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A Muon Telescope Detector (MTD) for STAR: A new opportunity to build on the outstanding success of the joint U.S.-China collaboration on the STAR TOF project T.Hallman STAR TOF Workshop, April 27- 28, 2009 Hangzhou, China TJH, TOF Workshop Hangzhou April 2009 1 A Muon Telescope Detector (MTD) for STAR Outline: • Motivation and introduction • Simulation • The R&D results for the MTD • Performance of a prototype MTD at STAR • Physics perspectives with full coverage • Conclusions TJH, TOF Workshop Hangzhou April 2009 2 S. Bass Physics Goals at RHIC LGT IdentifyCYM and& study the properties of matter with partonic degrees of freedom (flavor, color, sound, temperature …) hadronization PCM & clust. Penetrating probes Bulk NFD probes NFD & hadronic TM - “jets” and heavy flavor Electromagnetic probes: - v2 partonic collectivity TM hadronicratios. string - spectra at low pT&, particle PCM & hadronic TM (,e+e-) chiral symmetry - vector meson properties - thermal dileptons and photons TQGP - quarkonia (J/e+e-) color screening TJH, TOF Workshop Hangzhou April 2009 restoration 3 What has been discovered so far: T ~ 200-400 MeV, i 30-60 0 examined in the laboratory The hottest, densest matter yet It is highly opaque to colored probes– quarks and gluons – but not to photons S 4 3T s It flows as a relativistic quantum liquid with minimal shear viscosity Pedestal&flow subtracted It produces copious mesons and baryons with yield ratios and flow properties that suggest their formation via coalescence of valence quarks from a hot thermal bath. figure by D. d’Enterria S = sound attenuation length FluidQuasiParticlesHadrons (~ mean free path) Evidence for fluid breaking up into quasiFor reasonable T (~ 2TC ) and particles with quantum numbers of quarks (~ 1 fm/c) data suggest /s << 0.3 before hadrons These observations prove that a new state of matter has been created TJH, TOF Workshop Hangzhou April 2009 4 A next big step for RHIC: • Discovering the spectra and dynamics in the charm sector: – One major upgrade with this physics as a prime focus is the STAR Heavy Flavor Tracker – A new modest upgrade proposed in addition is a Muon Telescope Detector (MTD) to measure quarkonia and e-μ correlations – Benefits of MTD: • Different signal with different systematics for comparison (no conversions; much less Dalitz contribution) • Improved invariant mass resolution due to no Bremsstrahlung • New trigger capability unavailable otherwise • Ability to separate lepton pair production from heavy quark decays TJH, TOF Workshop Hangzhou April 2009 5 The next step for STAR 100M central Au+Au D0 + D0, RHIC II Topological PID pileup included STAR Heavy Flavor Tracker (HFT) - 2-layer Active Pixel Sensors: 30 m pitch thickness x/x0 ~ 0.3% per layer 2.5cm inner radius; 200s integration - 1-layer* Si strips - SSD: x/x0 ~ 1% || ≤ 1 pT > 0.5 GeV/c: e, D0,±,s,*, c , B… D-D correlation functions TJH, TOF Workshop Hangzhou April 2009 6 Another new STAR direction: di-muon study of quarkonia Quarkonium dissociation temperatures – Digal, Karsch, Satz The temperature at which various resonances dissociate is a matter of debate, A large area of muon telescope detector (MTD) at midBut there no debate rapidity, allows for theisdetection of: that different binding will lead to different dissociation +- patterns which can be used to study color screening in the medium • 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 their 