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 9/29/2006 FJPPL Meeting@KEK

Introduction → Jet energy resolution is the key in the ILC physics. 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. 9/29/2006 FJPPL Meeting@KEK

Geometry in Jupiter Solenoid TPC Hadron Calorimeter (HCAL) VTX, IT Muon Detector Electromagnetic Calorimeter (ECAL) Dodecagonal Shape As of August 06 9/29/2006 FJPPL Meeting@KEK

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 9/29/2006 FJPPL Meeting@KEK

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 9/29/2006 FJPPL Meeting@KEK

GLD-PFA 9/29/2006 FJPPL Meeting@KEK

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. 9/29/2006 FJPPL Meeting@KEK

Photon Likelihood (Input) - Five variables are selected to form the photon likelihood function. trkdis velocity meanlay Edep/nhits chi2 Photon Other 9/29/2006 FJPPL Meeting@KEK

Photon Likelihood (Output) linear Cut position is set to be 0.7. Other Photon log Photon Other 9/29/2006 FJPPL Meeting@KEK

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 9/29/2006 FJPPL Meeting@KEK

Neutral Hadron Likelihood (Input) - Four variables are selected to form the NHD likelihood function. velocity Edensity Edep/nhits meanlayer Neutral Hadron Satellite Hits 9/29/2006 FJPPL Meeting@KEK

Neutral Hadron Likelihood (Output) linear Satellite Hits Neutral Hadron Cut position is set to be 0.73. log Neutral Hadron Satellite Hits 9/29/2006 FJPPL Meeting@KEK

Z -> qqbar 9/29/2006 FJPPL Meeting@KEK

Z-pole Event Display End View Side View - 2cm x 2cm tile (GLD backup solution) is used in this study. 9/29/2006 FJPPL Meeting@KEK

Event Display e+ e- Z → qqbar @ 91.2GeV Next: 電子、陽電子衝突 Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Z → qqbar @ 91.2GeV 9/29/2006 FJPPL Meeting@KEK Next: 電子、陽電子衝突

Event Display Gamma Finding Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Gamma Finding 9/29/2006 FJPPL Meeting@KEK

Event Display Charged Hadron Finding Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Charged Hadron Finding 9/29/2006 FJPPL Meeting@KEK

Event Display Satellite Hits Finding Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Satellite Hits Finding 9/29/2006 FJPPL Meeting@KEK

Event Display Remaining : Neutral Hadron Yellow : Photon Red, Green : Charged Hadron Black, Blue : Neutral Hadron Remaining : Neutral Hadron 9/29/2006 FJPPL Meeting@KEK

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 9/29/2006 FJPPL Meeting@KEK

Jet Energy Resolution - Z → uds @ 91.2GeV, new calorimeter geometry, 2cm x 2cm tile In barrel region, ILC goal of 30% has been achieved. Performance in 0.7<|cosθ|<0.8 is too bad. → Already fixed. All angle 9/29/2006 FJPPL Meeting@KEK

Energy Dependence - Energy dependence of jet energy resolution. Bad performance for higher energy. Not so bad performance for < 100 GeV Jet. 9/29/2006 FJPPL Meeting@KEK

Linearity - Good linearity. Jet energy can be corrected. 9/29/2006 FJPPL Meeting@KEK

Zh → nn h First look at the Zh events with Jupiter and realistic PFA. 9/29/2006 FJPPL Meeting@KEK

Typical Event Display Two jets from Higgs can be seen. 9/29/2006 FJPPL Meeting@KEK

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 9/29/2006 FJPPL Meeting@KEK

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. 9/29/2006 FJPPL Meeting@KEK

Fitted Results Very Preliminary Prob > 0.02 Higgs mass resolution is significantly improved. … But, Peak at prob=1 indicates the fitting didn’t work well. 9/29/2006 FJPPL Meeting@KEK

Stretch Functions Too Narrow Strange = Overestimated The stretch function should form a normal Gaussian if the X and s are proper. Too Narrow = Overestimated Strange Need to understand. 9/29/2006 FJPPL Meeting@KEK

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. 9/29/2006 FJPPL Meeting@KEK