1. 12/20/2006ILC-Sousei Annual Meeting @ KEK1 Particle Flow Algorithm for Full Simulation Study ILC-Sousei Annual Meeting @ KEK Dec. 20 th -22 nd, 2006 Tamaki Yoshioka ICEPP, Univ. of Tokyo Contents 1. Introduction 2. Particle Flow Algorithm 3. PFA Performance 4. Summary

2. 12/20/2006ILC-Sousei Annual Meeting @ KEK2 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.

3. 12/20/2006ILC-Sousei Annual Meeting @ KEK3 Muon detector Calorimeter Tracker Vertex detector Coil GLD Detector GLD detector - One of the detector concepts for the ILC experiment. - The world-wide consensus of the performance goal for the jet energy resolution is - For more detail, please see the GLD Detector Outline Document (DOD) → physics/0607154

4. 12/20/2006ILC-Sousei Annual Meeting @ KEK4 GLD Detector Concept - To get good energy resolution by PFA, separation of particles (reducing the density of charged and neutral particles at CAL surface) is important. Often quoted “Figure of Merit” B : Magnetic field R : CAL inner radius σ: CAL granularity R M : Effective Moliere length - GLD concept 1. Large inner radius of ECAL to optimize the PFA. 2. Large tracker for excellent dp t /p t 2 and pattern recognition. 3. Moderate B field (~3T).

5. 12/20/2006ILC-Sousei Annual Meeting @ KEK5 Geometry in Jupiter Muon Detector Solenoid Hadron Calorimeter (HCAL) Electromagnetic Calorimeter (ECAL) TPC VTX, IT Dodecagonal Shape As of December 06

6. 12/20/2006ILC-Sousei Annual Meeting @ KEK6 229.8cm 349.4cm 299.8cm 419.4cm Readout Line =10cm 270cm Endcap.InnerRadius=40cm Barrel HCAL Barrel ECAL Endcap ECAL Endcap HCAL Barrel.InnerRadius=210cm Barrel.HalfZ=280cm 210cm 280cm Calorimeter Geometry in Jupiter IP

7. 12/20/2006ILC-Sousei Annual Meeting @ KEK7 Calorimeter Structure ECAL W/Scinti./Gap 3/2/1 (mm) x 33 layers HCAL Fe/Scinti./Gap 20/5/1 (mm) x 46 layers Absorber Active Layer Current cell size : 2x2cm Can be changed.

8. 12/20/2006ILC-Sousei Annual Meeting @ KEK8 Z-pole Event Display End ViewSide View - Z → qq (uds) @ 91.2GeV, tile calorimeter, 2cm x 2cm tile size

9. 12/20/2006ILC-Sousei Annual Meeting @ KEK9 Particle Flow Algorithm for GLD Flow of GLD-PFA 1.Photon Finding 2.Charged Hadron Finding 3.Neutral Hadron Finding 4.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.

10. 12/20/2006ILC-Sousei Annual Meeting @ KEK10 Photon Likelihood Track Distance VelocityMean Layer Edep/Nhits chi2 - Five variables are selected to form the photon likelihood function. Photon Other Output PhotonOther

11. 12/20/2006ILC-Sousei Annual Meeting @ KEK11 Particle Flow Algorithm for GLD Flow of GLD-PFA 1.Photon Finding 2.Charged Hadron Finding 3.Neutral Hadron Finding 4.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.

12. 12/20/2006ILC-Sousei Annual Meeting @ KEK12 Charged Hadron Finding - Basic Concept : Extrapolate a 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). Charged Track Calorimeter input position Hit Cells distance ECAL HCAL - Tube radius for ECAL and HCAL can be changed separately. - Calculate the distance for any track/calorimeter cell combination. Extrapolated Track Tube Radius

13. 12/20/2006ILC-Sousei Annual Meeting @ KEK13 Particle Flow Algorithm for GLD Flow of GLD-PFA 1.Photon Finding 2.Charged Hadron Finding 3.Neutral Hadron Finding 4.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.

14. 12/20/2006ILC-Sousei Annual Meeting @ KEK14 Neutral Hadron Likelihood - Four variables are selected to form the NHD likelihood function. Neutral Hadron Satellite Hits Velocity Energy Density Edep/Nhits Mean Layer Output Neutral Hadron Satellite Hits

15. 12/20/2006ILC-Sousei Annual Meeting @ KEK15 Particle Flow Algorithm for GLD Flow of GLD-PFA 1.Photon Finding 2.Charged Hadron Finding 3.Neutral Hadron Finding 4.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.

16. 12/20/2006ILC-Sousei Annual Meeting @ KEK 16 Next: 電子、陽電子衝突 e+e+ e-e- Event Display Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Z → qqbar @ 91.2GeV

17. 12/20/2006ILC-Sousei Annual Meeting @ KEK 17 Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Event Display Gamma Finding

18. 12/20/2006ILC-Sousei Annual Meeting @ KEK 18 Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Event Display Charged Hadron Finding

19. 12/20/2006ILC-Sousei Annual Meeting @ KEK 19 Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Event Display Remove Satellite Hits

20. 12/20/2006ILC-Sousei Annual Meeting @ KEK 20 Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Event Display Remaining : Neutral Hadron

21. 12/20/2006ILC-Sousei Annual Meeting @ KEK21 - Almost no angular dependence : 31%/ √ E for |cos  |<0.9. - cf. 60 %/ √ E w/o the PFA (sum up the calorimeter energy) All angle - Z → uds @ 91.2GeV, tile calorimeter, 2cm x 2cm tile size Jet Energy Resolution (Z-pole)

22. 12/20/2006ILC-Sousei Annual Meeting @ KEK22 - Almost no angular dependence : 31%/ √ E for |cos  |<0.9. - cf. 60 %/ √ E w/o the PFA (sum up the calorimeter energy) All angle - Z → uds @ 91.2GeV, tile calorimeter, 2cm x 2cm tile size Jet Energy Resolution (Z-pole) With the PFA, we can start 1. detector optimization study (optimize cost performance). 2. full simulation physics study.

23. 12/20/2006ILC-Sousei Annual Meeting @ KEK23 Detector Optimization Ex) PFA performance for Z-pole events w/ different B-field. : 3Tesla : 4Tesla : 5Tesla Preliminary Detector design can be optimized with the PFA. (optimize cost performance) - B-field → Weak B-field dependence. - Calorimeter granularity (transverse/longitudinal) - Calorimeter radius - Cal. absorber material - TPC endplate thickness - etc …

24. 12/20/2006ILC-Sousei Annual Meeting @ KEK24 Full Simulation Physics Study Full simulation physics study with the PFA. - Signal : Zh → h - Background : ZZ only - 100fb -1 Very Preliminary

25. 12/20/2006ILC-Sousei Annual Meeting @ KEK25 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. Full simulation physics study has been started by using the PFA. ※ PFA/simulation session will be held tomorrow afternoon.