The PFA Approach to ILC Calorimetry

Intro
   ILC Physics -> (multi)jets in background-free environment
   Optimization of jet reconstruction -> particles from cells
   PFA approach
   PFA Goal for event reconstruction

PFA requirements on ILC Calorimetry
   0) optimal use of subdetectors for particle reconstruction
      photons - ECAL
      charged hadrons, electrons - tracker
      neutral hadrons - E/HCAL
      muons - tracker/muon chambers
   1) Separation of charged and neutral hadron showers in CAL
      high transverse granularity
      high longitudinal segmentation
      -> 3D separation of showers in CAL (emphasis on 3D!)
   2) separation of photon showers from mips and hadron showers in ECAL
      resolution requirement for photons ~ 20%/sqrt(E) (1 GeV contribution to 100 GeV jet)
      dense ECAL -> longitudinal separation of EM and HAD showers
      transverse cell size ~ Moliere radius for pi0 ID, shower pointing
      again -> 3D separation of showers
   3) shower (particle) reconstruction in HCAL
      high transverse granularity and longitudinal segmentation -> 3D reconstruction
      low requirement on energy resolution in HCAL, emphasis on shower reco
      -> digital or analog HCAL readout
      resolution requirement loose ~80%/sqrt(E) (3 GeV contribution to 100 GeV jet)

PFA-motivated Detector Models
   1) GLD - large IR, TPC tracker, dense ECAL (Pb/Scin), segmented Scintillator HCAL, etc.
   2) LDC - midsize IR, TPC tracker, dense ecal (W/Si), segmented A/D HCAL Scintillator, gas, etc.
   3) SiD - small IR, Si Strip tracker, dense ECAL (W/Si), segmented A/D HCAL Scin/gas, etc.
   -> common properties - dense ECAL, magnet outside calorimeter, high gran/seg, 

PFA Results
   1) Z Pole
   2) Jet reconstruction - Dijet mass results
      Physics processes
      Jet energies

Detector Optimization Studies
   1) B-field
   2) IR to ECAL
   3) HCAL granularity
   future studies for final model designs

Summary