# Presentation: 258716

## Overview of the STAR Heavy Flavor Tracker upgrade

- T. Hallman
- For the STAR Collaboration
- HFT Review
- Brookhaven National Laboratory
- February 25-26, 2008

## The outline of this talk

- The significance of the science the HFT will uniquely provide within 3 years of the start of upgraded detector operations
- The impact of the planned scientific program on the advancement of nuclear science given current and planned world-wide capabilities
- The feasibility of the approach
- The resources needed to carry out the planned scientific program
- Conclusions

**Notes:**
Question on “urgency”

## The starting point: what we have discovered thus far

-     The hottest, densest matter yet                  T ~ 200-400 MeV, i  30-60 0  examined in the laboratory

- S = sound attenuation length
-        (~ mean free path)
- For reasonable T (~ 2TC ) and 
- (~ 1 fm/c) data suggest /s << 0.3

- It appears to flow as a  relativistic
- quantum liquid with viscosity to energy
- density ratio lower than any other
- known liquid

- It is highly opaque to colored
- probes– quarks and gluons –
- but not to photons

- It produces copious mesons and
- baryons with yield ratios and flow
- properties that suggest their formation
- via coalescence of valence quarks
- from a hot thermal bath.

- FluidQuasiParticlesHadrons
- Evidence for fluid breaking up into quasi-particles with quantum numbers of quarks before hadrons

##                                         Most exciting?    What we have learned we don’t understand or can’t yet quantify 

-  We thought we knew that jet quenching was due to radiative energy loss by partons in-medium
-       BUT    charm & bottom quark hadrons appear suppressed as much as light quark hadrons
-       BUT    we really don’t know the spectra of charm and bottom
-       BUT    without knowing if the baryon/meson anomaly persists, level of suppression unsure
-       And     collisional energy loss may be important
-       BUT    we can’t tell that until we can answer the “Buts” above

- But if bottom is truly suppressed (as it now appears) the pQCD energy loss
- explanation is dead, and something completely different is going on

- Jet quenching is a _fact_

- Within three years of startup, the high S/N afforded for heavy quark mesons and baryons by the large acceptance full topological PID provided by the HFT will yield precision spectra for definitive answers to these questions

**Notes:**
Make connection from shear viscosity, etc to charm measurement explicit.

##                                    Most exciting?    

- We _think_ we know that the discovered matter flows as a  relativistic quantum liquid with viscosity to energy density ratio lower than any other known liquid

- S = sound attenuation length
-        (~ mean free path)
- For reasonable T (~ 2TC ) and 
- (~ 1 fm/c) data suggest /s << 0.3

- /s ÷ ħ/4

- He

- N

- H20

- Kovtun, Son, Starinets,
- Phys. Rev. Lett 94, 2005

- Lower viscosity
- bound~ 0.08
- (red line near 0)

- Superfluid
- helium

- T (K)

-       BUT    we can not be quantitative about how long it takes to thermalize
-                  we can not be sure when thermalization occurs (partonic stage, later??)
-                  we do not know the DOF, EOS, or speed of sound in the matter (is it really QGP?)

- Within three years of startup, the high S/N afforded for heavy quark mesons and baryons by the large acceptance topological PID provided by the HFT will yield precision v2 & correlations for charm  hadrons down to the hydro-dynamic regime to answer to these questions

**Notes:**
Make connection from shear viscosity, etc to charm measurement explicit.

## Within three years of startup, the HFT will allow us to:

- Break the log jam in developing a self-consistent picture of parton energy loss allowing us to tell if it provides a valid explanation or some entirely new mechanism of energy loss is at work
- Test whether the meson/baryon anomaly extends to the heavy quark sector and whether hadrons are really formed by statistical coalescence
- Determine if the partonic matter which forms the sQGP is thermalized by measuring v2 (with precision) for D mesons at low pT
- Understand mechanisms of charm production and correlated charm backgrounds to assess their effect on measurements of vector mesons
- Understand screening in the sQGP through measurements of spectra and total cross section for open charm in p+p, p+A, and A+A collisions as a function of sNN

- The unique capabilities of the HFT (ultra-thin, large acceptance, full kinematic reconstruction topological PID) will
-        open up the (3 body decay) charm, bottom hadron sector
-        allow v2 measurements of heavy quark hadrons down to the hydro regime
-        remove ambiguity/systematic uncertainty due to unknown parent pT
-         distribution
-        afford study of charm correlations in AA to understand mechanisms of
-         charm production and backgrounds to measurement of vector mesons
- These capabilities are unparalleled before the HFT and, despite a lot a good work in PHENIX and STAR, their lack is what will prevent definitive answers to:
-         baryon/meson anomaly for heavy quark hadrons
-         thermalization time (from D meson elliptic flow)
-         verification of the pQCD picture of parton energy loss
-           Unless and until the HFT is built and becomes operational

## Note added in proof: LRP discussion of what the fundamental science will be at RHIC (heavy ion and spin) in the next decade?

