r. lacey, suny stony brook phenix measurements of anisotropic flow in heavy-ion collisions at rhic...

R. Lacey, SUNY Stony Brook

PHENIX Measurements of Anisotropic Flow in Heavy-Ion Collisions at RHIC

Energies

PHENIX Measurements of Anisotropic Flow in Heavy-Ion Collisions at RHIC

Energies

1

Nuclear Chemistry Group , SUNY

Stony Brook, NY

for the PHENIX Collaboration

Arkadiy Taranenko

The 2nd International Conference on the Initial Stages in High-Energy Nuclear Collisions,

Napa Valley, California, 3-7/12/2014


PHENIX VPHENIX Vn n Measurements at RHIC Measurements at RHICPHENIX VPHENIX Vn n Measurements at RHIC Measurements at RHIC

2

1) Introduction

2) Methods / flow and non-flow

3) System size dependence of anisotropy?

4) Azimuthal anisotropy in small systems: d+Au and 3He+Au at 200GeV

5) PID Vn results and hadronization at RHIC

6) PID V2 results: comparison with LHC

7) Conclusions and Outlookε2

ε3

ε4


PHENIX Flow Measurements : MethodsPHENIX Flow Measurements : MethodsPHENIX Flow Measurements : MethodsPHENIX Flow Measurements : Methods

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1

1 2 cos ( )n nn

dNv n

d

n , 1, 2,3..,{ } co sn nv n n

Correlate hadrons in central Arms

with event plane (RXN, etc)

(I) pairs

1

1 2 cos( )a bn n

n

dNv v n

d

(II)

∆φ correlation function for EPN - EPS

∆φ correlation function for EP - CA

Central Arms (CA) |η’| < 0.35

(particle detection)

ψn RXN (||=1.0~2.8)

MPC (||=3.1~3.7)

BBC (||=3.1~3.9)From 2012:

- FVTX (1.5<||<3)


PHENIX Flow Measurements : MethodsPHENIX Flow Measurements : MethodsPHENIX Flow Measurements : MethodsPHENIX Flow Measurements : Methods

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ψn RXN (||=1.0~2.8)

MPC (||=3.1~3.7)

BBC (||=3.1~3.9)

Phys. Rev. Lett. 105, 062301 (2010) Vn (EP): Phys.Rev.Lett. 107 (2011) 252301

Good agreement between VGood agreement between Vn n results results

obtained by event plane (EP) and two-obtained by event plane (EP) and two-particle correlation method (2PC)particle correlation method (2PC)

No evidence for significant No evidence for significant ηη-dependent -dependent non-flow contributions from di-jets for non-flow contributions from di-jets for pT=0.3-3.5 GeV/c. pT=0.3-3.5 GeV/c. Systematic uncertainty : event plane: 2-5% for v2 and 5-12% for v3.

arXiv:1412.1038 , arXiv:1412.1043


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Recent PHENIX publications on flow at RHIC:Recent PHENIX publications on flow at RHIC:1) 1) Systematic Study of Azimuthal Anisotropy in Cu+Cuand

Au+Au Collisions at 62.4 and 200 GeV: arXiv:1412.1043

2) 2) Measurement of the higher-order anisotropic flow coefficients for identified hadrons in Au+Au collisions at

200 GeV : arXiv:1412.1038

Recent PHENIX publications on flow at RHIC:Recent PHENIX publications on flow at RHIC:1) 1) Systematic Study of Azimuthal Anisotropy in Cu+Cuand

Au+Au Collisions at 62.4 and 200 GeV: arXiv:1412.1043

2) 2) Measurement of the higher-order anisotropic flow coefficients for identified hadrons in Au+Au collisions at

200 GeV : arXiv:1412.1038

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• Eccentricity scaling is broken and v2/ɛ depends on the Knudsen number K=λ/Ṝ, where λ is the mean free path and Ṝ is the transverse size of the system. How viscous damping depends on the size of the colliding system / beam energy?

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Centrality dependence of v2 in CuCu/AuAu collisions at 62.4-200 GeVCentrality dependence of v2 in CuCu/AuAu collisions at 62.4-200 GeVCentrality dependence of v2 in CuCu/AuAu collisions at 62.4-200 GeVCentrality dependence of v2 in CuCu/AuAu collisions at 62.4-200 GeV

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σx & σy RMS widths of density distributionGeometric fluctuations included

Geometric quantities constrained by multiplicity density.


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ln n

n

v

R

ε

- Viscous Hydrodynamics

Slope parameter β″ is nearly the same for Au+Au at 62.4-200 GeV, but shows change from Au+Au to Cu+Cu at 200 GeV . Bigger viscous damping in smaller systems / different beam energy dependence?

