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Michael P. McCumber for the PHENIX Collaboration April 2007 APS Meeting Jacksonville, Florida

System Size and Energy Dependence of Jet-Induced Hadron-Hadron Angular Correlations in Heavy Ion Collisions at PHENIX. Michael P. McCumber for the PHENIX Collaboration April 2007 APS Meeting Jacksonville, Florida. Heavy Ion Collisions. Jet Suppression: Fast partons lose energy in the medium

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Michael P. McCumber for the PHENIX Collaboration April 2007 APS Meeting Jacksonville, Florida

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  1. System Size and Energy Dependence of Jet-Induced Hadron-Hadron Angular Correlations in Heavy Ion Collisions at PHENIX Michael P. McCumber for the PHENIX Collaboration April 2007 APS Meeting Jacksonville, Florida

  2. Heavy Ion Collisions Jet Suppression: Fast partons lose energy in the medium Lost energy should be deposited locally in the medium Where does the energy go? Does anything of the jets remain? Does the lost jet energy elicit a response from the medium? ? Michael P. McCumber

  3. PHENIX Detector “trigger hadron” (2.5-4.0 GeV/c) “partner hadron” (1.0-2.5 GeV/c) Beam View Central Arms |η| < 0.35 Charged tracking from DC, PC1, and PC3 at mid rapidity, η. Centrality and Reaction-plane from BBC and ZDC at large |η|. Michael P. McCumber

  4. Charged Hadron Correlations p-p collisions: ● Pair yield near Δφ=0 and Δφ=π ● Back-to-back jet scenario p+p nucl-ex/0611019 Central Heavy Ion Collisions: ● Requires significant subtraction of combinatoric event correlations (elliptic flow) ● Pair yield near Δφ=0 and Δφ≈2 ● Several qualitatively consistent scenarios PRC 73, 054903 (2006) Michael P. McCumber

  5. System and Energy Scan Away-side structure vs. beam species, beam energies, and centrality All cases: ● Peripheral similar to p-p ● Central shows development of “lobe”-like structure nucl-ex/0611019 Michael P. McCumber

  6. Npart Shape Scaling J(Δφ) nucl-ex/0611019 ● Shape saturates above 100 Npart Michael P. McCumber

  7. Testing Thickness Scaling thicker via trigger to reaction plane selection out mid in peripheral central thicker via centrality selection Cu+Cu Au+Au Michael P. McCumber

  8. Correlation & Jet Functions Jet Functions: ● Large dependence with centrality ● No observed dependence in jet functions with reaction-plane Michael P. McCumber

  9. Geometrical Thickness Distant Observer trms = 2 Rrms freq. 0 R-<R> trms is a typical radial thickness along lines of sight from within a reaction-plane bin Includes reaction-plane resolution Overlapping Wood-Saxon Distributions Michael P. McCumber

  10. Shape Metrics Little sensitivity with reaction plane binning Michael P. McCumber

  11. Away-side Jet-Induced Structure Systematic and detailed study of away-side shape Observe that the away-side shape scales with Npart No observed reaction-plane shape dependence Unable to differentiate: no thickness scaling expected thickness scaling from centrality variation New Reaction-Plane Detector Better resolution Better flow systematic errors Michael P. McCumber

  12. Backup Slides

  13. Au+Au 200 GeV – Cent 30-40% The inclusive distributions vary greatly with Ψ-φ bin due to large changes in the flow contribution. (QM 2005) The in-plane & out-plane JFs show no rxpn-dependence within the reported errors. Michael P. McCumber

  14. Angle Definitions “trigger hadron” (2.5-4.0 GeV/c) “partner hadron” (1.0-2.5 GeV/c) “reaction plane” Beam View Michael P. McCumber

  15. Acceptance Correction B A Event N Rolling buffer mixing technique Pooled by Event type: 5cm zvertex 5% centrality B Event N-1 A Event N-2 A B A B Event N-3 A B Event N-4 Acc(Δφ) The two-arm acceptance effects are removed by building a correction from event mixing. π 0 ΔΦAB Michael P. McCumber

  16. Correlation Functions Where we have both sufficient rx-pn resolution and sufficient event contribution, there exist large differences in the elliptic flow contribution. This can be seen here in central collisions as differences between in-plane and out-plane as C(Δφ) is dominated by the elliptic flow. Correlation Decomposition: Bielcikova, Esumi, Filimonov, Voloshin,& Wurm PRC69 (2004) 0211901 Michael P. McCumber

  17. Correlation Functions Michael P. McCumber

  18. Flow Functions Michael P. McCumber

  19. Jet Contribution Errors Michael P. McCumber

  20. Why Cu+Cu? If the Npart scaling is in fact related to the geometrical thickness through the medium, we should also see a dependence on line-of-sight through the medium. Need a small system to probe transition region, Cu+Cu is ideal in this regard. Cu+Cu Increasing Thickness? nucl-ex/0611019 Michael P. McCumber

  21. Shape Metrics by Npart Same Npart trend as previously measured. No observed difference between reaction plane bins Michael P. McCumber

  22. Shape Metrics by trms Overall trend as expected from Npart dependence. The current poor reaction-plane resolution does not give sufficient thickness sensitivity to distinguish between no reaction-plane dependence and the expectation from the centrality dependence. Michael P. McCumber

  23. Measuring Reaction-Plane Resolution Two Methods: Ollitrault-Voloshin Mean Projection Method Michael P. McCumber

  24. Reaction-Plane Detector Now fully installed Michael P. McCumber

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