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. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 STAR’s detector upgrades MRPC ToF barrel Ready for run 10 RPSD PMD FPD FMSFMS EMC barrel EMC End Cap DAQ1000 Ready for run 9 HFT; FGT: GEM-layers finished ongoing MTD R&D 1.Preserve large acceptance 2.Extend forward coverage 3.Particle Identification 4.Precise Secondary Vertex 5.Leptons/photons 6.Faster DAQ 7.Cost-effective, do it best 2

3. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 PMD STAR’s coverage 3 Photon capability from none to 4 

4. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Aim to keep the discoveries rolling …  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 p T  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 Underway R&D/Proposals More ideas 4

5. Ready for Run 9/10 5

6. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 DAQ 1000 - TPC FEE and DAQ upgrades 6  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 TPC is now a fast detector!!! blue pen PASAsALTROs brown ruler FPGAs Fiber Out via SIU FEE In

7. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 1/17/2008 Laser event (plus pileup) Data from DAQ1000 sector look good TPX dE/dx from TOF+TPX events DAQ1K at 1000Hz, 5—7% deadtime Commissioning in run 8 7

8. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 PID plays crucial roles at RHIC 8 200 GeV Au+Au STAR Preliminary

9. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Multi-gap Resistive Plate Chamber Time-of-Flight State-of-art MRPC: -0.9<  <0.9, 0<  <2 , r=220cm 6 gaps, 3x6cm 2 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

10. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Improving the “Time” in Time-of-Flight Run8: 76M pp events TOF+TPX 2001: No timing devices (except Time Projection Chamber) 2002: BBC (~1ns), ZDC (200ps) 2002-2008: TOF tray+VPD (<100ps) 2008-: finally TOF  t: 81ps 10

11. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Physics with the full TOF  Hadron and lepton PID at mid- rapidity – (Energy scan)  Identified p/  at high p T  Jet-related PID spectra & correlations  Fluctuation K/ , p/  – (Critical point)  Resonances ( , ,J/  ) hadronic and dilepton decay channels  Open Charm (daughter PID) Leading hadrons Medium 11

12. 12 Proposal In, Construction Starting

13. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Poor man’s open heavy flavor measurements 13  e  Electrons: EMC: pT>2 GeV/c TOF+TPC: 0.2<pT<4 Muon: TOF+TPC: pT~=0.2 K  : Combinatoric K  reconstruction

14. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 The Heavy Flavor Tracker 14 Thin 50  m Si pixels reduce limitations imposed by MCS and give 10  m space point resolution See Flemming’s talk later  Direct Topological reconstruction of Charm  Detect charm decays with small c , i.e. D 0  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

15. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Flavor structure of the polarized proton sea 15 Probe at RHIC via parity violating W ± production and decay. Experimental signature: high p T lepton from W decay: For √s=500 GeV p+p collisions. The quark is usually a valence quark large x Polarized PDFs only weakly constrained by fixed target data  Flavor separation possible via identification of W’s charge  Need forward tracking

16. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Forward GEM Tracker (FGT)  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 p T over full EEMC acceptance and vertex spread ( >90% out to η= 1.8) Probability to get the correct charge sign See Bernd’s talk later 16

17. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Current upgrade timeline 17 Run08Run10Run09Run12Run11Run13Run15Run14 FMS complete: d+Au and p+p data from Run 8 DAQ1000 complete Immediate improvement of 300% in sampled luminosity for rare probes (e.g. jets in p+p) Increase in Au+Au luminosity to 50 x 10 27 cm -2 sec -1 U+U available from EBIS DOE investment ~ $7M HFT partial implementation HFT complete full topological PID for c, b mesons DOE investment : upper limit of range ~ $14.7M Planned LHC 1 st heavy ion run DOE investment ~ $400k DOE investment ~ $1900k 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 FGT complete: Accurate charge sign determination for W’s, DOE investment ~ $1900k

