03/30/2011Zebo Tang, STAR MTD Workshop, Hefei1 J/  Results from STAR Zebo Tang University of Science and Technology of China (USTC) Center of Particle Physics and Technology The first Workshop on STAR MTD Production and Related Physics Hefei, Anhui, China, Marth 30 th – April 1 st, 2011

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei2 QCD phase diagram Net Baryon Density

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei3 Outline Introduction –J/  as a classic probe of QGP –J/  production mechanism in p+p collisions Electron identification and J/  reconstruction Results –J/  spectra in p+p collisions –J/  -hadron correlation in p+p collisions –J/  suppression in A+A collisions J/  with MTD Summary

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei4 J/  melting in QGP – Signature of deconfinement J/  dissociation due to color screening  Signature of the QGP formation

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei5 QGP thermometer Quarkonium dissociation temperatures – Digal, Karsch, Satz ? Plasma thermometer Dissociation temperature depends on binding energy  QGP temperature Model dependent

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei6 H. Satz, Nucl. Phys. A (783): (2007) Other effects J/  suppression at low p T 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 NA50, EPJ39,335 NA60, QM05 Feeddown (sequential suppression) Cronin effect Nuclear absorption Hadronic phase dissociation Gluon saturation Formation time effect … Precise measurements at broad kinetic range and systems are needed!

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei7 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 CSMLO COM J/  3S13S1 CDF measurement: PRL79,572

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei8 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 p T >5-7 GeV/c COM* improvement of polarization, NLO will come, valid at p T >3 GeV/c Decay feeddown (CDF):  (2s): 7%-15%, slightly increase with p T  c0,1,2 : ~30%, slightly decrease with p T B: Strong p T dependence LO Know your reference!

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei9 STAR detector MRPC ToF Barrel BBC FPD FMSFMS EMC Barrel EMC End Cap DAQ1000 COMPLETE Ongoing MTD R&D TPC HLT triggercomputing FTPC PMD 2  coverage at mid-rapidity (|  |<1) TPC+BEMC+(MRPC-TOF) in this analysis

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei10 Electron identification (TPC only) With TPC only: No electron ID at low p T Eifficult to get a good electron sample at high p T Possible to get a electron sample with reasonable purity at intermediate p T x sigma deviation from electron dE/dx curve Note: electron yield is much less than hadrons

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei11 Electron ID (EMC) Online fast trigger: Enhance high p T electron Enhance recorded luminosity Offline cuts: Matching between EMC and TPC Deposited energy (BTOW) Shower shape (BSMD)  x  0.05x0.05) ~5X 0 Low p T J/  : Intermediate p T electrons (TPC only) High p T J/  high p T electron (TPC+EMC) + Intermediate p T electron (TPC only)

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei12 Low-p T J/  signals 200GeV p+p L2 J/  trigger 200GeV d+Au MB trigger 200GeV Cu+Cu MB trigger 200GeV Au+Au MB trigger

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei13 High-p T J/  signals Tight cuts for correlation study Spectra in progress 2009 STAR, PRC80, (R), 2009

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei14 J/  spectra in p+p and Cu+Cu at 200 GeV Significantly extend p T 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

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei15 J/  p T spectra STAR, PRC80, (R), 2009 J/  x T scaling at high p T : n=5.6±0.2 (close to CS+CO prediction) Soft processes affect low p T J/  production STAR, PRC80, (R), 2009 Color singlet model: direct NNLO* still miss the high p T part. P. Artoisenet et al., Phys. Rev. Lett. 101, (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, (2003), and private communication.

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei16 Constrain bottom contribution No significant near side J/  -hadron azimuthal angle correlation Correlation show low B contribution (13  5) % STAR Preliminary h-h correlation J/-h correlation STAR, PRC80, (R), 2009 STAR, PRL95, (2005)

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei17 Correlations from Run9

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei18 B  J/  / inclusive J/  Consistent with previous results No significant beam energy dependence Can be used to constrain B production PRC80, (R), 2009 PLB370, 239, 1996 PLB200, 380, 1988 PRD71, , 2005

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei19 Associated hadron p T spectra 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 STAR, PRL95, (2005)

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei20 Low-p T J/  in Au+Au 200 GeV Model (green band) includes: color screening in QGP, dissociation in hadronic phase, statistical recombination, B → J/  feed-down and formation time effects New Au+Au results with minimum inner material soon (5x higher statistics with TOF) STAR Preliminary PHENIX: Phys. Rev. Lett. 98, (2007) STAR Preliminary 0-20% 20-80% STAR Preliminary 0-20% 20-80%

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei21 STAR, PRC80, (R), 2009 High-p T J/  in Cu+Cu 200 GeV STAR Cu+Cu 0-20%: R AA (p T >5) = 1.40.40.2  The only hadron measured to be not suppressed at high p T 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. R AA >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, (2007); T. Gunji, J. Phys.G 35, (2008) X. Zhao and R. Rapp, Phys. Lett. B664:253, 2008; Y.P. Liu, et al., Phys.Lett.B678:72-76,2009 Cu is too small?

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei22 82±13 6  J/  in 39 GeV 91±22 4  Clear signal seen in 39GeV Au+Au with TOF Expect ~1000 (13  ) J/  from full MB data Able to cover p T range (0, 5) GeV/c Much higher statistics and recorded integral luminosity at 62 and 200GeV dE/dx after TOF cut

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei23 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 p T J/  in central Au+Au collisions High  /hadron enhancement S/B~2 in central Au+Au

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei24 MTD in RHICII era J/  MTD+HFT: Trigger and topologically reconstruct B  J/ , J/    MTD+TOF: J/  +ccbar? Charmonium higher states?

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei25 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 p T high-p T J/  away side hadron production consistent with gluon/quark fragmentation  In heavy-ion collisions First observation of no suppression for hadron at high p T at STAR in 200GeV Cu+Cu collisions Clear signals seen in 39 GeV Au+Au with TOF, covers p T from 0 to 5 GeV/c Thank you! It is just a start!

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei26 Extra

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei27 Future dramatic improvement of J /  at low p T EMC+TOF+HFT (large acceptance): J/  production Different states predicted to melt at different T in color medium Charmonia (J/  ), bottonia (  ) Quarkonium dissociation temperatures – Digal, Karsch, Satz pT (e)>1.5 GeV/c PHENIX Acceptance: ||<0.35,=2*/2 STAR TOF-Upgrade Acceptance: ||<0.9,=2* J /  yields from 1 billion minbias Au+Au events: 43.8x10 -9 /0.040x10 9 *292*0.5*1.8*0.5= 144,000  0.3% v 2 error  J/  pp N N bin  y R AA dE/dx after TOF cut

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei28 Detector upgrades: HFT and MTD Heavy Flavor Tracker: Muon Telescope Detector: n   >0 STAR Preliminary Prototype in run VII   e + e - rejection Topologically reconstruct J/  from B decay Rejection power: ~16 Muon identification simulation

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei29 Jpsi-h correlation from PYTHIA

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei30 J/  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 p T is similar to at SPS at similar N part : 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, (2001); Yan, Zhang and Xu, Phys.Rev.Lett.97, (2006); PHENIX: Phys.Rev.Lett.98, ,2007. At SPS, suppression decreases versus p T : 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/ ; X. Zhu, P. Zhuang, PRC67, (2003) NA60, QM08

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei31 High p T J/  in heavy ion collisions How the formation time effect, jet energy loss and hot wind dissociation affect the high p T J/psi in the medium: 2-component approach: dissociation + recombination R AA increases slightly with p T including formation time and B decay X. Zhao, WWND2008; X.Zhao and R. Rapp, hep-ph/ Formation time effect: R AA increases with p T (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: R AA decreases versus p T STAR: PRL98(2007)

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei32 Compare to SPS Similar trend also observed at SPS, might from different physics origin RHIC: Cu+Cu,, consistent with no suppression at p T > 5 GeV/c SPS: In+In,, consistent with no suppression at p T > 1.8 GeV/c NA60, QM08 NA50, 158 AGeV PLB499,85 and NPA774,59 R CP

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei33 J/  -h correlation from PYTHIA

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei34 Summary J/  in p+p and Cu+Cu collisions: p T spectra in p+p: extended to ~14 GeV/c follows x T scaling with n=5.6 at p T >5 GeV/c, deviates from scaling at low p T J/  -hadron azimuthal correlation in p+p: no significant near side correlation constrain the contribution from B  J/  +X away-side spectra consistent with h-h correlation  gluon or light quark fragmentation J/  R AA indication of R AA increasing at high p T production mechanisms: described by NRQCD soft processes affect low p T production constrain decay contribution constrain B production and B  e constrain production mechanism: CSM or COM medium properties

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei35 09/17/2010 MTD Review, Lijuan Ruan (BNL) 35 Single Muon and J/  Efficiency J/  efficiency 1.muon efficiency at |η| 2 GeV/c 2.muon-to-pion enhancement factor: muon-to-hadron enhancement factor: including track matching, tof and dE/dx 4.dimuon trigger enhancement factor from online trigger: in central Au+Au collisions G. Lin, Yale Univ.

03/30/2011Zebo Tang, STAR MTD Workshop, Hefei36 J/  measurements in Heavy Ion Collisions SPS: Anomalous suppression  Significant evidence of deconfinement in central Pb+Pb PLB 477,28 (2000) NA 50, PLB 477,28 (2000) RHIC: Similar suppression as SPS, why? Balance of dissociation and regeneration? Other effects