- H1. Quantitative determination of viscosity (/s).  Thus, clearly
-        answering the question is QCD matter the most perfect fluid?
- H2. Quantitative determination of color field strength via qhat.
- H3. Heavy quarkonia and light vector meson probes to determine
-        color interactions in medium.  Direct connection with lattice QCD.
- H4. Experimental verification or null result on critical point.
- H5. Detailed measurements of collective excitations of the fluid and
-        extraction of medium properties.
- H6. Quantitative understanding of gluon saturation Qs in Au
- S1. Mapping out of gluon contributions g(x) as a function of x.
- S2. Determination of G with comparable errors to .
- S3. Measurement of sea quark polarization via W bosons.
- S4. Detailed study of transverse spin physics (including information
-        on orbital angular motion).

- The HFT will provide data central to addressing five of the six compelling heavy ion questions to be answered by RHIC in the next decade

**Notes:**
Make connection clear

## The upgraded STAR Detector

- Time Projection Chamber

- DAQ and TPC
- FEE Upgrade

- Forward GEM Tracker

- Barrel EMC

- Barrel Time Of Flight

- Forward Meson
- Spectrometer

- Beam-Beam Counters

- Solenoidal Magnet

- HFT:
- 2 layers of MAPS, 1 layer of strips (+ existing double-sided SSD)

- VPD

- Photon
- Multiplicity
- Detector

## The HFT

-  2-layer Active Pixel Sensors: 30 m pitch
-   thickness x/x0 ~ 0.28% per layer
-   2.5cm inner radius;  200s integration
-  1-layer* Si strips
-  SSD: x/x0 ~ 1%
-   || ≤ 1
-   pT > 0.5 GeV/c:    e, D0,±,s,*, c , B...
-   D-D correlation functions

**STAR Heavy Flavor Tracker (HFT)**

- 100M central Au+Au
- D0 + D0, RHIC II
- Topological PID
- pileup included

## STAR/RHIC Upgrades: The Big Picture

**p+p, 200**

- FY08

- FY10

- FY09

- FY12

- FY11

- FY13

- FY15

- FY14

- FMS complete:
- d+Au and p+p
- data from Run 8

- DAQ1000 complete
- Immediate improvement
- of 300% in sampled luminosity for rare probes
- (e.g. jets in p+p)

**d+Au**

** ****Au+Au BES**

**p+p, 500, W******** **

- Increase in Au+Au luminosity to
- 50 x 1027 cm-2 sec-1
- U+U available from EBIS
- DOE investment ~ $7M

**p+p**

**Au+Au**

**p+p, 500 ********G**** **

** ****U+U**

**1****st**** priority**

**2****cnd ****config**

** ****Au+Au 200**

**p+p, 500, W******** **

- HFT partial
- implementation

** ****Au+Au **

**p+p ,500**

- HFT complete
- full topological PID for
- c, b mesons
- DOE investment : upper
- limit of range ~ $14.7M

- Planned LHC
- 1st heavy ion run

- DOE investment ~ $400k

** ****U+U **

**p+p, 200**

-   DOE investment ~ $1900k

**TOF complete:**
**PID information for   > 95% of kaons**
**and protons in the STAR acceptance**
**Clean e****±**** ID down to 0.2 GeV/c**
- DOE investment ~ $4900k
- Chinese investment ~ $2700k

- FGT complete:
- Accurate charge sign determination
- for W’s, DOE investment ~ $1900k

** ****Au+Au **

**p+p ,500**

## What is the

**p+p, 200**

- FY08

- FY10

- FY09

- FY12

- FY11

- FY13

- FY15

- FY14

- DAQ1000 complete
- Immediate improvement
- of 300% in sampled luminosity for rare probes
- (e.g. jets in p+p)

