  The energy loss of fast partons traversing the strongly interacting matter
produced in high-energy nuclear collisions is one of the most interesting
observables to probe the nature of the produced medium. The multipurpose
Compact Muon Solenoid (CMS) detector is well designed to measure these hard
scattering processes with its high resolution calorimeters and high precision
silicon tracker. Analyzing data from pp and PbPb collisions at a center-of-mass
energy of 2.76 TeV parton energy loss is observed as a significant imbalance of
dijet transverse momentum. To gain further understanding of the parton energy
loss mechanism the redistribution of the quenched jet energy was studied using
the transverse momentum balance of charged tracks projected onto the direction
of the leading jet. In contrast to pp collisions, a large fraction the momentum
balance for asymmetric jets is found to be carried by low momentum particles at
large angular distance to the jet axis. Further, the fragmentation functions
for leading and subleading jets were reconstructed and were found to be
unmodified compared to measurements in pp collisions. The results yield a
detailed picture of parton propagation in the hot QCD medium.
