event anisotropy measurement in high-energy heavy-ion collisions at rhic

Seminor at LANL, 29/Mar/2005 ShinIchi Esumi, Univ. of Tsukuba 1

Event anisotropy measurement in high-energy heavy-ion collisions at RHIC

ShinIchi Esumi Univ. of Tsukuba

Contents

(1) flow measurements in PHENIX(2) identified hadron v2

(3) charmed and photon v2

(4) relation of v2 and jets(5) azimuthal angle dependent HBT


Au+Au collisions in sqrt(sNN)=200GeV with

Relativistic Heavy Ion Collider (RHIC) at BNL

PHENIXmid-rapidity hadron/electron/ photon spectrometer

Forward-rapidity muon spectrometer


BBC/ZDC : centralityDch/PC1,2,3 : trackingTof : hadron PIDRich : electron PIDEmcal : electron/photon PID


Target

Projectile

b:impact parameter

Reacti

on pl

ane Reaction plane

initial geometryfinal momentum anisotropy

parton

parton

hadrons

A+A

p+pExperimentally, the R.P. is defined by the event anisotropy by itself, when one uses participants.


Reaction plan

e

x

y

Reaction plan

e

x

y

Σ wi*sin(2i) tan(22) =

Σ wi*cos(2i)

21

Σ wi*sin(i) tan(1) =

Σ wi*cos(i)

Reaction plane definition

plane with the directed moment

plane with the elliptic moment

(wi: 1 or pT or ET)

i

i


reaction plane based analysis (geometrical origin / smeared by resolution)

dN / d(-true) = C (1 + 2vncos(n(-true))) : azimuthal angle for particles true (or meas.) : true (or measured) reaction plane angle vn

’ = <cos(n(-meas.))> : measured anisotropy parameter vn = <cos(n(-true))> = vn

’/R.P.: corrected anisotropy parameter R.P. = <cos(n(meas.-true))> : reaction plane resolution

pair wise correlation analysis (no resolution / larger non-flow effect)

Nreal () / Nmixed() = C (1 + 2vn2cos(n()))

ij

F() = A exp(-0.5( /width)2) + B (1+2v22cos(2))

Gauss term is to account for some of the non-flow contribution.


Beam-beam counter(BBC) ||=3~464pmts in each BBC charged particles

two central arms (CNT) ||<0.35Dch,PCs,TOF,EMCALtracking, momentum, PID

collision point

beam line

dNch

/d

-6 -3 0 3 6

Zero Degree CalorimeterShower-Max DetectorSpectator neutron energyBeam position

BBC

CNT

ZDC/SMD

MuonMuon arm +Silicon multiplicity(MVD) endcap

MVD

Reaction plane detectors in PHENIX

South North


MIP calibration for each pmtRing gain correctionAverage sin/cos shift correctionremoving 4 special pmtsNormalized sumx/y distribution correctionConventional flattering (shifting angle) correction

Beam-Beamcounter


Measurement with the MVD

• The MVD is currently configured as a silicon pad detector covering a 1.8<||<2.6 for collisions at z==0. Effective range (with vertex smearing) is 1.1<||<3.3 .

collisionvertex

• Geometry:Each end (North/South) has 12 wedges. Each wedge has 12 columns of 21 pads.

(6048 channels total)


BBC

“Beam’s eye” view of ZDC

ZDC – Zero Degree CalorimeterBBC – Beam Beam CountersFHC – Forward Hadron Calorimeter

ZDC location in RHIC tunnel


“Naked” ZDC module

Clear PPMA fibers

Tungsten absorber plates

Schematic of ZDC module assy

LED flasher

Scintillator strips

WLS fibers

16ch. PMT “M16”

Shower Maximum Detector (SMD)

ZeroDegreeCalorimeter (ZDC)

horizontal-strips

vertical-strips


SMD1 (South) SMD2 (North)

Y (c

m)

X (cm) X (cm)

(X-CX)/X

(Y-C

Y)/

Y

(X-CX)/X

SMD1 SMD2

beam spot distribution


SMD1vsSMD2BBC1vsBBC2 SMDvs BBC

BBC1vs

BBC2

back-to-back back-to-back spectator neutrons vss from participants are flowing opposite.

MVD1vs

MVD2 BBCvs

MVD

directed plane

elliptic plane


mid-rapidity hadron, electron, and photon spectrometer


STAR large acceptance hadron tracking chambersecondary vertex


large acceptancewith full tracking

reaction plane method2 particle correlation method4th order cumulant method


particleR.P. (rad)

beam linereaction plane

neutron spectatorcharged particles(pions) at mid

beam

pT cut


PHOBOS : nucl-ex/0406021

PHENIX Preliminary

indication of v2 saturation at RHIC energy


Thermal model with blast-wave

hydro is really good to be truth!!What will happen with resonances?

