Global and Collective Dynamics at PHENIX

Takafumi Niida for the PHENIX CollaborationUniversity of Tsukuba

“Heavy Ion collisions in the LHC era” in Quy Nhon

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outline

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Introduction of vn

Higher harmonic flow (vn) of Identified particle 2 particle correlations with vn

Azimuthal HBT w.r.t event plane Summary

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Higher harmonic event plane Initial density fluctuations cause higher harmonic flow vn

Azimuthal distribution of emitted particles:

3

Ψ2

Ψ3

Ψ4

Ψn : Higher harmonic event planeφ : Azimuthal angle of emitted particles

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vn measurement via Event plane method

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0 5-5

ZDC/SMD

dN/d

RXN in: 1.5<||<2.8 & out: 1.0<||<1.5

MPC: 3.1<||<3.7

BBC: 3.0<||<3.9

CNT: ||<0.35

Ψn : Determined by forward detector RXNφ : Measured at mid-rapidity

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Charged hadron vn at PHENIX

v2 increases with increasing centrality, but v3 doesn’t

v3 is comparable to v2 in 0-10%

v4 has similar dependence to v2 5

PRL.107.252301

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v3 breaks degeneracy

v3 provides new constraint on hydro-model parameters Glauber & 4πη/s=1 : works better KLN & 4πη/s=2 : fails

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V2

V3

PRL.107.252301

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Recent Results at PHENIX vn of Identified particle 2 particle correlations with vn

Azimuthal HBT w.r.t event plane

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Motivation of PID vn

vn is sensitive probe to the QGP bulk property Important to check the following features seen in v2

Mass splitting at low pT

Baryon/Meson difference at mid pT

How is the scaling property of vn ?

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vn of Identified particle

Mass splitting at low pT : Hydrodynamics Baryon/Meson difference at mid pT

: Quark coalescence 9

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PID vn with modified scaling

Known nq scaling fails in v3, v4

Modified scaling works well for vn : vn(KET/nq)/nqn/2

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PID v2 at high pT

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0-20% 20-60%

Extend PID to high pT by combining TOF(MRPC) and Aerogel Cherenkov Counter

Quark number scaling is better for KET/nq than pT/nq

But it breaks at KET/nq~0.7GeV for non-central collisions

PRC.85.064914(2012)

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Recent Results at PHENIX vn of Identified particle 2 particle correlations with vn

Azimuthal HBT w.r.t event plane

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Motivation of 2 particle correlations with vn

Ridge and Shoulder can be seen in Δφ-Δη correlationThey can be explained by vn ?

vn subtractions are needed to get real jet correlations

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Ridge

2< pTasso < pT

trig GeV/C

Phys. Rev. C 80, 064912 (2009) Phys. Rev. C 78, 014901 (2008)○:p+p●: Au+Au

Shoulder

v2 subtracted

Δφ

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Pb+Pb 2.76TeV

2 particle correlations with |Δη| gap

vn reproduce Ridge & Shoulder well in 0-5%

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QM’11 J. Jia ATLAS Flow Plenary

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2 particle correlations without |Δη| gap

Most-central : Away side yield are suppressed Mid-central : Away side yield still remain 15

V2, V3 & V4(F4) ZYAM subtracted

PHENIX PRELIMINARY Au+Au 200GeV 0-20%

inc. γ-had.

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Recent Results at PHENIX Particle Identified vn

2 particle correlations with vn

Azimuthal HBT w.r.t event plane

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Motivation of Azimuthal HBT w.r.t v2 plane

Final eccentricity can be measured by azimuthal HBTIt depends on Initial eccentricity, pressure gradient, expansion time,

and velocity profile etcGood probe to investigate system evolution 17

momentum anisotropy v2

Initial spatial anisotropy (eccentricity)

v2 Plane

Δφ

How is final eccentricity ?

