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Zebo Tang, 高能核物理导论 110/10/2009
唐泽波中国科学技术大学近代物理系
相对论重离子碰撞中J/的产生
• Introduction
• J/ production at low pT
• J/ production at high pT
Zebo Tang, 高能核物理导论 210/10/2009
Discovery of J/
PRL33, 1404-1406 (1974) PRL33, 1406-1408 (1974)
Zebo Tang, 高能核物理导论 310/10/2009
Features of J/
cc bound state, r~0.4 fmMass=3.097 GeV/c2, Width=93.2 keV/c2
Zebo Tang, 高能核物理导论 410/10/2009
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
LO
Know your reference!LO CSM LO COM
J/ 3S1
J/
CDF measurement: PRL79,572
Zebo Tang, 高能核物理导论 510/10/2009
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
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!
Zebo Tang, 高能核物理导论 610/10/2009
Low pT spectra in p+p
CSM+s-channel cut works well at intermediate pT
Zebo Tang, 高能核物理导论 710/10/2009
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
Zebo Tang, 高能核物理导论 810/10/2009
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
Zebo Tang, 高能核物理导论 910/10/2009
PolarizationCesar Luiz da Silva, QM2009
Zebo Tang, 高能核物理导论 1010/10/2009
Feeddown
R(ψ’) =8.6±2.5% PHENIXR(c) <42% (90%C.L.) PHENIX
Susumu X. Oda, QM2008
Zebo Tang, 高能核物理导论 1110/10/2009
Disentangle contributions via Correlations
• J/-hadron correlation can also shed light on different source contribution to J/ production
• CSM vs. COM
1)
no near side correlation
2)
strong near side correlation
g g g /J
g g b b hadron
B X /J X
PLB 200, 380(1988) and PLB 256,112(1991)
Zebo Tang, 高能核物理导论 1210/10/2009
BJ/
No significant near side correlationB contribution (13 5) %Little room for parton fragmentation
STAR PreliminaryarXiv:0904.0439
Zebo Tang, 高能核物理导论 1310/10/2009
Quark Gluon Plasma
Quark Gluon Plasma:
1) Deconfined and
2) Thermalized state of quarks and gluons
Zebo Tang, 高能核物理导论 1410/10/2009
Color screening of heavy quarks
J/ dissociation due to color screening Signature of the QGP formation
Ágnes Mócsy, QM2009
T. Matsui and H. Satz, PLB178, 416 (1986) 23 years story
Zebo Tang, 高能核物理导论 1510/10/2009
Plasma Thermometer
?
Quarkonium dissociation temperatures – Digal, Karsch, Satz
Ágnes Mócsy, QM2009
Zebo Tang, 高能核物理导论 1610/10/2009
J/ suppression in heavy-ion collisions
Peripheral Central
200 AGeV O+U collisions
NA38, PLB220, 471 (1989)
Zebo Tang, 高能核物理导论 1710/10/2009
Nuclear absorption
Inelastic J/ scattering (dissociation) on primordial target and projectile nucleons
suppression of J/
Before the formation of QGP
nothing to do with QGP Cold nuclear matter (CNM) effect
A. Sibirtsev, K. Tsushima and A. W. Thomas, PRC63, 044906
C. Gerschel and J. Hufner, PLB 207, 253 (1988)
Zebo Tang, 高能核物理导论 1810/10/2009
Description of absorption
Fully explained the J/ suppressionNo screening effect?
C. Gerschel and J. Hufner, Z. Phys. C 56, 171 (1992)
Zebo Tang, 高能核物理导论 1910/10/2009
Anomalous J/ suppression
NA50, NPA 610, 404 (1996)
Zebo Tang, 高能核物理导论 2010/10/2009
Anomalous J/ suppression
NA50, Eur. Phys. J. C 39, 335 (2005)
A signal of QGP formation within a “threshold-suppression” scenario
J. P. Blaizot and J. Y. Ollitraut, PRL 77, 1703 (1996)
Zebo Tang, 高能核物理导论 2110/10/2009
Evidence of deconfinementNA 50, PLB 477,28 (2000)
c direct J/
Zebo Tang, 高能核物理导论 2210/10/2009
More CNM effects
Zebo Tang, 高能核物理导论 2310/10/2009
Shadowing/anti-shadowing
P. Amaudruz et al., NPB 441, 3 (1995) S. R. Klein and R. Vogt, PRL 91, 142301 (2003)
Zebo Tang, 高能核物理导论 2410/10/2009
Cronin effect
• Main features:
• pT2 (and T) linearly increase with L
(mean thickness of nuclear matter)
• Phenomenological description with the expression
LpLp gNppTT 22 )(
with an energy dependent pT2pp and
a common slope:gN= 0.081±0.002 (GeV/c)2/fm
Multi-scattering of the incoming gluon
Zebo Tang, 高能核物理导论 2510/10/2009
Hadronic co-mover dissociation
Sergei G. Matinyan and Berndt Muller, PRC 58, 2994 (1998)
S. Gavin, M. Gyulassy and A. Jackson, PLB 207, 257 (1988)R. Vogt, M. Prakash, P. Koch and T. H. Hansson, PLB 207, 263 (1988)
Inelastic J/ scattering (dissociation) on secondary produced hadronic comovers
Suppression of J/ Nothing to do with QGP Another CNM effect
Zebo Tang, 高能核物理导论 2610/10/2009
Parton-induce break-up in QGP
The anomalous suppression depends on our understanding of CNM effects
Zebo Tang, 高能核物理导论 2710/10/2009
Move to higher energy
Zebo Tang, 高能核物理导论 2810/10/2009
J/ suppression at RHIC
• Similar suppression as that at SPS• More suppression at forward rapidity
Global error = 7%Global error = 12%
Scomparin (proc. QM06) : nucl-ex/0703030
GeVsNN 200
Zebo Tang, 高能核物理导论 2910/10/2009
CNM constraints from dAu results
Zebo Tang, 高能核物理导论 3010/10/2009
CNM constraints from dAu results
Mid-rapidity Forward/backward rapidity
Zebo Tang, 高能核物理导论 3110/10/2009
Forward rapidity
high xlow x
Gluon saturation from non-linear gluon interactions for the high density at small x; amplified in a nucleus.
