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Heavy Flavor Upgrades for STAR and PHENIX at RHIC Jim Thomas Lawrence Berkeley National Laboratory

Heavy Flavor Upgrades for STAR and PHENIX at RHIC Jim Thomas Lawrence Berkeley National Laboratory With correspondence from Axel Drees, SUNYSB Characterization of the QGP with Heavy Quarks Physikzentrum, Bad Honnef June 25-28, 2008. Motivation: Heavy Flavor Energy Loss, v 2 , s.

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Heavy Flavor Upgrades for STAR and PHENIX at RHIC Jim Thomas Lawrence Berkeley National Laboratory

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  1. Heavy Flavor Upgrades for STAR and PHENIX at RHIC Jim Thomas Lawrence Berkeley National Laboratory With correspondence from Axel Drees, SUNYSB Characterization of the QGP with Heavy Quarks Physikzentrum, Bad Honnef June 25-28, 2008

  2. Motivation: Heavy Flavor Energy Loss, v2, s 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 STAR PRL, 98, 192301 (2007) Surprising results - - challenge our understanding of the energy loss mechanism - force us to re-think about the collisional energy loss - Requiresdirect measurements of C- and B-hadrons.

  3. Essential Ingredients • Direct measurement of C and B hadrons requires • High Luminosity • Excellent PID • Excellent spacial resolution at the event vertex • Large Acceptance, High Rate and High Efficiency Tracking

  4. News from RHIC: Stochastic Cooling Works • Stochastic cooling works at RHIC • van der Meer method • Measure at one point and send the control signal across cord of the ring • First time accomplished with a bunched beam • Longitudinal cooling of one ring gave a 20% increase in Luminosity • Goals • Longitudinal cooling achieved in one ring in 2007 • Longitudinal cooling in the other ring in 2008 • Transverse cooling in one ring in ‘09 • Transverse cool the other in ’10 or ’11 • Goals • 50 x 1026 (not 80 x 1026 ) • Electron cooling is out … Goal: Align the arrival times of the packets in the two beams

  5. STAR Solenoidal field Large Solid Angle Tracking TPC’s, Si-Vertex Tracking RICH, EM Cal, TOF PHENIX Axial Field High Resolution & Rates 2 Central Arms, 2 Forward Arms TEC, RICH, EM Cal, Si, TOF, -ID Measurements of Hadronic observables using a large acceptance spectrometer Leptons, Photons, and Hadrons in selected solid angles (especially muons) Heavy Flavor Upgrades for STAR and PHENIX

  6. STAR Upgrades • Full Barrel MRPC TOF to improve PID • DAQ Upgrade (order of magnitude increase in rate) • High precision Heavy Flavor Tracker near the vertex • Mid Rapidity Muon Trigger & Tracker

  7. 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

  8. Multi-Gap Resistive Plate Chamber TOF State-of-art MRPC: -0.9 < h < 0.9, 0 < f < 2p, r = 220cm 6 gaps, 3x6cm2 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

  9. Improving the “Time” in Time-of-Flight • 2001: • No timing devices (except Time Projection Chamber) • 2002: • BBC (~1ns), ZDC (200ps) • 2002-2008: • TOF tray+VPD (<100ps) Run8: 76M pp events TOF+TPX • 2008 • TOF st: 81ps

  10. 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 !

  11. Dual CERN D-RORC with fibers on the board Single D-RORC with 1 fiber mezzanine Mezzanine DDL ALICE FEE & DAQ • 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)

  12. 4 layers of Si at mid rapidity, 2 PXL + 1 IST + 1 SSD (existing) The Heavy Flavor Tracker • A new detector • 18 mm silicon pixels • to yield 6 mm space point resolution • 436 M pixels • Strasbourg MAPS chips • Direct Topological reconstruction of Charm • Detect charm decays with small ct, including D0 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 CBM/MAPS: See related posters by C. Dritsa and Selim Seddiki

  13. Concept of HFT Layers 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 Numbers quoted above are for a Kaon at 750 MeV/c A pion at 1 GeV/c would achieve ~ 25 m at the vertex

  14. The Pixel Detector surrounds the vertex with Si End view 8 cm radius 2.5 cm radius Inner layer Outer layer ‘D-Tube Duct and Support See Poster by J. Kapitan and J. Thomas ALICE style carbon support beams (green) Since modified to increase Sensor Clearances A thin detector using 50 m Si to finesse the limitations imposed by MCS

  15. 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!

