Zebo Tang University of Science and Technology of China (USTC)

RHIC&AGS Users' Meeting, BNL, June 1-5, 2009 1Zebo Tang, USTC

Zebo TangUniversity of Science and Technology of China (USTC)

Open and Closed Charm measurements at RHIC


Open charm measurements at RHIC

STAR measurements:

Signal/Spectra

D0 K c + X (y=0, low pT) c e + X

Flow & energy loss

Radial flow from NPE

RAA from NPE

Correlations

D*-jet, e-h, e-D0

PHENIX measurements:

Signal/Spectra

D0 K-+0 c + X (<y>=1.65, pT>1 GeV/c) c e + X e+e-

Flow & energy loss

Elliptic flow from NPE

RAA from NPE

Correlations

e-h, e-


Energy lossPHENIX: PRL98(2007)172301STAR: PRL98(2007) 192301

Strong suppress, energy lossSimilar magnitude as light hadronsBottom yields and bottom energy loss?


Heavy flavor feeddown

Good high pT J/ measurements are neededSmall effect on RAA

No conclusion change

Carla M. Vale, QM2009


Correlation

arXiv:0903.4851

B is also suppressedRadiative energy loss unfavored

Bertrend Biritz, QM2009

PHENIX, arXiv:0903.4851


Jet flavor conversion?

pT (GeV/c)

STAR preliminary

hardparton

path length L

Quark

Quark

path length L

Quark

gluon

hardparton

Kaon consistent with Jet conversionHow about charm and bottom?How about LHC energy?

Yichun Xu, QM2009


Forward rapidityCarla M. Vale, QM2009

More suppression at forward rapidity? need more statistics, better systematic control, and in Au+Au


Quarkonium melting in medium

?

• Suppression has long be proposed as a signature of QGP formation

• Plasma thermometer

• Quarkonium production mechanism

Ágnes Mócsy, QM2009


Charmonium production mechanism

NRQCD

Color singlet

Color octet

Color singlet model (CSM), LO

underpredicted CDF data by order of magnitude

Color octet model (COM), LO

good agreement with CDF cross section

disagreement with CDF polarization

CSM*, NLO

better agreement

NNLO* applicable at pT>5-7 GeV/c

COM*

improvement of polarization,

NLO will come, valid at pT>3 GeV/c

CSM+s-channel cut

valid at low pT

Decay feeddown (CDF):

(2s): 7%-15%, slightly increase with pT

c0,1,2: ~30%, slightly decrease with pT

B: Strong pT dependence

LO

Know your reference!


Charmonium measurements at RHIC

STAR measurements:

Mid-rapidity (ee)

L2 J/ trigger:

low pT in p+p

EMC trigger:

high pT in p+p, Cu+Cu, d+Au

BJ/ in p+p

Minbias:

low pT in Au+Au, Cu+Cu, d+Au

Forward rapidity (ee)

J/ and c in p+p (2.5<<4.0)

PHENIX measurements:

Mid-rapidity (ee)

J/ in p+p, d+Au, Cu+Cu, Au+Au (low and intermediate pT)

’ and c in p+p

Forward rapidity ()

J/ in p+p, d+Au, Cu+Cu, Au+Au

(1.2<||<2.2)


Low pT spectra in p+p

CSM+s-channel cut works well at intermediate pT


High pT spectra in p+p

Significantly extend previous measurements from 5 to 14 GeV/c

CEM, LO COM describe overall trend, leave little to no room for feeddown

NNLO* CSM, steeper than data

STAR Preliminary


xT scaling

n is related to thenumber of point-likeconstituents takingan active role in theinteraction

n=8: diquark scattering

n=4: QED-like scattering

and proton at pT>2 GeV/c: n=6.6±0.1 (PLB 637, 161(2006))

J/ at high pT: n=5.6±0.2 (close to CS+CO prediction)

Soft processes affect low pT J/ production

pT>2 GeV/c

STAR Preliminary

pT>5 GeV/c


Forward rapidity

J/ cJ/Further constrain models

High xF intrinsic heavy flavor

Chris Perkins, QM2009


PolarizationCesar Luiz da Silva, QM2009


Feeddown

R(ψ’) =8.6±2.5% PHENIXR(c) <42% (90%C.L.) PHENIX

Susumu X. Oda, QM2008


BJ/

No significant near side correlationB contribution (13 5) %Little room for parton fragmentation

