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Quarkonium measurements with STAR. Zhangbu Xu Brookhaven National Laboratory. Outline: High- p T J/ y results J/ y spectrum and flow J/ y- h correlations The story of B and J/ y decay feed-down Outlook. H. Satz, Nucl. Phys. A (783):249-260(2007). J/ y.

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Zhangbu Xu Brookhaven National Laboratory


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    1. Quarkoniummeasurements with STAR Zhangbu Xu Brookhaven National Laboratory • Outline: • High-pT J/y results • J/y spectrum and flow • J/y-h correlations • The story of B and J/y decay feed-down • Outlook

    2. H. Satz, Nucl. Phys. A (783):249-260(2007) J/y High pT J/y in heavy ion collisions Hot wind dissociation J/y suppression at low pT could be from 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? H. Liu, K. Rajagopal and U.A. Wiedemann PRL 98, 182301(2007) and hep-ph/0607062 2-component approach Predicted increase RAA X. Zhao and R. Rapp, hep-ph/07122407Y.P. Liu, et al., Phys.Lett.B678:72-76,2009 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

    3. Quarkonia in QGP • Color screening effect 1) • Recombination 2) • Gluon energy loss 3) • Heavy quark energy loss 3) • Decay feed-down • (comover, cold matter effect) at (hadronic phase, initial stage) • Can we use effects in HI to figure out the J/ production and medium properties? How do the quarkoniabehave in the presence of sQGP? 1) T. Matsui and H. Satz, Phys. Lett. B178, 416 (1986) 2) R. L. Thews and M. L. Mangano, Phys. Rev. C73, 014904 (2006) 3) M. B. Johnson et al., Phys. Rev. Lett. 86, 4483 (2001) and R. Baier et al., Ann. Rev. Nucl. Part. Sci. 50, 37 (2000)

    4. EMC+TPC electrons: |h|<1, pT>4.0 GeV/c TPC only electrons: |h|<1, pT>1.2 GeV/c High pT J/y in p+p at 200 GeV EMC trigger J/y pT p+p 2005 EMC+TPC electrons: |h|<1, pT>2.5 GeV/c TPC only electrons: |h|<1, pT>1.2 GeV/c (S+B)/B: 24/2 3 pb-1 No background at pT>5GeV/c J/y pT p+p 2006 (S+B)/B: 54/14 11 pb-1 Reach higher pT (~14GeV/c) Need to see good signal before taking next step!

    5. J/y spectra in p+p and Cu+Cu at 200 GeV Model comparisons: Color singlet model (CS):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+ color octet (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 Collaboration, Phys. Rev. C 80 (2009) 41902 Statistics: red curve is NOT a fit, 4th data point too low?

    6. xT scaling in p+p collisions arXiv: 0904.0439 xT scaling:  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 (the power parameter close to CS+CO prediction) 3. Soft processes affect low pT J/ production

    7. Nuclear modification factor RAA • Consistent with no suppression at high pT: RAA(pT>5 GeV/c) = • 1.4±0.4±0.2 • RAA(pT>5GeV/c) > 0.6 • (97% C.L.) • RAA increase from low pT to high pT arXiv: 0904.0439 • 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. • Different fromAdS/CFT+ Hydro prediction (99% C.L.) H. Liu, K. Rajagopal and U.A. WiedemannPRL 98, 182301(2007);T. Gunji, J. Phys.G 35, 104137 (2008) • Formation time, gluon dissociation, recombination, B reproduces the trend • X. Zhao and R. Rapp (2007), arXiv:0712.2407; Y.P. Liu, et al., Phys.Lett.B678:72-76,2009

    8. J/ flow and thermalization • There are quite reasonable evidences: J/ suppression open charm recombination (yields, rapidity, centrality) • Elliptic flow has not been measured • Spectrum must reflect radial flow and degree of thermalization • To compare the results among pp, peripheral AA and central AA, using non-extensive statistics

    9. Tsallis statistics describes hadron spectra

    10. No flow pattern in J/ spectra

    11. No sign of flow at SPS either

    12. J/ flow and thermalization • Spectrum must reflect radial flow and degree of thermalization: • no signal of radial flow • Non-extensive Blast-wave is wrong (likely)?but RAA is relatively flat at low pT • Cancellation from recombination, flow and suppression (3 = zero)? • Suppression only of the excited states? • What is elliptic flow for J/? And the arguments are?

