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

Two particle hadron correlations with higher 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 trig dependent correlations

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

2

Higher harmonic plane & flow

3

Fluctuations of initial collision geometry lead to higher harmonic deformation Deformation is transferred to momentum space by collective expansion

(hydrodynamics) higher harmonic anisotropy emerged

Azimuth. distribution

Correlation among 2 -3 -4


Ridge

2< pTasso < pT

trig GeV/C

Phys. Rev. C 80, 064912 (2009)

v3 : possible source of “Ridge” and “Shoulder”

4

Flow correlation from v3 term ~ v3 subtraction would reduce Ridge and Shoulder ⇒ possible source

Ridge : near side long range correlations

Shoulder: double hump at away side of correlations (also long in )

Phys. Rev. C 78, 014901 (2008)○:p+p●: Au+Au

Shoulder

v2 subtracted


2 particle correlations at

5

Shoulder structures almost disappeared at 0-20% Shoulder is described by v3 and v4{} at small

vn : central track () with forward EP()

2-3 1-2GeV⊗


2 particle correlations at

6

Ridge and Shoulder are described by higher vn at large

Track at with EP from full FCAL

vn with EP Method

vn with 2Par. Cor Method

Charged particle pair with large rapidity gap e.g.

Pb+Pb 2.76TeV

No

Flow

Sub

trac

tion

￮ measured correlations


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 gap

Shoulder structure in small gap is tested with v2 v3 and v4 subtractions

Peripheral collisions Ridge Shoulder

small --------- tested

large not yet not yet

Central collisions Ridge Shoulder

small (Au+Au 200GeV)

--------- Described

large (Pb+Pb 2.76TeV)

Described Described

Motivation


Data set & measured value

8

Au+Au 200GeV, 3.2 billion Minimum Bias Events taken in 2007 2 particle charged hadron correlations at , Centrality : 0-50%

Trigger pT = 2~4 GeV, Associate pT = 1~2 GeV

vn{n} of central tracks ()was measured with Event Plane method ()

C2[data]:jet+flow+cross term…

Simulated Flow with measured vn and i-j correlations

ZYAM Method Subtraction Applied

Pair yield per a trigger trigdpaird


v2, v3 and v4{} subtracted correlations at


Shoulder almost disappeared at centrality 0-10% as previous results

“New” shoulders emerged in peripheral collisions systematic error is relatively large

Fitting to flow subtracted correlations

10

cos3() and cos4() terms are balanced at in central collisions

cos4() term is almost 0 in peripheral collisions cos3() and cos4() terms aren’t balanced, dip at is

emphasized

Fit function:

v2, v3, v4{} subtracted with cos =v4{}/v4{}

☐:PHENIX PreliminaryBands indicates systematic width


Fitting to flow subtracted correlations

11

cos3() and cos4() terms are balanced at in central collisions

cos4() term is almost 0 in peripheral collisions cos3() and cos4() terms aren’t balanced, dip at is

emphasized

Fit function:

v2, v3, v4{} subtracted with cos =v4{}/v4{}

☐:PHENIX PreliminaryBands indicates systematic width


&dependent analyses are in progress


12

Trigger selected 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 correlations

trig dependent correlations


13

Jet , Trig.

1

2

3

4

5

6

7

8

1

2

3

4

5

6

7

8

Jet , Trig.

None Triggered

Triggered 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


14

Triggered 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


15

Summary & Outlook

16

v2 v3 and v4{} subtracted correlations are measured within 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 cosand coscomponents

trig dependent correlations Jet correlation might be independent of trig experimental sensitivity might be not enough

Outlook for correlations reduce systematic error width include v5 and v6 contributions &dependent analyses are in progress!!


Backup Slides


n resolution and i - j correlations

18

arXiv:1105.3928v1 [nucl-ex]


Higher harmonic flow

19

arXiv:1105.3928v1 [nucl-ex]


PRL 105, 062301(2010)

v2 , v3 and v4{} with model comparison

20

arXiv:1105.3928v1 [nucl-ex]QM2011 Flow Plenary S. Esumi


21

Jiangyong, JiaQM11’ Flow Plenary


Fourier analysis of the per trigger yield jet function

22

Moriond QCD 2011John-Chin-Hao-Chen

cos3term from Jet

cos3term from Jet+bulk+Jet-bulk interplay?



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

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