PRL112, 082302(2014)


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Flow in symmetric colliding systems : Cu+Cu vs Au+Au

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Phys.Rev.Lett. 107 (2011) 252301

Strong centrality dependence of v2 in AuAu, CuCu

Weak centrality dependence of v3

2( )expn T

n

v pn

ε

Scaling

expectation:

Simultaneus measurements of

v2 and v3 Crucial constraint for η/s


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Centrality/Pt dependence of v2, v3 in 200 GeV Cu+Au

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- Clear centrality dependence of v2

- No Significant centrality dependence of v3

Same centrality dependence as seen in symmetric collisions: Au+Au and Cu+Cu


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v2, in 200 GeV Cu+Au vs Cu+Cu/Au+Au

10Phys.Rev. C84 (2011) 067901

The observed system size dependence of v2: AuAu>Cu+Au>CuCu originate from the differences in initial ɛ2


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v3 in 200 GeV Cu+Au vs Cu+Cu/Au+Au

11Phys.Rev. C84 (2011) 067901

The observed system size independence of v3 Is expected from the similar values of ɛ3


Long range correlation in d+Au/3He+Au

12Ridges are seen on both Au-going and 3He-going sides


The v2 and v3 in 3He+Au

The v2 of 3He+Au

is similar to that of d+Au

A clear v3 signal is observed in 0-5% 3He+Au collisions

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The v2 of and p in d+Au

Mass ordering for identified hadron is observed in both d+Au and p+Pb ---- consistent with hydrodynamic flow

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v2 of Identified charged hadrons Au+Au/Cu+Cu at 200 GeV arXiv:1412.1043


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v2 , v3 , v4 of Identified charged hadrons Au+Au at 200 GeV arXiv:1412.1038


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Scaling Properties of Vn Flow at 200 GeV arXiv:1412.1038

/2 n, 2, /2

vv ( ) ~ v or

( )n

n q T q nq

KEn

NCQ-scaling holds well for v2,v3,v4 below 1GeV in KET space, at 200GeV

2

2 2

( )exp ( 4)

( )n T n

T

v pn

v p

ε ε

vn is related to v2


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arXiv:1412.1038 , arXiv:1412.1043

V2(pt) shape if very similar for charged pions between RHIC/LHC: 10-14% difference

The difference in eccentricities between : ɛ2(PbPb at 2.76TeV) and ɛ2(Au+Au at 200 GeV) will increase the difference by 5-7%.

PHENIX ALICE: CERN-PH-EP-2014-104 e-Print: arXiv:1405.4632

Comparison with LHC ALICE Pb+Pb at 2.76 TeV : charged pions


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arXiv:1412.1038 , arXiv:1412.1043PHENIX ALICE:: arXiv:1405.4632

Comparison with LHC ALICE Pb+Pb at 2.76 TeV : (anti)protons

apply blueshift to RHIC data


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arXiv:1412.1038 , arXiv:1412.1043

Difference in kaons between RHIC and LHC looks complicated, especially the difference between charged and neutral kaons at LHC.

PHENIX ALICE: CERN-PH-EP-2014-104 e-Print: arXiv:1405.4632

Comparison with LHC ALICE Pb+Pb at 2.76 TeV : kaons


Summary

• V2 and V3 studied in different colliding systems: Au+Au/Cu+Cu and Cu+Au:

– Similar magnitudes and trends observed both v2 and v3, independent of system

– Viscous damping effects appear to be larger for smaller systems

• The ridge is observed in d+Au and 3He+Au. – Similar magnitudes observed for v2– v3 signal observed for 3He+Au– Mass ordering observed; splitting less than observed at LHC

• The vn of identified charged hadrons presented as a function of pT and centrality

– Mass ordering for all harmonics at all centralities studied – Measurements can be scaled by generalized quark number

scaling

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22

Backup Slides


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A B

Geometric fluctuations included

Geometric quantities constrained by multiplicity density.

*cosn nnε

Phys. Rev. C 81, 061901(R) (2010)

arXiv:1203.3605

σx & σy RMS widths of density distribution

Geometric quantities for scaling

Geometry

Roy A. Lacey, Stony Brook University, QM2014


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PHENIX Flow Measurements : Event Plane ResolutionPHENIX Flow Measurements : Event Plane ResolutionPHENIX Flow Measurements : Event Plane ResolutionPHENIX Flow Measurements : Event Plane Resolution


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centrality (%)

n=2 RXNn=3 RXNn=4 RXNn=2 MPCn=3 MPC

n =

<co

s n

(n

(mea

s.) -

n(t

rue))>

200GeV Au+Au

PHENIX Preliminary

PHENIX Flow Measurements : Event Plane ResolutionPHENIX Flow Measurements : Event Plane ResolutionPHENIX Flow Measurements : Event Plane ResolutionPHENIX Flow Measurements : Event Plane Resolution

ψn RXN (||=1.0~2.8)

MPC (||=3.1~3.7)

BBC (||=3.1~3.9)

Overall good event plane resolution

for Vn measurements and study beam energy dependence of the flow.


