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The STAR Upgrade Progra m. Flemming Videbæk Brookhaven National Laboratory For the STAR collaboration. Winter Workshop on Nuclear Dynamics, Feb 2013. Overview. Introduction Near Term Upgrades Muon Telescope Detector (MTD) Realization & Planned Physics from MTD
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The STAR Upgrade Program Flemming Videbæk Brookhaven National Laboratory For the STAR collaboration Winter Workshop on Nuclear Dynamics, Feb 2013
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
How to explore QCD: from hot to cold • 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
STAR: A Correlation Machine Tracking: TPC Electromagnetic Calorimetry: BEMC+EEMC+FMS (-1 ≤ ≤ 4) Particle ID: TOF Recent upgrades: DAQ1000 TOF Plus upgrades to Trigger and DAQ Muon Telescope Detector (runs 13/14) Heavy Flavor Tracker (run 14) Forward GEM Tracker (runs 12/13) Full azimuthal particle identification over a broad range in pseudorapidity
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
STAR-MTD physics motivation • Thelarge area of muon telescope detector(MTD) at mid-rapidity allows forthe detection of • Di-muon pairs from QGP thermal radiation,quarkonia, light vector mesons, resonances in QGP, and Drell-Yan production • Single muonsfrom thesemi-leptonicdecays 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+Aucollisions andexcellent mass resolution results in separation ofdifferent upsilon states • e-muon correlation candistinguish heavy flavor production from initial lepton pair production
Concept of design of the STAR-MTD Multi-gap Resistive Plate Chamber (MRPC): gas detector, avalanche mode A detectorwith long-MRPCs covers the whole iron bars and leavesthe 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
MTD Performance from Run 12 e-muon di-muon Efficiency pT(GeV/c) 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 Y Resolution (cm) pT(GeV/c)
Quarkonium from MTD • J/: S/B=6 in d+Au and S/B=2 in central Au+Au collisions • Excellent mass resolution: separate different upsilon states • 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
Heavy Flavor Tracker (HFT) Inner Field Cage Magnet Return Iron Outer Field Cage FGT TPC Volume Solenoid EAST WEST
Heavy Flavor Tracker (HFT) HFT SSD IST PXL • PIXEL • two layers • 18.4x18.4 m pixel pitch • 10 sectors, delivering ultimate Pointing resolutionthat allows for direct topological identification of charm. • New monolithic active pixel sensors (MAPS) technology • SSD • Existing single layer detector, double side strips (electronic upgrade) • ISTOne layer of silicon strips along the beam direction (r-φ) , guiding tracks from the SSD toPIXEL detector. - proven technology
Aluminum conductor Ladder Flex Cable PXL Detector Design Carbon fibersector tubes (~ 200µm thick) Ladder with 10 MAPS sensors (~ 2×2 cm each) 20 cm The 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
Production sector Production sector on metrology stage
Intermediate Si Tracker 24 ladders, liquid cooling Details of wire bonding Prototype Ladder S:N > 20:1 >99.9% live and functioning channels
Silicon Strip Detector (SSD) 44 cm 20 Ladders 4.2 Meters ~ 1 Meter Ladder cards
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
DCA resolution performancer-ϕ and z 0.4% X0 GEANT: Realistic detector geometry + Standard STAR tracking including the pixel pileup hits at RHIC-II luminosity Goal with Al-based cable (Cu cable -> 55 micron for 750 MeV/c K) 18
Physics – Run-14,15 projections RCP=a*N10%/N(60-80)% • Assuming D0Rcp distribution as charged hadron. • 500M Au+Aum.b. events at 200 GeV. • Charm RAA • Energy loss mechanism! • Color charge effect! • Interaction with QCD matter! Assuming D0 v2 distribution from quark coalescence. 500M Au+Aum.b. events at 200 GeV. - Charm v2 Medium thermalization degree Drag coefficients! 19
B tagged J/ STAR arXiv: 1208.2736. Prompt • 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 J/ from B 20
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
Future Plans • Beam Energy Scan II ( Hui’s talk Monday) • Exploit pA physics • Prepare STAR for eRHIC on 2020-2025 timescale (eSTAR)
Inner TPC Upgrade Current pad plane layout. 13 rows and gaps. Fill all inner sector with active pads. Configuration still under discussion • 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.
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 • polarizedprotons off nucleican be studied at RHIC. • Forward-forward correlations and Drell-Yanare also very powerful tools to unravel the dynamics of forward transverse spin asymmetries –Collins vsSivers effects, TMDs or Twist-3, … Easier to measure Easier to interpret
Forward Instrumentation Upgrade ~ 6 GEM disks Tracking: 2.5 < η < 4 2017+ Forward Calorimeter System (FCS) FHC (E864) Pb-Sc HCal FHC (E864) W-Powder EMCal RICH/Threshold Baryon/meson separation • Forward instrumentation optimized for p+A and transverse spin physics • Charged-particle tracking • e/h and γ/π0 discrimination • Possibly baryon/meson separation proton nucleus
Plans for Forward Upgrade • Calorimeter: • EM: Pb-glass (FMS) augmented by Tungsten SPACAL • Smaller Moliere radius for better 2-γ separation • Keep high E resolution • Hadron calorimetry for e/h discrim., jet reconstruction • Very Forward GEM Tracker (VFGT) • Likely GEM-based • Details of the design depend on experience with FGT • Particle Identification • RICH problematic with accessible pT resolution • Threshold Cerenkov detector under consideration • Detector will not be included in initialupgrade • Schedule: proposal this year, construction start 2015+ • Ready for data 2017 at the earliest
Summary STAR 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+Aprogram • 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
Particle Identification in STAR TPC TOF TPC TPC K pd π e, μ TOF Log10(p) Charged hadrons Hyperons & Hyper-nuclei MTD HFT Jets EMC Neutral particles Jets & Correlations High pTmuons Heavy-flavor hadrons Multiple-fold correlations among the identified particles! Nearly perfect coverage at mid-rapidity
What are the properties of cold nuclear matter?Is there evidence for saturation of the gluon density? STAR PHENIX, Phys. Rev. Lett. 107, 172301 (2011) preliminary • 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+)
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
Calorimeter: SPACAL works 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. Viable EMC detector technology developed through EIC R&D A prototype hadron calorimeter module will be built in 2013
p+A: Where to measure? Most promising at RHIC energies: y ~ 3-4 Q2 ~ few GeV2 N.B. Lines only schematic, kinematic control limited in p+A From 2->2 parton scattering, many sources of smearing LHC mid-y ~ RHIC y=4
Inner Detector Support (IDS) IDS East Support Cylinder Outer Support Cylinder West Support Cylinder PIT Middle Support Cylinder PST Shrouds MSC Pixel Insertion Tube Pixel Support Tube ESC Installed for run-12 OSC Inner Detector Support Carbon Fiber Structures provide support for 3 inner detector systems and FGT. All systems are highly integrated into IDS. WSC
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).
Tracking: proof of principle Pt Resolution in STAR Forward TPC Charged hadron Rcp at |η|~3.1 J. Putschke, Thesis nucl-ex/0703016 |η|~3.1 STAR magnetic field allows for moderate pT resolution in forward direction e.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
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 38
Access bottom production via electrons • Two approaches: • Statistical fit with model assumptions • Large systematic uncertainties • With known charm hadron spectrum to constrain or be used in subtraction 39
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? 40