1. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)1 STAR MTD: Physics Motivation, R&D Results and Requirements Outline: Physics motivation with the STAR-MTD Simulation and R&D results Trigger details for the full system Conclusions Lijuan Ruan for STAR-MTD group (Brookhaven National Laboratory) http://www.star.bnl.gov/~ruanlj/MTDreview2010/mtd.htm http://drupal.star.bnl.gov/STAR/system/files/MTD_proposal_v14.pdf

2. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)2 What Have We Learnt So Far at RHIC A hot, dense medium with partonic degrees of freedom created at RHIC: Jet quenching Baryon enhancement, number of constituent quark scaling in elliptic flow … Next: Is the system thermalized and how does the system thermalize? What are the properties of the strongly-coupled system? What is the phase structure of QCD matter? What exotic particles are produced at RHIC? What is the mechanism for partonic energy loss? Does QCD matter demonstrate novel symmetry properties? What is the nature of the initial state in nuclear collisions …

3. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)3 Muons: Penetrating Probes The initial temperature of sQGP; the mass origin of hadrons; color screening features of heavy quarkonia … MeasurementsPhysics low mass di-muonsthermal radiation of QGP; in-medium modifications of vector meson (    ), chiral symmetry restoration intermediate mass di-muonsthermal radiation of QGP; heavy flavor modification; resonances in sQGP large mass: heavy quarkoniaT of QGP, color screening, quarkonium production mechanism

4. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)4 Charm Contribution to Di-lepton Spectrum NA60, PRL96,162302(2006) PHENIX, PRC81,034911(2010) 1.Charm contribution to di-lepton spectra is significant at low mass at RHIC. 2.Charm contribution to di-lepton spectra might be dominant in the intermediate mass region. Its correlation makes a big difference to access the thermal radiation contribution from QGP.

5. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)5 Cocktail Simulation in 200 GeV p+p at STAR Particle spectra from data were fit with Tsallis function, and were used as an input to full GSTAR simulation to generate e+e- invariant mass cocktail. Same cuts were applied in simulation as in data. Z. Tang et al., PRC 79,051901(R)(2009); M. Shao et al., J. Phys. G: Nucl. Part. Phys. 37 (2010) 085104 STAR: π , K S, K*, , ρ PHENIX: η, ω, J/  ccbar: star measured cross section as input; STAR Collaboration, PRL94(2005)062301 bbar/ccbar ratio from PYTHIA

6. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)6 STAR-MTD Physics Motivation A 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, possible correlations of quarks and gluons as 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 trigger capability for low to high pT J/  in central Au+Au collsions excellent mass resolution, separate different upsilon states e-muon correlation to distinguish heavy flavor production from initial lepton pair production

7. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)7 Concept of Design of the STAR-MTD A detector with long-MRPCs covers the whole iron bars and leave the gaps in- between uncovered. Acceptance: 45% at |  |<0.5 118 modules, 1416 readout strips, 2832 readout channels Long-MRPC detector technology, HPTDC electronics (same as STAR-TOF)

8. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)8 Single Muon and J/  Efficiency J/  efficiency 1.muon efficiency at |η| 2 GeV/c 2.muon-to-pion enhancement factor: 50-100 3.muon-to-hadron enhancement factor: 100-1000 including track matching, tof and dE/dx 4.dimuon trigger enhancement factor from online trigger: 40-200 in central Au+Au collisions G. Lin, Yale Univ.

9. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)9 Comments on Simulations SimulationsConditions Efficiency of single muon and J/  Include TPC tracking efficiency, MTD acceptance, matching between TPC and MTD J/  and  signal versus background J/ ,  R AA, v 2 projection µ-e correlations Signal from STAR measurements; Inclusive muons: reconstructed from prototype performance from Runs 7-8, track matching included, tof cut is not applied

10. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)10 High Mass Di-muon Capabilities 1.J/  : S/B=6 in d+Au and S/B=2 in central Au+Au 2.With HFT, study B  J/  X; J/    using displaced vertices 3.Excellent mass resolution: separate different upsilon states Heavy flavor collectivity and color screening, quarkonia production mechanisms: J/  R AA and v 2 ; upsilon R AA … Quarkonium dissociation temperatures – Digal, Karsch, Satz Z. Xu, BNL LDRD 07-007; L. Ruan et al., Journal of Physics G: Nucl. Part. Phys. 36 (2009) 095001

11. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)11 Υ Future Measurement Projection J/  R AA and v 2 ; Υ R AA versus N part … J/  Z. Tang, USTC

12. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)12 Upsilon Statistics Using MTD at |y|<0.5 Delivered luminosity: 2013 projected; Sampled luminosity: from STAR operation performance Upsilon in 500 GeV p+p collisions can also be measured with good precision. Collision system Delivered lumi. 12 weeks Sampled lumi. 12 weeks (70%) Υ countsMin. lumi. precision on Υ (3s) (10%) Min. lumi. precision on Υ (2s+3s) (10%) 200 GeV p+p 200 pb -1 140 pb -1 390420 pb -1 140 pb -1 500 GeV p+p 1200 pb -1 840 pb -1 6970140 pb -1 50 pb -1 200 GeV Au+Au 22 nb -1 16 nb -1 177010 nb -1 3.8 nb -1

13. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)13 High luminosity for Υ & J/  from e + e - STAR high p T J/ 

14. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)14 Compared to Υ  e + e - with HFT Material budget with HFT similar to that at year 2004 With HFT, it’s hard to separate different upsilon states; e + e - channel samples collisions of |v z |<5 cm; can not sample full luminosity due to more material at |v z |>5 cm

15. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)15 Distinguish Heavy Flavor and Initial Lepton Pair Production: e-muon Correlation e  correlation simulation with Muon Telescope Detector at STAR from ccbar: S/B=2 (M eu >3 GeV/c 2 and p T (e  )<2 GeV/c) S/B=8 with electron pairing and tof association MTD: construction starts in FY2011; project completion in FY2014 Z. Xu, BNL LDRD 07-007; L. Ruan et al., Journal of Physics G: Nucl. Part. Phys. 36 (2009) 095001 NA60, PRL100,022302(2008) R. Rapp, hep-ph/0010101

16. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)16 The details for the R&D modules ConditionsModules and readout Cosmic ray and Fermi-lab T963 beam testsdouble stacks, module size: 87(z)  17(  ) cm 2, Performance: 60 ps, ~0.6 cm at HV  6.3 kV Run 7: Au+Au Run 8: p+p, d+Au double stacks, 2 modules in a tray, module size: 87(z)  17(  ) cm 2, Readout: trigger electronics, Time resolution: 300 ps Run 9: p+p Run 10: Au+Au, cosmic ray double stacks, 3 modules in a tray, module size: 87(z)  17(  ) cm 2, Readout: TOF electronics; trigger electronics for trigger purpose. Run 11single stack, 1 module in a tray, module size: 87(z)  52(  ) cm 2, Readout: TOF electronics; trigger electronics for trigger purpose, Cosmic ray test performance: <100 ps

17. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)17 The R&D Results for the MTD Long MRPC Technology with double-end readout HV:  6.3 KV gas mixture: 95% Freon + 5% isobutane time resolution: ~60 ps spatial resolution: ~1cm efficiency: >95% 950 mm 256 mm 25 mm Y. Sun et al., nucl-ex/0805.2459; NIMA 593, 430 (2008)

18. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)18 HV:  6.3 KV gas mixture: 95% Freon + 5% isobutane time resolution: ~60-70 ps spatial resolution: ~0.6-1cm efficiency: >95% consistent with cosmic test results Y. Sun et al., NIMA 593, 430 (2008) Fermi Lab Beam Test Results (T963 May 2-15 2007) T963 spokesperson: Z. Xu

19. 03/30/201119 Run 10 Performance: Time and Spatial Resolution MTD workshop at USTC, Lijuan Ruan (BNL) Cosmic ray trigger (Z. Xu) Total resolution: 109 ps Start resolution (2 TOF hits): 46 ps Multiple scattering: 25 ps MTD intrinsic resolution: 96 ps System spatial resolution: 2.5 cm, dominated by multiple scattering L. Li, UT Austin σ: 109 ps σ: 2.5 cm pure muons average p T : ~6 GeV/c

20. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)20 Trigger Capability with MTD Acceptance RHIC II lumonisity in terms of collision rate: 40 k Hz; Au+Au projection: based on Run 10 prototype performance. Run10 Au+Au B. Huang, USTC L0 trigger timing resolution (assumed) di-muon trigger efficiency of the timing cut 140 ps  3.6σ (100%) 200 ps  2.5σ (98%) 300 ps  1.7σ (80%) 1 ns trigger window: 80 Hz for dimuon trigger

21. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)21 MTD Trigger System The primary physics goal requires triggering on di-muon events sampling full luminosity. To select muons and reject hadronic showers that punch through the magnet steel, a timing cut will be applied to the MTD signals. Since the MTD pickup strips are ~90 cm in length and readout from both ends, the sum (E+W)/2 will be calculated in the trigger and compared to the collision time. The average arrival time at MTD boxes in different eta region is different due to difference in path length. The occupancy in the MTD is very low, only one east and one west signal is sent to trigger from the 60 strips of 5 MTD boxes in the same eta region at 5 nearby backlegs. This allows for a correction on the arrival time in the high eta region at trigger level. The correction could be larger than 1 ns in the highest eta region.

22. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)22 MTD Trigger System Each 12 strip MRPC is readout by 4 NINO frontend ASICs on a MINO card. Each NINO reads out 6 east ends or 6 west ends. The NINO produces a logic output signal if any of the 6 inputs is above threshold. The 10 NINO signals and the corresponding east/west signals are logically combined by the MTRG card and a single east and west signal is sent to trigger from 5 MTD boxes in the same eta range at the 5 nearby backlegs. Each QT can produce 8 (E+W)/2 sums. 4 QT boards required in all. The QT is currently in use for the STAR trigger system.

23. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)23 MTD System Requirement MTD requirements: Time resolution less than 100 ps, spatial resolution ~ 1 cm. The mechanics design must allow a convenient replacement of individual MTD box and access to the BEMC box. The system must be able to operate in the fringe field from 0.5 Tesla STAR magnet field. The system must operate at low noise rate. The total noise rate should be less than 0.5 M Hz, 1 Hz/cm 2. The system must be safe, meet all BNL safely requirements. The system must not impair the performance of other STAR detectors.

24. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)24 Organization MTD group: Brookhaven National Laboratory: L. Ruan, Z. Xu, K. Asselta, W. Christie, C. D’Agostino, J. Dunlop, J. Landgraf, T. Ljubicic, J. Scheblein, R. Soja, A.H. Tang, T. Ullrich University of California, Berkeley: H.J. Crawford, J. Engelage University of California, Davis: M. Calder′on de la Barca S′anchez, R. Reed, H.D. Liu Rice University: J. Butterworth, G. Eppley, F. Geurts, W.J. Llope, D. McDonald, T. Nussbaum, J. Roberts, K. Xin, L. Bridges University of Science & Technology of China: H.F. Chen, B.C. Huang, C. Li, M. Shao, Y.J. Sun, Z.B. Tang, X.L. Wang, Y.C. Xu, Z.P. Zhang, H. Zeng, Y. Zhou Texas A&M University: Y. Mohammed, S. Mioduszewski University of Texas, Austin: A. Davila, G.W. Hoffmann, L. Li, C. Markert, L. Ray, J. Schambach, D. Thein, M. Wada Tsinghua University: J.P. Chen, K.J. Kang, Y.J. Li, Y. Wang, X.L. Zhu Variable Energy Cyclotron Centre: Z. Ahammed, P.P. Bhaduri, S. Chattopadhyay, A.K. Dubey, M.R. Dutt-Mazumdar, P. Ghosh, S.A. Khan, S. Muhuri, B. Mohanty, T.K. Nayak, S. Pal, R. Singaraju, V. Singhal, P. Tribedy, Y.P. Viyogi

25. Q4 (FY09) Q1-2 (FY10) Q3-4 (FY10) Q1-2 (FY11) Q3-4 (FY11) Q1-2 (FY12) Q3-4 (FY12) Q1-2 (FY13) Q3-4 (FY13) Q1 (FY14) MRPC Module Proposal Design US MTD Constru. Electronics Tray Install/Com mission Physics Data MTD Schedule Finish the project by Mar, 2014 and make 80% of the full system ready for year 2014 run MTD proposal submitted to BNL in Feb. 2010;STAR-MTD review held in Sep. 2010. The project approved in Mar. 2011. Now in the process of setting up charge numbers. 03/30/201125MTD workshop at USTC, Lijuan Ruan (BNL) Design Production

26. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)26 Summary MTD will advance our knowledge of Quark Gluon Plasma: trigger capability for low to high p T J/  in central Au+Au collsions excellent mass resolution, separate different upsilon states e-muon correlation to distinguish heavy flavor production from initial lepton pair production different background contribution provides complementary measurements for dileptons The prototype of MTD works at STAR from Run 7 to Run 10. Results published at L. Ruan et al., Journal of Physics G: Nucl. Part. Phys. 36 (2009) 095001; 0904.3774; Y. Sun et al., NIMA 593 (2008) 430. muon purity>80%; the primary muon over secondary muon ratio: good for quarkonium program the trigger capability with L0 and L2: promising for dimuon program: Upsilon, J/  elliptic flow v 2 and R AA at high p T The larger Run 11 modules with slightly wider readout strips show a comparable performance as the modules in Runs 7-10, based on cosmic ray tests at USTC and Tsinghua.

27. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)27 Backup

28. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)28 STAR-MTD in Year 2007 and 2008 iron bars as hadron absorber 403 cm away from TPC center, |  |<0.25 beam speciesinteraction rate (Hz)trigger rateSampled Leventsmatched hits Au+Au20 k0.5-2 Hz 270  b -1 0.31 M7 k d+Au100 k0.5-2 Hz29 nb -1 1.60 M78 k p+p300 k0.5-2 Hz404 nb -1 0.56 M8 k

29. 03/30/2011MTD workshop at USTC, Lijuan Ruan (BNL)29 Performance of a Prototype at STAR MTD hits: matched with real high p T tracks  z distribution has two components: narrow (muon) and broad (hadron) ones spatial resolution (narrow Gaussian) is ~10 cm at p T >2 GeV narrow to broad ratio is ~2; can be improved with dE/dx and tof cut are the particles in the narrow Gaussian muons?

30. 03/30/201130 Runs 9-10 Prototype Issues from Runs 7-8: Time resolution for the full system: 300 ps Start resolution: 160 ps (start detector with trigger readout) Multiple scattering: 70 ps Intrinsic MTD resolution: 200-300 ps Is this real?  install a prototype with TOF electronics in run9 MTD workshop at USTC, Lijuan Ruan (BNL) Runs 9-10: 3 modules, one tray covered: 87(z)  51(  ) cm 2 18 channels on each side 2 TINO,TDIG, TTRG boards, 1 TCPU board Both ends go to trigger QT