Simulation of Colour Evolution in QCD Scattering Processes

Abstract

We investigate the effects of colour evolution in QCD scattering processes and how these can be implemented in both analytical and numerical approaches. We split this in to four parts where each part is given in one chapter.In the first chapter we give a brief summary of the important aspects of QCD which are needed as a basis for the rest of the investigation. In addition to this, we describe different sets of formalisms for handling colour within interactions. We then give a brief review of the components of a Monte-Carlo event generator.In the second chapter we review previous work by the author on jet vetoes and their implementation in the Monte-Carlo event generator Herwig++. We describe the analytical method for studying jet vetoes and then discuss the differences between this method and that which is used in the original parton shower of Herwig++. Once this is done we make changes to both the analytical approach and Herwig++ in order to investigate these differences. We then show the results for an improved parton shower as a result of this investigation. In the third chapter we consider the effects of tuning the parameters within Herwig++. We investigate what parameters are likely to have the most changes to observables given the modifications made in the previous chapter. We then produce seven tunes to different sets of observables and discuss said tunes.In the fourth and final chapter we discuss the effects of sub-leading colour within the analytical approach and in a potential numerical setup. We discuss a set of potential algorithms for implementing sub-leading colour within a standalone parton shower.

Date of Award	3 Jan 2014
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Michael Seymour (Supervisor)