4.3 Quark mass versus meson mass, showing the massless pion when m$_{q}$ = 0. We plot the square root of the quark mass to demonstrate the linear relationship. . . . . . . . . . . . . . . 69 4.4 A plot of m$_{ρ}$ vs m 2 π in the Constable-Myers background on the left. Lattice data [1] (preliminary, quenched and at finite spacing) for the same quantity is also shown on the right. . . 71 5.1 Experimentally, the ρ mesons follow very closely the relation- ship m 2 n ∼ n . The dots are the physical values . . . . . . . . 81 7.1 The mass squared of the n lightest ρ meson excitations for different values of the UV cutoff. The dots represent the experimental values. . . . . . . . . . . . . . . . . . . . . . . 100 7.2 The decay constant F 1 / 2 ρ for different ρ excitations, plotted for varying UV cutoffs . . . . . . . . . . . . . . . . . . . . . 102 8.1 Hadronization . . . . . . . . . . . . . . . . . . . . . . . . . . 108 8.2 A re-enactment of a single e $^{+}$e − collision detected at CERN 108 8.3 The normalised holographic hadron basis functions for the π 0 stack (left) and the ρ meson stack (right) . . . . . . . . . . . 114 vi