Quark Shell Model Calculations of Baryon Interactions

In this thesis, the form of baryon-baryon interactions is investigated using a non-relativistic quark potential model, within the framework of the shell model. It describes the further development of the previous quark model studies carried out by the group. The two nucleon (or baryon) system is treated as a system of six quarks, split into two clusters. A two-body interaction potential based on gluon exchange between individual quarks is introduced, along with a phenomenological confinement potential. The energy of the system is calculated for different values of the cluster separation, to build up a picture of the overall interaction. The model is then extended to include 6q(qq) configurations in the model space, as a crude approximation to describing the meson excitations which are essential to a full description of the interaction. An appropriate potential is included to describe these qq excitation effects. Chapter 1 provides an introduction to the nucleon-nucleon interaction and the quark model in general, and describes non-relativistic quark potential models. Chapter 2 gives background information on the shell-model and its applications and goes on to describe how such models from nuclear physics have been carried over into quark model calculations. It also gives more details of previous work in the area. In chapter 3, the theory behind the model and the details of its implementation are discussed in detail. Chapter 4 describes the gluon exchange potentials used in the model and the calculation of the matrix elements associated with them. The results of the calculations and analysis of the wavefunctions are given in chapter 5. In chapter 6, we examine the results in more detail and end with a critique of the model as it currently stands