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Summary

 High pT central Au+Au vs p+p at midrapidity at RHIC:
 Observation 1: Light-flavor (u,d,s) spectra suppressed by a factor 4-5.
- (possible suppression already at √s ≈ 20 GeV).

 Observation 2: Intermediate pT light-flavor composition inconsistent with known fragmentation functions in free space.

 Observation 3: Heavy-flavor (c) spectra unsuppressed (?).

 Observation 4: Direct photon spectra unsuppressed.

 High pT d+Au vs p+p at midrapidity at RHIC:

 Observation 5: Spectra enhanced by a factor ~1.3

 “Explanation” (1,2 via 4,5): pQCD hard scattering + final-state parton energy loss + parton recombination:

 Dense thermal QCD medium.

 High pT in d+Au at forward rapidities at RHIC:

 Observation 6: Spectra suppressed by a factor ~2-3.

 “Explanation” (6): possible evidence of high twist effects at small-x.