**d+Au**

** ****Au+Au BES**

**p+p, 500, W******** **

- Increase in Au+Au luminosity to
- 50 x 1027 cm-2 sec-1
- U+U available from EBIS
- DOE investment ~ $7M

**p+p**

**Au+Au**

**p+p, 500 ********G**** **

** ****U+U**

**1****st**** config**

**2****cnd ****config**

** ****Au+Au 200**

**p+p, 500, W******** **

- HFT partial
- implementation

** ****Au+Au **

**p+p, 500 **

- HFT complete
- full topological PID for
- c, b mesons
- DOE investment : upper
- limit of range ~ $14.7M

** ****U+U **

**p+p,200 **

-   DOE investment ~ $1900k

**TOF complete:**
**PID information for   > 95% of kaons**
**and protons in the STAR acceptance**
**Clean e****±**** ID down to 0.2 GeV/c**
- DOE investment ~ $4900k
- Chinese investment ~ $2700k

- Thermalization
- Time? Does
- Thermalization
- Happen when the
- DOF are partonic?

- What is the real
- magnitude of charm
- hadron suppression?
- Does pQCD energy
- loss still make
- sense?

- Physics
- provided by
- the HFT
- (+ DAQ1000)
- (+ TOF)
- (+ Luminosity)

** ****Au+Au **

**p+p, 500 **

- Does the baryon/
- meson anomaly
- persist to heavy
- quark hadrons?

## The scientific roadmap:

- Spring	     2009	 Is there compelling evidence for the Colored Glass Condensate?
- Fall          2009      What is the role of orbital motion and final state interactions of partons in
-                                     generating the proton spin? (near side 0 - 0 and away side 0-jet correlations)
- Summer  2010      Is there evidence for in-medium modification of the intermediate vector bosons
-                                     based on comparison of their leptonic and hadronic decays?
- Fall          2010      What is the x-dependence of the gluon contribution to the proton spin; are there
-                                     large contributions which cancel so that G ~ 0 ?
- Summer  2011      Does a Critical Point exist in the phase diagram of QCD? Where?
- Summer  2012      What is the detailed suppression pattern for the Upsilon; does color screening in
-                                     the sQGP describe what is observed?
- Summer  2012	 Has the hydro limit really been saturated at RHIC?
- Fall          2012	 Quantitatively, what is color field strength seen by a energetic parton in the
-                                     sQGP?
- Winter     2013      What is the flavor dependence of the polarized anti-quark sea in the proton?
- Fall         2013       Are partons thermalized in the first 1 fm/c at RHIC (D meson v2); RCP for D’s
- Fall         2014      Quantitatively (RAA), what is the suppression of charm and bottom hadrons at RHIC
- Summer 2015      Does the meson/baryon anomaly persist for heavy quark hadrons?

## HFT Projected Milestones

- Presuming the project gets a “go-ahead” now and proceeds with all deliberate speed, taking into account time for construction, commissioning, data taking, and analysis, answers to some important questions will come ~ 2014

- Does it still make sense?
- _Absolutely: _
- We need to learn the properties of the new matter discovered _at RHIC_. The matter at the LHC will be different
- Some of the most fundamental questions (e.g. what is the thermalization time how perfect is our perfect liquid; does the meson-baryon anomaly extend to heavy quark hadrons,..) absolutely _require_ large acceptance topological PID for charm and bottom especially into the hydro regime. This will not be done at RHIC without the HFT
- Conclusion: this is a long-term investment in the future of the RHIC program  it is crucial that we get started soon.

- CD-0 							January 2008
- CD-1 							October 2008
- CD-2/3 						August 2009
- CD-4 							June 2013
- Modified East Cone with West Cone in for Summer ’09		June 2009
- Installation of Engineering Prototype			September 2010
- Engineering Prototype in Beam				January 2011
- Ladders with “Ultimate” chip Installed			September 2011
- Inner layers with “Ultimate” chip In Beam			January 2012
- IST Installed						July 2012
- Project Complete 					FY13

**Notes:**
Latest version

## What does the HFT provide uniqely

- There will be a complementary detector in PHENIX (VTX)
- 2 layers of ALICE/ATLAS-style pixels, 2 layers of strips
- Provides non-photonic electrons (triggered); B → J/Ψ + x (triggered) and high pT D’s
- Separation of D and B yields by fitting of dca distribution (sensitive to uncertainty of unknown parent pT distribution
- In STAR:
- 2 layers of 50 m thick active pixel sensors + 2 layers of strips (thinness essential to minimize multiple scattering for low pT D’s
- _Complete topological identification of the parent particle (e.g. D’s) down to the hydrodynamic regime_  vastly improved Signal/Background
- Topological reconstruction of charm and bottom baryons and mesons including 3 body decays

- 100M central  (1 week) Au+Au D0 + D0, RHIC II
-             Topological PID, pileup included

**Notes:**
Refine PHENIX and STAR statements. Lambda c money plot. Emphasize PHENIX do good things; STAR will do that and other unique things.

