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J/ y Results from STAR

The first Workshop on STAR MTD Production and Related Physics Hefei, Anhui, China, Marth 30 th – April 1 st , 2011. J/ y Results from STAR. Zebo Tang University of Science and Technology of China (USTC) Center of Particle Physics and Technology. Net Baryon Density. QCD phase diagram.

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J/ y Results from STAR

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  1. The first Workshop on STAR MTD Production and Related Physics Hefei, Anhui, China, Marth 30th – April 1st, 2011 J/y Results from STAR Zebo Tang University of Science and Technology of China (USTC) Center of Particle Physics and Technology Zebo Tang, STAR MTD Workshop, Hefei

  2. Net Baryon Density QCD phase diagram Zebo Tang, STAR MTD Workshop, Hefei

  3. Outline • Introduction • J/y as a classic probe of QGP • J/y production mechanism in p+p collisions • Electron identification and J/y reconstruction • Results • J/y spectra in p+p collisions • J/y-hadron correlation in p+p collisions • J/y suppression in A+A collisions • J/y with MTD • Summary Zebo Tang, STAR MTD Workshop, Hefei

  4. J/y melting in QGP – Signature of deconfinement J/y dissociation due to color screening  Signature of the QGP formation Zebo Tang, STAR MTD Workshop, Hefei

  5. Plasma thermometer ? Quarkonium dissociation temperatures – Digal, Karsch, Satz QGP thermometer Model dependent Dissociation temperature depends on binding energy  QGP temperature Zebo Tang, STAR MTD Workshop, Hefei

  6. H. Satz, Nucl. Phys. A (783):249-260(2007) Other effects 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 suppressed 30% c and 10% ’: dissociated • Feeddown (sequential suppression) • Cronin effect • Nuclear absorption • Hadronic phase dissociation • Gluon saturation • Formation time effect • … NA50, EPJ39,335 NA60, QM05 Precise measurements at broad kinetic range and systems are needed! Zebo Tang, STAR MTD Workshop, Hefei

  7. Color octet Color singlet NRQCD J/y 3S1 J/y Charmonium production mechanism • 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 CDF measurement: PRL79,572 Know your reference! LO CSM LO COM Zebo Tang, STAR MTD Workshop, Hefei

  8. Color octet Color singlet NRQCD Charmonium production mechanism • 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 LO Decay feeddown (CDF): y(2s): 7%-15%, slightly increase with pT cc0,1,2: ~30%, slightly decrease with pT B: Strong pT dependence Know your reference! Zebo Tang, STAR MTD Workshop, Hefei

  9. MTD EMC Barrel MRPC ToF Barrel EMC End Cap FMS BBC FPD TPC PMD FTPC trigger computing DAQ1000 COMPLETE HLT Ongoing R&D STAR detector TPC+BEMC+(MRPC-TOF) in this analysis 2 coverage at mid-rapidity (|h|<1) Zebo Tang, STAR MTD Workshop, Hefei

  10. Electron identification (TPC only) Note: electron yield is much less than hadrons x sigma deviation from electron dE/dx curve • With TPC only: • No electron ID at low pT • Eifficult to get a good electron sample at high pT • Possible to get a electron sample with reasonable purity at intermediate pT Zebo Tang, STAR MTD Workshop, Hefei

  11. (DhxDf=0.05x0.05) ~5X0 Electron ID (EMC) • Online fast trigger: • Enhance high pT electron • Enhance recorded luminosity Offline cuts: Matching between EMC and TPC Deposited energy (BTOW) Shower shape (BSMD) Low pT J/y: Intermediate pT electrons (TPC only) High pT J/y: high pT electron (TPC+EMC) + Intermediate pT electron (TPC only) Zebo Tang, STAR MTD Workshop, Hefei

  12. Low-pT J/y signals 200GeV p+p L2 J/y trigger 200GeV d+Au MB trigger 200GeV Au+Au MB trigger 200GeV Cu+Cu MB trigger Zebo Tang, STAR MTD Workshop, Hefei

  13. 2009 • Tight cuts for correlation study • Spectra in progress High-pT J/y signals STAR, PRC80, 041902(R), 2009 Zebo Tang, STAR MTD Workshop, Hefei

  14. J/y spectra in p+p and Cu+Cu at 200 GeV • Significantly extend pT range of previous measurements in p+p at RHIC to 14 GeV/c • Agreement of charm measurements between STAR and PHENIX ~3 orders Online fast trigger is important with limited DAQ rate and Data processing capability Zebo Tang, STAR MTD Workshop, Hefei

  15. STAR, PRC80, 041902(R), 2009 J/ xT scaling at high pT: n=5.6±0.2 (close to CS+CO prediction) Soft processes affect low pT J/ production J/y pT spectra STAR, PRC80, 041902(R), 2009 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. G. C. Nayak, M. X. Liu, and F. Cooper, Phys. Rev. D68, 034003 (2003), and private communication. Zebo Tang, STAR MTD Workshop, Hefei

