Mini-Jet Production in Proton-Antiproton Interactions and Particle Production in Heavy-Ion Collisions

Sammanfattning: The thesis is based on the data analysis and detector development of the EMU01/CERN, E863/BNL and UA1/CERN experiments. Particle fluctuations are studied with the scaled factorial moments in the fragmentation region of oxygen-induced emulsion interactions from 3.7 to 200 A GeV. The intermittency indices show an energy independent behaviour in the target and projectile regions of pseudorapidity. In order to study the origin of the fluctuations, jet-like and ring-like substructures of particles produced in the azimuthal plane are investigated for the S-Au, S-Em and O-Em interactions at 200 A GeV. The study shows that the two-particle azimuthal correlations can be well understood if Bose-Einstein correlations and gamma conversion are included. A nuclear rescattering model, which incorperates the FRITIOF model, has been developed. The model can well describe multiplicity distributions of slow recoiling protons, evaporation particles and their correlations with particles produced in high energy heavy-ion collisions. In the autumn of 1994, truly heavy nuclei (Pb) were accelerated to 158 A GeV/c at the CERN/SPS. In order to improve the measurements of Pb-induced collisions, an automatic system based on the CCD technique and image processing was developed. This system has been used to measure densities of the particles produced. Mini-jet production is studied using the UA1 1987 minimum bias data sample for p bar p interaction at 630 GeV of C.M.S energy. The study shows that the transverse energy distribution of mini-jets is in good agreement with the QCD prediction. The angular distributions of two leading jets show the behaviour of elastic scattering of partons with gluon exchange.