  The spectrum of Cherenkov gluons is calculated within the framework of
in-medium QCD. It is compared with experimental data on the double-humped
structure around the away-side jet obtained at RHIC. The values of the real and
imaginary parts of the nuclear permittivity are obtained from these fits. It is
shown that accounting for an additional smearing due to resonance-like
production of final hadrons allows to achieve an agreement with experimental
data.
