STAR’s Upgrades – A Path to the Future Helen Caines Yale University RHIC/AGS Users Meeting

1. STAR’s Upgrades – A Path to the Future Helen Caines Yale University RHIC/AGS Users Meeting May 2008 Workshop on RHIC Upgrades Outline: Just Used Installed for Run 9 Under Construction Contemplating

2. STAR’s detector upgrades MTD MRPC ToF barrel Ready for run 10 EMC barrel EMC End Cap • Preserve large acceptance • Extend forward coverage • Particle Identification • Precise Secondary Vertex • Leptons/photons • Faster DAQ • Cost-effective, do it best RPSD FMS FPD PMD finished DAQ1000 Ready for run 9 ongoing HFT; FGT: GEM-layers R&D

3. STAR’s coverage PMD Photon capability from none to 4p

4. DAQ1000 Upgrade order of magnitude increase in rate (1KHz) extra livetime opens the door to rare physics Full Barrel MRPC TOF extended hadron identification at intermediate pT Lepton identification at low momentum Heavy Flavor Tracker High precision Silicon tracker near the primary vertex Opens door to direct topological charm and beauty reconstruction Forward GEM Tracker End cap tracker for particle sign determination for W Muon Telescope (BNL LDRD) Forward Reaction Plane Detector A Crystal Calorimeter for low E photons Pb converter for - HBT GEM alignment detector Aim to keep the discoveries rolling … Underway R&D/Proposals More ideas

5. Ready for Run 9/10

6. ALTROs PASAs blue pen Fiber Out via SIU FPGAs FEE In brown ruler DAQ 1000 - TPC FEE and DAQ upgrades TPC is now a fast detector!!! • 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 • Zero suppression done at FEE. 16-20x smaller • Make the FEE smaller. less heat • Almost no deadtime –rare physics program • By only archiving “associated” clusters – build on L3 algorithms … 5 kHz ! Prototype in run 7, 1 sector in run8, Full system in run9

7. Commissioning in run 8 TPX dE/dx from TOF+TPX events DAQ1K at 1000Hz, 5—7% deadtime 1/17/2008 Laser event (plus pileup) Data from DAQ1000 sector look good

8. 200 GeV Au+Au STAR Preliminary PID plays crucial roles at RHIC

9. Multi-gap Resistive Plate Chamber Time-of-Flight 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

10. 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-: • finally TOF st: 81ps

11. Hadron and lepton PID at mid-rapidity – (Energy scan) Identified p/p at high pT Jet-related PID spectra & correlations Fluctuation K/p, p/p – (Critical point) Resonances (,,J/) hadronic and dilepton decay channels Open Charm (daughter PID) Leading hadrons Medium Physics with the full TOF

12. Proposal In, Construction Starting

13. p e m Poor man’s open heavy flavor measurements Electrons: EMC: pT>2 GeV/c TOF+TPC: 0.2<pT<4 Muon: TOF+TPC: pT~=0.2 Kp: Combinatoric Kpreconstruction

14. The Heavy Flavor Tracker • Direct Topological reconstruction of Charm • Detect charm decays with small ct, i.e. D0 K  • New physics • Charm collectivity and flow to test thermalization at RHIC • Charm Energy Loss to test pQCD in a hot and dense • Aiming for CD1 in Fall Thin 50 m Si pixels reduce limitations imposed by MCS and give 10 mm space point resolution See Flemming’s talk later

15. Probe at RHIC via parity violating W± production and decay. Flavor structure of the polarized proton sea Polarized PDFs only weakly constrained by fixed target data Flavor separation possible via identification of W’s charge Experimental signature: high pT lepton from W decay: For √s=500 GeV p+p collisions. The quark is usually a valence quark large x   Need forward tracking

16. 6 triple-GEM disks covering 1 <  < 2 outer radius ~ 40 cm inner radius varies with z position W charge sign reconstruction prob. >80% for 30 GeV pT over full EEMC acceptance and vertex spread ( >90% out to η= 1.8) Probability to get the correct charge sign Forward GEM Tracker (FGT) See Bernd’s talk later

