the possible effect of anomalous dimensions and higher dimension operators, and find that for the cases we consider, the results are changed minimally. Here our starting point is the model described in section 5.5, chosen both because of its simplicity, and because the model is smooth for the entire IR spectrum. Whereas before we were looking for solutions to the equations of motion that went like f$_{n}$ ( r ) ∼ r − 2 as r → ∞ , we now look for solutions that go like f$_{n}$ ( r ) ∼ r − 2 at r = Λ. Λ is the cutoff, above which QCD be- comes perturbative or, in the holographic dual, the scale below which the supergravity approximation is trustable. Λ will be determined phenomeno- logically. For convenience, we reproduce the equation of motion for the vector meson spectrum (5.29) here: The results for the first five radial excited states with several different values of Λ are shown in figure 7.1. Note that the Λ = ∞ reproduces that of section 5.5, as expected. The best phenomenological fit is when the cutoff is set at 194 MeV, and gives an rms error of just 1.8%. This is a startling result, not just because the fit is so good, but also because it suggests that the regime of validity of a gravity dual to QCD is rather small. Similar conclusions were made in [144]. It is worth pointing out that with this value of Λ, we predict the next 3 excited ρ mesons to be at 2320 MeV, 2475 MeV and 2626 MeV. Experimen- tal searches have reached up to 2510 MeV, and so far the highest excited ρ 99 7.2 A UV Cutoff ∂$_{z}$ ( e − z 2 z ∂$_{z}$v$_{n}$ ) + m 2 n e − z 2 z v$_{n}$ = 0 (7.1)