  Jet reconstruction in heavy-ion collisions is strongly affected by soft
background from the underlying event. For an appropriate interpretation of the
jet observables it is essential to understand the influence of the background
and its fluctuations on the reconstructed jets. With this purpose we study
random cones and the response of a known probe embedded in a heavy-ion events.
The embedded probe can be a single high-p_T track or a jet from a simulated or
real pp event. This allows a detailed study of background fluctuations and
verification of the performance of background subtraction methods.
