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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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
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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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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, …
2/8/201324
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
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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
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?