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Azimuthal HBT radii for kaons Observed oscillation for Rside, Rout, Ros

Final eccentricity is defined as εfinal = 2Rs,2 / Rs,0

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in-plane

out-of-plane

PRC70, 044907 (2004)

@WPCF2011

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Eccentricity at freeze-out

εfinal ≈ εinitial/2 for pion Indicates that source expands to in-plane direction, and still elliptical PHENIX and STAR results are consistent

εfinal ≈ εinitial for kaon Freeze-out time is faster than that of pion? Due to different mT between π/K? 19

ε final = ε initial

PRC70, 044907 (2004)@WPCF2011

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kT dependence of azimuthal pion HBT radii

Oscillation can be seen in Rs, Ro, and Ros for each kT regions

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mT dependence of εfinal

εfinal of pions increases with mT in most/mid-central collisions

There is still difference between π/K even in same mT

But the difference is at most within 2 σ of systematic errors

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mT dependence of relative amplitude

Relative amplitude of Rout in 0-20% doesn’t depend on mT

Does it indicate emission duration between in-plane and out-of-plane is different ? 22

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Azimuthal HBT w.r.t v3 plane

Final triangularity could be observed by azimuthal HBT w.r.t v3 plane(Ψ3) if it exists at freeze-outDetailed information on space-time evolution can be obtained

Analysis is ongoing

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Initial spatial fluctuation(triangularity)

momentum anisotropytriangular flow v3

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Summary vn of Identified particle

PID vn have been measuredModified scaling vn(KET/nq)/nq

n/2 works well for vn

Quak number scaling for v2 breaks at high pT in non-central collisions

2 particle correlations with vn

Away side yield are suppressed in most central collisions, but still remain in non-central collisions

Azimuthal HBT w.r.t v2 plane

εfinal increase with mT, while relative Rout,2 doesn’t depend on mT in central collisions

Difference of εfinal between π/K is seen even in same mT,

but note it is within 2σ of sys. error

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Back up

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PID vn vs centralarity

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Same trends are seen in each centrality bins

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“v2 at high pT” vs centrality

27Scaling starts breaking at 10-20%

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mT dependence of azimuthal pion HBT radiiin 0-20%

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What is HBT ?

Quantum interference between identical two particles Powerful tool to explore space-time evolution in HI collisions HBT can measure the source size and shape at freeze-out,

Not whole size But homogeneity region in expanding source

21 ppq

detector

detector

1p

2p

ToutTside

T

kqkq

ppk

//,2

21

)exp(1)(~1

)()(),(

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21

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invinvqRq

pPpPppPC

P(p1) : Probability of detecting a particle

P(p1,p2) : Probability of detecting pair particles

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〜 1/R

assuming gaussian source

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3D HBT radii “Out-Side-Long” system

Bertsch-Pratt parameterization Core-halo model

Particles in core are affected by coulomb interaction

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Rlong: Longtudinal sizeRside: Transverse sizeRout: Transverse size + emission durationRos: Cross term between Out and Side

detector

detector

1p

2p

R long

Rside

Rout

Sliced view

Beam

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Centrality / mT dependence have been measured for pions and kaons No significant difference between both species

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The past HBT Results for charged pions and kaons

mT dependencecentrality dependence

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Analysis method for HBT Correlation function

Ratio of real and mixed q-distribution of pairs q: relative momentum

Correction of event plane resolution U.Heinz et al, PRC66, 044903 (2002)

Coulomb correction and Fitting By Sinyukov‘s fit function Including the effect of long lived resonance decay

32)2exp(

]1[])1([2222222

222

outsideoslonglongoutoutsideside

halocore

qqRqRqRqRG

FGCCC

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Correlation function for charged pions

Raw C2 for 30-60% centrality Solid lines is fit functions

R.P

R.P

R.P

R.P

1DInv

3DSide Out Long

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Azimuthal HBT radii for pions Observed oscillation for Rside, Rout, Ros

Rout in 0-10% has oscillation Different emission duration between in-plane and out-of-plane?

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out-of-plane

in-plane

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Correlation function for charged kaons

Raw C2 for 20-60%

R.P

R.P

R.P

R.P

1DInv

3DSide Out Long

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STAR Result (w.r.t psi2) PRL.93, 012301(2004)

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