  Azimuthal correlations of high-pT charged hadron pairs from
(di-)jet-fragmentation are studied at mid-rapidity in Au+Au collisions at
vsNN=200 GeV. The distribution of jet-associated partner hadrons (1.0< pT <2.5
GeV/c) per trigger hadron (2.5< pT <4.0 GeV/c) is found to vary with collision
centrality, both in shape and in yield, indicating a significant effect of the
nuclear collision medium on the (di-)jet fragmentation process.
