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PFA Study with Jupiter

PFA Study with Jupiter. Contents : 1. Introduction 2. GLD-PFA 3. Z->qqbar Study 4. Zh Study 5. Summary. FJPPL Meeting @ KEK September 29 th , 2006 Tamaki Yoshioka ICEPP, Univ. of Tokyo. Introduction. Most of the important physics processes to be studied in the ILC

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PFA Study with Jupiter

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  1. PFA Study with Jupiter Contents : 1. Introduction 2. GLD-PFA 3. Z->qqbar Study 4. Zh Study 5. Summary FJPPL Meeting @ KEK September 29th, 2006 Tamaki Yoshioka ICEPP, Univ. of Tokyo FJPPL Meeting@KEK

  2. Introduction • Most of the important physics processes to be studied in the ILC • experiment have multi-jets in the final state. • → Jet energy resolution is the key in the ILC physics. • The best energy resolution is obtained by reconstructing • momenta of individual particles avoiding double counting among • Trackers and Calorimeters. • - Charged particles (~60%) measured by Tracker. • - Photons (~30%) by electromagnetic CAL (ECAL). • - Neutral hadrons (~10%) by ECAL + hadron CAL (HCAL). • → Particle Flow Algorithm (PFA) • In this talk, general scheme and performance of the GLD-PFA, • using the GEANT4-based full simulator (Jupiter),will be presented. FJPPL Meeting@KEK

  3. Geometry in Jupiter Solenoid TPC Hadron Calorimeter (HCAL) VTX, IT Muon Detector Electromagnetic Calorimeter (ECAL) Dodecagonal Shape As of August 06 FJPPL Meeting@KEK

  4. Calorimeter Geometry in Jupiter Readout Line =10cm 349.4cm BarrelHD 229.8cm BarrelEM 210cm 270cm EndcapHD Barrel.InnerRadius=210cm EndcapEM Endcap.InnerRadius=40cm IP Barrel.HalfZ=280cm 419.4cm 280cm 299.8cm FJPPL Meeting@KEK

  5. Calorimeter Structure Active Layer Absorber Current cell size : 2x2cm Can be changed. ECAL W/Scinti./Gap 3/2/1 (mm) x 33 layers HCAL Fe/Scinti./Gap 20/5/1 (mm) x 46 layers FJPPL Meeting@KEK

  6. GLD-PFA FJPPL Meeting@KEK

  7. Particle Flow Algorithm for GLD Flow of GLD-PFA • Photon Finding • Charged Hadron Finding • Neutral Hadron Finding • Satellite Hits Finding • *Satellite hits = calorimeter hit cell which does not belong • to a cluster core Note : Monte-Carlo truth information is used for muon and neutrino. FJPPL Meeting@KEK

  8. Photon Likelihood (Input) - Five variables are selected to form the photon likelihood function. velocity meanlay trkdis chi2 Edep/nhits Photon Other FJPPL Meeting@KEK

  9. Photon Likelihood (Output) linear • Cut position is set • to be 0.7. Other Photon log Photon Other FJPPL Meeting@KEK

  10. Charged Hadron Finding • Basic Concept : • Extrapolate the charged track and calculate a distance between • a calorimeter hit cell and the extrapolated track. Connect the cell • that in a certain tube radius (clustering). Extrapolated Track • Calculate the distance • for any track/calorimeter • cell combination. HCAL Tube Radius Hit Cells • Tube radius for ECAL • and HCAL can be changed • separately. distance ECAL Calorimeter input position Charged Track FJPPL Meeting@KEK

  11. Neutral Hadron Likelihood (Input) - Four variables are selected to form the NHD likelihood function. velocity Edensity Edep/nhits meanlayer Neutral Hadron Satellite Hits FJPPL Meeting@KEK

  12. Neutral Hadron Likelihood (Output) linear Neutral Hadron Satellite Hits • Cut position is set • to be 0.73. log Neutral Hadron Satellite Hits FJPPL Meeting@KEK

