Heavy Quarks and Quarkonia Production at RHIC as a Probe of hot and dense QCD medium

1
Heavy Quarks and Quarkonia Production at RHIC as
a Probe of hot and dense QCD medium
1

• Taku Gunji
• Center for Nuclear Study
• University of Tokyo

ISMD09, Gomel, Belarus, 09.05.2009 09.09.2009
2
Major Discovery at RHIC
2

• Evidence of Strongly Coupled QGP
• Large energy loss of fast partons/colored opaque
  medium
• Partonic flow/nearly perfect liquid
• Further detail insights of the sQGP
• Particle correlations (23 particles, g-jets,
  jets-jets)
• Thermal photons or di-leptons
• Low mass vector mesons
• Heavy quarks and Quarkonia

R. Lacey et al. PRL 98092301, 2007
3
Heavy Quark
3
B. Mueller, nucl-th/0404015

• mHQ T, LQCD
• Creation only at the beginning of
• collisions via hard process (gluon-fusion)
• Well calibrated in pp collisions
• Detail understanding on
• Energy loss mechanism
• Dead cone effect, collisional energy loss,
  relaxation time
• Transport properties of the medium
• Diffusion of heavy quarks by Brown motion
  (Langivin equation)

strong coupling limit h/s 1/4p D x (2pT)
1/2TD
weak coupling limit h/s 4/15 n ltpgt ltr1/5 TD
G.D. Moore, D Teaney PRC71, 064904 (2005)
4
Heavy Quarkonia
4

• Color Debye Screening in the medium
• Attraction between qqbar pairs is reduced.
• Color force is shorter range
• and binding is weaker.
• When screening radius (?T-1)
• become less than binding radius,
• qqbar is never bound.
• Recombination from uncorrelated heavy quark pairs
• Possible for J/y but unlikely for ? at RHIC
• Sensitive to charm production and charm transport
• in the medium

H. Satz (SQM08)
5
Cold Nuclear Matter Effects
5

• Modification of gluon PDF
• Depletion of gluon PDF in heavy nuclei at small x
  (shadowing)
• Large uncertainty for heavy nuclei
• Saturation due to balance of gg?g and g?gg
  process (CGC)
• Initial state energy loss multiple scattering
  (Cronin)
• Nuclear Absorption (for Quarkonia)
• Breakup interaction of pre-resonance or resonance
  by spectator nucleons

6
Heavy Quark Measurement at RHIC
6

• Single leptons (e,m) via semi-leptonic decay
• c-hadrons ? e anything (B.R. 9.6)
• D0 (B.R. 6.87) D? (B.R. 17.2)
• Cannot separate c/b.
• Direct meas. via hadronic decay
• Direct measurement (inv. Mass)
• D0?Kp (B.R.3.85)
• Challenging meas. (S/N)
• e-h correlation
• c/b separation
• Mass and Df space.
• di-electrons

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PHENIX and STAR
7

• PHENIX
• Electrons hadrons, ylt0.35
• p Rejectiongt103_at_90 eff. (MB)
• Muons, 1.2ltylt2.2
• Cut 98 of hadrons by absorber.
• Heavy quark measurement through
• single leptons, e-h, ee pairs
• STAR
• Hadrons electrons, ylt1
• Larger acceptance for hadrons.
• Heavy quark measurement
• through single electrons, e-h
• and direct reconstruction (D?Kp)

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Heavy Quark Production
8

• Short summary of heavy quark production in pp
  collisions. (reported by S. Lebedev)
• Electron pT spectrum from heavy quarks is
  consistent with FONLL calculation.
• 50 of electrons at pTgt5GeV are from bottom
  quarks.

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Heavy Quark Production in AuAu collisions
9

• Single electron measurement by PHENIX STAR

PHENIX PRL98 173301 (2007)
STARarXiv0805.0364
Curves binary scaled pp ref.
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Heavy Quark RAA and v2
10

• RAA and v2

PHENIX PRL98 173301 (2007)

• Strong suppression of heavy
• quark production
• Suppression level is almost
• same as p0 and h in high pT.

PHENIX PRL98 173301 (2007), QM2008
v2 of single electrons from heavy quark decays
dN/d(?-y) N (1 2v2cos(2(?-y)))

• Non-zero flow of heavy quarks
• Behavior of v2 in high pT is
• promising (bottom dominant).

11
Models and h/s of the medium
11

• Langevin based models
• Rapp van Hees PRC 71034907, 2005
• DHQ x 2 pT 4-6

• G-1 ttherm 5 fm/c (15) for c(b)

• This gives h/s (4/3-2)/4p
• close to conjectured limit1/4p
• Significantly below h/s of He(4K)

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Recent Progress I
12

• Quarkonia contribution corrected
• 16 contribution from J/y in high pT region
  (pTgt5 GeV)
• Centrality dependence of single electron v2

A. Dion, QM2009

• RAA not significantly changed
• with the correction.

