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A Very High Momentum Particle Identification Detector for the ALICE experiment at the LHC.

Edmundo García Chicago State University for the VHMPID Group. A Very High Momentum Particle Identification Detector for the ALICE experiment at the LHC. 28 th Winter Workshop on Nuclear Dynamics. Dorado del mar Puerto Rico, April 8, 2012. Cherenkov Radiation.

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A Very High Momentum Particle Identification Detector for the ALICE experiment at the LHC.

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  1. EdmundoGarcía Chicago State University for the VHMPID Group A Very High Momentum Particle Identification Detector for the ALICE experiment at the LHC. 28th Winter Workshop on Nuclear Dynamics Dorado del mar Puerto Rico, April 8, 2012

  2. Cherenkov Radiation symmetric dipole distribution incoherent destructive interference symmetric dipole distribution coherent Cherenkov radiation The 1958 Physics Nobel Prize was awarded jointly to P. A. Cherenkov, I. M. Frank and I. Yevgenyevich “for discovery and interpretation of Cherenkov effect”

  3. From the Physics to the Detector First used by E605 Fermilab Helium Radiator CaF2 window

  4. Recent Cerenkov Detectors COMPASS ALICE LHCb HMPID

  5. High Momentum Particle Identification Detector Cherenkov Ring MIP

  6. Outline • Introduction • The Detector • Technical Notes • Physics Possibilities • Final Notes HMPID

  7. 7 A Large Hadron Collider Experiment TRD EMCAL TPC PMD MUON HMPID ITS PHOS TOF

  8. Selected Detector PID in ALICE

  9. 9 ALICE PID separation @ 3s separation @ 2s VHMPID VHMPID Existing gap between low and high pT ALICE for detailed (3 s) hadron PID

  10. Very High Momentum Particle Identification Detector 3sPID of π, K, p on a track-by-track basis

  11. ALICE rdE/dx and VHMPID • rdE/dx • Statistical, reachinghigh-pT • Clean π sample • Protons are difficult • No kaon PID • VHMPID • Track-by-track • Difficult at low pT • Limited acceptance (maximum 30% of central barrel)

  12. Estimated improvements in Particle Production • Error bars statistical plus systematic • Lager yield of protons • Pytha • Medium modification prediction by Wiedemannet al

  13. Flow Jet Fragmentation • TPC based on analysis of 2010 data • Improvement based on VHMPID stat & syst. error • Ratio of fragmentation functions • Errors depend on PID systematics, statistics, and jet energy determination

  14. ALICE Integration • VHMPID + (DCaL) or PHOS system in 5 sector (20o each) • 30% central barrel acceptance • C4F10 (C4F8O) at gas pressure 3 atm, 40o C • Radiator length 50 cm keeping basic performance tracking layer 3 cm photo detector 9 cm radiator 50 cm mirror and insulation 9 cm tracking layer 3 cm

  15. Triggering TRD • Transition Radiation Detector trigger • 6 tracking layers 400 – 600 resolution • Readout 200 Hz 5% dead time • Trigger based on matching at least 4 track segments, track threshold 5 GeV/c pT

  16. Triggering HPTD • Close Cathod Chambers* • Provides L0 trigger for pp • Provides of L1 trigger PbPb • MIP detection *G. Hamar, G. Kiss, D. Varga: Nucl.Instrum.Meth. A648 163-167 (2011)

  17. Performance Simulations Mirror misalignment simulation Center 1 Chromatic dispersion limited detector resolution Center 2 10 GeV/c pions and kaons Reconstructed Cherenkov angle in PbPb background

  18. VHMPID prototype

  19. High-pTphysics in proton-proton collisions F • Preset FF set are extracted from global data fits from and RHIC spectra • NLO calculations uncertainty is large in the comparison to experimental data • Improved PID in ALICE could significantly contribute to improve the constraints on the FFs with through high-pT identified particle spectra S. Albino, A Kniehl, G. Kramer Nucl.Phys.B803, 42-104,2008 S. Albino, A Kniehl, G. Kramer Nucl.Phys. B803, 42-104,2008 CDF et al Phys. Rev. D. 79, 112005 , 2009 S. Albino, A. Kniehl, G. Kramer Phys. Rev. Lett 104, 242001, 2010

  20. Track - by - Track PID and Jets application • Investigate the production mechanism of heavy prompt quarkonia by studying the kinematics of jet associated particles. • Characterize of the jets accompanying the J/ production in p-p collisions such as the scalar sum of transverse momentum, the fragmentation function, the cone radius, or jet composition. • Compare jet characteristics in p-p and A-A collisions A.C. Kraan, arXiv:0807.3123v1 [hep-ex]

  21. Study of Hadronization and Jet Quenching in Pb-Pb • Need more differential probes to understand hadronizationin medium and medium properties. • Particle identification at high pT , should be the basis for most potentially new measurements P. Levai, D. Berenyi, A. Pasztor, and V.V. Skokov, Jour. Phys. G38 (2011) Sapeta, Wiedemann Eur.Phys.J.C55:293-302,2008

  22. High-momentum resonance production • Reconstructed - meson peak in invariant mass distribution for k+k- pairs in min. bias PbPb collisions at 5.5 ATeV • VHMPID acceptance based on 5 Million central HIJING events • S/B 10 : 1

  23. Backup Transparencies

  24. The ‘golden cuts’ on rdE/dx distributions for TPC

  25. Present vs. ideal TPC performance Kaon contamination in pp slightly higher at similar pT compared to PbPb Resolution in pp (5.4%) slightly better (6.1% in PbPb)

  26. Photoelectrons Charged particle at saturation in 50 cm of C4F10 at 3 atm

  27. C4F10 dependence vs resolution 50 cm radiator

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