## R&D in Run 7 – real data with real Si pixels

- density at r = 5 cm, z = 145 cm

*R&D in Run 7 – real data with real Si pixels*

- A Three Layer Telescope with MimoSTAR II Chips.
- A full system test from PXL to DAQ
- using a 128x128 array of pixels.  A very clean environment.

- Coincidences from real particles
- Excellent S/N
- Sparse occupancy of real hits

- ~

-                     Basic Feasibility of Technology has been tested

## Pixel Parameters

|   Number of pixels |    135,168,000   |
| --- | --- |
|   Pixel dimension |    30 m  30 m |
|   Resolution of one pixel |    9 m |
|   Detector Chip active area |    19.2 mm  19.2 mm |
|   Detector Chip pixel array |    640  640 |
|   Number of ladders |    33   |
|   Ladder active area |    192 mm  19.2 mm |
|   Number of barrels |    2 |
|   Outer barrel (24 ladders) |    r  = 8.0 cm |
|   Inner barrel (9 ladders) |    r  = 2.5 cm |
|   Frame read time |    0.2 sec |
|   Rapidity Coverage |     1.2 units |
|   Thickness: Si on Ladder (w/Al cable)   |    0.28  % X0 |
|   Beam Pipe Thickness |    0.5 mm or 0.14 % X0 |

- The proposed design meets the physics driven requirements

**Notes:**
A general problem is the coverage in z is quite a bit smaller – comes from second HFT layer as far I can decide.

## The HFT will open the (3-body) charm & bottom hadron sector

- Simulations of the
- most challenging
- 3-body decays
- are encouraging
- so far

- This capability, which will be provided uniquely at RHIC by the HFT, is crucial for determining whether the baryon/meson anomaly extends to
- heavy quark hadrons

## Estimated Cost Range

- Escalation included
- Overhead and labor rates is from the institution where the work is performed
- Risk-based contingency estimation

| WBS | Task Name | Cost (estimate) in $K | Average % Cont. | Cont. in $K | Lower Range in $K (Est. TPC) | Upper Range in $K |
| --- | --- | --- | --- | --- | --- | --- |
| 1.1 | Research and Development | 1,461  | 0 | 0  | 1,461  | 1,461  |
| 1.2 | Pixel | 1,985  | 46 | 1,125  | 3,110  | 4,354  |
| 1.3 | Strip Detector | 2,345  | 36 | 878  | 3,223  | 4,351  |
| 1.4 | Integration | 1,665  | 41 | 946  | 2,611  | 3,656  |
| 1.5 | Software | 0  | 0 | 0  | 0  | 0  |
| 1.6 | Project Management | 732  | 0 | 0  | 732  | 878  |
| Total |  | 8,188  | 29  | 2,949  | 11,138  | 14,701  |

## STAR Perspective on HFT Upgrade

- Importance  of the HFT upgrade for STAR/RHIC ?

- It’s crucial, STAR is anxiously waiting for this new capability to:
-   Determine if pQCD provides a self-consistent picture of parton energy loss or some
-    entirely new mechanism of energy loss is at work
-   Determine if the partonic matter which forms the sQGP is thermalized by measuring
-    v2  (with precision) for D mesons at low pT
-  Test whether the meson/baryon anomaly extends to the heavy quark sector and
-    whether hadrons are really formed by statistical coalescence
-  Study charm correlations to understand mechanisms of charm production and
-   backgrounds to measurement of vector mesons
-  Make critically needed measurements of spectra and total cross section for
-   open charm in p+p, p+A, and A+A collisions as a function of sNN

## Conclusions

-    Scientific mission is clear; scientific merit very high in international
-     perspective; need is urgent
-    Basic detector performance and feasibility demonstrated
-     through R&D and simulation
-    General project status: optimized concept exists which meets physics
-     driven requirements
-    Simulations on performance / final tuning of design in progress
-    Basic feasibility of design proven
-    Preparation for construction project ongoing
-    Strong committed team in place, working hard

