been carried out for the peripheral events of O-16 -emulsion interactions at an incident momentum of 4.5A GeV /c , Ne-22 -emulsion interactions at an incident momentum of 4.1A GeV /c and Si-28 -emulsion interactions at an incident momentum of 4.5A GeV /c . Events having no target fragments have been designated as peripheral events. Our study reveals that the average multiplicity of shower particles ( < Ns > in peripheral events can be expressed as a function of the projectile mass AP according to the relation < Ns >=(1.23 +/- 0.09( stat .)+/- 0.12( sys .))AP(0.24 +/- 0.07( stat .)+/- 0.12( sys .)) . On the other hand, in peripheral events the average multiplicity of multi-charged fragments ( < NF > varies with the mass number of the projectile beam according to the relation < NF >=(0.065 +/- 0.005( stat .)+/- 0.06( sys .))AP(0.76 +/- 0.07( stat .)+/- 0.06( sys .)) . The dispersion of multiplicity distribution for singly charged and doubly charged projectile fragments and also for shower particles increases with the increase in the projectile mass. Dispersion values of the multiplicity distribution for the multi-charged fragments decreases with the increase in the projectile mass. The study of different fragmentation modes during the emission of multi-charged projectile fragments reflects that the production of a single projectile fragment with charge Z < 2is the most probable mode of multi-charge projectile fragments emission. The probability of the production of single projectile fragment with charge Z < 2 increases with the increase in the projectile mass.