• Significant bias from near-side jet for |Δη|<0.5

• Consistent for larger Δη at pT<4 GeV

• Deviation again for pT>4 GeV due to swing of recoil jet

• EP method ( |Δη|< 2.5 with EP from full FCAL: 3.3<|Ƞ|<4.8 )

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Effect of rapidity gap on VEffect of rapidity gap on Vn n measurements at LHC measurements at LHCEffect of rapidity gap on VEffect of rapidity gap on Vn n measurements at LHC measurements at LHC

J. Jia [ ATLAS Collaboration ]

QM 2011

ATLAS AN: http://cdsweb.cern.ch/record/13524588


• Significant bias from near-side jet for |Δη|<0.5

• Consistent for larger Δη at pT<4 GeV

• Deviation again for pT>4 GeV due to swing of recoil jet

• EP method ( |Δη|< 2.5 with EP from full FCAL: 3.3<|Ƞ|<4.8 )

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Effect of rapidity gap on VEffect of rapidity gap on Vn n measurements at LHC measurements at LHCEffect of rapidity gap on VEffect of rapidity gap on Vn n measurements at LHC measurements at LHC

J. Jia [ ATLAS Collaboration ]

QM 2011

ATLAS AN: http://cdsweb.cern.ch/record/13524585


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Differential v2(pT): Comparison with STAR Multi-particle methods

Ratio V2 {STAR} / V2{PHENIX EP} < 1.0 for 4p cumulant and LYZ method .

LYZ : Lee-Yang-Zeros Method

Lee-Yang-Zeros Method4p cumulant method


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Elliptic Flow Measurements V2 (pT , centrality) in PHOBOS/STAR/PHENIX

TPC FTPCZDC/SMD

FTPCZDC/SMD

η

Central Arms BBC/MPCBBC/MPC ZDC/SMDZDC/SMD

|η| < 1.3

|η|<0.35η

2.5 <|η|< 4.0 |η| > 6.3

3.1<|η|<3.7

RXNRXN

|η| > 6.61.0<|η|<2.8

3.1<|η|<3.9

STAR

PHENIX

2.05<|η|<3.2η

EPEP

PHOBOSη = 0-1.6

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Elliptic Flow of Charged Hadrons: Au+Au at 39-200 GeV

No significant change in v2(pT) for √s = 39 -200 GeV !

Precision DataPrecision DataPrecision DataPrecision Data


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PHENIX: Extensive anisotropy DataPHENIX: Extensive anisotropy Data

Phys. Rev. Lett. 105, 062301 (2010)

High precision double differential measurements

Phys.Rev.C81:034907,2010

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• KET/nq< 1GeV – soft physics

Hydrodynamic flow

•Interplay soft-hard 3.0 < pT< 5 GeV/c ?

•Hard dominates: pT> 5 GeV/c

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PHENIX Preliminary

PHENIX Preliminary

KET & nq scaling validated for v2 as a function of centrality

Flow scales across centralityFlow scales across centralityFlow scales across centralityFlow scales across centrality

PHENIX PreliminaryPHENIX Preliminary

PHENIX Preliminary PHENIX Preliminary

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VV44 : A Small, But Sensitive Observable For Heavy Ion Collisions : A Small, But Sensitive Observable For Heavy Ion Collisions

Do we have qualitative agreement ? Answer is : YES!!!

J.Phys.G35:104105,2008,J.Phys.G36:064061,2009

PHENIX: QM 08, WWND 08, DNP 08, QM 09 STAR: WWND 09, QM 2009

STAR preliminary

STAR preliminary

V4 ~ k * (V22) – very small signal

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Are Flow Measurements at RHIC Reliable?: PHENIX / PHOBOS

from PHOBOS QM06 proc. J. Phys. G34 S887 (2007)

EP{2}EP{1}η

PHOBOS EP: 2.05<|η|<3.2

Overall good agreement between differential flow measurements

EP: 1.0<|η|<2.8

EP: 3.1<|η|<3.7

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Are Flow Measurements at RHIC Reliable?: PHENIX / STAR (2)

For 0-20% central collisions STAR V2 > PHENIX V2 :

Is rapidity gap in STAR TPC too small ? Need detailed comparison with STAR FTPC results (2.5 <|η|< 4.0 )

Do we have the same centrality definition between experiments?


V2{EP} – standard EP method

V2{EP2} – modified EP method

EP-StarEP-Star

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Are Flow Measurements at RHIC Reliable?: PHENIX / STAR (1)

Overall good agreement for mid-central collisions with STAR results obtained using modified EP method ( exclude |Δη|<0.5 )

r. lacey, suny stony brook phenix measurements of anisotropic flow in heavy-ion collisions at rhic...

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