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Status Report of Electron Trigger Study from VRDC

Status Report of Electron Trigger Study from VRDC. Takashi Matsumoto ( Waseda Univ ./CNS) and Kenta Shigaki (KEK) at Heavy/Light PWG Meeting on March 9, 2000. Presentation Outline. VRDC - data set of vector meson signals dedicated to electron trigger study Analysis Plan

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Status Report of Electron Trigger Study from VRDC

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  1. Status Report of Electron Trigger Study from VRDC Takashi Matsumoto (Waseda Univ./CNS) and Kenta Shigaki (KEK) at Heavy/Light PWG Meeting on March 9, 2000

  2. Presentation Outline • VRDC • - data set of vector meson signals dedicated to • electron trigger study • Analysis Plan • New Results • - present simulation method • - electron trigger efficiency • - Pt dependence • - Z vertex dependence • Ongoing Studies • Summary T.Matsumoto at PHENIX Heavy/Light Meeting

  3. VRDC Data Set • VRDC Simulation • - requested by K.Shigaki through spin PWG • - generated by N.Hayashi et al. at CC-J • 60 K single J/y → e+ eー events • - Pt = 0.0, 0.6, 1.2, 1.8, 2.4, 3.0, 3.6, 4.5, 6.0, 8.0 GeV • 54 K single f→ e+ eーevents • - Pt = 0.0, 0.3, 0.6, 0.9, 1.2, 1.5, 2.0, 3.0, 4.0 GeV • Z-vertex =0, 10, 20 cm • Include 2 K events in each setting • Both electrons are required to be in PHENIX central • arm acceptance with magnetic bending T.Matsumoto at PHENIX Heavy/Light Meeting

  4. Analysis Plan • In-depth Study of Trigger Efficiency • - Pt dependence • - Z vertex dependence • - event selection • - geometrical acceptance • - pair reconstruction • Detailed Simulation of EMCal-RICH Electron Trigger • - EMCal LVL-1 (Ersatz trigger board) • - RICH LVL-1 • - look-up • Goal • - establish EMCal-RICH look-up scheme • - finalize LVL-1 electron trigger hardware specifications T.Matsumoto at PHENIX Heavy/Light Meeting

  5. Present Simulation Method (K.Shigaki) • Simple matching of 8 trigger blocks per arm • RICH Threshold : 3.5 photon per trigger tile • EMCal cluster energy threshold : 0.3, 0.6, 0.9, 1.2, 1.5 GeV • Simulate the trigger with EMCal only and EMCal+RICH T.Matsumoto at PHENIX Heavy/Light Meeting

  6. Pt of J/y vs. Electron Trigger Efficiency of J/y 1 • Plots • - blue : EMCal only • - red : EMCal+RICH • - solid lines : single electron trigger • - dotted lines : double electron trigger • Single electron trigger • - EMCal threshold needs to be <1.2 GeV • Double electron trigger • - Pt dependent trigger bias EMCal Threshold =0.3 GeV 0 J/psi pt [GeV] 8 1 0.6GeV 0 J/psi pt [GeV] 8 1 Trigger Efficiency with Different EMCal Threshold 0.9GeV 0 J/psi pt [GeV] 8 1 1.2GeV 0 8 J/psi pt [GeV] 1 1.5GeV 0 J/psi pt [GeV] 8

  7. Pt of f vs. Electron Trigger Efficiency of f 1 • Plots • - blue : EMCal only • - red : EMCal+RICH • - solid lines : single electron trigger • - dotted lines : double electron trigger • single electron trigger • - EMCal threshold need to be <0.6GeV • - low Pt f will be missed • with higher threshold. • Double electron trigger • - low efficiencies • - Pt dependent bias • Lower limit of EMCal trigger threshold • at ～500MeV due to ASIC design • - may be a problem to trigger f EMCal threshold =0.3GeV 0 4 phi pt [GeV] 1 0.6GeV 0 4 phi pt [GeV] 1 Trigger Efficiency with Different EMCal Threshold 0.9GeV 0 4 phi pt [GeV] 1 1.2GeV 0 phi pt [GeV] 4 1 1.5GeV 0 4 phi pt [GeV]

  8. Z-vertex Dependence (single electron trigger) J/y f Red : ratio of efficiency zvx10cm/zvx 0cm Green : ratio of efficiency zvx 20cm/zvx 0cm Ratio of trigger efficiency between non-zero vertex events and zero vertex events EMC Threshold =0.6 GeV EMC Threshold =1.2 GeV J/y Pt [GeV] f Pt [GeV] • A hint of Z vertex effect ? • Larger effect is expected with finer trigger segmentation • - need further study T.Matsumoto at PHENIX Heavy/Light Meeting

  9. Ongoing Studies (and Goals) • Use EMCal tower by tower energy instead of cluster energy • and simulate Ersatz trigger board (KS, done) • Tune the RICH triggerthreshold (TM) • Implement versatile EMCal-RICH look-up (KS) • Redo studies of • - efficiency for electron channels • - pair reconstruction to select good J/y and f events (TM) • - rejection power against minimum bias A+A • (including p+p) events • Establish EMCal-RICH look-up scheme • Finalize LVL-1 electron trigger hardware specifications T.Matsumoto at PHENIX Heavy/Light Meeting

  10. Summary • Electron trigger study is ongoing using VRDC data set • Single electron trigger seems preferred • -double electron trigger introduces Pt dependent bias • Effect of non-zero Z vertex is under investigation • More result will come! T.Matsumoto at PHENIX Heavy/Light Meeting

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