Some aspects of multiparticle production in high energy nuclear interactions

Abstract

We report some results on mean normalized multiplicity (RA). This quantity shows independence with energy for pion-nucleus and proton-nucleus interactions both. The variation of RA4 with mean number of collisions made by incident hdaron inside the nucleus has also been studied. Keywords: Mean normalized multiplicity, multiparticle production, created charged particles and nuclear emulsion. Subject classification PACS 13.85 - Hadron - induced high - and superhigh - energy interactions, energy > 10 GeV. I. Introduction The main concern of high energy physics is the study of fundamental particles. After having understood the properties of fundamental particles and the laws governing their interactions, one can apply these to more complex system of particles. Going back to the last many decades, one finds that there has been a growing realization that nuclear targets can give snapshots of the space-time development of a strong interaction process. Hence, it was thought that collisions of hadrons with nuclei may provide some information regarding elementary particles and their interactions which can never be known using a simple hydrogen target. People use complex atomic nuclei in high energy experiments as targets because of the fact that it gives quite unexpected and interesting results. From theoretical point of view it is believed that at high energy a nuclear collision forces the projectile to interact with the whole lot of hadronic matter within a very short period of time. Therefore, by studying the penetration of projectile in nuclear matter, one may get some very useful informations of high energy reactions within very small distances and quite short times from impact which is definitely not possible in normal particle-particle reactions. In the present investigation nuclear emulsion technique was used to collect the interactions/events which is when seen under a compound microscope look like a star. Nuclear emulsion is a material which memorises the tracks of charged particles. When a particle (projectile) collides with the nuclei (target) of emulsion, a large number of secondary particles are produced. There are three categories of secondary particles which are produced. First are the shower particles, they are mostly pions and are produced in forward cone, the other two are grey and black particles. The grey and black particles are also called as slow particles. The number of shower, grey and black particles in an interaction/event are termed as Ns, Ng and Nb. When grey and black particles are taken together, they are called as heavy tracks/particles and their number is written by Nh(=Ng+Nb). Many workers (1-12) have studied nuclear interactions using this technique. In this paper we report some results on mean multiplicity, its dependence on energy and average number of collisions made by the incident particle inside the nucleus.