PHENIX Results

Y. Akiba (RIKEN Nishina Center)

for PHENIX Collaboration

RHIC/AGS User’s meeting

2008.05.29

The RHIC Physics Program

RHIC

New State of Partonic Matter Origin of Nucleon Spin

PHENIX Data-Sets

Collided 4 different species in 8 years: AuAu, dAu, pp, CuCu6 energies run: 9.2 GeV, 19 GeV, 22.5 GeV, 62.4 GeV, 130 GeV, 200 GeV

3

times

30

times

Year Species Ãs [GeV ] ºLdtNtot (sampled)Data SizeRun1 2000 Au - Au 130 1 µb-1 10 M 3 TB

Au - Au 200 24 µb-1 170 M 10 TBAu - Au 19 < 1 M

p - p 200 0.15 pb-1 3.7 B 20 TBd - Au 200 2.74 nb-1 5.5 B 46 TBp - p 200 0.35 pb-1 6.6 B 35 TB

Au - Au 200 241 µb-1 1.5 B 270 TBAu - Au 62.4 9 µb-1 58 M 10 TBCu - Cu 200 3 nb-1 8.6 B 173 TBCu - Cu 62.4 0.19 nb-1 0.4 B 48 TBCu - Cu 22.4 2.7 µb-1 9 M 1 TB

p - p 200 3.8 pb-1 85 B 262 TBp - p 200 10.7 pb-1 233 B 310 TBp - p 62.4 0.1 pb-1 10 B 25 TB

Run-7 2007 Au - Au 200 725 µb-1 4.6 B 570 TBd - Au 200 81 nb-1 160 B 437 TBp - p 200/500

Au - Au low energy

Run5

Run-6

Run-8

2002/03

2006

2007/08

2005

2001/02Run2

Run3

Run4 2003/04

PHENIX publications

• 67 papers published since 2001– Phys. Rev. Lett. 41– Phys. Rev. C 19– Phys. Rev. D 5– Phys. Letter B 2– Nucl. Phys. A 1

(white paper)

• Total citation: ~5900– 500+ 1

– 250-500 5– 100-250 11– 50-100 18

• 19 +3 papers published + accepted since January 2007– PRL 9 +1– PRC 7 +2– PRD 2– PLB 1

• 8 papers in review

• PHENIX “White Paper” is now a “Renowed” (500+) status, with total of 504 citation.

5

Proton Spin

1

2

1

2q Lq

z G Lgz

Well measuredonly ~30% of spin

A future challenge

Spins + orbital angular momentum needto give the observed spin 1/2 of proton

Measuredat RHIC

π0 ALL : work horse for G(x)

• pQCD works for pT>2GeV/c

RUN5 resutls: PRD76 (2007) 051106

• 0 ALL constraint on G

RUN6 0 ALL

Scaling Errors not included

• Final RUN6 results will be published soon

• Gives much stronger constraint on G

More ALL measurements

Many independent probes to understand gluon spin

NEWNEW

NEW

NEW

Forward 0 AN at large xF with MPC

3.0<<4.0

p+p0+X at s=62.4 GeV p+p0+X at s=62.4 GeV

AN of muons from charm/bottom decays

• AN of charm decay muons is measured for the first time

“Max” value of AN of charm isnot well constrained

NEW

3D source imaging

3D source imaging reconstructs source parameters

reverse engineer the correlation function by an input source function.

The analysis suggests that there is a long tail of the source distribution

Solutoin of the long-standing “HBD puzzle”?

arXiv:0712.4372, PRL accepted

Scaling of v2 of hadrons

• More data on v2(pT) of hadrons are accumulated• When v2/nq vs KET/nq (KET=transverse kinetic enery), all data points

are on a universal curve, suggesting that v2 developed in partonic stage

PRL98,162301(2007)

Phi meson (small interaction cross section) also followsthe number of quark (nq) scaling.