- STAR is anxious to get at the science this upgrade will make possible

## Backup Slides

##  + jet

**p+p, 200**

- FY08

- FY10

- FY09

- FY12

- FY11

- FY13

- FY15

- FY14

- FMS complete:
- d+Au and p+p
- data from Run 8

**d+Au**

** ****Au+Au BES**

**p+p, 500, W******** **

**p+p**

**Au+Au**

**p+p, 500 ********G**** **

** ****U+U**

**1****st**** priority**

**2****cnd ****config**

** ****Au+Au 200**

**p+p, 500, W******** **

** ****Au+Au **

**p+p **

- Yes or no?

- First significant
- Measurement of
- G(x) at s = 200

- Strong “classical”
- fields; coherence

- Is the observed transverse asymmetry due to Orbital motion of initial-state
- partons (Sivers) or final state
- interactions of produced
- particles (Collins) ?

- s = 200 GeV, ~80 pb-1

-   p+p   + jet

**X****BJ**

- DAQ1000 complete
- Immediate improvement
- of 300% in sampled luminosity for rare probes (e.g. jets in p+p). Some probes also require increased luminosity (W’s, Upsilons,  + jet, etc.)

-  What is RAA for the Upsilon?

-  + jet

- What is the
- real energy loss In the medium 
- its DOF

## How to Quantify /s at RHIC?

- _How to Quantify ____/s at RHIC?_

**Perfect Fluid?**

- S = sound attenuation length
-        (~ mean free path)
- For reasonable T (~ 2TC ) and 
- (~ 1 fm/c) data suggest /s << 0.3

- Ultimately Needed:
- Continued progress on viscous relativistic hydrodynamic theory
- Radial, directed, elliptic flow measurements for several identified hadron species.  Particularly valuable:
- Multi-strange hadrons φ, Ξ, Ω (reduced coupling to hadron gas phase) to determine viscous effects in the hadronic phase
- D mesons (establish thermalization time scale)

- D meson

- B meson

## Yes or no?

**p+p, 200**

- FY08

- FY10

- FY09

- FY12

- FY11

- FY13

- FY15

- FY14

- FMS complete:
- d+Au and p+p
- data from Run 8

**d+Au**

** ****Au+Au BES**

**p+p, 500, W******** **

**p+p**

**Au+Au**

**p+p, 500 ********G**** **

** ****U+U**

**1****st**** config**

**2****cnd ****config**

** ****Au+Au 200**

**p+p, 500, W******** **

** ****Au+Au **

**p+p **

- Strong “classical”
- color fields; coherence

- Is the observed transverse asymmetry due to orbital motion of initial-state
- partons (Sivers) or final state
- interactions of produced
- particles (Collins) ?

** ****Au+Au **

**p+p **

- Near term science
- provided by the
- Forward Meson
- Spectrometer (FMS)

##  + jet

**p+p, 200**

- FY08

- FY10

- FY09

- FY12

- FY11

- FY13

- FY15

- FY14

**d+Au**

** ****Au+Au BES**

**p+p, 500, W******** **

**p+p**

**Au+Au**

**p+p, 500 ********G**** **

** ****U+U**

**1****st**** config**

**2****cnd ****config**

** ****Au+Au 200**

**p+p, 500, W******** **

** ****Au+Au **

**p+p **

- First significant
- Measurement of
- G(x) at s = 200,
- 500 GeV

- s = 200 GeV, ~80 pb-1

-   p+p   + jet

**X****BJ **

- DAQ1000 complete
- Immediate improvement
- of 300% in sampled luminosity for rare probes (e.g. jets in p+p). Some probes also require increased luminosity (W’s, Upsilons,  + jet, etc.)

-  What is RAA for the Upsilon?

-  + jet

- What is the
- real energy loss In the medium 
- its DOF

- What do gluons at low x contribute to the proton
- spin?

-   Science enabled by DAQ1000

** ****Au+Au **

**p+p **

## Science

**p+p, 200**

- FY08

- FY10

- FY09

- FY12

- FY11

- FY13

- FY15

- FY14

- DAQ1000 complete
- Immediate improvement
- of 300% in sampled luminosity for rare probes
- (e.g. jets in p+p)

**d+Au**

** ****Au+Au BES**

**TOF complete:**
**PID information for   > 95% of kaons**
**and protons in the STAR acceptance**
**Clean e****±**** ID down to 0.2 GeV/c**

**p+p, 500, W******** **

**p+p**

**Au+Au**

**p+p, 500 ********G**** **

** ****U+U**

** ****Au+Au 200**

**p+p, 500, W******** **

** ****Au+Au **

**p+p **

- Is there
- compelling
- evidence for
- a critical
- point? If so,
- where is it ?

