Studies of the fragmentation process in hadronic decays of Z⁰ boson
This thesis is based on the work that was done during 1992--1996 at the DELPHI detector at LEP. Its main parts are outlined below. The brief Introduction gives an overview of the science of Particle Physics, its development and contemporary status. The first chapter represents an introduction to the DELPHI detector at LEP, describing the main features of the LEP machine and the DELPHI detector a