Stochastic cooling in hadron colliders

Stochastic cooling in big hadron colliders is hampered by the high particle density, the bunch structure and by an unexpectedly large "RF-activity" up to very high frequencies. The more modest goal of tail cleaning in the LHC is made difficult due to the high discrimination required for pick-ups which selectively observe the beam halo only. This paper reviews sources of these difficulties, which have so far frustrated attempts to apply stochastic cooling to bunched beams at high energy.