The theory and phenomenology of perturbative QCD based jet quenching

The study of the structure of strongly interacting dense matter via hard jets is reviewed. High momentum partons produced in hard collisions produce a shower of gluons prior to undergoing the non-perturbative process of hadronization. In the presence of a dense medium this shower is modified due to scattering of the various partons off the constituents in the medium. The modified pattern of the final detected hadrons is then a probe of the structure of the medium as perceived by the jet. Starting from the factorization paradigm developed for the case of particle collisions, we review the basic underlying theory of medium induced gluon radiation based on perturbative Quantum Chromo Dynamics (pQCD) and current experimental results from Deep Inelastic Scattering on large nuclei and high energy heavy-ion collisions, emphasizing how these results constrain our understanding of energy loss. This review contains introductions to the theory of radiative energy loss, elastic energy loss, and the corresponding experimental observables and issues. We close with a discussion of important calculations and measurements that need to be carried out to complete the description of jet modification at high energies at future high energy colliders. (C) 2010 Elsevier B.V. All rights reserved.