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 The , ’, ’’ should behave differently than the J/ • (1S) no melting at RHIC standard candle • (2S) likely to melt at RHIC (analog J/) • (3S) melts at RHIC (analog ’) Features • co-mover absorption small • recombination negligible at RHIC TJH, TOF Workshop Hangzhou April 2009 7 The basic idea: an MRPC with long strips Long MRPC Technology with doubleend readout 256 mm Time Resolution (ps) Efficiency (%) 950 mm 25 mm HV: 6.3 KV gas mixture: 95% Freon + 5% isobutane time resolution: ~ 60 ps spatial resolution: ~ 1cm efficiency: > 95% Y. Sun et al., nucl-ex/0805.2459; NIMA 593, 430 (2008) TJH, TOF Workshop Hangzhou April 2009 8 The STAR Detector MRPC ToF barrel MTD (BNL LDRD) EMC barrel EMC End Cap 75% for run 9 RPSD FMS FPD TPC PMD Complete Ongoing DAQ1000 Take data HFT: R&D FGT TJH, TOF Workshop Hangzhou April 2009 R&D 9 Concept of Design Efficiency for detecting muons (top) and hadrons (bottom) after the STAR return steel A pseudo 2 detector with scintillator covering the whole iron bars, leaving the gaps in-between Basic strategy: detect charged56.6% particles which do not range out in the return uncovered. Geometric Acceptance: at ||<0.8 steeldetection of the STAR magnet, tracks inefficiency: the STAR0.5-1% TPC match 1. muon efficiency: ~45%,whose pion detection at pT>2 within GeV/c 400 ps with the hit position in a multi-gap resistive plate chamber having long longitudinal 2. muon-to-pion enhancement factor: 50-100 within MTD geometric acceptance strips read out on both ends 3. muon-to-hadron enhancement factor: 100-1000 including track matching, TOF and dE/dx 4.This dimuontogether trigger enhancement factor will fromgreatly online trigger: 10-50our capability for J/ and with DAQ1000 enhance TJH, TOF April 2009 other dilepton studies at RHIC II Workshop and aHangzhou possible future electron-ion collider 10 Simulation: J/ efficiency with full MTD J/ efficiency J/ efficiency acceptance STAR A pseudo 2 detector with scintillator covering the whole iron bars and left the gaps in-between uncovered. Acceptance: 56.6% at || < 0.8 1. J/ efficiency acceptance: > 1% at low pT, ~ 10% at high pT TJH, TOF Workshop Hangzhou April 2009 11 Novel & Compact Muon Detector • Novel and compact -------- Concept timing, position track segments + fastHits • Muon is a penetrating probe → affords (complementary) J/ trigger, separates +- 1s, 2s, 3s states • Useful for RHIC II and possible Electron Ion Collider (EIC)) • Works with accelerator high luminosity upgrades • R & D needed to address: spatial and time resolution, muon identification capability, trigger capability and hadron rejection power TJH, TOF Workshop Hangzhou April 2009 12 Fermi Lab Beam Test Setup (T963 May 2-15 2007) 449” 252” 73” 72” 191” 81 45 C1, C2 70” 164” 33 TOF2 MRPC1&2 MWPC2 MWPC5 MWPC1 MWPC3 TOF1 TOF3 11” GEMs MWPC4 Upper stream Down stream TOF1 AND Trigger, common start TOF2 Test the performance of two long MRPC modules under different working conditions. Comprehensive scans on HV, gas mixture, position, beam energy, etc … (T963 spokesman: Zhangbu Xu) TJH, TOF Workshop Hangzhou April 2009 13 Beam Test Results 100 90 500 Tracking position vs mean time position Timing Resolution (ps) USTC Tsinghua module as trigger 80 400 300 Scintillator as trigger 70 200 60 Single charged particle efficiency (%) 100 50 36 40 44 48 52 40 E (kV/cm) 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 45 50 55 E (kV/cm) Tracking position