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Physics with the ALICE TRD

Physics with the ALICE TRD. Ken Oyama Physikalisches Institut, Heidelberg for the ALICE Collaboration Physics at LHC, Jun.7, 2006, Krakow. Overview. ALICE studies the characteristics of the quark matter produced in the Pb+Pb collisions at sqrt(s NN ) = 5.5 TeV.

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Physics with the ALICE TRD

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  1. Physics with the ALICE TRD Ken Oyama Physikalisches Institut, Heidelberg for the ALICE Collaboration Physics at LHC, Jun.7, 2006, Krakow

  2. Overview • ALICE studies the characteristics of the quark matter produced in the Pb+Pb collisions at sqrt(sNN) = 5.5 TeV. • Expected dN/d = 1500 ~ 3000. • TRD is for electron ID and trigger. ITS TRD TPC TRD Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  3. Physics Motivations for the ALICE TRD Systematic measurements of the following observables in p+p, p+A and A+A collisions • Single electron momentum spectra • D  e + X (17 % b.r.) • B  e + X … talk by R. Turrisi. • Di-electron mass spectra • J/ (3.1 GeV)  e+e- (6 % b.r.) • ’ (3.7 GeV)  e+e- (0.76 % b.r.) • Y (9.5 GeV)  e+e- (2.4 % b.r.) • Y’ (10 GeV)  e+e- (1.3 % b.r.) • q+q  e+e- Thermal • q+q  e+e- Drell-Yan • Jet spectra & shape • Medium induced momentum and shape modification • Information about the de-confined QGP medium state : • Color potential screening  J/ suppression, Upsilon suppression • Initial scattering information and effect of the medium to it : • Jet quenching Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  4. ALICE TRD Principle • Charged particles at  > 1000 give T.R. photons. • Thin (< 0.25 X0) detector with low power (~ 60 kW for 1.2 M channels) readout electronics on it. Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  5. TRD: Requirements and Performance central Pb–Pb pp pT resolution < 4 % at 100 GeV/c for dNch/dy ~ 5000 • Purpose : • Electron ID at p > 1 GeV/c. • Fast (6 s) trigger for high-pT+ PID. • Improved momentum resolution. • Parameters : • || < 0.9, 0 << 2 • 540 modules (18 super-modules) • 28 m3 Xe/CO2 (85:15) • 1.2 M readout channels beam test @ PS simulation Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  6. SPS / RHIC  LHC • Charmonium melting pattern will be seen clearly. • Much larger Initial production rate will enhance the charmonium yield. • Strong centrality dependent secondary J/ production by statistical hadronization  J/ enhancement. T<Tc T>Tc Overall understanding is necessary T>>Tc x 20 [H. Satz, hep-ph/0602245] c and b Initial production rate [P. Braun Munzinger, K. Redlich, and J. Stachel, nucl-th/0304013] Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  7. J/Ψ and Upsilon Measurements (I) 120k J/ S/N=1.2 • Simulation with nPDF+shadowing predicted[*] quarkonia yields embedded into HIJINGpara events (<dN/dy> ~ 3000). • Separations of J/, ’, Y, Y’ and Y’’ are possible. 10 % Centrality 2x108 events 106 run time (a.y.) 900 Y S/N=1.1 250 Y’ S/N=0.4 [W. Sommer, ALICE PPR] [*] A. Accardi et al.,arXiv:hep-ph/0308248 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  8. J/Ψ and Upsilon Measurements (II) • Momentum dependence and S/N. • J/ yield can be measured for more than 10 GeV/c. Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  9. Jet Energy and Shape Measurements (I) Pb q Q Pb q vacuum medium jT pT • hard/tot ~ 98 % (RHIC: 50 %) [K.Kajantie, QM2002]. • Leading particle energy reaches more than 100 GeV. x1000 yield at 20 GeV compare to RHIC. • In Pb+Pb: • Jet quenching as probe of medium property. • Ncoll scaling violation. • Modification in jT distribution. Phys.Lett.B595:165-170,2004 e > 15 GeV/fm3; dNg/dy > 1100 • Softer pT distribution • Broader jT distribution • Less collimation PHENIX QM2005 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  10. Jet Energy and Shape Measurements (II) • Underlying background from hot matter ~ 2 TeV in R < 1.0, ~ 150 GeV in R < 0.3 (assumption: dN/dy ~ 5000 and <pT> ~ 500 MeV/c). • 1 ALICE year collects enough statistics of jets. • Jet quenching is visible already in ET spectrum. • S/N becomes smaller than 1 at 1 GeV jT energy. jT: momentum transverse to the jet-direction A. Morsch, ALICE PRR Effective month of running 106 s (107 central events). RC<0.4 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  11. Jet Triggering with TRD • One TRD module (size : R2 = d2 + d2 = 0.362+0.352 ~ 0.52) can count the number of high pT charged tracks  available online at L1. • Expected jet rate exceeds 1 Hz for ET > 100 GeV. • Jet trigger becomes efficient at ET ~ 100 GeV where triggering is necessary to have statistics. Expected jet rate [D. Miskowiec]  CKIN(3)=50  CKIN(3)=100  CKIN(3)=200 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  12. ALICE TRD Construction Status in Heidelberg Current plan of 1st super-module delivery to CERN: Aug. 15 Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  13. Summary • ALICE with TRD can measure Quarkonia signals (J/, ’, Y, Y’, Y’’) and study properties of the Quark Gluon Plasma (good for also B-decay). • TRD can provide trigger for jet at ET > 100 GeV. • The first TRD super-module (out of 18) construction is on going. It will be delivered to CERN in August. Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  14. Backup Slides Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  15. J/Ψ and Upsilon Measurements (III) Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  16. Jet Shape Measurement in Other Way •  = ln( 1/x ) = ln( ETjet / p ) (x = p / ETjet : momentum fraction) is sensitive for energy loss. leading particle region <q> = 1.7 GeV2/fm 10 50 leading particle region non-leading fragments region • q = 2/ : transport coefficient •  : typical momentum transfer, •  : mean free path Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  17. Position and Angle Resolution Large chambers Prototype Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  18. TRD Mechanical Construction Polypropylene fibers (Freudenberg LRP375BK) Rohacell foam (HF71) Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  19. Electron Identification by TRD Total charge spectra Counts Integrated Charge Depos. Energy (keV) Max. cluster position Likelihood distribution Extract probabilities Distribution of maximum cluster position LQ Method: Likelihood with total charge Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

  20. Quarkonia Production Rate Color Evapolation Model prediction for 5.5 TeV p+p collision [A. Accardi et al.,arXiv:hep-ph/0308248] Ncoll scaling (Glauber model) 2.6x10-2 * ~1000  26 Shadowing (EKS98) Branching ratio Physics at LHC, Cracow, Ken Oyama for the ALICE Collaboration

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