  Multiple interactions between parton showers and the surrounding QCD matter
are expected to underlie the strong medium-modifications of jet observables in
ultra-relativistic heavy ion collisions at RHIC and at the LHC. Here, we note
that such jet-medium interactions alter generically and characteristically the
color correlations in the parton shower. We characterize these effects in a
color-differential calculation of the medium-induced gluon radiation spectrum
to first and second order in opacity. By interfacing simple branching histories
of medium-modified color flow with the Lund hadronization model, we analyze how
the medium modification of color correlations can affect the distribution of
hadronic fragments in jets. Importantly, we observe that jet-medium
interactions give rise to the medium-induced color decoherence of gluons from
the parton shower. Since hadronization respects color flow and since each color
singlet in a parton shower is hadronized separately, this medium-induced color
decoherence leaves characteristic signatures in the jet fragmentation pattern.
In particular, it can contribute to the quenching of leading hadron spectra.
Moreover, it can increase strongly the yield of soft hadronic fragments from a
jet, while the distribution of more energetic hadrons follows naturally the
shape of a vacuum-like fragmentation pattern of lower total energy.