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Recent progress - II
13

• electron-hadron correlation in AuAu collisions
• How the away side peak is diluted while charm
  traversing the medium? Close relation to charm
  interaction in the medium.
• Single muon spectra in CuCu collisions

A. Dion, QM2009
C.M. Vale, QM2009
PHENIX PRELIMINARY
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charm and bottom RAA
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• RAA(e) rRAAb(1-r)RAAc, rb/(cb) in pp

STAR, S. Sakai, SQM08

• RAAc RAAb correlation
• Dominant uncertainty is
• normalization in RAA analysis
• RAAblt 1 B meson suppressed
• Radiative E-loss only is ruled out.
• Dissociation/Resonance
• Rad Elastic (collisional E-loss)
• AdS/CFT drag momentum loss
• Important measurement to
• differentiate E-loss mechanism.
• Future direct measurement
• of RAAc and RAA b

pTgt5 GeV/c
I Phys. Lett. B 632, 81 (2006) dNg/dy
1000 II Phys. Lett. B 694, 139 (2007) III
Phys.Rev.Lett.100(2008)192301
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Heavy Quarkonia Production
15

• Short summary of heavy quarkonia production in
  pp collisions. (reported by S. Lebedev)
• J/y in pp are well described by new s-channel
  cut CSM except for polarization at forward
  rapidity
• Feed down 8 from y and lt42 (90CL) from cc
• ? cross section in pp follows world trend vs.
  energy

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J/y Production in dAu collisions
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• Rcp (central/peripheral)

L. A. Linden Levy, QM2009

• J/y in dAu _at_ PHENIX
• -2.2ltylt-1.2 x0.09
• y0 x0.02
• 1.2ltylt2.2 x0.003

0-20
20-40
40-80

• Stronger suppression at positive rapidity seems
  to be qualitatively consistent with the
  expectation from gluon shadowing.

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Gluon PDF and sbreakup
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• Effects from gluon PDF(EKS, nDSg) nuclear
  absorption

• Tendency of Rcp seems to be in accord with that
  of modification of gluon PDF.
• Larger variation in the forward is larger
  sbreakup?
• larger absorption/larger initial state energy
  loss/CGC?

EKS s 0,1,2,3,4,15
20-40
A. D. Frawley , workshop in ECT, 2009
PHENIX E866 HERA-B
0-20
Lourenco, Vogt, Woehri - arXiv0901.3054
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J/y RAA in AuAu/CuCu _at_ RHIC
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RAA (1.2ltylt2.2) lt RAA (ylt0.35) RAA at SPS
(0ltylt1)
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CNM effects in AA and RAA/RAA(CNM)
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• Estimation of CNM effects in AA
• Extrapolation of RdAu to RAA(CNM)

A. D. Frawley , workshop in ECT, May, 2009 Joint
CATHIE-INT, mini-program, June, 2009

• RAA(CNM) estimated from RdAu show significantly
  stronger suppression at forward rapidity
• The estimated suppression (50 in most central)
  due to hot and dense effects seems to be very
  similar at both rapidities.

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Comparison of SPS and RHIC
20

• SPS vsNN 20 GeV, RHIC vsNN 200 GeV

M. J. Leicth, Joint CATHIE-INT mini-program,
June, 2009
R. Arnaldi, workshop in ECT, 2009

• Good agreement between
• SPS PbPb and RHIC AuAu.
• Stronger suppression (0.5 in
• central AuAu) than CNM could be
• due to hot and dense medium effects.

AuAu ? using PHOBOS data (Phys.Rev.C65 061901
(2002) PbPb ? using NA50 data (Phys.Lett.B 530
1-4 (2002) 43-55)
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high pT J/y and v2
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Zebo Tang, RHICAGS 2009

• Many competing effects
• screening (suppress low pT)
• recombination (enhance low pT)
• CNM effects (suppress low pT)
• AdS/CFT Hot wind (suppress high pT)
• Suppression at Low pT J/y and RAA is
• consistent with flat tendency.
• Need to have more statistics and
• need to evaluate in dAu collisions.

• First J/y v2 measurement by PHENIX.
• v2 -10 ? 10 ? 2 ? 3 (y0)
• v2 -9.4 ? 10.4 0.3-0.4 ?3
• J/y from recombination should have large v2
  (10-20) due to charm flow. v2lt0 to v2gt0 mass
  ordering?
• charm collectivity?
• Need more data.

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? suppression at RHIC
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• First study of ?(1S2S3S) suppression at RHIC

L. A. Linden Levy, QM2009
? in dAu From STAR
? in AuAu From PHENIX

• RdA 0.98 /- 0.32 /- 0.28
• Upper limit RAA lt 0.64 90 CL.
• First measurement of Upsilon suppression at RHIC.
• Melting of ?(2S3S) 27 and
• ? from cb feed down 25?

