The ALICE PHOS && EMCAL geometrical and reconstruction efficiency


  • The goal of the study
    • Extract the raw yield of neutral mesons(pi0, eta and omega)
    • Correct the raw spectra

  • Simulation, reconstruction and analysis conditions
    • In simulation: PHOS and EMCAL -> Full detector
    • PHOS: further improve the calibration?
    • EMCAL: non-linearity correction, calibration, misalignment
    • MC: AliAnalysisTaskPtMC, RealData: AliAnaPi0 or combined these two
    • study the pi0->2gamma, eta->2gamma and omega->pi0gamma->3gamma, all the other channels are switched off
    • AliRoot v4-19-Rev-10 and v4-19-Rev-20
    • By calling the OCDB
      • alien://Folder=/alice/data/2010/OCDB (v0)
      • alien://Folder=/alice/cern.ch/user/g/gconesab/ClusterizerNxN/OCDB/") (v1)
    • Only calorimeters of PHOS and EMCAL
    • EMCAL: eta(-0.8,0.8) phi(70,130)
    • PHOS: eta(-0.13,0.13) phi(250,330)
    • Cuts to be used in the analysis: http://indico.cern.ch/getFile.py/access?resId=minutes&materialId=minutes&confId=113031
    • Bad/hot channels: The edge of cells/towers are removed and assumpted as "BAD"
      • PHOS
        • PHOS_bad_cells_OCDB:
          PHOS_bad_cells_OCDB.gif
        • In simulation: phos_bad_channels:
          phos_bad_channels.gif
      • EMCAL
        • EMCAL_bad_towers_OCDB:
          EMCAL_bad_towers_OCDB.gif
        • In simulation: emcal_bad_channels:
          emcal_bad_channels.gif

  • Definition of reconstruction efficiency
    • define
      • as the below. In MC, we ask the two decay photons from pi0 and eta are in PHOS(3) or EMCAL(4) acceptance:
        effdefinition.png
      • EMCAL: pi0 position and width with (v0: 2010 OCDB):
        emcal_pi0_v0.jpg
      • EMCAL: Pi0 (up) and eta(down) peak position, width and reconstruction with N*N clusterization (v1).:
        eta_and_pi0_v1.jpg
      • PHOS: Pi0 (up) and eta(down) peak position, width and reconstruction.(A bug was found in the reading the PHOS MC info. The efficiency is lower than at http://indico.cern.ch/conferenceDisplay.py?confId=110523 Corrected here.):
        phos_eta_pi0.jpg

  • Acceptance (pure simulation without going through the detectors. All the decay daughers should be in detector acceptance.)
    • PHOS (3Ms) and EMCAL(4SMs) geometrical acceptance to the neutrual mesons:
      acceptance.jpg

  • Reconstruction efficiency (all the neutral mesons with only going through the EM-calorimeters) * Reconstruction efficiency with em-calorimeters:
    receff.jpg

  • Uncertainties
    • Acceptance: 1)pure simulation, by using the Config.C and sim.C to generate galice.root and Kinematics.root for the analysis. 2) witch all the other decay channels but pi0->2gamma, eta->2gamma and omega->2gamma with flat distribution. 3) phi: (0, 360) and eta (-1,1) 4) fitted by the function f(x) = (a+bx)[1-exp((-x-c)/d)]
    • Conversions

-- RenzhuoWan - 09-Nov-2010

Topic attachments
I Attachment History Action Size Date Who Comment
GIFgif EMCAL_bad_towers_OCDB.gif r1 manage 15.2 K 2010-11-09 - 15:52 RenzhuoWan  
GIFgif PHOS_bad_cells_OCDB.gif r1 manage 13.1 K 2010-11-09 - 15:51 RenzhuoWan  
JPEGjpg acceptance.jpg r1 manage 57.1 K 2011-03-02 - 14:59 RenzhuoWan PHOS (3Ms) and EMCAL(4SMs) geometrical acceptance to the neutrual mesons
PNGpng effdefinition.png r1 manage 23.1 K 2010-11-10 - 22:30 RenzhuoWan  
GIFgif emcal_bad_channels.gif r1 manage 62.6 K 2010-11-09 - 15:46 RenzhuoWan  
JPEGjpg emcal_pi0_v0.jpg r1 manage 82.2 K 2010-11-10 - 23:01 RenzhuoWan  
JPEGjpg eta_and_pi0_v1.jpg r1 manage 438.7 K 2010-11-10 - 22:24 RenzhuoWan  
GIFgif phos_bad_channels.gif r1 manage 43.5 K 2010-11-09 - 15:48 RenzhuoWan  
JPEGjpg phos_eta_pi0.jpg r1 manage 379.1 K 2010-11-10 - 22:45 RenzhuoWan  
JPEGjpg receff.jpg r1 manage 51.9 K 2011-03-02 - 15:05 RenzhuoWan Reconstruction efficiency with em-calorimeters
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Topic revision: r8 - 2011-05-12 - RenzhuoWan
 
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