  16. Charm Hadron v2 - 200 GeV Au+Au minimum biased collisions (500M events). - Charm collectivity  drag/diffusion constants  medium properties!

  17. Even the Lc 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

  18. A more complete view of the STAR Upgrade plan HFT complete full topological PID for c, b mesons DOE investment : upper limit of range ~ $14.7M 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 FMS complete: d+Au and p+p data from Run 8 HFT partial implementation DOE investment ~ $400k Run08 Run09 Run10 Run11 Run12 Run13 Run14 Run15 Planned LHC 1st heavy ion run Increase in Au+Au luminosity to 50 x 1027 cm-2 sec-1 U+U available from EBIS DOE investment ~ $7M DAQ1000 complete Immediate improvement of 300% in sampled luminosity for rare probes (e.g. jets in p+p) FGT complete: Accurate charge sign determination for W’s, DOE investment ~ $1900k DOE investment ~ $1900k

  19. Future PHENIX Subsystems MuTrig Station 1 Silicon VTX and FVTX MuTrig Station 2 Nose Cone Calorimeter MuTrig Station 3

  20. PHENIX Upgrade Plan for Heavy Flavor • A vertex detector to detect displaced vertices from the decay of mesons containing charm or bottom quarks. • A powerful addition to PHENIX because currently there is no tracking inside the magnetic field • A forward calorimeter to provide photon+jet studies over a wide kinematic range. • A muon trigger upgrade to preserve sensitivity at the highest projected RHIC luminosities.

  21. Silicon Vertex Tracker (VTX) VTX barrel |h|<1.2 Endcap 1.2<|h|<2.7 Pixel Detectors at R ~ 2.5 & 5 cm Strip Detectors at R ~ 10 & 14 cm Pixel barrel (50 mm x 425 mm) Strip barrels (80 mm x 3 cm) Endcap (extension) (75 mm x 2.8 mm) 1 - 2% X0 per layer barrel resolution < 50 mm endcap resolution < 150 mm

  22. e X D  beam DCA, distance of closest approach PHENIX Barrel VerTeX Detector • VTX characteristics • 2 inner pixel layers (50x425 mm2) to measure DCA radial position at 2.5 and 5 cm with ~ 1.2% X/X0 • 2 out strip-pixel (80x1000 mm2) for p measurement and tracking at 10 and 14 cm with ~ 3.% X/X0 • DCA resolution: given mostly by inner layer • Sufficient single hit resolution (~15 mm) • Close to beam axis to reduce effect of multiple scattering • |h|<1.2 • ~ 2p |z| 10 cm

  23. Expected RAA(ce) and RAA(be) with VTX PHENIX VXT ~ 2 nb-1 RHIC II increases statistics by factor >10 Decisive measurement of RAA for both c and b

  24. PHENIX VXT ~2 nb-1 Expected v2(be) and v2(ce) with VTX RHIC II increases statistics by factor >10 Decisive measurement of v2 for both c and b

  25. Cerenkov Silicon endcap Muon from hadron decays Muon from W U-Tracker Nosecone Calorimeter Tail Catcher D-Tracker Forward Upgrade Components • Muon trigger • U-tracker (MuTr or new) • D-tracker (timing with RPC’s) • Cerenkov • Endcap Vertex Tracker • silicon pixel detectors • Nosecone EM Calorimeter • W-silicon (42 X/X0) • shower max • tail catcher charm/beauty & jets: displaced vertex g,g-jet,W,p0,h,c: calorimeter W and quarkonium: improved m-trigger rejection

  26. PHENIX Forward VerTeX Detector • FVTX characteristics • Cover both muon arms with 4 pixelpad layers/endcap • 2p coverage in azimuth and 1.2 < | h | < 2.4 • ≥ 3 space points / track • DCA resolution < 200 µm at 5 GeV • Maximum Radiation Length < 2.4% • Fully integrated mechanical design with VTX

  27. prompt pm DCA r-z resolution (cm) Muon acceptance Momentum (GeV) Tracking and DCA Resolution with the FVTX General performance • 3 or more planes hit per track • Central Au+Au occupancy < 2.8% • Good matching between FVTX and muon tracker • Sufficient DCA resolution (<200 mm) to separate prompt, heavy quark, and p-K decays.

