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Goal

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

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Goal

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  1. Goal • Answer question: • Was the approximate constancy of RAA 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 RAA • Suppression magnitude • Constancy with pT • If GLV didn’t predict ~ constant RAA 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 “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 • Use fixed opacity – clearly too simple but opacity 2-4 all ~ constant in unmeasured region.

  3. Test #2 “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 • 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.

  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 • RAA looks less flat with pt for both cases ??

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

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

  7. Comparison: Sarcevic 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 • Compares constant dE/dx, LPM (BDMS), and Bethe-Heitles (incoherent) vs pt. • Bethe-Heitler “best”.

  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? Cassing, Gallmeister Greiner Nucl.Phys.A735:277-299,2004, hep-ph/0311358 • (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.

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