Resonance effects are important in single spectra, but not too much in v2, because of pT shift of heavy particles having smaller v2 and linear pT dependence of v2.


Phys

.Lett

. B59

7 (20

04) 3

28-33

2, X. D

ong e

t.al.

Phys

.Rev

. C70

(200

4) 02

4901

, V. G

reco e

t.al

Pion deviation is explained by resonance decays

pT shift is the dominant effect compared to the smearing given by the opening angle.


stat. error onlysys. error <20% (62GeV) 15% (200GeV)

v 2 /n

quar

k

pT /nquark [GeV/c]

62.4 GeV Au+Au: preliminary

200 GeV Au+Au, charged ,K,p : PRL91, 182301 (2003)

0 : preliminary


hydro + jet

quark coalescence

recombination + fragmentation

Data prefer “quark coalescence / recombination” based picture rather than “hydro + jet” picture at intermediate pT.

QGP


minimum bias Au+Au at sNN = 200 GeV

PHENIX preliminary

some remainingmass ordering

PHENIX preliminary

quark + hadron flow

Tfo

early freeze-out

SPS

Similar effect from the time-difference is seen in v2

Almost NOmass ordering


Hadronic cascade fails in magnitude (too small, it needs a big push from QGP), but it shows clear meson / baryon difference.


hydro + jet

Jets dominate the high pT part of spectra.


PHENIX STAR

And they (jets) are suppressed.

v2


Charm quarks are binary scaled (lower pT) or suppressed (high pT) w.r.t light quarks, but it could be enhanced and suppressed (looked like binary scaled). The v2 of charm would give a hint for the answer to the question.

Converter method Cocktail subtraction method


PHENIX Preliminary

RAA (2.5<pT<5.0 GeV/c)

Nuc

lear

mod

ifica

tion

fact

or

Converter method

Cocktail subtraction method

pT (GeV/c)


inclusive ee v2

charmed ee v2

If charm quarks also flow, charm quarks are thermalized and / or suppressed (interact with matter) similarly to the light quarks.

STAR SQM04

nucl-ex/0502009


run2 Au+Au ~10 J/’sin PHENIX central arm (ee)

run4 Au+Au ~100 times in statisticscompared with run2

Single muon and muon pair in PHENIX muon arm …


Inclusive Single

PHENIX Preliminary

Run2 AuAu 200 GeV

Direct photons are enhanced w.r.t. production, but it’s just because is suppressed, and the direct photons are in fact binary scaled.


vertical bar : stat. errorcurves, gray box : sys. error

phenix preliminary

Note : Inclusive photon = including all of the decay effect from hadrons

phenix preliminary phenix preliminary

pT [GeV/c]

, 200 GeV Au+Au , 200 GeV Au+Au , 200 GeV Au+Au

Direct photons should not have any flow by definition, but …Alternatively ratio can be measured by assuming v2

=0.

The difference here and the ratio will give us a measure of direct v2.


STAR2

part

icle

cor

rela

tion

(v2 +

non

-flow

)The difference here is given by the real flow (v2).


STAR : nucl-ex/0409033 non-flow reduced

v2{2}

v2{RP}

v2{4}STAR Preliminary

charged particle v2

v2{2}

v2{RP}

If jet suppression ends somewhere, should v2 go to zero?


PHENIX Preliminary

Reac. plane v2 does have less non-flow because of the gap.Non-flow are removed in 2 part. corr. 2nd cumulant …



semi-old STAR data

old STAR data

no jet-quenching


phenix preliminary

}nucl-ex/0305013

Au+Au 200 GeV Au+Au 200 GeV

v2 reduction of charged particles in the previous page could be enlarged by the baryon/meson ratio.


1<p T

(ass

ocia

te) <

1.5G

eV2.

5<p T

(ass

ocia

te) <

3GeV

hadron-hadron correlation (full pT reference)

(rad)

pure harmonic function fit

1.1

1.0

0.91.1

1.0

0.9

harmonic +near-side Gaussfunction fit

0. 0. 0.

harmonic +near-side +Far-side Gaussfunction fit

harmonic function fixed to themeasured v2

Au+Au 200GeV PHENIX preliminary

Another way to get the v2 : (v2)2 is given by the pair correlation

Ways to reduce the jet correlation with additional Gauss terms

A{1+2 (v2)2 cos(2)} + Gauss term

QM04


4 < pT(trig.) < 6 GeV/c

Is the away-side jet-like?

