List of Tables 1.1 Experiments that have detected heavy quarkonium-like states. . . . . . . . . 2 1.2 Experimentally confirmed heavy quarkonium-like states. In all cases the num- ber in parentheses indicates the mass in units of MeV. This system of units is called natural units and is discussed in Appendix A. . . . . . . . . . . . . 3 1.3 Phenomenological values of the light and heavy quark masses as given in Ref. [20]. 5 1.4 Summary of thesis research. . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 viii