Two particle hadron correlations withhigher harmonic reaction plane in Au+Au
200 GeV collisions at RHIC-PHENIX	 

T.Todoroki for the PHENIX Collaboration
University of Tsukuba, RIKEN Nishina Center
WPCF 2011 at University of Tokyo 	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
 ηtrig dependent Δη correlations	2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	2	

Higher harmonic plane & flow	 Fluctuations of initial collision geometry lead to higher harmonic deformation
Deformation is transferred to momentum space by collective expansion (hydrodynamics)
 higher harmonic anisotropy emerged 	

Φ3	

Φ2	

Φ4	Azimuth.
distribution	
Correlation amongΦ2	  -­‐ Φ3	  -­‐ Φ4	

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	

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v3 : possible source of “Ridge” and “Shoulder”	 
Phys. Rev. C 80, 064912 (2009)
Phys. Rev. C 78, 014901 (2008)

2< pTasso < pTtrig GeV/C	

○:p+p●: Au+Au	

v2 subtracted	Ridge	Shoulder	
Ridge : near side long rangeΔη correlations

Shoulder: double hump at away sideof Δφ correlations (also long in Δη)	

 Flow correlation from v3 term ~

v3 subtraction would reduce Ridge and Shoulder ⇒ possible source

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	

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2 particle correlations at |Δη|<0.7	 
vn : central track (|η|<0.35)
with forward EP(1.0<|η|<2.8)	

2-3⊗1-2GeV	 Shoulder structures almost disappeared at 0-20%
 Shoulder is described by v3 and v4{Φ4} at small |Δη|	

2011-Sep.21st	

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

2 particle correlations at 2<|Δη|<5	No	  Flow	  Subtrac;on	  ￮ measured correlations 	
vn with EP Method 	
Track at |η|<2.5	  with	  EP	  from	  full	  FCAL	  3.3<|η|<4.8	

Pb+Pb	  2.76TeV	  vn with 2Par. Cor Method 	Charged	  par;cle	  pair	  with	  large	  rapidity	  gap	  e.g.	  	  |Δη|>2	

 Ridge and Shoulder are described by higher vn at large |Δη|
2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo		
6	Motivation	  Ridge and Shoulder can be described by vn in central collisions

Central collisions 	

Ridge	

Shoulder	small |Δη|	  (Au+Au	  200GeV)	

---------	

Described	

large |Δη|	  (Pb+Pb	  2.76TeV)	

Described	

Described	

 Whether Ridge and Shoulder can be described by vn atperipheral collisions?
How is the correlation changed depending on |Δη| gap Shoulder structure in small |Δη| gap is tested with v2 v3 and v4 subtractions

Peripheral collisions 	

Ridge	

Shoulder	small |Δη|	---------	

tested	large |Δη|	

not yet	

not yet	

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	7	Data set & measured value	  Au+Au 200GeV, 3.2 billion Minimum Bias

Events taken in 2007

2 particle charged hadron correlations at |Δη|<0.7, Centrality : 0-50%
 Trigger pT = 2~4 GeV, Associate pT = 1~2 GeV
vn{Φn} of central tracks (|η|<0.35) was measured with Event Plane method (|η|:1.0-2.8)

C2[data]:jet+flow+cross term…	

Pair yield per a trigger
1/ΝtrigdΝpair/dΔφ	ZYAM Method Subtraction Applied	

Simulated Flow with measured vnand Φi-­‐Φj correlations	

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	

8	v2, v3 and v4{Φ4} subtracted correlations at |Δη|<0.7	 

 Shoulder almost disappeared at centrality 0-10% as previous results
 “New” shoulders emerged in peripheral collisions
 systematic error is relatively large
2011-Sep.21st	

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

9	Fitting to flow subtracted correlations	 
Fit function:	v2,	  v3,	  v4{Φ4}	  subtracted	  with	  	  <cos(4(Φ4-Φ2)>	  =v4{Φ2}/v4{Φ4}	  	☐:PHENIX Preliminary	Bands indicatessystematic width	cos3(Δφ) and cos4(Δφ) terms are balanced at Δφ=π in central collisions
 cos4(Δφ) term is almost 0 in peripheral collisions	 cos3(Δφ) and cos4(Δφ) terms aren’t balanced, dip at Δφ=π is emphasized

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	10		  Fitting to flow subtracted correlations	 
Fit function:	v2,	  v3,	  v4{Φ4}	  subtracted	  with	  	  <cos(4(Φ4-Φ2)>	  =v4{Φ2}/v4{Φ4}	  	☐:PHENIX Preliminary	Bands indicatessystematic width	cos3(Δφ) and cos4(Δφ) terms are balanced at Δφ=π in central collisions
 cos4(Δφ) term is almost 0 in peripheral collisions	 cos3(Δφ) and cos4(Δφ) terms aren’t balanced, dip at Δφ=π is emphasized

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	

11		  Φ2 & Φ3 dependent	  analyses	  are	  in	  progress	 

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	12	ηtrig dependent Δη correlations	 
φJet , φTrig.
ηJet , ηTrig.
8
1763
25476854321

 Trigger η selected Δη correlation could be the probe tosurvey the geometry and/or dynamics of QGP bulk in pseudo
rapidity directions with same analogy of Reaction Plane
dependent Δφ correlations

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	

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Triggered Δη correlations 	 

None Triggered	 plus/minus triggered correlations have same shape with nonetriggered correlations
jet-bulk interaction was not observed experimental sensitivity might be not enough due to limited pseudo rapidity

coverage 	
2011-Sep.21st	

T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	14	Triggered Δη 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 	
2011-Sep.21st	

T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	15	Summary & Outlook	  v2 v3 and v4{Φ4} subtracted Δφ correlations are measured

within |Δη|<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 cos3Δφ and cos4Δφ components ηtrig dependent Δη correlations

Jet correlation might be independent of ηtrig
 experimental sensitivity might be not enough Outlook for Δφ correlations

reduce systematic error width
 include v5 and v6 contributionsΦ2 & Φ3 dependent	  analyses	  are	  in	  progress!! 	

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	

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Backup Slides	 2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	

17	Φn resolution and Φi - Φj correlations 	

arXiv:1105.3928v1 [nucl-ex]

2011-Sep.21st	

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

18	Higher harmonic flow	 arXiv:1105.3928v1 [nucl-ex]

2011-Sep.21st	PRL 105, 062301(2010)	

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

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v2 , v3 and v4{Φ4} with model comparison	 QM2011 Flow Plenary S. Esumi	

2011-Sep.21st	

arXiv:1105.3928v1 [nucl-ex]

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

20	Jiangyong, Jia
QM11’ Flow Plenary	

2011-Sep.21st	

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

21	Fourier analysis of the per trigger yield jetfunction 	 cos3Δφ term	  from	  	  Jet+bulk+Jet-­‐bulk	  interplay?	

cos3Δφ term	  from	  Jet	

Moriond QCD 2011
John-Chin-Hao-Chen	

2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	

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2011-Sep.21st	T.Todoroki, Univ. of Tsukuba, WPCF 2011 @Hongo Tokyo	

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