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Physics objectives and performance requirements

Physics objectives and performance requirements. L ijuan Ruan for the STAR Collaboration ( Lawrence Berkeley National Laboratory ). Outline: Performance requirements PID capability Physics objectives Summary. Performance requirements and achievements. Requirements:

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Physics objectives and performance requirements

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  1. Physics objectives and performance requirements LijuanRuan for the STAR Collaboration (Lawrence Berkeley National Laboratory) Outline: • Performance requirements • PID capability • Physics objectives • Summary DOE TOF Review, BNL, September 25, 2006

  2. Performance requirements and achievements Requirements: • Good timing resolution: < 100 ps in Au+Au collisions. • Small occupancy per channel: < 10-15%. • Rate capability: 200 Hz/cm2. • High efficiency: > 90%. • Fit into CTB. • Safe and not impair the performance of other STAR detectors Achievements from the prototype: • 86 ps timing resolution achieved in Au+Au. • 3 cm  6 cm, 120326 read out, large granularity • Rate capability: 500 Hz/cm2 (test beam, CERN) • High efficiency: > 95% • Will benefit from or enhance the performance of other STAR detectors, to be shown later DOE TOF Review, BNL, September 25, 2006

  3. Timing resolution summary • The new method was developed to achieve better resolution, shown in red texts. • New electronics TOT is fine. • No age effect. DOE TOF Review, BNL, September 25, 2006

  4. Hadron/Electron PID capability TPC |1/β-1|<0.03 electrons Clean electron PID can be obtained up to PT < 3 GeV/c.  measure the semileptonic decay of open charm. (STAR Collaboration, PRL94(2005)062301) TOF PID: (, K) ~ 1.6, p ~ 3 GeV/c. rdE/dx PID: (, p) 2.5-12 GeV/c TOF+rdEdx PID: 0.3-5 GeV/c STAR Collaboration, PLB616(2005)8; nucl-ex/0606003. DOE TOF Review, BNL, September 25, 2006

  5. Physics topics from TOF in STAR • Identified hadron spectra • freeze-out dynamics • hadronization mechanism • Identified particle correlations • Chemical and kinetic properties of in-medium jet associated spectra • Fluctuations and correlations • Lepton program • In-medium vector meson properties • Heavy flavor • Baseline detector for future upgrades DOE TOF Review, BNL, September 25, 2006

  6. PID Spectra – Freeze-out dynamics STAR’s strength of measuring many particle species: exp(-(Mi-mB)/Tch) The K(p): pT<0.75(1.1) GeV/c. Resonant and multi-strangeness states have large errors: PID misidentification, efficiency … Chemical freeze-out: distribution of particle species Kinetic freeze-out: momentum spectra DOE TOF Review, BNL, September 25, 2006

  7. 200 GeV Au+Au STAR Preliminary PID physics at intermediate pT • Number of constituent quark (NCQ) • Transition regime 2<pT<5 GeV/c • Multi-strangeness baryons • Heavy Mesons (K*, ) Surprising discoveries at RHIC: Coalescence of quarks? New hadronization mechanism? DOE TOF Review, BNL, September 25, 2006

  8. What can TOF bring – spectra, efficiency, background rejection • Kp pT range (1 < pT < 3 GeV/c), efficiency > 80% •  efficiency x 8 • Resonances x 2--10 • Reject correlated background due to misidentified particles. • Eliminate this systematic error ( 20%) DOE TOF Review, BNL, September 25, 2006

  9. Physics topics from TOF in STAR • Identified hadron spectra • freeze-out dynamics • hadronization mechanism • Identified particle correlations • Chemical and kinetic properties of in-medium jet associated spectra • Fluctuations and correlations • Lepton program • In-medium vector meson properties • Heavy flavor • Baseline detector for future upgrades DOE TOF Review, BNL, September 25, 2006

  10. Jet quenching at RHIC • One of the major discoveries at RHIC • How coalescence works? • Vacuum fragmentation at pT>6 GeV/c? • How jet energy dissipates in the medium? DOE TOF Review, BNL, September 25, 2006

  11. Identified baryon and meson spectra in Au+Au collisions: another publication from TOF prototype • particle spectra up to very high pT = 12 GeV/c. • TOF: pT up to 5 GeV/c,important for coalescence region. STAR: nucl-ex/0606003, accepted by PRL. DOE TOF Review, BNL, September 25, 2006

  12. Leading hadrons Medium Jet associated spectra/correlations Jet dissipates energy • Away-side spectra approaching the bulk • Chemically and thermally? • Need PID 1<pT<4 GeV/c Not be able to do without FULL TOF • Another surprise waiting for discovery? DOE TOF Review, BNL, September 25, 2006

  13. near Medium away mach cone near Au+Au Central 0-12% Triggered Medium away deflected jets Correlations • Jet  Bulk • Three particle correlations • Indicates deflected jets and mach cone. d+Au Au+Au central DOE TOF Review, BNL, September 25, 2006

  14. Identified particle hD,fDcorrelations for 200 GeV p+p using TPC dE/dx Unlike sign (Analysis by D. Prindle) pp All charges KK pp Like sign STAR Preliminary Marginal statistics and ptcoverage with dE/dx Large h,f acceptance TOF extends PID correlation studies to include: - flavor and baryon dependent hadronization dynamics - semi-hard processes in medium - distinguish energy/thermal vs pressure/flow structures L. Ray DOE TOF Review, BNL, September 25, 2006

