1. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC1 A barrel TOF for STAR at RHIC Outline  Introduction  Performance of STAR-TOF prototypes  Physics results: achieved & expected  Summary and outlook Jian WU for the STAR Collaboration Department of Modern Physics, USTC

2. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC2 Introduction Solenoidal Tracker At RHIC (STAR)

3. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC3 Introduction Why STAR-TOF ?  Identified hadron spectra freeze-out dynamics hadronization mechanism Heavy flavor  Identified particle correlations Chemical and kinetic properties of in-medium jet associated spectra Fluctuations and correlations Heavy flavor  Lepton program In-medium vector meson properties Heavy flavor TPC dE/dx for low momentum range: π/K 0.6 GeV/c proton/meson 1.0 GeV/c TOF will extend momentum range of PID !

4. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC4 Introduction STAR-TOF requirement  Overall timing resolution: < 100 ps in Au+Au collisions.  Occupancy per channel: < 10%.  Rate capability: 200 Hz/cm 2.  High efficiency: > 90%.  Replaces Central Trigger Barrel.

5. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC5 Introduction STAR TOF group Module construction, QA and calibration BNL, LBL, MEPI, NASA, UNAM, RICE, UCLA, UT-Austin, U. Washington, Yale Huazhong Normal University, IHEP(Beijing), IMP(Lanzhou), SINAP, Tsinghua, USTC Electronics, tray assembly, and integration & Project supported by DOE(US) & NSFC, MST,CAS(China)

6. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC6 Performance of STAR-TOF prototypes Design of Multi-gap Resistive Plate Chamber for TOFr MRPC strip size ： 3.15cm×6.30cm Gas gap ： 6×0.22mm Technology first developed by ALICE-TOF group E. Cerron Zeballos et al. Nucl. Instr. Meth. A 374, 132(1996) M.C.S. Williams et al. Nucl. Instr. Meth. A 478, 183(2002) Module size: 21.2×9.4×1.79 cm 3

7. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC7 Performance of STAR-TOF prototypes TOFr Tray Configuration Covers 6  in azimuth and 1 in pseudo-rapidity at radius ~ 2.2 m

8. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC8 Performance of STAR-TOF prototypes Tray Level TOF Electronics (Final) J. Schambach ， DOE TOF Review

9. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC9 Performance of STAR-TOF prototypes TOFr Tray in STAR W.J. Llope ， DOE TOF Review TOFr5 for Runs 5 & 6

10. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC10 Performance of STAR-TOF prototypes TOF Starter: pseudo-Vertex Position Detector ±5.4m, 4.43<|  |<4.94,  ~19% (Upgraded in 2006 ×6 acceptance ) 200GeV/n_pair Au+Aud+Aup+p Trigger Efficiency 100%30%10%  t (ps) 2585140

11. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC11 Performance of STAR-TOF prototypes Achievements from the prototype  86 ps overall timing resolution achieved in 200GeV Au+Au collisions.  3.15 cm  6.30 cm, 200GeV Au+Au occupancy<10%  Rate capability: ~300 Hz/cm 2 (test beam, CERN)  High efficiency: > 95%

12. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC12 Performance of STAR-TOF prototypes Time resolutions in Runs Operation conditions Time Resolution (ps) pVPD TOFr (overall) TOFr (intrinsic) Run III 200GeV d+Au ~85~120 ~85 200GeV p+p ~140~160~80 Run IV 62GeV (Au+Au) ~55~105~89 200GeV (Au+Au) FF/RFF ~27~86(74)~82(70) HF ~20~82(74)~80(71) Run V 200GeV Cu Cu (ToT) ~ 50~105(92)~92(75) 62GeV Cu Cu (ToT) ~ 82~125~94 M. Shao QM2006 Poster

13. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC13 Performance of STAR-TOF prototypes Hadron/Electron PID capability Hadron PID: ( , K) ~1.6 GeV/c p ~ 3 GeV/c. STAR Collaboration, PLB 616(2005)8 |1/β-1|<0.03 Clean electron PID can be obtained up to P T < 3 GeV/c.  This has been used to measure the semi-leptonic decay of open charm. STAR Collaboration, PRL 94(2005)062301

14. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC14 Performance of STAR-TOF prototypes Muon identification at low p T e μ π 0.15<pT<0.25 GeV/c, DCA<3cm Chen ZHONG (QM2006) Session: Heavy quark production

15. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC15 Performance of STAR-TOF prototypes φ background suppression STAR Preliminary TOF+TPC : one kaon from φ identified by TPC, the other by TOF TPC+TPC : the 2 kaons from φ identified using only TPC Au+Au 200GeV min-bias

16. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC16 Performance of STAR-TOF prototypes PID by combining TOF+TPC TOF alone, ( , K) ~1.6 GeV/c, p ~ 3 GeV/c. TOF+dE/dx+rdE/dx ( ,p) 0.3~12 GeV/c M. Shao et al., NIMA 558, (419) 2006

17. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC17 Physics results Phys. Rev. Lett. 97 152301(2006)

18. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC18 Physics results  Identified baryon and meson distributions at large transverse momenta from Au+Au collisions at 200 GeV, Phys. Rev. Lett. 97 152301(2006)  PID Cronin Effect in d+Au, Phys. Lett. B 616 (2005) 8  Charm Cross section and spectra in p+p, d+Au, Phys. Rev. Lett. 94 (2005) 062301  A lot of conference proceedings, QM04, SQM04, QM05, SQM06 talks.  6 Ph. D theses.  10 NIM publications: Nucl.Instrum.Meth.A 478:176-179, 2002 (B. Bonner et al) Nucl.Instrum.Meth.A 492:344-350, 2002 (M. Shao et al) Nucl.Instrum.Meth.A 508:181-184, 2003 (B. Bonner et al) Nucl.Instrum.Meth.A 533:60-64, 2004 (F. Geurts et al) Nucl.Instrum.Meth.A 537:698-702, 2005 (Y. Wang et al) Nucl.Instrum.Meth.A 538:243-248, 2005 (J. Wu et al) Nucl.Instrum.Meth.A 538:425-430, 2005 (Y. Wang et al) Nucl.Instrum.Meth.A 547:334-341, 2005 (Y. E. Zhao et al) Nucl.Instrum.Meth.B 241:306, 2005 (W.J. Llope) Nucl.Instrum.Meth.A 558:419, 2006 (M. Shao et al) Imagine what we can accomplish with Full TOF (120 trays)

19. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC19 Physics results expected Physics with Full Barrel TOF - I Event reduction factor for two particle decays (achieving the same signal statistical significance) Particlep T range (GeV/c)(TPC+TOF)/TPC K* 0 0-12.0 K* 0 1-21.85 K* 0 2-31.74 K* 0 3-51.39  0-25.0  2-53.42 Λ*Λ* 0-1.611.4 D0D0 0-54.6

20. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC20 Physics results expected Physics with Full Barrel TOF - II TPC+TOF+SSD+HFT ~ 200M Central AuAu events : 22K  and 6K  vector meson for one year RHIC running

21. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC21 Physics results expected Physics with Full Barrel TOF - III MeasurementPhysics Goal all particle v2, especially increasing the efficiency for multi-strange particle v2 measurement Fix the partonic collectivity parameters Fluctuation/ correlation studies with PIDUnderstand the nature of possible phase transition Away-side jet fragmentation yields, spectraSearch for Mach cone Yields, spectra of high-mass resonances Map out most of the resonances (if it is not all) from RHIC Unlike-particle (e.g.,  -  ) correlations Spatial and temporal distributions of hadron production Charmed hadron flow and yield ratios Charm collectivity and thermalization of light quarks (u,d,s) Heavy quark jets; D,B-meson spectra at high p T Probe partonic medium and understand the nature of parton interactions, i.e. parton energy loss Inclusive lepton and di-lepton spectra and invariant mass distributions Study possible in-medium modification of hadrons. e + e  pair production in UPCStrong field QED effects  o longitudinal polarization correlations CP violation search

22. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC22 Summary and outlook MRPC Status & Plans Status  MRPC Standard production procedure setup  Quality check measurements defined  Web Parameter Database installed

23. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC23 Summary and outlook MRPC Status & Plans Tray assembly instruments at UT-Austin MRPC production facility at Tsinghua and USTC

24. Nov.14-20, 2006 QM2006 Shanghai J.WU USTC24 Summary and outlook  The advantages of new technology – MRPC: good timing resolution, high efficiency, cost effective large area Time of Flight detector.  The prototype of TOF detectors in STAR work well, and satisfy the requirements.  TOF prototype detectors have already provided important physics results! The End Thanks! Thanks!