  16. Constrain bottom contribution STAR, PRL95, 152301 (2005) J/y-h correlation STAR, PRC80, 041902(R), 2009 STAR Preliminary h-h correlation • No significant near side J/-hadron azimuthal angle correlation • Correlation show low B contribution (13  5) % Zebo Tang, STAR MTD Workshop, Hefei

  17. Correlations from Run9 Zebo Tang, STAR MTD Workshop, Hefei

  18. BJ/y / inclusive J/y PRC80, 041902(R), 2009 PLB200, 380, 1988 PLB370, 239, 1996 PRD71, 032001, 2005 • Consistent with previous results • No significant beam energy dependence • Can be used to constrain B production Zebo Tang, STAR MTD Workshop, Hefei

  19. Associated hadron pT spectra STAR, PRL95, 152301 (2005) • Near side: Consistent with no associated hadron production • Away side: Consistent with h-h correlation • away-side seems to come from gluon/light quark fragmentation Zebo Tang, STAR MTD Workshop, Hefei

  20. Low-pT J/y in Au+Au 200 GeV • Model (green band) includes: color screening in QGP, dissociation in hadronic phase, statistical recombination, B → J/y feed-down and formation time effects • New Au+Au results with minimum inner material soon (5x higher statistics with TOF) 0-20% 0-20% 20-80% 20-80% STAR Preliminary STAR Preliminary STAR Preliminary STAR Preliminary PHENIX: Phys. Rev. Lett. 98, 232301 (2007) Zebo Tang, STAR MTD Workshop, Hefei

  21. STAR, PRC80, 041902(R), 2009 • RAA>AdS/CFT+Hydro, 99% C.L. Contrast to AdS/CFT+Hydro prediction • 2-component models describes the overall trend H. Liu, K. Rajagopal and U.A. Wiedemann PRL 98, 182301(2007); T. Gunji, J. Phys.G 35, 104137 (2008) X. Zhao and R. Rapp, Phys. Lett. B664:253, 2008; Y.P. Liu, et al., Phys.Lett.B678:72-76,2009 High-pT J/y in Cu+Cu 200 GeV Cu is too small? • STAR Cu+Cu 0-20%: RAA(pT>5) = 1.40.40.2 • The only hadron measured to be not suppressed at high pT in RHIC Heavy-ion collisions • Contrast to open charm. CS vs. CO? CNM effect？Formation Time? 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. Zebo Tang, STAR MTD Workshop, Hefei

  22. 82±13 6s dE/dx after TOF cut J/y in Au+Au @ 39 GeV 91±22 4s • Clear signal seen in 39GeV Au+Au with TOF • Expect ~1000 (13s) J/y from full MB data • Able to cover pT range (0, 5) GeV/c • Much higher statistics and recorded integral luminosity at 62 and 200GeV Zebo Tang, STAR MTD Workshop, Hefei

  23. Muon Telescope Detector (MTD) Advantages over electrons no  conversion much less Dalitz decay contribution less affected by radiative losses in the materials Trigger capability for low to high pT J/ in central Au+Au collisions High m/hadron enhancement S/B~2 in central Au+Au Zebo Tang, STAR MTD Workshop, Hefei

  24. J/ J/ MTD in RHICII era MTD+HFT: Trigger and topologically reconstruct BJ/y, J/ymm MTD+TOF: J/y+ccbar? Charmonium higher states? Zebo Tang, STAR MTD Workshop, Hefei

  25. Summary • In 200 GeV p+p collisions • Extended previous spectra measurements to 14 GeV/c • Large S/B ratio allows correlation study • B has sizeable (not dominant) contribution at high pT • high-pT J/y away side hadron production consistent with gluon/quark fragmentation • In heavy-ion collisions • First observation of no suppression for hadron at high pT at STAR in 200GeV Cu+Cu collisions • Clear signals seen in 39 GeV Au+Au with TOF, covers pT from 0 to 5 GeV/c It is just a start! Thank you! Zebo Tang, STAR MTD Workshop, Hefei

  26. Extra Zebo Tang, STAR MTD Workshop, Hefei

  27. Future dramatic improvement of J / at low pT EMC+TOF+HFT (large acceptance): J/ production Different states predicted to melt at different T in color medium Charmonia (J/), bottonia () dE/dx after TOF cut pT (e)>1.5 GeV/c Quarkonium dissociation temperatures – Digal, Karsch, Satz PHENIX Acceptance: |h|<0.35, f=2*p/2 STAR TOF-Upgrade Acceptance: |h|<0.9, f=2*p J/y yields from 1 billion minbias Au+Au events: 43.8x10-9/0.040x109*292*0.5*1.8*0.5=144,0000.3% v2 error sJ/y spp N Nbine y RAA Zebo Tang, STAR MTD Workshop, Hefei

