T. Todoroki for the PHENIX Collaboration University of Tsukuba, RIKEN Nishina Center

1. T. Todoroki for the PHENIX Collaboration University of Tsukuba, RIKEN Nishina Center WPCF 2011 at University of Tokyo Two particle hadron correlations with higher harmonic reaction plane in Au+Au 200 GeV collisions at RHIC-PHENIX

2. Outline • Introduction • Higher harmonic plane and flow • Ridge and Shoulder • Previous 2 particle correlation results • Motivation • Data set and measured values • Results • v2 v3 and v4 subtracted correlations • htrig dependent Dh correlations T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

3. Higher harmonic plane & flow F3 • Fluctuations of initial collision geometry lead to higher harmonic deformation • Deformation is transferred to momentum space by collective expansion (hydrodynamics) • higher harmonic anisotropy emerged F2 F4 Azimuth. distribution Correlation among F2 - F3 - F4 T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

4. v3 : possible source of “Ridge” and “Shoulder” • Flow correlation from v3 term ~ • v3 subtraction would reduce Ridge and Shoulder ⇒ possible source Phys. Rev. C 78, 014901 (2008) Phys. Rev. C 80, 064912 (2009) ○:p+p ●: Au+Au 2< pTasso < pTtrig GeV/C v2 subtracted Ridge Shoulder Ridge : near side long range Dh correlations Shoulder: double hump at away side of Df correlations (also long in Dh) T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

5. 2 particle correlations at |Dh|<0.7 • Shoulder structures almost disappeared at 0-20% • Shoulder is described by v3 and v4{F4} at small |Dh| vn : central track (|h|<0.35) with forward EP(1.0<|h|<2.8) 2-3⊗1-2GeV T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

6. 2 particle correlations at 2<|Dh|<5 • Ridge and Shoulder are described by higher vn at large |Dh| ￮ measured correlations vn with EP Method Track at |h|<2.5 with EP from full FCAL 3.3<|h|<4.8 No Flow Subtraction Pb+Pb 2.76TeV vn with 2Par. Cor Method Charged particle pair with large rapidity gap e.g. |Dh|>2 T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

7. Motivation • Ridge and Shoulder can be described by vn in central collisions • Whether Ridge and Shoulder can be described by vn at peripheral collisions? • How is the correlation changed depending on |Dh| gap • Shoulder structure in small |Dh| gap is tested with v2 v3 and v4 subtractions T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

8. Data set & measured value • Au+Au 200GeV, 3.2 billion Minimum Bias Events taken in 2007 • 2 particle charged hadron correlations at |Dh|<0.7, Centrality : 0-50% • Trigger pT = 2~4 GeV, Associate pT = 1~2 GeV • vn{Fn} of central tracks (|h|<0.35)was measured with Event Plane method (|h|:1.0-2.8) C2[data]:jet+flow+cross term… Pair yield per a trigger 1/NtrigdNpair/dDf ZYAM Method Subtraction Applied Simulated Flow with measured vn and Fi-Fj correlations T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

9. v2, v3 and v4{F4} subtracted correlations at |Dh|<0.7 • Shoulder almost disappeared at centrality 0-10% as previous results • “New” shoulders emerged in peripheral collisions • systematic error is relatively large T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

10. Fitting to flow subtracted correlations • cos3(Df) and cos4(Df) terms are balanced at Df=p in central collisions • cos4(Df) term is almost 0 in peripheral collisions • cos3(Df) and cos4(Df) terms aren’t balanced, dip at Df=p is emphasized Fit function: v2, v3, v4{F4} subtracted with <cos(4(F4-F2)> =v4{F2}/v4{F4} Bands indicates systematic width ☐:PHENIX Preliminary T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

11. Fitting to flow subtracted correlations • cos3(Df) and cos4(Df) terms are balanced at Df=p in central collisions • cos4(Df) term is almost 0 in peripheral collisions • cos3(Df) and cos4(Df) terms aren’t balanced, dip at Df=p is emphasized Fit function: v2, v3, v4{F4} subtracted with <cos(4(F4-F2)> =v4{F2}/v4{F4} Bands indicates systematic width ☐:PHENIX Preliminary T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

12. F2&F3 dependent analyses are in progress T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

13. htrig dependent Dh correlations Jet , Trig. • Trigger h selected Dh correlation could be the probe to survey the geometry and/or dynamics of QGP bulk in pseudo rapidity directions with same analogy of Reaction Plane dependent Df correlations 8 7 6 5 4 3 2 1 Jet ,Trig. 1 3 5 7 2 4 6 8 T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

14. Triggered Dh correlations • plus/minus triggered correlations have same shape with none triggered correlations • jet-bulk interaction was not observed • experimental sensitivity might be not enough due to limited pseudo rapidity coverage None Triggered T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

15. Triggered Dh correlations • plus/minus triggered correlations have same shape with none triggered correlations • jet-bulk interaction was not observed • experimental sensitivity might be not enough due to limited pseudo rapidity coverage T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

16. Summary & Outlook • v2 v3 and v4{F4} subtracted Df correlations are measured within |Dh|<0.7 in Au+Au 200GeV collisions • Shoulder almost disappeared in central collisions as previous results • “New” shoulder emerged in peripheral collisions • this was due to the imbalance of cos3Df and cos4Df components • htrig dependent Dh correlations • Jet correlation might be independent of htrig • experimental sensitivity might be not enough • Outlook for Df correlations • reduce systematic error width • include v5 and v6 contributions • F2&F3 dependent analyses are in progress!! T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

17. Backup Slides T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

18. Fn resolution and Fi - Fj correlations arXiv:1105.3928v1 [nucl-ex] T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

19. Higher harmonic flow arXiv:1105.3928v1 [nucl-ex] PRL 105, 062301(2010) T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

20. v2 , v3 and v4{F4} with model comparison arXiv:1105.3928v1 [nucl-ex] QM2011 Flow Plenary S. Esumi T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

21. Jiangyong, Jia QM11’ Flow Plenary T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

22. Fourier analysis of the per trigger yield jet function cos3Df term from Jet+bulk+Jet-bulk interplay? cos3Df term from Jet Moriond QCD 2011 John-Chin-Hao-Chen T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo

23. T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo