  Calculations using the AdS/CFT correspondence can be used to unveil the
short-distance structure of a strongly coupled plasma, as it would be seen by a
`hard probe'. The results of these calculations admit a natural physical
interpretation in terms of parton evolution in the plasma: via successive
branchings, essentially all partons cascade down to very small values of the
longitudinal momentum fraction x and to transverse momenta smaller than the
saturation momentum Q_s\sim T/x. This scale Q_s controls the energy loss and
the transverse momentum broadening of an energetic jet propagating through the
plasma. This picture has some striking consequences, like the absence of jets
in electron-proton annihilation at strong coupling, of the absence of particle
production at forward and backward rapidities in hadron-hadron collisions,
which look very different from the corresponding predictions of perturbative
QCD and also from the known experimental situation.
