1. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 1 People: F. Bieser, R. Gareus, L. Greiner, H. Matis, M. Oldenburg, F. Retiere, H.G. Ritter, K.S., A. Shabetai(IReS), E. Sichtermann, H. Wieman, N. Xu, E. Yamamoto The Heavy-Flavor Tracker (HFT)

2. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 2 Motivation Q G P nucleon boundary irrelevant nucleus Heat J.C. Collins and M.J. Perry, Phys. Rev. Lett. 34 (1975) 1353. Compress Quark Gluon Plasma: Deconfined and thermalized state of quarks and gluons  Equilibration: - hadron yields  Partonic Collectivity: - Spectra of multi-strange baryons  Thermalization: - heavy-quark flow - (thermal photons, di-leptons)

3. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 3 Outline 1)Physics with the Heavy Flavor Tracker (HFT)  spectra  elliptic flow  heavy flavor (c,b) energy loss  vector mesons 2)Tracking with ITTF  track resolution  tracking efficiency  pile-up / ghost tracks 3)Summary

4. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 4 Open Charm is The Future Quark coalescence works Partonic Collectivity ! At p t (q) > 1 GeV/c medium transparent Need low p t data !

5. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 5 Charm Production First direct measurement at RHIC Reducing errors –Measure all charm hadrons –Cover large momentum range What do we learn? –Test pQCD –Gluon pdf

6. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 6 Open Charm Flow PHENIX: measure electrons from c, b  e + X Large stat. and syst. errors ! Need direct open charm reconstruction !

7. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 7 Open Charm Yields No thermal creation of c or b quarks; m(c) = 1.1GeV >> T c and b quarks interact with lighter quarks  thermal recombination ? –D s + yield very sensitive ! –J/  suppression vs recombination ? Pythia p-p 200 GeV Au-Au Thermal* D + /D 0 0.330.455 D s + /D 0 0.200.393  c + /D 0 0.140.173 J/  /D 0 0.00030.0004 No suppression F. Retiere

8. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 8 Heavy-Flavor Energy Loss Heavy(H) quarks suffer smaller energy loss than light(L) quarks –Dead cone effect –QCD analog Ter-Mikayelian effect; nucl-th/0305062 D/  ratio sensitive to color charge Differential study of energy loss Yu.L. Dokshitzer and D.E. Kharzeev. Phys. Lett. B519 (2001) 199. L = 5fm L = 2fm

9. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 9 Measure Vector Mesons Detectors  TPC+TOF8 M2 M TPC+TOF+SVT+HFT200K100K    e + e - : leptons do not re-scatter  probe the medium at early stage  Background:   e + e -  HFT discriminates background ! Zhangbu Xu et al.

10. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 10 Reconstruct Open Charm High precision ~3-6 µm hit-resolution Low mass - 1 GeV/c particles - need low multiple scattering 40 µm 80 µm 160 µm320 µm 640 µm H. Matis

11. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 11 Two layers 24 ladders total length: 16cm inner radius: 1.5cm outer radius: 5.65cm new beampipe, 760  m Be position resolution: 3-10  m  x~250  m Si-equivalent Monte Carlo Calculations SVT HFT beampipe

12. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 12 Dca - Distributions  Au+Au @200GeV  5% central  Track dca – resolution: ~20  m  small tail due to multiple scattering  low mass detector !

13. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 13 Tuning the Tracker  Au+Au @200GeV  5% central  optimize efficiency vs number of ghost tracks  Best max. search window : 500microns  consistent with projections from SVT p t = 0.5 – 1.0 GeV/c

14. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 14 Efficiency  Au+Au @200GeV  5% central  Heavy-Flavor Tracker: 40-50%  can we increase SVT efficiency ?  Does SSD help ?

15. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 15 Pile-Up and Ghost Tracks  Au+Au @200GeV  5% central  + 40 pile-up events  10x central occupancy  ~2-3% ghost tracks  How does this influence the D 0 invariant mass spectrum ? 5% central 5% central + pileup

16. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 16 Residuals vs z z (cm) 5  m 50  m z Residual (mm) y Residual (mm)  10 GeV/c    Residuals in x-y plane : < 5  m  Residuals in z plane : < 50  m M. Oldenburg

17. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 17 Open Charm Reco-Performance Uncertainty in N events:  30% System N events for 3  D 0 signal N events for 3  D + s signal TPC+SVT12.6 M500 M (K 0 s + K + ) TPC+SVT+TOF2.6 M100M TPC+SVT+ HFT 100 K 50 K (neural net) 80 M (  +  + ) TPC+SVT+HFT+TOF10 K 5 M (  +  + ) F. Retiere, A. Shabetai

18. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 18 Summary  Heavy-Flavor efficiency 40-50%  Ghost tracks 2-3%, in pile-up  Improve Efficiency: SVT, SSD(?)  Measure spectra and of elliptic flow of D 0, D , D + s,   C  Probe thermalization  Use Heavy-Flavor to probe medium  Measure Vector mesons

19. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 19 y-residuals [mm] and vs z [cm] (green = mean, red = width; left = outer layer, right = inner layer)

20. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 20 Significance A. Shabetai (IReS )

21. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 21 Single Track Efficiency

22. STAR upgrade workshop, Yale, Jun 15 - 17, 2004 22 The Heavy Flavor Tracker Two layers –1.6 cm radius –4.8 cm radius 24 ladders –2 cm by 20 cm –CMOS Sensors Precise (<10  m), thin and low power –50  m thick chip + air cooling < 0.3% radiation length Power budget 100 mW/cm 2