1. 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

2. 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

3. v3 : possible source of “Ridge” and “Shoulder”
2< pTasso < pTtrig GeV/C
Phys. Rev. C 80, (2009)
Phys. Rev. C 78, (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

4. 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

5. ￮ 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

6. 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

7. 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|: )
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

8. 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

9. 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

10. 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

11. 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

12. Backup Slides
JPS 2011 Autumn

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

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

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

16. Jiangyong, Jia
QM11’ Flow Plenary
JPS 2011 Autumn

17. 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

18. JPS 2011 Autumn