More on the scaling of v2: phi flow

PRL99, 052301 (2007)

v2 of Direct photon and J/e+e-

First ever at RHIC,

v2 - J/µ+µ- coming soon

J/Psi coalescence ?

NEW

PHENIX preliminary

Direct v2 Min Bias Au+Au 200 GeV (Run 4)

Sign of direct v2 (at high pT): – Positive == parton emission quenched– Negative == parton emission (Brems.)

enhanced

v4 - scales with v2

V4

pT (GeV/c)

V4/(nq)2

KET /nq (GeV/c2)KET (GeV/c2)

v2 scales with nq, v4 with nq2 partonic degree of freedom

V4

PHENIX preliminary

NEW

π0 pT spectra at √sNN = 200 GeV

RUN2 Au+Au PRL91,072301

RUN4 Au+Au arXiv:0801.4020 [nucl-ex]

RAA measurements now extends to 20 GeV/c

Quantitative analysis

Comparison with GRV model: dNg/dy=1400 arXiv:0801.1665 PRC accepted

RAA beam energy dependence (Cu+Cu)

Cu+Cu 22,62,200 GeV (Run 5)

• Model calculations indicate quenching expected at sNN = 22 GeV, but Cronin effect dominates

• Species dependence to probe space/time of suppression

arXiv:0801.4555

19

RAA of hadrons and direct photon (AuAu 200GeV)

• Same suppression pattern for 0 and : Consistent with parton energy loss and fragmentation in the vacuum

• RAA for ‘s larger than 0 RAA for 2 < pT < 5 GeV/c. Why?

• Ncoll scaling for direct (except for highest pT point?– Isospin effect?)

More Direct photon RAA Results

Central Cu+Cu 200 GeV (Run 5) Direct RAA vs Npart

PHENIX Preliminary

PHENIX PreliminaryMin Bias Au+Au 62 GeV (Run 4)

• Direct photon RAA 1• Is there other evidence for nuclear

effects?– Reduced/enhanced radiation due to jet

quenching

NEW

NEW

Modification of jet correlation

• Two particle of two high pT track (jet correlation) is modified in central Au+Au collisions.

• Many theory attempts to explain these effect

• Probing the medium response to fast partons

PRL97,052301 (2006) Au+Au

More detailed study of jet correlation

224

2

/

)(

kurtosis

rms

nn

D

)(

)()(

)(

DG

DGG

J

PRL98, 232302 (2007)

jet correlations vs reaction plane

unchanged near-side peak in the final jet functions when moving away from Reaction plane, indication for away side modification.

-h Correlations

“measures” recoil parton momentum– Measure fragmentation function D(Z)

-h p+p 200 GeV (Run 5)

~D(z)

J/ suppression in Au+Au

• High statistics measurement of J/ in AuAu in wide rapidity range– Mid-rapidty J ee– Forward rapidty J/

• Strong suppression of J/ is observed– Consistent with the

prediction that J/s are destroyed in de-confined matter

• Surprisingly, the suppression is stronger at forward rapidity than in mid-rapidity– J/ formation by

recombination of charm pairs in deconfined matter?

PRL98,172301 (2007)

RAuAu (run 4) = RAuAu (run 7)

• Forward rapidity only (for now)

• More bins at higher centrality

• Confirm the trend– RAA(y≈1.7) < RAA(y≈0)

NEW

J/ d+Au: Cold Nuclear Matter

• Increased Run 5 p+p statistics (x10 Run 3) as baseline

• Improved & consistent p+p and dAu analysis– Improved alignment, resolution,

yield extraction,… – Cancellation of systematic errors

in RdAu

• Result: CNM = Shadowing(EKS) + Breakup = 2.8 mb– Consistent within errors with

previous results– and with Breakup=4.2+/-0.5mb

(SPS result)

PRC77_024912 (2008)

+1.7-1.4

J/ RdAu 200 GeV

J/ RAA Cu+Cu and Au+Au

• Approx 2x more J/ in Cu+Cu sample than Au+Au sample– More precise Npart<100 info

• Curves show RAA prediction from ad hoc CNM fit to RdAu separately at y=0 and y > 1.2

• CNM from RdAu fit describes suppression for Npart < 100.

