  In-medium production of leading hadrons in hard reactions, carrying the main
fraction of the jet momentum, involves two stages: (i) the parton originated
from the hard process propagates through the medium radiating gluons due to the
initial hard collision, as well as to multiple interactions in the medium; (ii)
perturbative color neutralization, e.g. picking up an anti-colored parton
produced perturbatively, followed by evolution and attenuation of the
(pre)hadron in the medium. The color neutralization (or production) length for
leading hadrons is controlled by coherence, energy conservation and Sudakov
suppression. The pT-broadening is a sensitive and model independent probe for
the production length. The color neutralization time is expected to shrink with
rising hard scale. In particular, we found a very fast energy dissipation by a
highly virtual parton: half of the jet energy is radiated during the first
Fermi. Energy conservation makes the production of leading hadrons at longer
times difficult.
