# Presentation: 694341

**Heavy Flavor Upgrades for STAR and PHENIX**
**Jim Thomas**
**Lawrence Berkeley National Laboratory**
**Characterization of the QGP with Heavy Quarks**
**Physikzentrum Bad Honnef**
**June 25-28, 2008**

## Heavy Flavor Energy Loss

**Surprising results** -
-  - challenge our understanding of the energy loss mechanism
-  - force us to RE-think about the collisional energy loss
-  - **Requires***** *****direct measurements of C- and B-hadrons.**

- 1) Non-photonic
- electrons decayed
- from  - charm and
- beauty hadrons
- 2) At pT ≥ 6 GeV/c,
- RAA(n.e.) ~ RAA(h±)
- contradicts naïve
- pQCD predictions

## Heavy Flavor Upgrades for STAR and PHENIX

**Heavy Flavor Upgrades for STAR and PHENIX**

## Detector Upgrades

**Each detector discovers    a different part of the Elephant’s story**
**The detector upgrades are designed to complete the coverage of the physics program **
**and open new vistas**
**the charm and beauty sector ... dE/dx, flow, coalescence, NCQ scaling**

## STAR Upgrades

**Full Barrel MRPC TOF **
**DAQ Upgrade (order of magnitude increase in rate)**
**High precision Heavy Flavor Tracker near the vertex**

## The TOF Upgrade

**The TOF Upgrade**

**Multiplate RPC technology**
**Beautiful electron ID**
**85 ps timing resolution after slewing corrections**
**Each tray has 72 channels****	**
**90 full trays this year, with new electronics **
**Funded by the DOE & CNSF**
**Construction and install in 2008, and 2009**

**Notes:**
STAR Time of Flight (TOF):  A fast, fine-grain barrel array of multi-gap resistive plate chambers (MRPC) that will surround the STAR TPC.  In addition to doubling the momentum range over which p,k, and p can be identified,  when the TOF measurement is combined with the TPC dE/dx measurement, electrons can be cleanly identified from the lowest momentum measured (~200MeV/c) up to a few GeV/c.  This capability complements the STAR electromagnetic calorimeter which works well for momenta above ~2GeV/c and provides the capability in STAR to measure the soft lepton and di-lepton spectra.  The presence of a high granularity fast detector covering the TPC barrel will also allow pile-up events in the TPC to be filtered out in the analysis.  This is especially important for the collision rates that are expected in p-p collisions at the highest luminosity.  The TOF detector is a joint US-China project with a collaboration of Chinese institutions providing the MRPC modules and the US providing the readout electronics and mechanical infrastructure.   This is a line-item (MIE) project with a DOE cost of $4.7M.  It is funded in FY 2006, with completion in 2009. 

## Multi-Gap Resistive Plate Chamber TOF

**State-of-art MRPC:**
** ****-0.9 < ********< 0.9,    0 < ********< 2********,    r = 220cm 6 gaps,    3x6cm****2**** pad; **
**23K channels,    120 modules  **

**Most significant collab. to date between USA & China in HEP detector research **

**1 tray   in runs 2-7**
**5 trays in run 8 **

**~75% in run 9**
**100% in run 10**

## Improving the “Time” in Time-of-Flight

**Run8: 76M pp events TOF+TPX**

**  ****2001:**
**      ****No timing devices****            (except Time Projection Chamber)**
**  ****2002:  **
**      ****BBC (~1ns), ZDC (200ps)**
**  ****2002-2008: **
**      ****TOF tray+VPD (<100ps) **
** **

**  ****2008**
**    ****TOF ********t: ****81ps**

## TPC FEE and DAQ Upgrade – DAQ 1000

**TPC FEE and DAQ Upgrade – DAQ 1000**

**Faster, smaller, better ...  ( 10x )**
**Current TPC FEE and DAQ limited to 100 Hz**
**Replace TPC FEE with next generation CERN based chips  ... 1 kHz readout**
**Make the FEE smaller  to provide space for a forward tracking upgrade**
**Further improvements by only archiving “associated” clusters – build on L3 algorithms ... 5 kHz !**