  28. Detector upgrades: HFT and MTD Prototype in run VII n>0 STAR Preliminary Heavy Flavor Tracker: e+e-rejection Topologically reconstruct J/ from B decay Rejection power: ~16 Muon Telescope Detector: Muon identification simulation Zebo Tang, STAR MTD Workshop, Hefei

  29. Jpsi-h correlation from PYTHIA Zebo Tang, STAR MTD Workshop, Hefei

  30. NA60, QM08 J/y measurements in Heavy Ion Collisions • Due to color screening, J/ was thought be dissociated in the medium. T. Masui and H. Satz, Phys. Lett. B178, 416(1986). • At RHIC, the suppression at low pT is similar to at SPS at similar Npart: recombination due to large charm cross section. P. Braun-Munzinger and J. Stachel, Phys. Lett. B490,196 (2000); L. Grandchamp and R. Rapp, Phys. Lett. B523, 60 (2001); M. I. Gorenstein et al., Phys. Lett. B524, 265 (2002); R. L. Thews, M. Schroedter, and J. Rafelski, Phys. Rev. C63, 054905 (2001); Yan, Zhang and Xu, Phys.Rev.Lett.97, 232301 (2006); PHENIX: Phys.Rev.Lett.98, 232301,2007. • At SPS, suppression decreases versus pT: Cronin effect , Nuclear absorption and formation time effect.M. C. Abreu et al., Phys. Lett. B499, 85 (2001); X. Zhao, WWND2008; X. Zhao and R. Rapp, hep-ph/07122407; X. Zhu, P. Zhuang, PRC67, 067901(2003) Zebo Tang, STAR MTD Workshop, Hefei

  31. STAR:PRL98(2007) 192301 High pT J/y in heavy ion collisions How the formation time effect, jet energy loss and hot wind dissociation affect the high pT J/psi in the medium: 2-component approach: dissociation + recombination RAA increases slightly with pT including formation time and B decay X. Zhao, WWND2008; X.Zhao and R. Rapp, hep-ph/07122407 Formation time effect:RAA increases with pT (formed out of medium) K. Farsch and R. Petronzio, PLB 193(1987), 105 ; J.P. Blaizot and J.Y. Ollitrault, PLB 199(1987),499 Jet energy loss: open charm strongly suppressed observed in the medium AdS/CFT + Hydro: RAA decreases versus pT Zebo Tang, STAR MTD Workshop, Hefei

  32. SPS: In+In, , consistent with no suppression at pT > 1.8 GeV/c RHIC: Cu+Cu, , consistent with no suppression at pT > 5 GeV/c Compare to SPS PLB499,85 and NPA774,59 NA50, 158 AGeV RCP NA60, QM08 Similar trend also observed at SPS, might from different physics origin Zebo Tang, STAR MTD Workshop, Hefei

  33. J/y-h correlation from PYTHIA Zebo Tang, STAR MTD Workshop, Hefei

  34. Summary • J/ in p+p and Cu+Cu collisions: • pT spectra in p+p: • extended to ~14 GeV/c • follows xT scaling with n=5.6 at pT>5 GeV/c, deviates from scaling at low pT • J/-hadron azimuthal correlation in p+p: • no significant near side correlationconstrain the contribution fromBJ/+X • away-side spectra consistent with • h-h correlation  gluon or light quark fragmentation • J/ RAA • indication of RAA increasing at high pT • production mechanisms: • described by NRQCD • soft processes affect low pT production • constrain decay contribution • constrain B production and Be • constrain production mechanism: CSM or COM • medium properties Zebo Tang, STAR MTD Workshop, Hefei

  35. Single Muon and J/ Efficiency G. Lin, Yale Univ. J/ efficiency • muon efficiency at |η|<0.5: 36%, pion efficiency: 0.5-1% at pT>2 GeV/c • muon-to-pion enhancement factor: 50-100 • muon-to-hadron enhancement factor: 100-1000 including track matching, tof and dE/dx • dimuon trigger enhancement factor from online trigger: 10-50 in central Au+Au collisions 09/17/2010 Zebo Tang, STAR MTD Workshop, Hefei MTD Review, Lijuan Ruan (BNL) 35

  36. J/y measurements in Heavy Ion Collisions NA 50, PLB 477,28 (2000) SPS: Anomalous suppression  Significant evidence of deconfinement in central Pb+PbPLB 477,28 (2000) RHIC: Similar suppression as SPS, why? Balance of dissociation and regeneration? Other effects Zebo Tang, STAR MTD Workshop, Hefei

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