1 Zhangbu Xu 许许许许 () University of Science & Technology of China Brookhaven National Laboratory Heavy-Flavor at RHIC • Introduction • Open Heavy Quarks • J/y results • Tools to probe Temperature, viscosity of QCD matter under extreme conditions 实实实实实实实实实实 QCD 实实实实实实实实 实实实实实实实 体 Zhangbu Xu
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Zhangbu Xu (许长补) University of Science & Technology of China Brookhaven National Laboratory
Heavy-Flavor at RHIC. Zhangbu Xu (许长补) University of Science & Technology of China Brookhaven National Laboratory. Introduction Open Heavy Quarks J/ y results Tools to probe Temperature, viscosity of QCD matter under extreme conditions 实验上研究极端条件下 QCD 强场的温度及其流体力学的基本参数. - PowerPoint PPT Presentation
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Zhangbu Xu (许长补) University of Science & Technology of China
Brookhaven National Laboratory
Heavy-Flavor at RHIC
• Introduction• Open Heavy Quarks• J/y results• Tools to probe Temperature, viscosity
of QCD matter under extreme conditions实验上研究极端条件下 QCD 强场的温度及其流体力学的基本参数
Zhangbu Xu
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Fundamentals of QCD relevant to our fieldT.D. Lee, 1995
• Quark Confinement• Symmetry Breaking
Gluons carry color-chargeAsymptotic Freedom
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SU(3) Color Factors
QCD : For SU(3) : Nc = 3 CA = 3, CF = 4/3
CF ~ strength of a gluon coupling to a quarkCA ~ strength of the gluon self coupling TF ~ strength of gluon splitting into a quark pair
CA/CF=9/4
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Energy Loss and QCD
Experimentally observable (of Eloss) related to basic ingredientof QCD - Gauge Group through Color FactorsOr extracting an effective Color Factor
R. Baier et al., NPB 483 (1997) 291 M. Gyulassy et al., PRL 85 (2000) 5535 S. Wicks et al, nucl-th/0512076
hardparton
path length L
One mechanism of energy loss : Medium induced gluon radiation Eg
Eq
~ 9/42 L<q>
CE sa ^ C
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Consequence of CA/CF=9/4 in A+A
Other models: S. Wicks, I. Vitev, QM08
WHDG, arXiv:nucl-th/0512076
Energy loss
STAR Preliminary
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STAR Preliminary
• Heavy quark suppression ~= light flavor
• Bottom suppression ~=charm suppression
PRL97,98
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Fragmentation Functions
• Will these ingredients be sufficient for p+p collisions?
• How will p+p collisions provide additional information for our understanding of QCD and for model developments
• What will be modified in A+A collisions1. FF 2. Running of aS3. Effective Color Charge factor
Deadcone effect of Energy loss Brownian motion in thermal system
Upper bound on escaping parton p
Heavy object in sQGP with AdS/CFTY.L. Dokshitzer, D. Kharzeev, PLB519(2001)199WHDG, arXiv:nucl-th/0512076
D.E. Kharzeev, arXiv:0806.0358,0809.3000
G. Moore, D. Teaney PRC 71 (2005) 064904;H. Van Hees, R. Rapp PRC 71 (2005) 034907
H. Liu, K. Rajagopal and U.A. Wiedemann PRL 97, 182301(2006)J. Casalderrey-Solana, D. Teaney PRD 74(2006) 085012
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Brownian motion and thermalization
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Brownian motion:
arXiv:0805.0364
Hadronic excited states increase interaction cross-sections
Can Energy Loss and Thermalization explain data?
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PHENIX: PRL98(2007)172301
New Precise vertex detector upgrades In STAR (HFT) and PHENIX (VTX) precision charm hadron spectra and v2 with improved kinematics.
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Fundamentals of QCD relevant to our fieldT.D. Lee, 1995
• Quark Confinement• Symmetry Breaking
Gluons carry color-chargeAsymptotic Freedom
Quarkonium in heavy ion collisions
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J/yH. Satz, Nucl. Phys. A (783):249-260(2007)
J/y suppression at low pT could befrom suppressed excited states (y’, cc)F. Karsch, D. Kharzeev and H. Satz, PLB 637, 75 (2006)
High pT direct J/y suppression related to hot wind dissociation?