    13. What should RAA be? R. Arnaldi (NA60) QM08 There are only couple of (non-over-reaching) choices: both have significant impact on our understanding of J/ and medium propertiesup: recombination/flow, formation timedown: energy loss, AdS/CFT So far, more indication of up than down Cu, In system too small? Data in tape from RHIC run10 Au+Au will tell!

    14. J/y-hadron correlation Near side correlationBottom decay or fragmentation Good S/B ratio makes this measurement possible Heavy quark fragmentation TPC FMS S.J. Brodsky, J.-P. Landberg, arXiv: 0908.0754

    15. 1) no near side correlation 2) strong near side correlation PLB 200, 380(1988) and PLB 256,112(1991) Disentangle contributions via Correlations • J/y-hadron correlation can also shed light on different source contribution to J/y production • May be used to distinct bottom decay, charm associate production

    16. Yields in near/away side Zebo Tang Thesis 2009 • Associated hadron spectra with leading J/y: • Away side: Consistent with leading charged • hadron correlation measurement (h-h)away-side from gluon or light quark fragmentation • Near side: Consistent with no associated hadron production BJ/y not a dominant contributor to inclusive J/y • constrain J/y production mechanism

    17. J/ Constrain bottom yields arXiv: 0904.0439 STAR Preliminary • correlations shows B contribution (13  5) % • can be used to further constrain B yields • Bottom decay kinematics, less production origin

    18. Constrain bottom yields arXiv: 0904.0439 arXiv: 0904.0439 STAR Preliminary • pQCD predicts significant BJ/ • can be used to further constrain B yields • M. Cacciari, P. Nason and R. Vogt PRL 95(2005),122001; CLEO collaboration PRL 89(2002),282001

    19. BJ/ is a golden channel Xin Dong Much better kinematic correlation No mixing of D+B No direct J/ decay feed-down Experimentally clean measurement

    20. HFT upgrade STAR HFT proposal, Wei Xie et al. BX+J/+-simulation in progress

    21. Future dramatic improvement of J / at low pT significance ~ 5.7 σ 0-20% d+Au dE/dx after TOF cut pT (e)>1.5 GeV/c PHENIX Acceptance: |h|<0.35, f=2*p/2 STAR TOF-Upgrade Acceptance: |h|<0.9, f=2*p J/y yields from 300M minbiasAu+Au events: 43.8x10-9/0.040x3x108*292*0.5*1.8*0.5=40,0000.6% v2 error sJ/y spp N Nbine y RAA Joint CATHIE-TECHQM, BNL, 12/14/09

    22. High luminosity for Υ & J/ L.Ruan et al., 0904.3774, JPG36(2009); Z. Xu, BNL LDRD project 07-007 STAR Muon Telescope Detector simulation STAR EMC MTD: excellent mass resolution for Υ separate different Υstates

    23. Muon Telescope Detector L.Ruan et al., 0904.3774, JPG36(2009)

    24. Summary (J/y) • J/y spectra in 200 GeV p+p collisions at STAR • Extend the pT range up to ~14 GeV/c • Spectra can be described by CEM and CSM. • High pT J/y follows xT scaling with n=5.6 • Spectra at high pT can be used to constrain B production • J/y-hadron azimuthal correlation in p+p • no significant near side correlationExpect strong near-side correlation from BJ/y+XCan be used to constrain J/y production mechanism • Away-side spectra consistent with h-h correlationindicates gluon or light quark fragmentation • J/y RAA from 200 GeV Cu+Cu collisions at STAR • Extend RAA from pT = 5 GeV/c to 10 GeV/c • Indication of RAA increasing at high pT

    25. Future Upsilon RAA Au+Auand p+p runs with TOF and DAQ1000 J/ elliptic flow Upsilon states (1S+2S+3S, MTD) J/ displace vertex (HFT+MTD)

    26. arXiv:1005:1627