Nuclear geometry of jet quenching
  The most suitable way to study the jet quenching as a function of distance traversed is varying the impact parameter b of ultrarelativistic nucleus-nucleus collision (initial energy density in nuclear overlapping zone is almost independent of b up to b R_A). It is shown that b-dependences of medium-induced radiative and collisional energy losses of a hard parton jet propagating through dense QCD-matter are very different. The experimental verification of this phenomenon could be performed for a jet with non-zero cone size basing on essential difference between angular distributions of collisional and radiative energy losses. 
I.P.Lokhtin, A.M.Snigirev