STAR upgrade workshop, Yale, Jun , 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)

STAR upgrade workshop, Yale, Jun , Motivation Q G P nucleon boundary irrelevant nucleus Heat J.C. Collins and M.J. Perry, Phys. Rev. Lett. 34 (1975) 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)

STAR upgrade workshop, Yale, Jun , 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

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

STAR upgrade workshop, Yale, Jun , 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

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

STAR upgrade workshop, Yale, Jun , 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 D s + /D  c + /D J/  /D No suppression F. Retiere

STAR upgrade workshop, Yale, Jun , 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/ 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

STAR upgrade workshop, Yale, Jun , 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.

STAR upgrade workshop, Yale, Jun , 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

STAR upgrade workshop, Yale, Jun , 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

STAR upgrade workshop, Yale, Jun , Dca - Distributions   5% central  Track dca – resolution: ~20  m  small tail due to multiple scattering  low mass detector !

STAR upgrade workshop, Yale, Jun , Tuning the Tracker   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

STAR upgrade workshop, Yale, Jun , Efficiency   5% central  Heavy-Flavor Tracker: 40-50%  can we increase SVT efficiency ?  Does SSD help ?

STAR upgrade workshop, Yale, Jun , Pile-Up and Ghost Tracks   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

STAR upgrade workshop, Yale, Jun , 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

STAR upgrade workshop, Yale, Jun , 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

STAR upgrade workshop, Yale, Jun , 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

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

STAR upgrade workshop, Yale, Jun , Significance A. Shabetai (IReS )

STAR upgrade workshop, Yale, Jun , Single Track Efficiency

STAR upgrade workshop, Yale, Jun , 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