Hot wind dissociation
H. Liu, K. Rajagopal and U.A. WiedemannPRL 98, 182301(2007) and hep-ph/0607062M. Chernicoff, J. A. Garcia, A. Guijosa hep-th/0607089
2-component approachPredicted decrease RAA X. Zhao and R. Rapp, hep-ph/07122407
Color singlet model predicted an increase RAA
(formed outside of medium)K. Farsch and R. Petronzio, PLB 193(1987), 105 J.P. Blaizot and J.Y. Ollitrault, PLB 199(1987),499
T. Gunji, QM08
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Recombination of open charm to J/
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c
c
c
c
c
cc c
QGPc+cJ/
G.D. Moore and D. Teaney, Phys. Rev. C 71, 064904(2005); H. van Hees, V. Greco and R. Rapp, Phys. Rev.C 73, 034913 (2006); X. Zhu et al., Phys. Lett. B 647,366 (2007); N. Xu and Z. Xu, Nucl. Phys. A 715, 587c(2003); Z.W. Lin and D. Molnar, Phys. Rev. C 68, 044901(2003); V. Greco, C.M. Ko and R. Rapp, Phys. Lett. B595, 202 (2004); S. Batsouli et al., Phys. Lett. B 557, 26(2003).P. Braun-Munzinger and J. Stachel, Phys. Lett. B 490,196 (2000); A. Andronic et al., Phys. Lett. B 571, 36(2003); L. Grandchamp and R. Rapp, Phys. Lett. B 523,60 (2001); M. I. Gorenstein et al., Phys. Lett. B 524,265 (2002); R.L. Thews, M. Schroedter and J. Rafelski,Phys. Rev. C 63, 054905 (2001);M.I. Gorenstein et al.,J. Phys. G 28, 2151 (2002)…
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color screening and quarkonium supression
H. Satz, Nucl. Phys. A (783):249-260(2007)
J/y suppression at low pT maybe from excited stats (y’, cc) F. Karsch, D. Kharzeev and H. Satz, PLB 637, 75 (2006); B. Alessandro et al. (NA50), Eur. Phys. J. C 39 (2005) 335; R. Arnaldi et al. (NA60), Quark Matter 2005; PHENIX: Phys.Rev.Lett.98, 232301,2007.
60% from direct J/y: not suppressed30% cc and 10% y’: dissociated
60% direct J/psi
Nu Xu QM09
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Production Mechanism from J/ spectra in p+p Model comparisons:
Color singlet model: direct NNLO still miss the high pT part. P. Artoisenet et al., Phys. Rev. Lett. 101, 152001 (2008), and J.P. Lansberg private communication.
LO CS+CO: better agreement with the measurements, leave little room for higher charmonium states and B feeddown contribution. G. C. Nayak, M. X. Liu, and F. Cooper, Phys. Rev. D68, 034003 (2003), and private communication.
CS and LO CS+CO have different power parameters different diagram contribution?
power parameter: n=8 for NNLO CS n=6 for LO CS+CO
STAR Preliminary
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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 = 1.1 ± 0.3 ± 0.2
• Indicates RAA increase from low pT to high pT • Contrast to AdS/CFT+ Hydro prediction
Jet quenching: strong open charm suppression. A. Adil and I. Vitev, Phys. Lett. B649, 139 (2007), and I. Vitev private communication; S. Wicks et al., Nucl. Phys. A784, 426 (2007), and W. A. Horowitz private communication.
• Formed out of medium? Karsh, Liu, Zhuang, RappAffect by heavy quark/gluon energy loss
• Decay from other particles?
STAR Preliminary
J/y-hadron correlation
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(S+B)/B: 54/14
5.4s
Heavy quark fragmentation
Near side correlationBottom decay or fragmentation
Good S/B ratio makes this measurement possible
J/y-hadron correlation in p+p
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h-h correlation• No significant near side J/y-hadron
azimuthal angle correlation• Constrain B meson’s contribution to
J/y yield• Hints of CSM?
J/ Observations
p+p collisions• Low-pT deviates from xT scaling
soft process dominant • J/-h correlation:
near-side weak away-side same as light quarks diagram: q+gJ/+jet
• High-pT RCuCu ~=1Formation timeAdS/CFT (hot wind)Color SingletCu system size too small
21Zhangbu XuZebo Tang’s afternoon talk
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A novel and compact muon telescope detector for QCDLab
A large area of muon telescope detector (MTD) at mid-rapidity, allows for the detection of
• di-muon pairs from QGP thermal radiation, quarkonia, light vector mesons, possible correlations of quarks and gluons as resonances in QGP, and Drell-Yan production • single muons from their semi- leptonic decays of heavy flavor hadrons• advantages over electrons: no conversion, much less Dalitz decay contribution, less affected by radiative losses in the detector materials