37 Chapter 2: Motivation this case where p n = (1 − z ) p i and p f = (1 − ϵ ) / (1 − z ) p n = (1 − ϵ ) p $^{i}$. In [243] rela- tive branching results closely resembled those from truncation; redistributing probability evenly gives excess weight to low ϵ probabilities, which—due to the steeply falling spectrum—disproportionately affects the results. As can be seen from the above equations the Poisson convolution must have all interme- diate energy loss steps evaluated at the same p$_{T}$ , or else it will not be properly normalized. For large fractional energy loss, the apparent case at $_{Rhic}$, this is not a good approximation; it is not clear how large an effect this has on physical observables. P$_{n}$$_{+1}$ ( ϵ | p$_{T}$ ) = 1 n + 1 ∫ dz 1 − z P$_{n}$ ( z | p$_{T}$ ) dN$_{g}$ dx ( ϵ − z 1 − z | p$_{T}$ ) , (2.9) Around the same time Wang began the development of the ‘Higher-Twist’ formalism [280–284]. Similarly to GLV, the derivation builds up the energy loss from single hard scatterings but differs by making some alternative as- sumptions in their evaluation. Most important, the arbitrary potential in GLV—usually taken as Yukawa—is replaced by an arbitrary gluon distribu- tion function. This obscures the relation between jet suppression patterns and physical medium quantities such as density and temperature. For a review comparing the two results see [297]. Motivated by the ‘dead cone’ work of Dokshitzer and Kharzeev [298]—just as in QED, in QCD a massive charge also radiates less—and hoping for a