17. Current upgrade timeline 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 HFT complete full topological PID for c, b mesons DOE investment : upper limit of range ~ $14.7M 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

18. Ideas in germination

19. Photon converter gg HBT for direct photons Muon Telescope Detector J/y trigger GEM Calibration High pT resolution Reaction Plane Detector Improved resolution for v2 measurements Online trigger tracking Triggering and data reduction Ideas in Germination

20. Direct gs: Produced in all stages of collision. Emitted without re-scattering Directly sensitive to T evolution Swamped by p0 decay bkgrd. Direct g HBT Simulations show that a real measurement is possible in STAR with minimum addition (converter). However HBT correlations only exist between direct photons. Correlation peak gives direct photon yield down to low pT Importantly, HBT gives information on temperature vs. size development through all stages of collision! Simulation: Central Au-Au Analysis challenging

21. The photon converter 10% radiation length Pb photon converter at R~43 cm (inside TPC) Converter retractable so that for most of the run it would not interfere with tracking in |h|<1 region. Analysis effic. improved, especially at low relative momentum. Reconstruct one g via converter and other in BEMC Run with DAQ1000 to measure gg HBT at low pT.

22. 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-

23. 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)

24. 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 A BNL 2007 LDRD project Full Hijing AuAu event

25. pT > 2 GeV/c STAR Preliminary pT (GeV/c) z (cm) Performance in STAR Data p m pT (GeV/c) Simulations z (cm) • z distribution of matched MTD hits has two components: • narrow (m) and broad (hadron) ones • from data: pT>2 GeV/c, (z) of muon: ~10 cm • from simu: pT=2.5 GeV/c, (z) of muon: ~9 cm • hadron rejection: 200-300 (via track matching) • time resolution: 300 ps  Improve our electronics for full scale detector

26. Can we understand the distortion at high luminosity and maintain the momentum resolution? Can we analyze all the data from DAQ1000 effectively? Can we improve our reaction plane, especially at low energies? Novel “Problems” just around the corner

27. GEM alignment detector • As luminosity increases the TPC distortions due to residual charge in chamber increase. • Resolution  • Focus on high pT  • Vital that we can correct for these distortions on track-by-track basis • Capitalize on GEM technology and readout developed for FGT and place a few detectors outside of TPC radius • Measure precise points (~100 mm) on tracks at outer radius of TPC in strategic locations to provide a strong constraint on the space charge distortion corrections.

28. DAQ1000, 12 weeks, 50% data-time, 1000Hz: 3.63 billion events, how to handle???? Central 0-5%: pT>4 GeV/c, (h++h-) raw yield: 6.52e-02 per event, 236M evts pT>5 GeV/c, (h++h-) raw yield: 1.37e-02 per event, 50M evts pT>6 GeV/c, (h++h-) raw yield: 4.15e-03 per event, 15M evts p+p: pT>4 GeV/c, (h++h-) raw yield: 3.10e-04 per event, 1.13M evts pT>5 GeV/c, (h++h-) raw yield: 6.52e-05 per event, 237K evts pT>6 GeV/c, (h++h-) raw yield: 1.97e-05 per event, 72K evts Online tracking for high pT charged hadron Needs ~20% primary track momentum resolution at 5 GeV/c EMC and GEM Patches for calibration online?

29. Dielectron and background rates for TPC+TOF+EMC+Online Events needed could be reduced from ~1billion to <100 million Using seeds from EMC+TOF reduces tracks from 1000s to a few Seeds from EMC+TOF for Dilepton tracking EMC EMC MTD could provide dimuon seeds At least 10% dE/dx resolution ~150ps TOF calibration Both ideas need further exploration!

30. Forward ToF detector MRPC ToF rings at forward rapidity 2.75<|η|<3.75 128 MRPC modules located at z = ±6.5m. Granularity to provide good estimate of the reaction-plane even in U+U collisions. PID forward, tracking from FTPC’s v1 and particle ratios Start-time signal for barrel ToF for low E scan (current VPD may not fire due to small acceptance and low mult. VPD covers only 55% of area in range 4.4<η<4.9) Good background rejection during low E scan

31. On the right path towards an upgraded future