1. Goal Answer question: –Was the approximate constancy of R AA in GLV calculations a pre-diction or post-diction. Why is this important ? –Jamie made a good argument: There are only two clear features in single-particle R AA –Suppression magnitude –Constancy with p T If GLV didn’t predict ~ constant R AA then it’s hard to argue that it uniquely describes the observed suppression. Especially given Sarcevic et al analysis showing similar feature from Bethe-Heitler energy loss.

2. Test #1 Use fixed opacity – clearly too simple but opacity 2-4 all ~ constant in unmeasured region. “DISCOVERY OF JET QUENCHING AT RHIC AND THE OPACITY OF THE PRODUCED GLUON PLASMA”, P. Levai et al, Nucl. Phys. A698: 631- 634,2002 -- nucl-th/0104035

3. Test #2 Both charged & pion ~ constant with pt Pion shows some slope vs pt h +/- less suppressed at 7-8 GeV/c for same gluon dn/dy. “THE ROLE OF JET QUENCHING IN THE ANTI-P GREATER THAN OR EQUAL TO PI- ANOMALY AT RHIC”, Proceedings of International Europhysics Conference on High-Energy Physics, July 2001, hep-ph/0109198

4. Test #3 JET TOMOGRAPHY OF AU+AU REACTIONS INCLUDING MULTIGLUON FLUCTUATIONS, Gyulassy, Levai, Vitev, Phys.Lett.B538:282- 288,2002 Evaluates effect of fluctuations in # of emitted gluons R AA looks less flat with pt for both cases ??

5. Test #3 Compared to others/data Put test #3 R AA on same scales as other plots & data.  Calculations are consistent.  As is data out to 10 GeV !

6. Comparison: Wang Prediction before there was ANY data. Already uses R AA ! Clearly has the wrong trend with pT. Last Call for RHIC Predictions, X. Wang Nucl.Phys.A661:205-260,1999, nucl-th/9907090

7. Comparison: Sarcevic Compares constant dE/dx, LPM (BDMS), and Bethe- Heitles (incoherent) vs pt. Bethe-Heitler “best”. LARGE P(T) INCLUSIVE PI0 PRODUCTION IN HEAVY ION COLLISIONS AT RHIC AND LHC, Jeon Jalilian-Marian Sarcevic Jul 2002. Nucl.Phys.A723:467-482,2003, hep-ph/0207120

8. Conclusion The approximately flat suppression vs pt in GLV was “predicted” before the data existed. It results from full calculation –Log(E) is only an approximation –Presumably same approximation in BDMS.

9. What about Hadronic Reinteraction? (Only) 1/3 of true hadrons suffer final-state interactions. How reliable is this estimate ? What about “pre-hadrons” interactions ? –My opinion: ad-hoc cartoon (not even a calculation) of energy loss. Cassing, Gallmeister Greiner Nucl.Phys.A735:277- 299,2004, hep-ph/0311358