  28. Charmonium Spectroscopy with the FVTX • Remove p-K decays Background rejection factor 4 • Improve mass resolution: 170 MeV  100 MeV p-p Measurement of ‘ in central Au-Au collisions Au-Au

  29. Nose-Cone Calorimeter • Prototype silicon wafer • 3 different versions of “stri-pixel” detectors for the pre-shower and shower max layers • Extended physics reach • Dq/q polarizations via spin dependent W-production • Small x-physics in d-A • Extended A-A program • high pT phenomena: p0 and g-jet • Replace existing PHENIX “nose-cones” (hadronic absorbers for muon arms) with Si-W calorimeter (Tungsten with Si readout) • Major increase in acceptance forphoton+jet studies

  30. PHENIX Forward EM Calorimeter (NCC) W-silicon sampling calorimeter • NCC characteristics (DOE funding FY08) • 40 cm from interaction point, 20 cm depth • 2p coverage in azimuth and 0.9 < h < 3.0 • W-silicon sampling calorimeter • 1.4 cm Moliere radius • 42 X0 and 1.6 labs • Lateral segmentation 1.5x1.5 cm2 • 3 longitudinal segments • 2x2 tracking layers with 500 mm strips • p-g separation for overlapping showers PS tracking layers Main objective: direct photon and p0 measurements EM1 EM2 HAD

  31. μ μ γ Charmonium spectroscopy with the NCC Central Cu+Cu collisions subtracted spectrum η=1-1.5 S/B ~10% • J/ in muon arm, g in NCC • Conditional acceptance 58% if J/ detected • Determine invariant mass and subtract combinatorial background • Proof of principle MC simulation • pp should work, CuCu probable • Full MC simulation in progress subtracted spectrum η=1.5-2 S/B~2% mμμγ-mμμ (GeV/c2)

  32. Quarkonium Spectroscopy w/ Forward Upgrades Reference model based on consecutive melting without regeneration (Note: This results in small ’, C yields,other models like regeneration model will give similar yields for J/, ’, C !) (1S) RHIC 2 nb-1 With NCC/FVTX RHIC 2 nb-1 W/O NCC/FVTX RHIC 20 nb-1 With NCC/FVTX (2S) J c ’

  33. Timeline of PHENIX upgrades 2010 2012 2014 2008 RHIC cooling era for “RHIC II” Inner pixel layers Displaced vertex at mid rapidity VTX Large acceptance tracking |Dh|<1.2 Outer strip layers Displaced vertex at forward y FVTX Forward photon detection NCC Construction Physics

  34. Summary • The study of heavy flavor production provides key information to understand the properties of quark matter • 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 Guaranteed

  35. Backup Slides and even more information …

  36. Key Experimental Probes of Quark Matter • Rutherford experiment a atom discovery of nucleus SLAC electron scattering e  proton discovery of quarks QGP penetrating beam (jets or heavy particles) absorption or scattering pattern Nature provides penetrating beams or “hard probes” and the QGP in A-A collisions • Penetrating beams created by parton scattering before QGP is formed • High transverse momentum particles  jets • Heavy particles  open and hidden charm or bottom • Calibrated probes calculable in pQCD • Probe QGP created in A-A collisions as transient state after ~ 1 fm

  37. Hard Probes: Open Heavy Flavor Electrons from c/b hadron decays Status • Calibrated probe? • pQCD under predicts cross section by factor 2-5 • Charm follows binary scaling • Strong medium effects • Significant charm suppression & v2 • Upper bound on viscosity ? • Bottom potentially suppressed • Open issues: • Limited agreement with energy loss calculations! • What is the energy loss mechanism? • Are there medium effects on b-quarks? Answers require direct observation of charm and beauty Progress limited by: no b-c separation  decay vertex with silicon vertex detectors statistics (BJ/)  increase luminosity

