dips to a minimum near p$_{T}$ ∼ 10 GeV; one must be cautious, though, as many of the assumptions in the elastic energy loss derivations break down for p$_{T}$ ̸≫ M$_{Q}$ . 

Future$_{Rhic}$ detector upgrades will allow for individual charm and bottom quark detection. Predictions for R c $_{AA}$( p$_{T}$ ) and R b $_{AA}$( p$_{T}$ ) at$_{Rhic}$ from Eq. (5.1) and pQCD are shown in Fig. 5.5. As seen in Fig. 5.4 the power law production index grows quickly at $_{Rhic}$; we now expect the rapid increase in n$_{Q}$ to over- come the (relatively in comparison) slow decrease in ϵ$_{pQCD}$ so that, unlike at $_{Lhc}$, dR$_{AA}$/dp$_{T}$ ≯ 0. In fact Fig. 5.5 shows that the full numerical results for R Q AA from pQCD and AdS/CFT drag both decrease with p$_{T}$ . Nonetheless one may still examine the double ratio R $^{cb}$, Fig. 5.6. While the larger index makes the grouping less dramatic at Rhic one may still differentiate between pQCD and AdS/CFT drag. Due to its smaller multiplicities, the temperature of the medium at Rhic is smaller than will be seen at $_{Lhc}$; hence the AdS/CFT drag “speed limit”, Eq. (5.4), is higher at Rhic than $_{Lhc}$. 

## 5.4 Conclusions 

Possible strong coupling alternatives to pQCD in nuclear collisions were stud- ied based on a recent AdS/CFT model of charm and bottom energy loss. The predicted nuclear modification factors, R Q $_{AA}$, were found to be decreasing as a function of p$_{T}$ , as compared to increasing as predicted from pQCD. We showed that the momentum dependence differences in the individual R Q AA can 

