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

Higher harmonic plane & flow Fluctuations of initial collision geometry result in higher harmonic deformation Transferred to momentum space by collective expansion (hydrodynamics) higher harmonic anisotropy emerge F2 F3 F4 Azimuth. distribution Correlation among F2 - F3 - F4 JPS 2011 Autumn

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

2 particle correlations at |Dh|<0.7 with measured vn subtractions vn : central track (|h|<0.35) with forward EP(1.0<|h|<2.8) 2-3⊗1-2GeV Shoulder structures almost disappeared at 0-20% v3 and v4{F4} explains shoulder at small |Dh| JPS 2011 Autumn

￮ measured correlations Superposition of vn contributions reproduce Df correlation at large 2<|Dh|<5 ￮ 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 Higher vn explain ridge and shoulder at large |Dh| JPS 2011 Autumn

Motivation Ridge and shoulder explained by higher harmonic vn at central collisions Whether Ridge and Shoulder explained by higher harmonic vn at peripheral collisions? this analysis focus small |Dh| range confirm shoulder explained by vn or not at peripheral Central collisions Ridge Shoulder small |Dh| (Au+Au 200GeV) --------- Explained large |Dh| (Pb+Pb 2.76TeV) JPS 2011 Autumn

Pair yield per a trigger Analysis 2007, Au+Au 200GeV, Minimum Bias Events, 3.2 billion Events 2 particle charged hadron Df correlations at |Dh|<0.7, Centrality : 0- 50% Trigger pT = 2~4 GeV, Associate pT = 1~2 GeV vn{Fn} measurements by central track with forward Event Plane (|h|:1.0-2.8) C2[data]:jet+flow+cross term… Pair yield per a trigger 1/NtrigdNpair/dDf Zero Yield at Minimum Subtraction Simulated Flow with measured vn and Fi-Fj correlations JPS 2011 Autumn

v2, v3 and v4{F4} subtracted correlations Shoulder almost disappeared at centrality 0-10% as before “New” shoulder emerge in peripheral collisions with relatively-large systematic error… JPS 2011 Autumn

Fitting to flow subtracted correlations Bands indicates systematic width Fit function: v2, v4{F2} subtracted v2, v3, v4{F4} subtracted with <cos(4(F4-F2)> =v4{F2}/v4{F4} ☐:Work in progress ☐:PHENIX Preliminary cos3(Df) term survives both in central and peripheral cos4(Df) term has plus value in central but does almost 0 in peripheral dip at Df=p is emphasized JPS 2011 Autumn

Fitting to flow subtracted correlations Bands indicates systematic width Fit function: v2, v4{F2} subtracted v2, v3, v4{F4} subtracted with <cos(4(F4-F2)> =v4{F2}/v4{F4} ☐:Work in progress ☐:PHENIX Preliminary cos3(Df) term survives both in central and peripheral cos4(Df) term has plus value in central but does almost 0 in peripheral dip at Df=p is emphasized JPS 2011 Autumn

Summary & Outlook Measured v2, v3 and v4{F4} ZYAM subtracted correlations within |Dh|<0.7 up to centrality 50% Shoulder almost disappeared in central collisions as before “New” shoulder emerge in peripheral collisions cos3(Df) term survives in both in central and peripheral cos4(Df) term survives in central but disappeared in peripheral dip at Df=p is emphasized at peripheral with relatively-large systematic error… Outlook reduce systematic error width more peripheral centrality range JPS 2011 Autumn

Backup Slides JPS 2011 Autumn

Fn resolution and Fi - Fj correlations arXiv:1105.3928v1 [nucl-ex] JPS 2011 Autumn

Higher harmonic flow arXiv:1105.3928v1 [nucl-ex] JPS 2011 Autumn

v2 , v3 and v4{F4} with model comparison arXiv:1105.3928v1 [nucl-ex] QM2011 Flow Plenary S. Esumi JPS 2011 Autumn

Jiangyong, Jia QM11’ Flow Plenary JPS 2011 Autumn

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 JPS 2011 Autumn

JPS 2011 Autumn