Away-side looks jet like in p+p,but not in central Au+Au.

nucl-ex/0404010 0501016


Associated particles pT distributions

0.15<pT(asso.)<4 GeV/c

nucl-ex/0501016

STAR preliminary

re-distributed lost energy 4 < pT(trig.) < 6 GeV/c0.15 < pT(asso.) < 4 GeV/c


leading parton

hadrons

Q: Are jets source of v2?Q: Does reaction zone make flowing jets?

20-60%

STAR preliminary

20-60%

track1 - track2|

r.p.

in-plane pair

out-of-plane pair

in between

trigger particlein the selected angular window

Proof of the jet quenchingand the source of v2 at high pT

4 < pT(trig.) < 6 GeV/c 2 GeV/c< pT(asso.) < pT(trig.)


trigger hadron pT>3GeV/c

hadron-hadron correlation

0<pT<1 1<pT<2 2<pT<5

0-20%

20-40%

40-90%

associated hadron pT window

in-planemiddleout-of-plane

Fitted line shape is given by :

with fixed(1)v2(trigger)(2)v2(associated)(3)R.P. resolution(4)in/out bin width (nucl-ex/0311007)

and one freenormalization parameter fit is done in a limited range shown


c(

) [ar

b. u

nit]

QM04


flow subtracted hadron-hadroncorrelation data

trigger hadron pT>3GeV/c

hadron-hadron correlation

0<pT<1 1<pT<2 2<pT<5

0-20%

20-40%

40-90%


c(

) [ar

b. u

nit]


QM04

Seminor at LANL, 29/Mar/2005 ShinIchi Esumi, Univ. of Tsukuba 45photon-hadron correlation


0<pT<1 1<pT<2 2<pT<5

0-20%

20-40%

40-90%

trigger photon pT>2GeV/c

in-planemiddleout-of-plane


c(

) [ar

b. u

nit]

Fitted line shape is given by :

with fixed(1)v2(trigger)(2)v2(associated)(3)R.P. resolution(4)in/out bin width (nucl-ex/0311007)

and one freenormalization parameter fit is done in a limited range shown

QM04



trigger photon pT>2GeV/c

photon-hadron correlation

0<pT<1 1<pT<2 2<pT<5

0-20%

20-40%

40-90%

flow subtracted photon-hadroncorrelation data

c(

) [ar

b. u

nit]


QM04


in-plane pairin between pairout-of-plane pair

h - h

0 0 (rad) (rad)

real

/mix

ed flow subtractedpT

trigger(h) > 3GeV/c1< pT

associated(h) <2GeV/c

three curves are fixed bymeasured v2 and resolution

coalescence of jet-fragmentation could be one of the source of v2

PHENIX preliminary PHENIX preliminary

flow subtractedpT

trigger() > 2GeV/c1< pT

associated(h) <2GeV/c

PHENIX preliminary

in-plane pairin between pairout-of-plane pair

- h

PHENIX preliminary


• The correction for R.P was applied

• Sinyukov’s fit• Fitting by cos and s

in function

)2sin(RRR

)2cos(RRR

)2cos(RRR

)2cos(RRR

22,os

20,os

2os

22,l

20,l

2l

22,o

20,o

2o

22,s

20,s

2s

expected tendencies of sin or cos are seen !

A

B

In-plane

Out-Of-plane

Reaction Plane

Au Au

RsideRout


– Rs,2/Rs,0, Ro,2/Rs,0 and Ros,2/Rs,0 are larger at mid-central than at central.– Ro,2/Rs,0 , Ros,2/Rs,0 seem to be larger than Rs,2/Rs,0

– Rl,2/Rl,0 and the difference (Ro,2/Rs,0 - Rs,2/Rs,0 ) seem to be possitive? – anisotropy in geometry or (maybe more) in time/expansion

geo. geo. + time

cross term (geo. + time)/geo.


Summary

quark number scaling in v2 and Rcpquark degree of freedom / partonic flow

jet quenching / away side jet suppressionbinary scaling of direct photon / heavy quark?

chemical equilibrium in hadron yieldstrangeness saturation factor s ~ 1

thermal equilibrium in momentum spectralarge hadronic expansion and cooling


STAR preliminary

RCP for and K0s in d-Au


||ηη|<0.7|<0.7

preliminary

<Npart>


d+Au, 40-100%

Au+Au, 0-5%

STAR preliminary

3 < pT(trig.) < 6 GeV/c2 < pT(asso.) < pT(trig.)

correlation width

correlated yield3 < pT(trig.) < 4 GeV/c2 < pT(asso.) < pT(trig.)

|| < 1.0

STAR preliminary


• Pairs are divided into 4 Δφbins (width=45degree)

q_ot

her<

40M

eV/c

qα(GeV/c)

event anisotropy measurement in high-energy heavy-ion collisions at rhic

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