- Do we truly reach the hydro limit at RHIC?

-  K+K-

- Comparison

-  e+e-

- Enabled by
- DAQ1000 +
- TOF

** ****Au+Au **

**p+p **

- Is there
- evidence
- for chiral
- restoration?

## ~

**p+p, 200**

- FY08

- FY10

- FY09

- FY12

- FY11

- FY13

- FY15

- FY14

- DAQ1000 complete
- Immediate improvement
- of 300% in sampled luminosity for rare probes
- (e.g. jets in p+p)

**d+Au**

** ****Au+Au BES**

**p+p, 500, W******** **

- Electron lens development:
- increase in proton luminosity
- by ~ 2-3

- FGT complete:
- Accurate charge sign
- Determination for W’s

**p+p**

**Au+Au**

**p+p, 500 ********G**** **

** ****U+U**

**1****st**** config**

**2****cnd ****config**

** ****Au+Au 200**

**p+p, 500, W******** **

** ****Au+Au **

**p+p **

** ****Au+Au **

**p+p **

- What is the flavor dependence
- of the polarization of anti-quarks
- in the proton sea 
- what is the origin of the proton sea?

- Science provided by the STAR FGT

******d/d**

******u/u**

## IST parameters

|   Total number of strips/channels |    346,240   |
| --- | --- |
|   Number of barrels |    2 |
|   Number of ladders |    46   |
|   Outer barrel (27 ladders) |    r  = 17 cm |
|   Inner barrel (19 ladders) |    r  = 12 cm |
|   Detector Module active area |    4 cm  4 cm |
|   Thickness: Si on Ladder (w/APV25)   |    0.75  % X0 |
|   Strip dimension (outer) |    60 m  4 cm |
|   Orientation of Strips (outer)- 2 layers on one ladder |    Z  and R- |
|   Strip dimension (inner) |    60 m  2 cm |
|   Orientation of Strips (inner)  |    best resolution in  R- |
|   Resolution of one strip |    17 m |
|   Rapidity Coverage |     1.2 units |

**Notes:**
Two layer on outer ladder – in z and r-phi
Inner striplets

## R&D in Run 7 – real data with real Si pixels

- density at r = 5 cm, z = 145 cm

*R&D in Run 7 – real data with real Si pixels*

- A Three Layer Telescope with MimoSTAR II Chips.
- A full system test from PXL to DAQ at r = 10 cm, z = 1.5 m
- using a 128x128 array of pixels.  A very clean environment.

- Coincidences from real particles
- Excellent S/N
- Sparse occupancy of real hits

- ~

- HFT + IST Detector Configuration solidified in Dec-Jan by STAR Spokesperson reviews
- BNL Detector Advisory Committee Review held in late January 2007:
- “The Committee finds that the scientific case presented for the tracking upgrades is well established,
- and that the proposed detector configurations are well motivated technologically.  The collaboration
- has made a convincing case that compelling physics goals can be achieved with the resources requested..”

- “..The combined IST + HFT project will require the DOE critical decision process.  The first step is CD-0, the
- establishment of mission need.  STAR should make every effort to prepare a proposal by late spring of
- this year for submission to DOE in order to obtain first construction funds in FY’09.  This proposal will
- need to make the physics case in a compelling way.  It will need a reasonable but preliminary management
- plan, and should establish a reliable cost range...”

-                     HFT Proposal Status

- STAR internal review chair’d by Carl Gagliardi; subsequent transmittal to BNL Management and DOE
- Simulations and R&D ongoing as well as preparation for CD0 Review

## The HFT

-  2-layer Active Pixel Sensors: 30 m pitch
-   thickness x/x0 ~ 0.28% per layer
-   2.5cm inner radius;  200s integration
-  1-layer* Si strips
-  SSD: x/x0 ~ 1%
-   || ≤ 1
-   pT > 0.5 GeV/c:    e, D0,±,s,*, c , B...
-   D-D correlation functions

**STAR Heavy Flavor Tracker (HFT)**

- 100M central Au+Au
- D0 + D0, RHIC II
- Topological PID
- pileup included