Study of p0 Reconstruction in GEANT Simulation

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Study of p0 Reconstruction in GEANT Simulation
Shunji Nishimura CNS, Tokyo
Gabor David Stephen Markacs Craig Woody

• Analysis Projects
• Particle Identification Efficiency.
• Event Mixing Method.
• Energy Calibration.
• Other Basic Study

CNS / Waseda
Shunji Nishimura
Ken Oyama
Takao Sakaguchi
Takashi Matumoto SouIchiro Kametani
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p0 Reconstruction by PHENIX-EMCalDemonstration
using simulation (Presented in Nov./1999)
Realistic PID (efficiency / contamination)
Energy resolution (smearing, etc)
Parfect PID Perfect Energy
p0
Humm..
p0
p0
Energy resolution - FWHM of p0 peak 40MeV
Particle identification - Photon efficiency
70 - Contamination 20 - p0 efficiency 50
Condition - Pt (gg) gt 2.0GeV/c - Asym. lt 0.7 -
AuAu central collisions b lt
2fm 17 k events
We need better PID...
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Current Status (Feb./2000)
88 efficiency (Feb./2000)
70 efficiency (Nov./1999)
Step 0. No cut Step 1. TOF cut Step 2. Cut
with Primary energy dep. Maximum TOF
PC3 association
Photon
Contaminations from non-photon including
particles from non-vertex 20
Photon efficiency is improved. 70 ?
88
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Background particles (vertex position gt 2mm)
Few contamination after PID cuts
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Before (Nov./1999)
After (Feb./2000)
Perfect Energy
Energy Resolution Included
Asym. lt 0.5
p0 peak seems to be enhanced. More work will be
done on PID considering precise efficiency
evaluation.
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Energy Smearing from Multi-Particle Hits in
Cluster
E1
Single particle in cluster
All clusters
E2
Inv. Mass (Measured)
Smearing effect
Better energy resolution
Inv. Mass (Geant)
- Serious smearing effect due to muti-particle
hits in cluster. - Cant we improve energy
separation in clustering method?
Better S/N ratio...