  The difference between the structures of jets produced in heavy-ion and
hadronic collisions can best be exhibited in the correlations between particles
within those jets. We study the dihadron correlations in jets in the framework
of parton recombination. Two types of triggers, $\pi^+$ and proton, are
considered. It is shown that the recombination of thermal and shower partons
makes the most important contribution to the spectra of the associated
particles at intermediate $p_T$. In $pp$ collisions the only significant
contribution arises from shower-shower recombination, which is negligible in
heavy-ion collisions. Moments of the associated-particle distributions are
calculated to provide simple summary of the jet structures for easy comparison
with experiments.