  15. Energy scan: search for the critical point B √sNN ——————————————————— 180 MeV 25 GeV 420 MeV 7.5 GeV 725 MeV 4.5 GeV ——————————————————— Cleymans, et.al. J. Phys. G30 (2004) S1381 • Energy scan: run 9 • Mapping out the critical point: Fluctuation K/, p/  need PID, large acceptance. DOE TOF Review, BNL, September 25, 2006

  16. Physics topics from TOF in STAR • Identified hadron spectra • freeze-out dynamics • hadronization mechanism • Identified particle correlations • Chemical and kinetic properties of in-medium jet associated spectra • Fluctuations and correlations • Lepton program • In-medium vector meson properties • Heavy flavor • Baseline detector for future upgrades DOE TOF Review, BNL, September 25, 2006

  17. R. Rapp, hep-ph/0010101 QGP signature • Vector meson properties • Thermal dileptons/photons • Heavy flavor R. Rapp, hep-ph/0010101 DOE TOF Review, BNL, September 25, 2006

  18. Dilepton capability TPC+TOF+SSD+HFT ~ 200M central Au+Au events : 22Kand 6K vector meson pairs for one year RHIC running DOE TOF Review, BNL, September 25, 2006

  19. Muon identification at low pT 0.15<pT<0.25 GeV/c, DCA < 3 cm Nucl-ex/0607011, Y.F. Zhang et al., SQM2006. Significantly reduce the systematic uncertainty on the charm cross section measurement. DOE TOF Review, BNL, September 25, 2006

  20. Prototype TOF related charm results • Charm total cross section scales approximately with Nbin • Charm produced at initial impact, sensitive to the evolution/thermalization • Suppression at pT(e) >1.5 GeV/c  strong energy loss for charm • Full TOF improves (x5) charm hadronic reconstruction Nucl-ex/0607011, Y.F. Zhang et al., SQM2006, paper in preparation;STAR Collaboration, Phys. Rev. Lett. 94 (2005) 062301 DOE TOF Review, BNL, September 25, 2006

  21. e from D decay D0e+ K- X • D0e+ K- X • eK pair invariant mass and opening angle distributions from D decay is different from the combinatorial background. We use this as a tool to identify the e is from D decay. 3<pT(e)<6 GeV/c 3<pT(e)<6 GeV/c Φ<36 degree TOF will provide electron PID at intermediate pT and kaon identification (electron rejection at low pT) and extend kaon PID to ~2 GeV/c. DOE TOF Review, BNL, September 25, 2006

  22. pT (e)>1.5 GeV/c J/y at low pT PHENIX PRC 69(2004)014901 • Thermalization & Color DOF • Test color screening • Coalescence of charm quarks • PHENIX Acceptance: ||<0.35, =2  /2 • STAR TOF-Upgrade Acceptance: ||<0.9, =2   • J/ Acceptance: STAR=100PHENIX STARJ/y PHENIXJ/y DOE TOF Review, BNL, September 25, 2006

  23. Baseline detector for other upgrades • TOF provides 2 and ||<0.9 coverage • Future upgrades will benefit from or enhance the capability of this detector • .e.g. Heavy Flavor Tracker (HFT) and TOF can be a powerful device for dilepton and heavy flavor programs DOE TOF Review, BNL, September 25, 2006

  24. v2 scaling for coalescence jet quenching as parton energy loss energy dependence testing model prediction Heavy flavor yields and flow:color screening and partonic collectivity. forwardjet correlation:CGC Thermometers: dilepton, photon heavy quarkonium species. jet fragments tagged by a hard direct photon, a heavy flavor elliptic flow in U+U collisions. LHC and GSI energies fundamental QCD symmetries Critical needs from future experiments Near Term Long Term TOF • PID spectra • freeze-outs • hadronization • PID correlations • In-medium jet • Fluctuations and correlations • Lepton program • In-medium Vector Meson • Heavy Flavor • Baseline detector for future upgrades Near/Long Term: STAR white paper Nucl. Phys. A 757 (2005) 102 DOE TOF Review, BNL, September 25, 2006

  25. Backup DOE TOF Review, BNL, September 25, 2006

  26. STAR MRPC TOF publications • Identified baryon and meson distributions at large transverse momenta from Au+Au collisions at 200 GeV, nucl-ex/0606003, accepted by PRL. • PID Cronin Effect in d+Au, Phys. Lett. B 616 (2005) 8. • Charm Cross section and spectra in p+p, d+Au,Phys. Rev. Lett. 94 (2005) 062301. • A lot of conference proceedings, QM04, SQM04, QM05, SQM06 talks. • Two Ph. D theses. • 8 NIMA publications:Nucl.Instrum.Meth.A538:243-248,2005Nucl.Instrum.Meth.A533:60-64,2004Nucl.Instrum.Meth.A492:344-350,2002Nucl.Instrum.Meth.A508:181-184,2003Nucl.Instrum.Meth.A478:176-179,2002Nucl.Instrum.Meth.A538:425-430,2005Nucl.Instrum.Meth.A537:698-702,2005Nucl.Instrum.Meth.A558:419,2006 • More to come from prototype TOFr two Ph. D theses next year, 3 QM06 talks, 2 STAR papers in preparation. • Imagine what we can accomplish with Full TOF DOE TOF Review, BNL, September 25, 2006

  27. TPC PID identification by combining TPC+TOF TOF alone, (, K) ~1.6 GeV/c , p ~ 3 GeV/c. TOF+dE/dx,  and p can be identified up to 5 GeV/c. ( ,p) 0.3~12 GeV/cM. Shao et al., NIMA 558, (419) 2006 DOE TOF Review, BNL, September 25, 2006

  28. Reject gamma conversion • Background: g  e+e- • HFT discriminates background ! • Need low mass detector DOE TOF Review, BNL, September 25, 2006

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