Kharzeev, Levin, Nardi and Tuchin, 2009
Normal CNM descriptions (blue) give similar (or even smaller) suppression at mid vs forward rapidity• but if peaking in “anti-shadowing” region were flat instead (red dashed) then one would get larger suppression for forward rapidity as has been observed in AuAu data
Mike Leitch, WWND 2008
Zebo Tang, 高能核物理导论 3210/10/2009
Mid-rapidityWhy the J/ suppression is similar at RHIC as that at SPS?
1) Regeneration2) Sequential suppression
Zebo Tang, 高能核物理导论 3310/10/2009
Regeneration
Grandchamp, Rapp, BrownPRL 92, 212301 (2004) nucl-ex/0611020
Regeneration models give enhancement that compensates for screening• larger gluon density at RHIC expected to give stronger suppression than SPS• but larger charm production at RHIC gives larger regeneration• very sensitive to poorly known open-charm cross sections• forward rapidity lower than mid due to smaller open-charm density there• expect inherited flow from open charm• regeneration much stronger at the LHC!Issues:• need to know what happens to C & ’ & measure J/ flow• flat forward/mid RAA seems inconsistent with increasing regeneration & screening for more central collisionsMike Leitch, WWND 2008
Zebo Tang, 高能核物理导论 3410/10/2009
J/ elliptic flow
Inherit open charm flow or not? Regeneration?Too early to compare to models, need more statistics
Zebo Tang, 高能核物理导论 3510/10/2009
Sequential suppression
H. Satz, Nucl. Phys. A (783):249-260(2007)
J/ suppression at low pT maybe only from excited stats (’, c) F. Karsch, D. Kharzeev and H. Satz, PLB 637, 75 (2006)
60% from direct J/: not suppressed30% c and 10% ’: dissociated
NA50, EPJ39,335NA60, QM05
Zebo Tang, 高能核物理导论 3610/10/2009
Move to high pT
Zebo Tang, 高能核物理导论 3710/10/2009
Hot-wind dissociation
J/
H. Liu, K. Rajagopal and U.A. WiedemannPRL 98, 182301(2007) and hep-ph/0607062M. Chernicoff, J. A. Garcia, A. Guijosa hep-th/0607089
Possible to observe J/ suppression from directly produced J/ at high pT
Zebo Tang, 高能核物理导论 3810/10/2009
Jet energy lossSTAR: PRL98(2007) 192301
Strong suppress, energy lossSimilar magnitude as light hadrons
PHENIX: PRL98(2007)172301
c/be
hardparton
path length L
Quark
Quark
Zebo Tang, 高能核物理导论 3910/10/2009
Nuclear modification factor RAA
• Consistent with no suppression at high pT: RAA(pT>5 GeV/c) = 1.4± 0.4±0.2
• All RHIC measurements:
RAA(pT>5 GeV/c) = 1.1 ± 0.3 ± 0.2
• Indicates RAA increase from low pT to high pT
• Contrast to AdS/CFT+ Hydro prediction H. Liu, K. Rajagopal and U.A. Wiedemann PRL 98, 182301(2007), T. Gunji, JPG 35, 104137(2008) • How does production mechanism (CS vs. CO) affect energy loss?• Good jobs:
• transport+hydro: from initial produced instead of regenerated Y.Liu, Zhen Qu, N. Xu and P. Zhuang, arXiv:0901.2757; N. Xu, QM2009 • two-component model: leakage and B feeddown is important R. Rapp, X. Zhao, arXiv:0806.1239 Anti-shadowing?
Zebo Tang, 高能核物理导论 4010/10/2009
Upsilon
dAuR 0.98 0.32 (stat.) 0.28 (sys.)
Consistent with Nbin scaling
Cold Nuclear Matter effects
(Shadowing) are not large.
prelim
inary
RAuAu in progress
Zebo Tang, 高能核物理导论 4110/10/2009
Summary
J/ is a unique probe of the hot dense matter produced in heavy-ion collisions
Lots of CNM effects need to be considered
On the way to understand the screening better
As well as J/ production mechanism in hadron collisions