  38. Hard Probes: Quarkonium Deconfinement  Color screening Status • J/y production is suppressed • Large suppression • Similar at RHIC and SPS • Larger at forward rapidity • Ruled out co-mover and melting scenarios • Consistent with melting J/y followed by regeneration • Open issues: • Are quarkonia states screened and regenerated? • What is the regeneration (hadronization) mechanism? • Can we extract a screening length from data? • Recent Lattice QCD developments: Quarkonium states do not melt at TC J/y Answers require “quarkconium” spectroscopy Progress limited by: statistics (J/, Y)  increase luminosity statistical significance (’)  mass resolution photon detection (cC)  forward calorimeter

  39. e,m X D Au Au D B J/ p K X e e Direct Observation of Open Charm and Beauty Detection of decay vertex will allow a clean identification of charm and bottom decays m ct GeV mm D0 1865 125 D± 1869 317 B0 5279 464 B± 5279 496 • Heavy flavor detection with VTX and FVTX in PHENIX: • Beauty and low pT charm via displaced e and/or m -2.7<h<-1.2 , |h|<0.35 , 2.7<h<1.2 • Beauty through displaced J/  ee (mm) -2.7<h<-1.2 , |h|<0.35 , 2.7<h<1.2 • High pT charm through D   K|h|<0.35

  40. e X D  beam DCA, distance of closest approach Heavy flavor detection with the VTX • Results of simulation of Au+Au collision. • After a 2 cut, D0 decays clearly separated from bulk of hadrons 3<pT<4 GeV/c s ~ 40mm

  41. D/B Monte Carlo Simulations with FVTX

  42. Heavy Ion RAA with FVTX • Mechanisms for heavy/light quark suppression poorly understood • Clear distinction among models, e.g. I.Vitev’s radiative, collisional and dissociative energy loss predictions

  43. Heavy Ion RAA with FVTX (II) Statistical separation of charm and bottom with DCA cuts

  44. Future Quarkonium Spectroscopy with PHENIX • RHIC II luminosity upgrade • Electron cooling and stochastic cooling • Increase integrated luminosity 2 nb-1 to 20 nb-1 per run  precision measurements of RAA and v2 for J/ • FVTX: Track muons to primary vertex, • reject decay background (Kmn) • Improved mass resolution clean and significant ‘ • Background Rejection  Upsilon at mid rapidity • Rapidity dependence J/, ’, and  • FVTX: Detected displaced vertex for charm and beauty decays • Precise charm and beauty reference • NCC: add photon measurement at forward rapidity • Measurement of C →J/ γ possible

  45. Quarkonium Spectroscopy at RHIC II J/ measurements will reach high precision

  46. PHENIX Central Arm Upgrades • Vertex Spectrometer • flexible magnetic field • VTX: silicon barrel vertex tracker • HBD • Enhanced Particle ID • TRD (east) • Aerogel/TOF (west) VTX VTX HBD HBD Aerogel/TOF TRD charm/beauty: TRD e/ above 5 GeV/c e+e- continuum: Dalitz rejection High pT phenomena: , K, p separation to 10 GeV/c charm/beauty: displaced vertex

  47. Improving STAR’s muon capabilities Install a large area mid-rapidity muon telescope. Allows detection of: Di-muon pairs: Quarkonia, QGP thermal radiation, Drell-Yan Single muons : Heavy flavor semi-leptonic decays Advantage over e: No g conversion, Less Dalitz decay, Less radiative losses to detector material +- Simulations e+e-

  48. The Muon Trigger Detector concept Long MRPC Technology with double-end readout. 20x larger than ToF modules HV: 6.3 KV gas:95% Freon + 5% Isobutane 10 gas gaps: 250 mm time resolution: ~60 ps spatial resolution: ~1cm Prototype Installed in RUN 7-8 Place scintillators outside magnet covering iron bars Muon efficiency: 35-45% Pion efficiency: 0.5-1% Muon-to-Hadron Enhancement Factor: 100-1000 (including track matching, ToF, dE/dx)

  49. Hadron Rejection and Muon Trigger J/y trigger, separate +- states • Muon penetrates iron bars • Other particles are stopped • Good Time Resolution (60ps) • rejects background (>100) • 1 hit per 5 head-on Au+Au • Dimuon trigger (>25) • Large coverage: • diameter of 7 meters Iron bars Full Hijing AuAu event

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