  The detection with CoRoT of solar-like oscillations in nearly 800 red giants
in the first 150-days long observational run paves the way for detailed studies
of populations of galactic-disk red giants. We investigate which information on
the observed population can be recovered by the distribution of the observed
seismic constraints: the frequency of maximum oscillation power (nu_max) and
the large frequency separation (Deltanu). We propose to use the observed
distribution of nu_max and of Deltanu as a tool for investigating the
properties of galactic red-giant stars through comparison with simulated
distributions based on synthetic stellar populations. We can clearly identify
the bulk of the red giants observed by CoRoT as red-clump stars, i.e.
post-flash core-He-burning stars. The distribution of nu_max and of Deltanu
gives us access to the distribution of the stellar radius and mass, and thus
represent a most promising probe of the age and star formation rate of the
disk, and of the mass-loss rate during the red-giant branch.
  CoRoT observations are supplying seismic constraints for the most populated
class of He-burning stars in the galactic disk. This opens a new access gate to
probing the properties of red-giant stars that, coupled with classical
observations, promises to extend our knowledge of these advanced phases of
stellar evolution and to add relevant constraints to models of composite
stellar populations in the Galaxy.