vs mean time position TOF Workshop Hangzhou April 2009 Y. Sun et al., nucl-ex/0805.2459;TJH, NIMA 593, 430 (2008) σ = 0.6 cm 14 STAR-MTD in Year 2007 and 2008 collision system Interaction rate trigger rate Sampled L events matched hits Au+Au 20 k 0.5-2 Hz 270 b-1 0.31 M 7k d+Au 100 k 0.5-2 Hz 29 nb-1 1.60 M 78 k p+p 300 k 0.5-2 Hz 404 nb-1 0.56 M 8k • iron bars as hadron absorber • 403 cm away from TPC center, || < 0.25 • gas: 95% Freon and 5% iso-butane; HV: 6.3 KV TJH, TOF Workshop Hangzhou April 2009 15 Performance of an MTD prototype at STAR Comparison of hit position from tracking vs mean time in MTD • MTD hits: matched with real high pT tracks • z distribution has two components: narrow (muon) and broad (hadron) ones • spatial resolution (narrow Gaussian) is ~10 cm at pT > 2 GeV • narrow to broad ratio is ~2; can be improved with dE/dx and TOF cut Azimuthal location and transverse momenta for hits matched between the MTD and TPC tracks • are the particles in the narrow Gaussian muons? Location of prototype MTD tray in azimuth TJH, TOF Workshop Hangzhou April 2009 16 Compared to Simulation Expected spatial resolution for matched hits (TPC and MTD) from simulation muons pT (GeV/c) muons 20 pions 10 z (cm) 0 20 40 60 80 Δz (cm) From data: pT > 2 GeV/c, (z) of muon: ~10 cm From simulation: pT = 2.5 GeV/c, (z) of muon: ~9 cm Data and simulation show consistent results TJH, TOF Workshop Hangzhou April 2009 17 100 TPC – TOF position match window Muon Identification: Cut on TPC dE/dx STAR Preliminary STAR Preliminary The trick: |z|<20 At pT > 2 GeV/c the dE/dx for a μ in the TPC is 3-4 % (0.5 σ) higher than for a (about 2σ different Signal Background Total than a Kaon) Number of σ away from pion dE/dx in TPC for TPC tracks matched with MTD hits STAR Preliminary n<-1 So by cutting on the nσ --the STAR Preliminary difference in σ from the dE/dx expected for a pion track we can discriminate against , K background n>0 and K muon secondaries reduced by dE/dx cut in TPC • The narrow Gaussian distribution: dominated by muons TJH, TOF Workshop Hangzhou April 2009 18 TPC – TOF position match window Muon Identification: Cut on High Velocity and dE/dx STAR Preliminary STAR Preliminary The trick: What is measured in the TPC is momentum ( p = mv ) TPC – TOF position match window For a given momentum > vTOF By requiring velocity comparison in vTPC consistent with μ hypothesis, i.e. muonand pion >IsvKaon Muon , K 1/trackhits- 1/rawhits >0 And cutting on TPC dE/dx So if a , K momentum is assigned to a μ candidate, 1/βtrackhits - 1/βTOF< 0 n>0 STAR Preliminary STAR Preliminary STAR Preliminary Number of σ away from pion dE/dx in TPC for TPC tracks matched with MTD hits • the narrow Gaussian distribution: dominated by muons TJH, TOF Workshop Hangzhou April 2009 19 Using EMC Information to check how well hadrons showers are rejected by MTD hits The fraction of TPC tracks which match with a non zero EMC energy (> MIP) pT (GeV/c) EMC & non-MTD (A) (%) EMC & MTD (B) (%) 1.5-2 2.21 0.03 0.18 0.02 2-3 3.67 0.07 0.30 0.04 3-4 5.89 0.22 0.34 0.10 4-6 7.92 0.50 0.65 0.24 • B is a factor of 10 smaller than A. • Composition of hadrons is reduced from ~100% to ~10%; • Muons (prompt and hadron decays) increase from ~0 to ~90%. Requiring MTD hit rejects hadrons showers by a factor of ~ 10 • The narrow Gaussian is indeed dominated by muons: pion/kaon decay before the EMC TJH, TOF Workshop Hangzhou April 2009 20 Contributions to the inclusive muon yield