18. Ideas in germination 18

19. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Ideas in Germination 19  Photon converter   HBT for direct photons  Muon Telescope Detector  J/  trigger  GEM Calibration  High p T resolution  Reaction Plane Detector  Improved resolution for v 2 measurements  Online trigger tracking  Triggering and data reduction

20. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Direct  HBT 20 Direct  s:  Produced in all stages of collision.  Emitted without re-scattering  Directly sensitive to T evolution  Swamped by  0 decay bkgrd. Simulation: Central Au-Au Analysis challenging However HBT correlations only exist between direct photons. Correlation peak gives direct photon yield down to low p T Importantly, HBT gives information on temperature vs. size development through all stages of collision! Simulations show that a real measurement is possible in STAR with minimum addition (converter).

21. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 The photon converter 21 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 |  |<1 region. Analysis effic. improved, especially at low relative momentum. Reconstruct one  via converter and other in BEMC Run with DAQ1000 to measure  HBT at low p T.

22. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Improving STAR’s muon capabilities 22 Simulations 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  conversion, Less Dalitz decay, Less radiative losses to detector material  +  -  e + e -

23. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 The Muon Trigger Detector concept 23 Prototype Installed in RUN 7-8 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  m time resolution: ~60 ps spatial resolution: ~1cm 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. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Hadron Rejection and Muon Trigger 24 Iron bars 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 A BNL 2007 LDRD project J/  trigger, separate  +  - states Full Hijing AuAu event

25. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Performance in STAR 25  z distribution of matched MTD hits has two components: narrow (  ) and broad (hadron) ones from data: p T >2 GeV/c,  (  z) of muon: ~10 cm from simu: p T =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 p T > 2 GeV/c STAR Preliminary p T (GeV/c)  z (cm) Simulations   Data  z (cm) p T (GeV/c)

26. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Novel “Problems” just around the corner 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?

27. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 GEM alignment detector 27 As luminosity increases the TPC distortions due to residual charge in chamber increase. As luminosity increases the TPC distortions due to residual charge in chamber increase. Resolution  Resolution  Focus on high p T  Focus on high p T  Vital that we can correct for these distortions on track-by-track basis 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 Capitalize on GEM technology and readout developed for FGT and place a few detectors outside of TPC radius Measure precise points (~100  m) on tracks at outer radius of TPC in strategic locations to provide a strong constraint on the space charge distortion corrections. Measure precise points (~100  m) on tracks at outer radius of TPC in strategic locations to provide a strong constraint on the space charge distortion corrections.

28. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Online tracking for high p T charged hadron 28 DAQ1000, 12 weeks, 50% data-time, 1000Hz: 3.63 billion events, how to handle???? Central 0-5%: p T >4 GeV/c, (h + +h - ) raw yield: 6.52e -02 per event, 236M evts p T >5 GeV/c, (h + +h - ) raw yield: 1.37e -02 per event, 50M evts p T >6 GeV/c, (h + +h - ) raw yield: 4.15e -03 per event, 15M evts p+p: p T >4 GeV/c, (h + +h - ) raw yield: 3.10e -04 per event, 1.13M evts p T >5 GeV/c, (h + +h - ) raw yield: 6.52e -05 per event, 237K evts p T >6 GeV/c, (h + +h - ) raw yield: 1.97e -05 per event, 72K evts Needs ~20% primary track momentum resolution at 5 GeV/c EMC and GEM Patches for calibration online?

29. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Seeds from EMC+TOF for Dilepton tracking 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 Pt (GeV/c)Electron per event Rejection factor >1.00.3110 >1.50.06278 >2.00.0164000 EMC At least 10% dE/dx resolution ~150ps TOF calibration MTD could provide dimuon seeds Both ideas need further exploration!

30. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 Forward ToF detector 30 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 v 1 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. Helen Caines – RHIC/AGS Users Meeting - RHIC Prospects – May 2008 On the right path towards an upgraded future 31