**Notes:**
STAR DAQ1000:  Replaces the front-end electronics of the STAR TPC with a fully pipelined system using the readout chip designed for the ALICE TPC.  This will increase the readout rate from its present 100Hz to 1000 HZ, allowing very large data sets for untriggered rare processes, and virtually eliminating front-end dead time, thereby approximately doubling the luminosity seen by rare triggers.  The project is funded from RHIC operations capital at a cost of $1.8M, it should be implemented by FY 2008.
The implementation of the DAQ1000 upgrade will result in a sharp increase in the raw data volume to be processed by STAR in subsequent heavy ion runs.  This, in turn, will require an incremental investment in computing equipment for the RHIC Computing Facility.  This increment is presently estimated to be $4.5M, spread over the period FY08 – FY10.  The details are discussed in Sec. 7.  This item is listed as “STAR Computing Upgrade” in the cost summary of Table 6-1.

## Four steps to an order of magnitude increase in data acquisition rates

TPC FEE (BNL&LBL)
TPC RDO (BNL)
DAQ Transmitter (CERN)
DAQ Receiver (CERN)

**TPC FEE (BNL&LBL)**
**TPC RDO (BNL)**
**DAQ Transmitter (CERN)**
**DAQ Receiver (CERN)**

**ALICE FEE & DAQ**

## The Heavy Flavor Tracker

**A new detector**
**18 ********m silicon pixels**
**	****to yield 6 ********m space point resolution**
**436 M pixels**
**Direct Topological reconstruction of Charm**
**Detect charm decays with small c********, including  D****0**** ******** K ******
**New physics**
**Charm collectivity     and flow to test thermalization at RHIC**
**Charm Energy Loss to test pQCD in a hot and dense medium at RHIC**

## Concept of HFT Layers

| Graded Resolution from the Outside – In | Resolution() |
| --- | --- |
| TPC pointing at the SSD 	( 23 cm radius) | ~ 1 mm |
| SSD pointing at  IST 	    ( 14 cm radius) | ~ 400 m |
| IST pointing at Pixel-2  	    ( 8 cm radius) | ~ 400 m |
| Pixel-2 pointing at Pixel-1	(2.5 cm radius) | ~ 70 m |
| pixel-1 pointing at the vertex | ~ 40 m |

- Purpose of intermediate layers to get increasing resolution power with increasing hit-densities, so the high resolution hits in the inner pixel’s can be found, assigned and displaced vertices determined.

**SSD**

**IST**

**PIXEL**

## The Pixel Detector surrounds the vertex with Si

*Inner layer*
*Outer layer*

*End view*

*ALICE style carbon support beams (green)*

*2.5 cm radius*

*8 cm radius*

*Since modified to increase Sensor Clearances*

*‘**D-Tube Duct and Support*

**The Pixel Detector surrounds the vertex with Si**

**A thin detector using 50 ********m Si **
**to finesse the limitations imposed by MCS**

## D0 Reconstruction Efficiency

- -  Central Au+Au collisions: top 10%events.
- -  The thin detector allows measurements down to pT ~ 0.5 GeV/c.
- -  Essential and unique!

## Charm Hadron v2

- - 200 GeV Au+Au minimum biased collisions (500M events).
- - Charm collectivity  drag/diffusion constants  ***medium properties! ***

**Notes:**
Hydro model: Pasi Huovinen, private communication, January 2008.
Just to remind you: these calculations were doen using my "standard" set of parameters: initial time 0.6 fm/c, first order phase transition at T_c=165 MeV, chemical equilibrium all the way until until kinetic freeze-out, freeze-out at T_f=130 MeV reproduces pion spectra and (anti)proton p_T-slope, initial profiles as a combination of participant and binary collision scalings.

## Even the c

- 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

## A more complete view of the STAR Upgrade plan

**A more complete view of the STAR Upgrade plan**

**Run08**

**Run10**

**Run09**

**Run12**

**Run11**

**Run13**

**Run15**

**Run14**

**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)**

**Increase in Au+Au luminosity to**
**50 x 10****27**** cm****-2**** sec****-1**
**U+U available from EBIS**
**DOE investment ~ $7M**

**HFT partial **
**implementation**

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

**Planned LHC**
**1****st**** heavy ion run**

**DOE investment ~ $400k**

**  ****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**

## PHENIX Upgrade Plan

**An aerogel and time-of-flight system to provide complete ********/K/p separation for momenta up to 10~GeV/c.**
**A hadron-blind detector to detect and track electrons near the vertex **
**A vertex detector to detect displaced vertices from the decay of mesons containing charm or bottom quarks.**
**A muon trigger upgrade to preserve sensitivity at the highest projected RHIC luminosities.**
**A forward calorimeter to provide photon+jet studies over a wide kinematic range.**

## PHENIX Central Arm Upgrades 

**Enhanced Particle ID**
** ****TRD (east) **
** ****Aerogel/TOF (west)**

**Vertex Spectrometer**
**flexible magnetic field**
**VTX: silicon barrel vertex tracker**
**HBD and/or TPC**

**High p****T**** phenomena: **
**    ********, K, p separation to 10 GeV/c**

**charm/beauty:**
**    ****TRD  e/******** above 5 GeV/c **

**charm/beauty:**
**    ****displaced vertex **

**e+e- continuum:**
**    ****Dalitz rejection**
**  **

**HBD/TPC**

**VTX**

**HBD/TPC**

**VTX**

**TRD**

**Aerogel/TOF**

## Silicon Vertex Tracker (VTX)

**Strip barrels            ****	****(80 ********m x 3 cm)**
**Endcap (extension) ****	****(50 ********m x 2 mm)**

**1 - 2% X****0 ****per layer**
**barrel resolution  < 50 ********m **
**endcap resolution < 150 ********m**

**Silicon Vertex Tracker (VTX)**

**VTX barrel |********|<1.2**

**Pixel Detectors  at R ~ 2.5 & 5 cm **
**Strip Detectors at R ~ 10 & 14 cm **
**	**

**Endcap 1.2<|********|<2.7**

**Notes:**
PHENIX Si Barrel Vertex Detector:  The VTX will allow precision measurements of heavy quark production (charm and beauty) in A+A, p(d)+A and polarized p+p collisions. It will enable g + jet measurements over 2.4 units in pseudorapidity and almost 2p in azimuth. It will significantly increase the x-range for gluon shadowing and saturation measurements. The VTX is a four-layer silicon detector configured as concentric cylinders located in the PHENIX central spectrometer magnet and positioned immediately around a new 3 cm diameter beam pipe. The silicon sensors in the inner two layers are pixels (r = 2.5, 5.0 cm) and the outer two layers are strips (r = 10, 14 cm). The VTX barrel will cover |h| < 1.2.  This is a joint U.S. and Japanese effort.  The U.S. component is proposed as an MIE project with a DOE cost of $4.7M.  It has been reviewed, and a management plan accepted by DOE.  It is expected to be funded for a construction start in FY 2007, with completion in 2009.
PHENIX Si Forward Vertex Trackers:  The FVTX  extends the solid angle coverage of the VTX barrel. The FVTX will allow precision measurements of heavy-quark (charm and beauty) production in the forward and backward rapidity regions in A+A, p(d)+A, and polarized p+p collisions. It provides new coverage in the small Bjorken-x region where gluon saturation is thought to be important and significantly extends the range over which PHENIX can examine the gluon structure functions and their polarization. The FVTX will be composed of four silicon mini-strip planes in each of two endcaps matched to the muon arms. It will provide vertex tracking with a resolution of <200 mm over a large coverage in rapidity (1.2 < |h| < 2.2) with full azimuthal coverage. This would be a joint U.S. and Japanese effort.  The proposed DOE cost will be ~$4.5M.  There is not yet a formal proposal for this project.

## Forward Upgrade Components

**Endcap Vertex Tracker **
** ****silicon pixel detectors**
**Nosecone EM Calorimeter**
**W-silicon (20-50 X/X0)  **
**shower max**
**tail catcher**

**Muon trigger**
**U-tracker (MuTr or new)**
**D-tracker (timing with RPC’s)**
**Cerenkov**

**charm/beauty & jets:**
**    ****displaced vertex**** **

******-jet,W****************,********c****:**
**    ****calorimeter**** **

**W and quarkonium:**
**    ****improved ********-trigger rejection**** **

**Notes:**
PHENIX Muon Trigger:  The fast muon trigger system (MuTrig) will be used to select events containing W bosons produced in polarized p+p collisions. The measurement of single longitudinal spin asymmetry AL in W production makes it possible to determine the spin contributions of sea and valence quarks to the proton spin. The fast muon trigger system consists of three resistive plate chamber (RPC) stations installed in each of the PHENIX forward muon spectrometer arms. The MuTrig will have the same azimuthal and rapidity coverage as the existing PHENIX forward muon arms, and will use two-gap RPC technology developed for the CMS muon trigger at LHC. It is designed for a background reject of > 104 which is sufficient for efficient operation at the anticipated 9 MHz collision rates at RHIC for polarized p+p running at s 1⁄2  = 500 GeV.  This project is funded by the NSF, at a cost of ~$2M, and is led by the UIUC group.  Construction is scheduled to begin in FY 2007, with completion in 2009.

## Nose-Cone Calorimeter

**Replace existing PHENIX “nose-cones” (hadronic absorbers for muon arms) with Si-W calorimeter (Tungsten with Si readout)**
**Major increase in acceptance for****photon+jet studies**

**Prototype silicon wafer **
**3 different versions of “stri-pixel” detectors for the preshower and shower max layers**
**Extended physics reach **
** ********q/q  polarizations via spin dependent W-production**
**Small *****x*****-physics in d-A **
**Extended A-A program**
**high p****T**** phenomena: ********0**** and ********-jet **

**Notes:**
PHENIX Nose Cone Calorimeter (NCC):  The NCC is a compact tungsten-silicon sampling calorimeter (NCC) built to identify and make precision measurements of forward electromagnetic showers, provide jet identification, jet energy, /0 and g/hadron discrimination. The NCC has a circular geometrical coverage of a 50 cm radius at a distance of 40 cm from the nominal PHENIX collision point corresponding to a forward rapidity range from 0.9 to 3.5. Two calorimeter modules, one located on each of the pole faces of the PHENIX central spectrometer magnet, are built with an electromagnetic compartment, shallow hadronic compartment, a preshower section and a /0  identifier.
  The NCC is being developed by Russian and Japanese members of the PHENIX collaboration.  A full technical design is in preparation.  The estimated DOE cost is $4M 

## PHENIX Upgrades Schedule

|  | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Aerogel |  |  |  |  |  |  |  |  |  |  |
| TOF-W |  |  |  |  |  |  |  |  |  |  |
| HBD |  |  |  |  |  |  |  |  |  |  |
| VTX-barrel |  |  |  |  |  |  |  |  |  |  |
| VTX-endcap |  |  |  |  |  |  |  |  |  |  |
| NCC |  |  |  |  |  |  |  |  |  |  |
| MuTrigger |  |  |  |  |  |  |  |  |  |  |
| DAQ |  |  |  |  |  |  |  |  |  |  |

**R&D Phase**

**Construction Phase**

**Ready for Data**

**PHENIX Upgrades Schedule**

## Summary

**The scientific program at RHIC is rich and diverse**
**Rare probes and high pt phenomena are a rich source of new discoveries**
**Strangeness, Charm, and Beauty are likely to yield even more new discoveries**
**We have promising spin program that is making critical and unique measurements**
**The scientific program at RHIC will keep getting better**
**The performance of the accelerator is improving each due to a carefully planned set of upgrades.**
**STAR will explore charm, beauty, and higher pt spectra at ever increasing data acquisition rates.**
**PHENIX will add sophisticated PID and tracking near the vertex.**
**These upgrades will yield exciting new physics results**

**The Future is Very Bright**