K0short with both ’s in TPC out of MTD acceptance K0short with one in TPC in MTD acceptance By selecting a pion in the TPC which pairs correctly with a second pion for the K0short → + - hypothesis we create a “calibrated” pion beam that can be used to determine the percentage of muon candidates with MTD hits that come from secondary pion decays. The answer is about 30-40% By comparing the total inclusive muon signal to the previously measure yield for non-photonic electrons we can estimate how much of the inclusive muons signal is due to prompt muons vs secondary decays. the answer is the primary muons are about 6-10% of the total inclusive Pion contribution to muon (background): 30-40% Others from kaon (background): dominant contributor Primary muon (signal):6-10% With dE/dx cut, the S/B ratio is enhanced by a factor of 3. TJH, TOF Workshop Hangzhou April 2009 21 Physics Perspectives with Full Coverage 1. J/: S/B=7 in d+Au and S/B = 2 in central Au+Au 2. e correlation from ccbar: S/B = 2 (Meu> 3 GeV/c2 and pT(e) < 2 GeV/c) S/B = 8 with electron pairing and TOF association TJH, TOF Workshop Hangzhou April 2009 22 Position expected from MTD vs VPD timing Trigger Capability with Full Coverage collision system L0 rate reduction 0-80% Au+Au 0.19 0-5% Au+Au 0.53 60-80% Au+Au 0.03 d+Au 0.02 p+p 0.01 L2 reduction with TOF RHIC II luminosity (Hz) di-muon L2 rate ~ 0.3 100k ~ 500 (100) 0.003 2M 10 Position resolution available at the trigger level Estimate from projection σ~ 6 cm With TOF hit association, TJH, theTOFdi-muon L2 April reduction is 1/8 in central Au+Au Workshop Hangzhou 2009 23 Summary and Future Plan • Cosmic and beam tests: intrinsic timing resolution of long MRPC: ~60-70 ps spatial resolution: ~1 cm • The prototype of MTD works at STAR. ---- clear narrow muon peak ---- Muon purity can be achieved >80% • The primary muon over secondary muon ratio is good for quarkonium program • The trigger capability with L0 and L2 is promising for dimuon program: Upsion, J/ elliptic flow v2 and RAA at high pT One Final Comment… TJH, TOF Workshop Hangzhou April 2009 24 Chinese PHD Graduates at STAR • • • • • • • • • • • • • Shengli Huang, University of Science and Technology of China - USTC Hard and Soft Interactions in 200 GeV Proton-Proton Collisions Ph.D. thesis, 2004 R&D Work on MRPC cosmic ray test Lijuan Ruan, University of Science and Technology of China - USTC Pion, Kaon, Proton and Antiproton Spectra in d+Au and p+p Collisions at sqrt(sNN) = 200 GeV at the Relativistic Heavy Ion Collider Ph.D. thesis, 2004 First MRPC TOF results in the world (not just STAR) (Goldhaber Fellow) Xin Dong, University of Science and Technology of China - USTC Single Electron Transverse Momentum and Azimuthal Anisotropy Distributions: Charm Hadron Production at RHIC Ph.D. thesis, 2005 First non-photonic electron from Heavy-flavor using TPC+TOF electron PID (2005年度中国科学院院长特别奖) Zhixu Liu, Institute of Particle Physics Proton and Anti-Proton Production at mid-Rapidity from Au+Au Collisions at sqrt(sNN) = 200 GeV Ph.D. thesis, 2005 Work on Time-of-Flight Patch at STAR Guoliang Ma, Shanghai Institute of Applied Physics – SINAP f production Ph.D. thesis, 2006 (2006年度中国科学院院长奖) Yifei Zhang, University of Science and Technology of China - USTC Measurement of charm production cross-section and leptons from its semileptonic decay at RHIC Ph.D. thesis, 2007 TOF data in Au+Au collisions Haidong Liu, University of Science and Technology of China - USTC Production