STAR PreliminaryarXiv:0904.0439


Constrain bottom yields

• pQCD predicts significant BJ/ • correlations shows low B contribution• can be used to further constrain B yields• constrain Be

M. Cacciari, P. Nason and R. Vogt RL 95(2005),122001; CLEO collaboration PRL 89(2002),282001

STAR PreliminaryarXiv:0904.0439

Gang Wang, QM2008


RAA at low pT

PHENIX, PRL98, 232301

• Similar suppression as that at SPS• More suppression at forward rapidity• Regeneration? Sequential suppression?

J/


RAA at high pT

STAR Cu+Cu 0-20%:RAA(pT>5) = 1.40.40.2No suppression

RAA(pT~5.5)>0.6 (86% C.L.)RAA(pT~7.0)>0.6 (82% C.L.)Combined: 97%Indicates increase of RAA

RAA(pT~5.5)>AdS/CFT+Hydro (93% C.L.)RAA(pT~7.0)>AdS/CFT+Hydro (94% C.L.)Combined: 99%Contrast to AdS/CFT+Hydro prediction

PHENIX Spectra not available, prevents statistics analysisNo way PHENIX can make conclusion contrasting to STAR


RAA at high pT

• Consistent with no suppression at high pT: RAA(pT>5 GeV/c) = 1.4± 0.4±0.2

• Indicates RAA increase from low pT to high pT

• How does production mechanism (CS vs. CO) affect energy loss?• Contrast to AdS/CFT+ Hydro prediction (H. Liu, K. Rajagopal and U.A. Wiedemann PRL 98, 182301(2007), T. Gunji, JPG 35, 104137(2008)

• Good jobs: • two-component model, leakage and B feeddown is important (R. Rapp, X. Zhao, arXiv:0806.1239)

• transport+hydro, from initial produced instead of regenerated (Y.Liu, Zhen Qu, N. Xu and P. Zhuang, arXiv:0901.2757)


Elliptic flow

Inherit open charm flow or not? Regeneration?Too early to compare to models, need more statistics

pT integrated v2 = (-10±10)% @ |y|<0.35 and (-9.3 ± 9.2)% @ -1.2<|y|<1.2 Ermias T. Atomssa

QM2009


Future

PHENIXJ/500 GeV p+p

STARJ/eeL3 trigger, Online tracking

More and more statisticsBetter and better detectorsBetter and better techniques

Bright future, better understanding


backup


Why heavy flavorWicks et al, NPA 784 (2007) 426Muller nucl-th/0404015

• Heavy quark masses are not modified by QCD vacuum. Strong interactions do not affect them.

• Important tool for studying properties of the hot-dense matter created at RHIC energy.


Flow

1. Tfo = 220 MeV (best fit) – freeze out earlier <t> = 0.23 (best fit), <0.42 (1-) favor moderate or small radial flow.

2. Sizable v2 strong-interacting Quark Gluon Plasma

STAR Preliminary

PRL, 98, 172301 (2007), D. Hornback, QM2008STAR: nucl-ex/0805.0364, Y. Zhang, QM2008


STAR Preliminary

Beam pipe + SVT + SSD+ Dalitz

Beam pipe + Dalitz

TPC Inner Field cage

Cou

nt

Outlook: HF-lepton

Projection (0.4/nb)Run-8

Run-3

Run 8 data compared to run3

Material in front of TPC reduced by an order of magnitude

Final charm cross section is in progress


Outlook: Direct reconstruction

D0

Phys. Rev. Lett. 94 (2005)

S. Butyk (QM2008 poster)PHENIX Preliminary

Year5 pp 200 GeV

Before background

HFTSimulation

Small signal to background ratio

Precise vertexing will helps a lot

Still long way to go


How does open affect closed

Open charm Radial flow (thermal)

Sizeable elliptic flow

Strong suppression at high pT (energy loss)

Total charm cross section

Be

Charmonium Regeneration possible

Inherit elliptic flow

Lose energy (CO)

No energy loss (CS)

Model input

BJ/

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Zebo Tang University of Science and Technology of China (USTC)