2.6 Suppression of π 0 and charged hadron jets in central Au + Au collisions compared to binary scaled p + p reactions at √ s = 130 GeV at Rhic from 2001. Figure adapted from [192]. . . . . . 28 

2.7 (a) d + A results from STAR [218] show that high- p$_{T}$ suppres- sion is not due to initial state effects; figure adapted from [86]. (b) R γ $_{AA}$( N$_{part}$ ) ∼ 1 extends the results of (a) to show that jet suppression is not due to initial state effects in full A + A colli- sions. NLO prompt photon predictions [219–222] compare well to the PHENIX data [223]; figure adapted from [223]. . . . . 30 

2.8 Examples of surface bias in different nuclear geometries. Sim- plified nuclear geometries such as hard spheres, and especially hard cylinders, create greater surface bias. . . . . . . . . . . . 41 

2.9 (a) The energy loss model on a linear-linear scale appears to be losing sensitivity; increasing ˆ q appears to be less and less effective at decreasing R$_{AA}$ . (b) The same plot but on a log-log scale. It is clear from the fit that R$_{AA}$ (ˆ q ) ∼ 1 / ˆ q 1 / 2 and is equally sensitive at all values of ˆ q explored here. Figure adapted from [310]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 

2.10 A simple estimate of the large systematic theoretical error due to the running of the coupling. Convolved collisional + radiative energy loss calculations [243] of π 0 R$_{AA}$ ( p$_{T}$ ) at Rhic for fixed α$_{s}$ = . 3, .4, and .5. Figure adapted from [243]. . . . . . . . . . 44 

