130 Chapter 5: pQCD vs. AdS/CFT Figure 5.3: The double ratio of R c $_{AA}$( p$_{T}$ ) to R b $_{AA}$( p$_{T}$ ) predictions for Lhc using Eq. (5.1) for AdS/CFT and WHDG [152] for pQCD with a wide range of input parameters. The generic difference between the pQCD results tending to unity con- trasted to the much smaller and nearly p$_{T}$ -independent results from AdS/CFT can be easily distinguished at $_{Lhc}$. The “(” and “]” denote momenta after which pos- sible string theoretic corrections may need to be considered; the curves’ increasing transparency from “(” to “]” is meant to additionally emphasize this, see text. κL $^{2}$ˆ q log( p$_{T}$ /M$_{Q}$ ) /p$_{T}$ , with κ a proportionality constant and ˆ q = µ 2 $_{D}$/λ$_{g}$ . The most important feature in pQCD relative to AdS/CFT is that ¯ ϵ$_{pQCD}$ → 0 asymptotically at high- p$_{T}$ while ¯ ϵ$_{AdS}$ remains constant. n$_{Q}$ ( p$_{T}$ ) is a slowly increasing function of momentum, Fig. 5.4; thus R pQCD AA increases with p$_{T}$ whereas R AdS AA decreases. This generic difference can be observed in Fig. 5.2, which shows representative predictions from the full numerical calculations of