of meson, baryon and light nuclei (A=2,3): investigating freeze-out dynamics and roles of energetic quarks and gluons in Au+Au collisions at RHIC Ph.D. thesis, 2007 TOF data in Au+Au collisions Xiaoyan Lin, Institute of Particle Physics Non-Photonic Electron Angular Correlations with Charged Hadrons from the STAR Experiment: First Measurement of Bottom Contribution to Non-Photonic Electrons at RHIC Ph.D. thesis, 2007 Yan Lu, Institute of Particle Physics Centrality dependence of K_S and Lambda elliptic flow in Au+Au collisions at sqrt(s_NN)=200 GeV Ph.D. thesis, 2007 Aoqi Feng, Institute of Particle Physics Jinghua Di-hadron Azimuthal Correlations Relative to ReactionFu Plane in Au + Au Collisions at sNN = 200 GeV Ph.D. thesis, 2008 (IOPP/Tsinghua U.): Xiangming Sun, Lawrence Berkeley National Laboratory TopElectronics 100 for Heavy Flavor Tracker Statistical Model in Heavy Ion Collisions2005 and Readout Ph.D. thesis, 2008 Thesis in China Award Jinhui Chen, Shanghai Institute of Applied Physics – SINAP f production and v2 Ph.D. thesis, 2007 Jinghua Fu, IOPP, Wuhan, Ph.D. Thesis 2005 TJH, TOF Workshop Hangzhou April 2009 25 In conjunction with the STAR TOF project, 13 outstanding students have already received PhD’s on STAR research and have produced world class scientific results in the process Let’s continue this marvelous success story with further fruitful US-China collaboration on the next generation of detector instrumentation and scientific analyses on STAR Xin Dong (USTC): CAS Early Career Scientist Award Proposal for a Novel and Compact Muon Telescope Detector • • Submit it to Nucl. Phys. A for publication in two weeks. Expand it into a MTD proposal: Brookhaven National Laboratory Ken Asselta, Bill Christie, Lijuan Ruan, John Scheblein, Robert Soja, Zhangbu Xu University of California, Berkeley Hank Crawford, Jack Engelage Rice University Geary Eppley, Bill Llope, Ted Nussbaum University of Science and Technology of China Hongfang Chen, Cheng Li, Yongjie Sun, Zebo Tang Shanghai Institute of Applied Physics Xiang-Zhou Cai, Fu Jin, Yu-Gang Ma, Chen Zhong Texas A&M University Saskia Mioduszewski University of Texas -- Austin Jerry Hoffmann, Jo Schambach Tsinghua University Yi Wang, Xiaobin Wang Yale University TJH,Guoji TOF Workshop Hangzhou April 2009 Lin, Richard Majka 26 Towards the Future at STAR • • To install another tray with TOF electronics in run9 Collaborators for a proposal of full scale detector: 56.6% in azimuth, |eta|<0.8; current module design: 360 modules, 1440 read-out strips, 2880 readout channels; electronics expense: 400 k + 300 k $. • Based on Au+Au run7, L0 trigger for single hit: 0.19 per vpd-mb events in Au+Au collisions with full coverage. Online trigger enhancement for dimuon: 28. 1 billion MB Au+Au events : 60 M MTD triggered dimuon events: J/+-: 43.8*10-9/0.040*109*292*0.07*0.32*1.6*0.5=5600 +-: 91*1012/0.040*109*292*0.5*0.32*1.6*0.5=85 • • RHICII Lumonisinty: 20 nb-1 Au+Au and 360 pb-1 p+p run: p+p: J/+-: 43.8*10-9 *360*1012 *0.07*0.32*1.6*0.3=169 K +-: 91*10-12*360*1012 *0.5*0.32*1.6*0.3=2500 Au+Au: J/+- (630 K) +- (9300) TJH, TOF Workshop Hangzhou April 2009 27 Novel & Compact Muon Detector for QCDLab • Novel and compact -------Convention timing, position track segments + fastHits • QCDLab (RHIC II, eRHIC) • Works with accelerator high luminosity upgrades • Muon is penetrating probe J/ trigger, separate +- states; vector meson; thermal dileptons … TJH, TOF Workshop Hangzhou April 2009 28