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Future
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• Detector upgrade
• PHENIX
• Si-VTX/Forward Si-VTX/FoCAL
• STAR
• HFT(Si-VTX)/MRPC/DAQ
• Luminosity advance

100,000 J/? ??? 250 ? ? ?? 13,000 J/y ?ee 100 ?
?ee per year at highest RHIC luminosities
(AuAu, MB)
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Summary and Outlook
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• Heavy quark and quarkonia measurements in dAu,
  AuAu and CuCu have been performed at RHIC.
• Heavy quark measurement
• Strong suppression and flow of electrons from
  heavy quarks.
• Medium h/s 0.1, which is nearly lower
  conjectured limit.
• Further analysis is on going. (spectra/v2 in
  CuCu, correlations)
• Heavy quarkonia measurement
• Large deviation in RdAu with respect to modified
  gluon PDF at forward rapidities, effectively
  larger sbreakup at forward.
• Stronger suppression (RAA) at forward in AA due
  to CNM effects.
• RAA/RAA(CNM) are similar between mid-rapidity and
  forward rapidity and are in good agreement with
  SPS data. The value reaches to 0.5 in central
  AuAu collisions.
• More study and statistics will be needed for high
  pT J/y and v2.
• Detector upgrade and Luminosity advance will be
  helpful for future heavy quark and quarkonia
  measurement.

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Backup slides
26
Models
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• Many models can describe J/y suppression.
• Gluon dissociation recombination
• Statistical Hadronization
• Sequential Melting

Nu Xu, QM2009
X. Zhao, R. Rapp et al. arXiv0712.2407
T. Gunji et al. PRC 76 051901, 2007 Workshop in
ECT, May, 2009
27
Heavy quark production in pp collisions
Phys. Rev. Lett 97,252002 (2006)
Heavy flavor electron spectrum compared to
FONLL. Data/FONLL 1.71 with error Cross section
shape for pT gt 1.6 GeV/c agrees with FONLL
upper limit
28
c?e/b?e ratio in pp collisions
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Nuclear Modification factor
pTlt1.6 GeV/c pp data (converter) pTgt1.6
GeV/c pp scaled FONLL
PHENIX PRL98 173301 (2007)
Suppression level is the almost same as p0 and h
in high pT.
30
RAAc/RAAb
20
ATHIC Meeting 2008 10/13/2008 T. Gunji
RAAc/RAAb
W. Horowitz SQM07

• Further constraint of heavy quark transportation
• pQCD radel vs. AdS/CFT drag momentum loss
• High pT D and B measurement is necessary.

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Relativistic Heavy Ion Collider

• 4 Experiments STAR, PHENIX, BRAHMS, PHOBOS
• RHIC Heavy Ion Physics Running
• AuAu _at_ 200 GeV (2001/2002, 2004, 2007)
• CuCu _at_ 200 GeV (2004/2005)
• dAu _at_ 200 GeV (2002/2003, 2008)

32
21
h/s of the medium
diffusion constant

• Relation btw. Drag force and h/s
• Rapp and van Hees PRC 71034907, 2005
• DHQ x 2 pT 4-6.
• Moore and Teaney PRC 71064901, 2005
• DHQ x 2 pT 3-12.
• This gives h/s (4/3-2)/4p
• indicate small value and
• close to conjectured limit (h/4p)

strong coupl. h/s 1/4p D x (2pT) 1/2TD
weak coupl. h/s 4/15 n ltpgt ltr1/5 TD

33
Hydro Heavy Quarks
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Y. Akamatsu et al. arXiv0809.1499

• Relativistic treatment of Brown Motion
• Drag force is inspired by AdS/CFT calculations.

g (2.1 ? 0.5) from AdS/CFT
w.c
s.c
34
Hydro Heavy Quarks (2)
20
Y. Morino(CNS), Doctor Thesis (2009)

• Similar to Akamatsu-sans hydro HQ model
• AdS/CFT Drag force
• Experimental b/cb ratio
• Implement coalescence process for low pT
• Min. c2 fit

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3.) Heavy Quarks in the QGP
R. Rapp at SQM08

• Brownian
• Motion

Fokker Planck Eq.
Svetitsky 88,
Q
scattering rate diffusion constant
36
2.5 Comparison of Drag Coefficients
R. Rapp at SQM08

• pert. QCD with running coupling AdS/CFT
• increase with temperature except T-matrix
  (melting resonances)

37
2.1.3 Thermal Relaxation of Heavy Quarks in QGP

R. Rapp at SQM08
Charm pQCD vs. Resonances
Charm vs. Bottom
pQCD
D

• tctherm tQGP 3-5 fm/c
• bottom does not thermalize

• factor 3 faster with
• resonance interactions!

38
Major discovery at RHIC
2
ATHIC Meeting 2008 10/13/2008 T. Gunji
Universality of jet quenching

• Universal Bound Model
• Upper limit of energy, which can escape the
  medium.

39
Heavy Quarks
X-N. Wang at HP08
Wicks et al06,Djordjevic et al06
DEel for heavy quark is larger than light quarks
40
M. J. Leitch