  13. Z -> qqbar FJPPL Meeting@KEK

  14. Z-pole Event Display End View Side View - 2cm x 2cm tile (GLD backup solution) is used in this study. FJPPL Meeting@KEK

  15. e+ e- Yellow : Photon Red,Green : Charged Hadron Black,Blue : Neutral Hadron Z → qqbar @ 91.2GeV Event Display FJPPL Meeting@KEK Next: 電子、陽電子衝突

  16. Event Display Yellow : Photon Red,Green : Charged Hadron Black,Blue : Neutral Hadron Gamma Finding FJPPL Meeting@KEK

  17. Event Display Yellow : Photon Red,Green : Charged Hadron Black,Blue : Neutral Hadron Charged Hadron Finding FJPPL Meeting@KEK

  18. Event Display Yellow : Photon Red,Green : Charged Hadron Black,Blue : Neutral Hadron Satellite Hits Finding FJPPL Meeting@KEK

  19. Event Display Yellow : Photon Red,Green : Charged Hadron Black,Blue : Neutral Hadron Remaining : Neutral Hadron FJPPL Meeting@KEK

  20. Performance - Energy-weighted Efficiency and Purity Definition Efficiency : xxx  (total xx E in collected hits)/(true xxx total E in CAL) Purity : Pxxx (total xxx E in a cluster)/(total E in a cluster) xxx = Photon, CHD, NHD, Satellite both  and P values are energy-weighted FJPPL Meeting@KEK

  21. All angle • In barrel region, ILC goal of 30% has been achieved. • Performance in 0.7<|cosθ|<0.8 is too bad. → Already fixed. Jet Energy Resolution - Z → uds @ 91.2GeV, new calorimeter geometry, 2cm x 2cm tile FJPPL Meeting@KEK

  22. Energy Dependence - Energy dependence of jet energy resolution. • Bad performance for higher energy. • Not so bad performance for < 100 GeV Jet. FJPPL Meeting@KEK

  23. Linearity - Good linearity. Jet energy can be corrected. FJPPL Meeting@KEK

  24. Zh →nn h First look at the Zh events with Jupiter and realistic PFA. FJPPL Meeting@KEK

  25. Typical Event Display • Two jets from Higgs can be seen. FJPPL Meeting@KEK

  26. Zh → nn h @ 350GeV - Fast MC • w/o correction • w/ correction Higgs Mass Visible Energy • - Jet energy is corrected by an empirical • formula obtained by Z → qqbar studies. • - Selection Criteria • 90 < Evis < 200 GeV • pt >20 GeV/c Missing Mass FJPPL Meeting@KEK

  27. Kinematical Fit • - 6 Measured Variables • Jet1 : Ej1, qj1, jj1 • Jet2 : Ej2, qj2, jj2 (Note : Ej1 >Ej2) • - 3 Unmeasured Variables • Z0 : Ez, qz, jz • 4 Constraints • pj1cosjj1sinqj1 + pj2cosjj2sinqj2 + pZcosjZsinqZ = 0 • pj1sinjj1sinqj1 + pj2sinjj2sinqj2 + pZsinjZsinqZ = 0 • pj1cosqj1 + pj2cosqj2 + pZcosqZ = 0 • Ej1 + Ej2 + Ez – Ecm = 0 • (Note: jet mass is fixed : pfit = √{Efit2– (Emeas2 – pmeas2)} ) • → 1C-fit can be performed. FJPPL Meeting@KEK

  28. Fitted Results Prob > 0.02 Very Preliminary • Higgs mass resolution is significantly improved. … But, • Peak at prob=1 indicates the fitting didn’t work well. FJPPL Meeting@KEK

  29. Stretch Functions • The stretch function should form a normal Gaussian if the X and • s are proper. Too Narrow = Overestimated Strange Need to understand. FJPPL Meeting@KEK

  30. Summary • Realistic PFA has been developed using the GEANT-4 based full simulator of the GLD detector. • Jet energy resolution is studied by using Z->qq events. ILC goal of 30% has been achieved for Z-pole events. • ZH study based on current PFA performance is now ongoing. FJPPL Meeting@KEK

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