The summary & conclusions:

• 30 Million Au+Au events at √sNN = 200 GeV : d2N/dpTdh for p0 measured up to pT~ 8 GeV/c in 9 different centrality classes.

• Peripheral AuAu collisions behave effectively as pp collisions.

• Central AuAu spectra significantly below peripheral AuAu and pp binary scaling extrapolations:

  • 1. Increasing suppression with pT and centrality class: ~2.5 @ pT = 2 GeV/c, ~5. @ pT = 7 GeV/c (for most central bin)
  • 2. Consistent with AuAu data at √sNN= 130 GeV.
  • 3. Qualitat. agreement with pQCD calculations + <Eloss> ~ 0.3 - 1.0 GeV/fm
  • 4. Quenching sets in at 40-60% centrality.
  • 5. Different behaviour than expected for initial-state nuclear effects:
  • • No indication of Cronin-like enhancement (WA98).
    • Different pT (xT) dependence than in shadowing  antishadowing.
• Can the high- pT depletion be explained within a (dense) hadronic scenario ? Otherwise, probably the only remaining explanation calls for high energy- density partonic medium formation.

Notes: