## Chapter 2 Motivation 

Since there are so many theoretical indications for a phase transition in QCD at low baryon chemical potential and at T > T$_{c}$ ≃ 160 MeV, and since that unexplored phase would be a truly novel and interesting state of matter in which the ordinarily confined quarks and gluons—and not protons, neutrons, pions, etc.—are the pertinent degrees of freedom, one naturally asks how one might observe the creation of such conditions. Due to the techniques used to calculate them, the experimentally measured quantities associated with heavy ion collisions naturally separate themselves into low momentum, or bulk, and high momentum jet observables. 

Although heavy ion experiments have a long pedigree this discussion will focus mainly on Rhic data (see the white papers from the four experimen- tal collaborations at Rhic for a review [77, 85–87]); this thesis focuses on jet observables, for which cross sections were simply too small at previous exper- iments, and the data from $_{Rhic}$, as discussed below, is qualitatively different 

