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High pT identified particles @ PHENIX: Summary (II)
Experimental results:
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- Central AuAu collisions:
- Strong suppression (factor ~ 5) of p0 with respect to Ncoll scaling (approx. Npart scaling above ~ 4 GeV/c ).
- Suppression sets in over 50-70% centrality class (Npart ~ 50).
- No apparent suppression of (anti)protons up to ~4 GeV/c (“anomalous” p/p).
- Peripheral AuAu collisions:
- Behave effectively as pp collisions (i.e. as pQCD) for all species.
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Data vs. theory:
- Magnitude of suppression in agreement with parton energy loss scenarios assuming opaque medium formation (dNg/dy~900, l/L~3-4, dE/dx~7GeV/fm). [But also with hadronic dense medium ?].
- Flat pT dependence (so far) of suppression not described with LPM energy loss alone. Other effects (esp. Cronin broadening) needed at intermediate pT
- Parton coalescence proposed to explain baryon/pion~1 ratio at intermediate pT
- Gluon saturation prediction of Npart scaling of RAA vs centrality seems to work at high pT (but not at pT~Qs ? ).
Notes: