The STAR Upgrade Program

Flemming VidebækBrookhaven National Laboratory

For the STAR collaboration

Winter Workshop on Nuclear Dynamics,Feb 2013

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Overview

• Introduction• Near Term Upgrades

– Muon Telescope Detector (MTD)– Realization & Planned Physics from MTD– Heavy Flavor Tracker (HFT)– Realization & Planned Physics from HFT

• Future Plans (STAR decadal Plan)– iTPC – Forward upgrades for pA and eRHIC

• Status and Summary

2/8/2013

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• Hot QCD matter: high luminosity RHIC II (fb-1 equivalent)– Heavy Flavor Tracker: precision charm and beauty– Muon Telescope Detector: e+μ and μ+μ at mid-rapidity– Trigger and DAQ upgrades to make full use of luminosity– Tools: jets combined with precision particle identification

• Phase structure of QCD matter: Beam Energy Scan Phase II– Fixed Target to access lowest energy at high luminosity– Low energy electron cooling to boost luminosity for √sNN<20 GeV– Inner TPC Upgrade to extend η coverage, improve PID

• Cold QCD matter: high precision p+A, followed by e+A– Major upgrade of capabilities in forward direction– Existing mid-rapidity detectors well suited for portions of e+A program

2/8/2013

How to explore QCD: from hot to cold

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STAR: A Correlation MachineTracking: TPC Particle ID: TOF

Heavy Flavor Tracker (run 14)

Electromagnetic Calorimetry:

BEMC+EEMC+FMS(-1 ≤ ≤ 4)

Muon Telescope Detector (runs 13/14)

Plus upgrades toTrigger and DAQ

Recent upgrades:DAQ1000

TOF

Full azimuthal particle identification over a broad range in pseudorapidity

Forward GEM Tracker (runs 12/13)

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STAR near term upgrades

• Muon Telescope Detector (MTD)– Accessing muons at mid-rapidity– R&D since 2007, construction since 2010– Significant contributions from China & India

• Heavy Flavor Tracker (HFT)– Precision vertex detector– Ongoing DOE MIE since 2010– Significant sensor development by IPHC, Strasbourg

2/8/2013

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STAR-MTD physics motivation

The large area of muon telescope detector (MTD) at mid-rapidity allows for the detection of

• Di-muon pairs from QGP thermal radiation, quarkonia, light vector mesons, resonances in QGP, and Drell-Yan production

• Single muons from the semi-leptonic decays of heavy flavor hadrons• Advantages over electrons: no conversion, much less Dalitz decay

contribution, less affected by radiative losses in the detector materials, trigger capability in Au+Au collisions

• Trigger capability for low to high pT J/ in central Au+Au collisions and excellent mass resolution results in separation of different upsilon states

• e-muon correlation can distinguish heavy flavor production from initial lepton pair production

72/8/2013

Concept of design of the STAR-MTD

Multi-gap Resistive Plate Chamber (MRPC):

gas detector, avalanche mode

A detector with long-MRPCs covers the

whole iron bars and leaves the gaps in-

between uncovered. Acceptance: 45% at

||<0.5

118 modules, 1416 readout strips, 2832 readout

channels

Long-MRPC detector technology, electronics

same as used in STAR-TOF

MTD

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STAR-MTD

2/8/2013

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MTD Performance from Run 12

Commissioned e-muon (coincidence of single MTD hit and BEMC

energy deposition above a certain threshold) and di-muon triggers,

event display for

Cu+Au collisions shown above

Determined the electronics threshold for the future runs, achieved

90% efficiency at threshold 24 mV

Intrinsic spatial resolution: 2 cm

2/8/2013

e-muon di-muon

pT(GeV/c)

Y Re

solu

tion

(cm

)

pT(GeV/c)

Effici

ency

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Quarkonium from MTD

1. J/: S/B=6 in d+Au and S/B=2 in central Au+Au collisions

2. Excellent mass resolution: separate different upsilon states

3. With HFT, study BJ/ X; J/ using displaced vertices

Heavy flavor collectivity and color

screening, quarkonia production

mechanisms:

J/ RAA

and v2

; upsilon RAA

…

Z. Xu, BNL LDRD 07-007; L. Ruan et al., Journal of Physics G: Nucl. Part. Phys. 36 (2009) 095001

2/8/2013

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Heavy Flavor Tracker (HFT)

TPC Volume

Magnet

Return Iron

Solenoid

Outer Field Cage

Inner Field Cage

EASTWEST

FGT

2/8/2013

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Heavy Flavor Tracker (HFT)

SSDISTPXL

HFT Detector Radius(cm)

Hit Resolution R/ - Z (m - m)

Radiation length

SSD 22 20 / 740 1% X0

IST 14 170 / 1800 <1.5 %X0

PIXEL8 12/ 12 ~0.4 %X0

2.5 12 / 12 ~0.4% X0

SSD• Existing single layer detector, double side strips (electronic upgrade)

IST One layer of silicon strips along the beam direction (r-φ) , guiding tracks from the SSD to PIXEL detector. - proven technology

PIXEL • two layers• 18.4x18.4 m pixel pitch • 10 sectors, delivering ultimate Pointing

resolution that allows for direct topological identification of charm.

• New monolithic active pixel sensors (MAPS) technology

2/8/2013

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PXL Detector Design

MAPSRDObuffers/drivers

4-layer kapton cable with aluminium tracesAluminum conductor Ladder Flex Cable

Ladder with 10 MAPS sensors (~ 2×2 cm each)

Carbon fiber sector tubes (~ 200µm thick)

20 cmThe ladders will be instrumented with sensors thinned down to 50 micron Si.

Novel rapid insertion mechanism allows effective exchanges and repairs (~12 h)Precision kinematic mount guarantees reproducibility to < 20 microns

2/8/2013

Production sector

Production sector on metrology stage

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Intermediate Si Tracker

2/8/2013

Details of wire bonding24 ladders, liquid cooling

Prototype LadderS:N > 20:1>99.9% live and functioning channels

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Silicon Strip Detector (SSD)

4.2 Meters

~ 1 Meter

44 c

m

20 Ladders

Ladder cards

2/8/2013

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Physics of the Heavy Flavor Tracker at STAR

• Direct HF hadron measurements (p+p and Au+Au)(1) Heavy-quark cross sections: D0±*, DS, ΛC , B, …

(2) Both spectra (RAA, RCP) and v2 in a wide pT region: 0.5 - 10 GeV/c

(3) Charm hadron correlation functions, heavy flavor jets(4) Full spectrum of the heavy quark hadron decay electrons

• Physics(1) Measure heavy-quark hadron v2, heavy-quark collectivity, to study the medium properties e.g. light-quark thermalization(2) Measure heavy-quark energy loss to study pQCD in hot/dense medium e.g. energy loss mechanism(3) Analyze hadro-chemistry including heavy flavors

2/8/2013

GEANT: Realistic detector geometry + Standard STAR trackingincluding the pixel pileup hits at RHIC-II luminosity

Goal with Al-based cable (Cu cable -> 55 micron for 750 MeV/c K)

DCA resolution performancer-ϕ and z

182/8/2013

0.4% X0

192/8/2013

Physics – Run-14,15 projections

RCP=a*N10%/N(60-80)%

Assuming D0 v2 distribution from quark coalescence.

500M Au+Au m.b. events at 200 GeV.

- Charm v2 Medium thermalization degreeDrag coefficients!

Assuming D0 Rcp distribution as charged hadron.

500M Au+Au m.b. events at 200 GeV.

- Charm RAA Energy loss mechanism!Color charge effect!Interaction with QCD matter!

202/8/2013

B tagged J/

Prompt

J/ from B

Current measurement via J/-hadron correlation have large uncertainties.

Combine HFT+MTD in di-muon channel Separate secondary J/ from promptJ/ Constrain the bottom production at RHIC

STAR arXiv: 1208.2736.

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HFT project status

• HFT upgrade was approved CD-2/3 October 2011 and is well into fabrication phase

• All detector components have passed the prototype phase successfully

• A PXL prototype with 3+ sectors instrumented is planned for an engineering run and data taking in STAR in mid to end March

• The full assembly including PXL, IST and SSD should be available for RHIC Run-14, which is planned to be a long Au-Au run

2/8/2013

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Future Plans

• Beam Energy Scan II ( Hui’s talk Monday)• Exploit pA physics• Prepare STAR for eRHIC on 2020-2025 timescale

(eSTAR)

2/8/2013

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Better tracking and dE/dx PID capability h 1.0-1.7 region -- broad physics impact on

• transverse spin physics program • hyperon and exotic particle searches• high pT identified particles• BES Phase II+• Long range rapidity gap correlations.

2/8/2013

Inner TPC Upgrade

Current pad plane layout. 13 rows and gaps.Fill all inner sector with active pads.Configuration still under discussion

Some planned p+A measurements• Nuclear modifications of the gluon PDF

– Correlated charm production• Gluon saturation

– Forward-forward correlations (extension of existing π0-π0)• h-h• π0-π0

• γ-h• γ-π0

– Drell-Yan• Able to reconstruct x1, x2, Q2 event-by-event• Can be compared directly to nuclear DIS• True 2 1 provides model-independent access to x2 < 0.001

• polarized protons off nuclei can be studied at RHIC.

• Forward-forward correlations and Drell-Yan are also very powerful tools to unravel the dynamics of forward transverse spin asymmetries – Collins vs Sivers effects, TMDs or Twist-3, …

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Easier to measure

Easier to interpret

252/8/2013

• Forward instrumentation optimized for p+A and transverse spin physics– Charged-particle tracking– e/h and γ/π0 discrimination– Possibly baryon/meson separation

FHC (E864)

~ 6 GEM disksTracking: 2.5 < η < 4

RICH/Threshold Baryon/meson separation

proton nucleus2017+

W-Powder EMCal

FHC (E864)

Pb-Sc HCal

Forward Calorimeter System (FCS)

Forward Instrumentation Upgrade

262/8/2013

Calorimeter:1) EM: Pb-glass (FMS) augmented by Tungsten SPACAL

1) Smaller Moliere radius for better 2-γ separation2) Keep high E resolution

2) Hadron calorimetry for e/h discrim., jet reconstruction Very Forward GEM Tracker (VFGT)

3) Likely GEM-based4) Details of the design depend on experience with FGT

Particle IdentificationRICH problematic with accessible pT resolutionThreshold Cerenkov detector under consideration Detector will not be included in initial upgrade

Schedule: proposal this year, construction start 2015+Ready for data 2017 at the earliest

Plans for Forward Upgrade

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SummarySTAR has an ongoing upgrade program that will enable significant physics measurements in 2013-1017• Further high precision Heavy Flavor measurements will be carried out to

explore the sQGP• HFT upgrades will provide direct topological reconstruction for charm• MTD will provide precision Heavy Flavor measurements in muon channels

Future upgrades for 2017+ • Enhanced TPC capabilities for BES II (and eSTAR)• Forward Upgrades to exploit a p+A program

– Full calorimetry (EM+Hadronic) – Modern tracking technology to make most of existing

magnetic field • Strong set of measurements to be made. Both complementary to, and

supporting, those at a future eRHIC

2/8/2013

282/8/2013

Backup

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TPC

TOF

EMC

HFT

Neutral particles

e, μ

πK p d

TPC TOF TPC

Log10(p)

Multiple-fold correlations among the identified particles!Nearly perfect coverage at mid-rapidity

Hyperons & Hyper-nuclei

Jets

Heavy-flavor hadrons

MTD

High pT muonsJets & Correlations

Charged hadrons

Particle Identification in STAR

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What are the properties of cold nuclear matter?Is there evidence for saturation of the gluon density?

PHENIX, Phys. Rev. Lett. 107, 172301 (2011)

• RHIC may provide unique access to the onset of saturation– Complementarity: LHC likely probes deeply saturated regime

• Future questions for p+A– What is the gluon density in the (x,Q2) range relevant at RHIC?– What role does saturation of gluon densities play at RHIC?– What is Qs at RHIC, and how does it scale with A and x?– What is the impact parameter dependence of the gluon density?

Upgrades to both STAR and PHENIX to extend observables (focus on EM)

Timescale: medium-term (~2017+)

STAR preliminary

2/8/2013

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Measure charm correlation with MTD upgrade: ccbare+

An unknown contribution to di-electron mass spectrum is from ccbar, which can be disentangled by measurements of e correlation.

Simulation with Muon Telescope Detector (MTD) at STAR from ccbar:

S/B=2 (Meu

>3 GeV/c2 and pT

(e)<2 GeV/c)

S/B=8 with electron pairing and tof association

2/8/2013

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Also measured:

1.Uniformity of response across the towers.

2. Energy resolution with and without mirror.

3. Perform scans along the towers with electrons and muons. 4. Estimated effects of attenuation and towers non-uniformities on resolution.

2/8/2013

Viable EMC detector technology developed through EIC R&DA prototype hadron calorimeter module will be built in 2013

Calorimeter: SPACAL works

332/8/2013

p+A: Where to measure?Most promising atRHIC energies: y ~ 3-4Q2 ~ few GeV2

N.B. Lines only schematic, kinematic control limited in p+AFrom 2->2 parton scattering, many sources of smearing

LHC mid-y ~ RHIC y=4

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MSCPixel Insertion TubePixel Support Tube

IDSEast Support CylinderOuter Support CylinderWest Support Cylinder

PIT

PST

ESC

OSC

WSC

Shrouds

Middle Support Cylinder

Inner Detector Support

Inner Detector Support (IDS)

Carbon Fiber Structures provide support for 3 inner detector systems and FGT.All systems are highly integrated into IDS.

Installed for run-12

2/8/2013

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Insertion check setup

Two sector only shown in D-Tube (sector holding part). Next slides shows how this will be moved into position around the beam pipe (test setup).

2/8/2013

362/8/2013

Tracking: proof of principlePt Resolution in STAR Forward TPC

J. Putschke, ThesisCharged hadron Rcp at |η|~3.1

|η|~3.1

nucl-ex/0703016

STAR magnetic field allows for moderate pT resolution in forward directione.g. FTPC, position resolution ~100 μm

Some added momentum resolution can be garnered from radial magnetic field at poletip

Likely insufficient for RICH particle identification, but sufficient for charge sign discrimination in Drell-Yan: detailed simulations underway

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STAR inner detector Support

2/8/2013

38382/8/2013

Charmed baryons (Lambdac) – Run-16

cpK Lowest mass charm baryons c = 60 m

c/D enhancement? 0.11 (pp PYTHIA) 0.4-0.9 (Di-quark correlation in QGP)

S.H. Lee etc. PRL 100, 222301 (2008) Total charm yield in heavy ion collisions

39392/8/2013

Access bottom production via electrons

particle

c (m)

Mass

qc,b →x

(F.R.)

x →e (B.R.)

D0 123 1.865

0.54 0.0671

D± 312 1.869

0.21 0.172

B0 459 5.279

0.40 0.104

B 491 5.279

0.40 0.109

Two approaches: Statistical fit with model assumptions

Large systematic uncertainties With known charm hadron spectrum to constrain or be used in subtraction

40402/8/2013

Statistic projection of eD, eB RCP & v2

Curves:  H. van Hees et al. Eur. Phys. J. C61, 799(2009).

(Be) spectra obtained via the subtraction of charm decay electrons from inclusive NPEs: - no model dependence, reduced systematic errors.

Unique opportunity for bottom e-loss and flow. - Charm may not be heavy enough at RHIC, but how is bottom?