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Two particle correlations with respect to
higher harmonic plane in Au+Au 200 GeV
collisions at RHIC-PHENIX
Takahito Todoroki for the PHENIX Collaboration
Univ. of Tsukuba, RIKEN Nishina Center
JPS Annual Meeting 2012, Mar. 24-27th
@Kwansei Gakuin
26 Mar. 2012
物理学会年次大会
1/10
Outline
1. Introduction
Higher harmonic event plane(Fn) & flow(vn)
Backgrounds from vn in correlations
vn subtracted correlations
2. Physics Motivation
3. Analysis Overview
4. Results
F2 & F3 dependence
5. Summary
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Higher harmonic event plane & flow
• Previous picture; Assumed a “reaction plane” defined
by impact parameter vector and beam axis vector
• Recent picture; Higher harmonic deformation due to
fluctuations of collision geometry
 Deformation transferred to momentum space by
collective expansion → higher harmonic flow(vn)
F3
F2
F4
Azimuth.
distribution
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物理学会年次大会
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Backgrounds from vn in 2 particle correlations
Phys. Rev. C 80, 064912 (2009)
Phys. Rev. C 78, 014901 (2008)
2< pTasso < pTtrig GeV/C
v2 subtracted
Ridge
n=3
○:p+p
●: Au+Au
n=3
Shoulder
Ridge : near side long range
Dh correlations
Shoulder: double hump at away side
of Df correlations (also long in Dh)
• Backgrounds from vn
 vn (especially v3) subtraction reduce “Ridge” and “Shoulder”
 vn subtractions help to see more “real” correlation shape
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vn subtracted correlations
work in progress
V2V&4(F
V42(F
V2 &
) ZYAM
subtracted
2) subtracted
V2, V3 & V4(F4) ZYAM subtracted
• Shoulder is described by vn in central collisions
• Shoulder is still seen in mid-central collisions
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Physics Motivations
• vn subtracted correlations still show doublehump structure in ways side in mid-central
collisions
 Average of jets flying to various direction in bulk
• Detailed survey of away side peaks
 Two particle correlations with trigger selection relative
to F2 & F3
- Modification of away side w.r.t. F2 & F3
- Difference➇between F2 & F3
➆
➇
➆
➅
➅
➄
➄
➍
➍
➌
➋
➌
➊
➋
➊
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Analysis Overview
PHENIX
RXN in: 1.5<|h|<2.8
& out: 1.0<|h|<1.5
CNT: |h|<0.35
dN/dh
!
MPC: 3.1<|h|<3.7
3
BBC: 3.0<|h|<3.9
!
ZDC/SMD
!
-5
• vn measurements
0
5
4
h
 Forward Event Plane(RXN) - Charged Hadrons in mid-rapidity
- To exclude autocorrelations by jet
• Selection of Trigger Directions
 Forward Event Plane(RXN)-Charged Hadron Trigger in mid-rapidity
• 2 particle charged hadron correlations in azimuth
 Mid-rapidity Trigger – Mid-rapidity Associate, pT : 2-4 & 1-2 [GeV/c]
• Subtract vn modulated backgrounds by ZYAM Method
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2
F2 dependent correlations
out-of-plane
trigger case
Trig.
in-plane
trigger case
200GeV Au+Au -> h-h, 20-50%
(pTTrig=2~4, pTAsso=1~2GeV/c)
v2, v3 & v4{F4} subtraction
PHENIX work in progress
Trigger angle
selection w.r.t.
F2 for left(up) /
right(down)
Trig.
F2 R.P.
F2 R.P.
Flow subtracted
yield is shown
radially with
base line.
Trig.
Trig.
shift to out-of-plane
shift to in-plane
• Two competitive effects
Away-side peak shift to in/out of plane with in/out
of plane trigger
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物理学会年次大会
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: C2(data)
: vn backgrounds
In-plane
 F2 dominated by almond shape
 F3 dominated by fluctuations
 Would be related to differences
▪▫
-Correlation Functions
• Subtraction shows no
evident dependence
• Difference b/w F2 & F3
out-of-plane
F3 dependence before vn subtractions
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Summary
• Measured two particle correlations with trigger
selection relative to F2 & F3
• F2 dependent correlations show two competitive
effects
 Away-side peak shift to in/out of plane with in/out of
plane trigger
• F3 harmonic plane dependence wouldn’t be seen
 F2 dominated by almond shape
 F3 dominated by fluctuations
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物理学会年次大会
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Back Up Slides
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Charged hadron vn Centrality and pT dependences
PRL.107.252301 (ppg132)
charged particle vn : |h|<0.35
event plane Fn : |h|=1.0~2.8
• v3 is comparable to v2 at 0~10%
• v2 rises up when centrality goes up, but v3 hardly does
• v4{F4} ~ 2 x v4{F2}
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Degeneracy among models disentangled
by v3
PRL.107.252301 (ppg132)
B. Alver et. al., PRC82, 034913(2010).
B. Schenke et. al., PRL106, 042301(201
H. Petersen et. al., PRC82, 041901(2010
(Event Plane Method)
V2
V3
• v3 seems to prefer low viscosity
 Glauber+4ph/s =1 works better
 CGC-KLN+4ph/s =2 failed
• vn provides more constraints to hydrodynamics
calculations
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物理学会年次大会
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QM2011,
ATLAS
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Fourier decomposition of flow subtracted
correlations
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物理学会年次大会
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F2 dependence with v2 & v4(F2) subtraction
➊➇
➋➆
➌➅
➍➄
26 Mar. 2012
物理学会年次大会
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Trigger dependence relative to event plane
Trigger angle
selection w.r.t.
F2 separately for
left(up) /
right(down)
out-of-plane
trigger case
RHIC-PHENIX
Flow plenary
S.E.
in-plane
trigger case
Trig.
Trigger angle
selected 2-part.
corr. data are
plotted in polar
coordinate by
rotating F2 R.P.
angle as X-axis.
Flow subtracted
yield is shown
radially with base
line.
Trig.
200GeV Au+Au -> h-h, 20-50%
(pTTrig=2~4, pTAsso=1~2GeV/c)
v2,v4{F2} only subtraction
PHENIX preliminary
F2 R.P.
F2 R.P.
Trig.
Trig.
surface dominance
penetration dominance
Two competing processes seen
26 Mar. 2012
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F2 dependence with v2 & v3 & v4 subtraction
200GeV Au+Au -> h-h, 20-50%
(pTTrig=2~4, pTAsso=1~2GeV/c)
v2,v3,v4{F4} subtraction
1/NtrigdNpair/dDf
PHENIX Work in progress
➊➇
out-of-plane
➋➆
➌➅
➍➄
In-plane
Df [rad]
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物理学会年次大会
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