List of Figures vi 1.1 Momentum representation of two (a) two-jet events and (b) three-jet events. Figure adapted from [42]. . . . . . . . . . . . 6 1.2 (a) Heavy quark potential at T = 0 from LQCD calculations in [61]. The lattice results are well approximated by the Cornell potential, V ( r ) = − α/r + r . Figure adapted from [62]. (b) Lattice QCD results divided by experimental data for a range of nonperturbative quantities; the values agree to within statistical and systematic errors of 3% or less. Figure adapted from [63]. 7 1.3 R = σ ( e $^{+}$e − → hadrons) /σ ( e $^{+}$e − → µ $^{+}$µ $^{−}$) plotted against electron energy in GeV. Above 5 GeV, R is well approximated by N$_{c}$ $^{∑}$Q 2 f with N$_{c}$ = 3. Figure adapted from [7]. . . . . . . 8