  The energy loss of partons in high-energy nuclear collisions is one of the
most interesting observables to probe the nature of the produced medium.
Analyzing data from PbPb collisions at a center-of-mass energy of 2.76 TeV,
recorded with the Compact Muon Solenoid (CMS) detector, parton energy loss is
observed as a significant imbalance of dijet transverse momentum. To gain
further understanding of the parton energy loss mechanism and how it manifests
itself in the distribution of final state particles, fragmentation functions
are studied for the leading and subleading jet in bins of dijet imbalance.
