Parton Showers in a Phenomenological Context

摘要

Models for generating multiple parton final states, based on the Altarelli-Parisi equations, are presented. Algorithms are described for applications in e/sup +/e/sup -/ physics, leptoproduction and hadron physics. The two latter cases are somewhat special since composite objects are present in the initial state. Constraints from structure function evolution are properly taken into account. The scheme in leptoproduction is made selfconsistent in the sense that parton shower evolution does not affect the measurable structure functions. The scheme developed in e/sup +/e/sup -/ allows for a number of different features which are not given directly in this approach, i.e. matching onto matrix elements, coherence effects, argument in alpha /sub s/, implementation of kinematics etc. These options are systematically studied, using Lund string fragmentation for hadronization, and compared with experimental data. A note on alpha /sub s/ determinations in hadron-hadron collisions is also included. (ERA citation 14:009876)