Multiplicities of forward-backward particles in 32S-emulsion interactions at 4.5 A GeV/c
Abstract:An exclusive study of the characteristics of the interactions accompanied by the backward emission (Lab 90°) of relativistic and fast hadrons in the collisions of 4.5 A GeV/c32S beam with emulsion nuclei is carried out. The experimental multiplicity distributions of different particles emitted in the forward (Lab < 90°) and backward hemispheres due to the interactions with the two emulsion components (CNO, AgBr) are presented and analysed. The correlations between the multiplicities of the different emitted particles are also investigated. This study reveals that there are signatures for a collective mechanism, which plays a role in the production of particles in the backward hemisphere. Hence, the backward multiplicity distribution of the emitted shower or grey particles at 4.5 A GeV/c incident momentum can be represented by a decay exponential law formula independent of the projectile size. The exponent of the power was found to increase with decreasing target size. The experimental data favour the idea that the backward particles were emitted due to the decay of the system in the latter stage of the reaction. While the mean values of the shower particles emitted in the forward hemisphere nfs are strongly dependent on the projectile size and incident energy, the mean value of the multiplicity of the shower particles flying into the backward hemisphere nbs are found to be only a function of the target size (i.e. impact parameter). Therefore, the results yield quite interesting information regarding the mechanism of the backward particle production in heavy ion interactions. The present data are believed to support the mechanism, which considers the backward particle production as a consequence of the isotropic decay of a highly excited target system, in its rest frame, after the forward particle emission.
Document Type: Miscellaneous
Affiliations: 1: Physics Department, Faculty of Science, Cairo University, Egypt 2: Basic Science Department, Faculty of Engineering, Zagazig University, Shoubra, Egypt 3: Physics Department, Faculty of Science, Cairo University, El-Fayom Branch, Egypt 4: Reactor Physics Department, Nuclear Research Center, Atomic Energy Authority, Egypt 5: Faculty of Education, Suez Canal University, El-Suez, Egypt
Publication date: June 1, 2002