J/ RAA 200 GeV arXiv:0801.0220

RdAu constraints are not sufficient to say if suppression beyond cold nuclear matter is stronger at forward rapidity

Heavy flavor electron RAA and flow

Two models describes strong suppression and large v2

Rapp and Van Hee Moore and Teaney

From model comparison, viscosity to entropy ratio /s can be estimated

DHQ × 2πT = 4 - 6DHQ ~ 6 x /(+p) = 6 x /Ts

/s ~ (4/3 – 2)/4 The estimate of /s is close to the conjectured bound 1/4from AdS/CFT

PRL98,172301 (2007)Contraints on /s

Bottom Measurement

• Charm and bottom spectra both x above FONLL calculations– But ratio is in good agreement with FONLL

p+p 200 GeV Charm and bottom extracted via e-h mass analysis

NEW

NEW

31

total cross section of charm and bottom

√s dependence of cross section with NLO pQCDagrees with data

total cross section of bottom NEW

Is bottom also suppressed? Does it flow?

• p+p data indicates that a large contribution of b for pT>2 GeV/c

• The suppression in high pT is strong and new v2 data suggest significant flow of HF electron in high pT

– Is bottom also suppressed?

– Does bottom also flows?

PRELIMINARYRun-4

Run-7

Rapp & van Hees, PRC 71, 034907 (2005)

minimum-bias

PRL 98, 172301 (2007)

e± from heavy flavor

NEW

e+e- pairs in p+p

• Cocktail filtered in PHENIX acceptance

• Charm, Bottom, DY contributions from PYTHIA

• Excellent agreement!

arXiv:0802.0050

e+e- pairs in Au+Au

• Data and Cocktail absolutely normalized– Cocktail normalized to

Au+Au measurements• Except ccbar

• Low mass excess– 150 < Mee < 750 MeV– X 3.4±0.2(stat.)

±1.3(syst.)±0.7(model)

arXiv:0706.3034

PT Dependence of Au+Au Mee

• Low Mass excess is a low pT enhancement– Huge excess at

lowest pT

– Late Phase info

0 < pT < 8 GeV/c 0 < pT < 0.7 GeV/c

0.7 < pT < 1.5 GeV/c 1.5 < pT < 8 GeV/c

PHENIX Preliminary • Still significant at high pT

Next topic

NEW

Enhancement of almost real photon

Kinematic region of e+e- pairs

m<300 MeV and 1<pT<5 GeV/c

p+p

• Good agreement of p+p data and hadronic decay cocktail

• Small excess in p+p at large mee and high pT

Au+Au

• Clear enhancement visible above for all pT

pp Au+Au (MB)

1 < pT < 2 GeV2 < pT < 3 GeV3 < pT < 4 GeV4 < pT < 5 GeV

arXiv:0804.4168

Direct for p+p, Au+Au

• New p+p result with * method agrees with NLO pQCD predictions, and with the measurement by the calorimeter

• For Au+Au there is a significant low pT excess above p+p expectations

• Excess is exponential in shape with inverse slope T~ 220MeV

• Thermal photons from hydrodynamical models with Tinit=300 – 600MeV at 0=0.6-0.15fm/c are qualitative agreement with the data.NLO pQCD (W. Vogelsang)

Fit to pp

exp + TAA scaled pparXiv:0804.4168

Constrain the properties and evolution of the matter

Summary

• 2007-2008 is very productive for PHENIX

• Spin physics results– Constraint on gluon polarization from pi0 ALL

– More new ALL measurements

– AN of forward pi0, heavy flavor decay muons

• Many heavy ion physics results

3D imaging Flow

High pT hadrons Jet correlation

Direct photon Heavy quark

Dilepton Thermal(?) Photon

• These results start to give constraint on the properties of the dense matter formed at RHIC