Progress with the Development of Energy Flow Algorithms at Argonne José Repond for Steve Kuhlmann and Steve Magill Argonne National Laboratory Linear Collider Workshop, Amsterdam, April 1 – 4, 2003

Simulation Software Package JAS and GIZMO Conversion to GEANT4 soon Detector SD or ‘Small’ detector Si-W ECAL 5x5 mm 2 Scintillator-Fe HCAL 10x10 mm 2 Track pattern recognition included

Overview of Algorithm 1 st step - Track extrapolation thru Cal – substitute for Cal cells in road (core + tuned outlyers) - analog* or digital techniques in HCAL – S. Magill 2 nd step - Photon finder (use analytic long./trans. energy profiles, ECAL shower max, etc.) – S. Kuhlmann 3 rd step - Jet Algorithm on tracks and photons - Done 4 th step – include remaining Cal cells (neutral hadron energy) in jet (cone?) Optimize Cal segmentation for separation of charged/neutral clusters * V. Morgunov, CALOR2002

Define D-weight: - for every cell - area of ~ 40 cells - D-weight = #/40 E-weight: - simply take energy of cell     cell density weight = 3/40 area ~ 40 cells red – E fraction for density > 1/# blue – E fraction outside area # cells in window digital cal analog cal T rack E xtrapolation/ S hower L ink A lgorithm

D-Weights: in ECAL at Interaction Layer layers after π interacts Response to single π with 10 GeV… #events·weight If D-weight: ≡ 1 Breit-Wigner ≡ n/40 Gaussian θ φ

D-Weights: in HCAL at Interaction Layer 10 If D-weight: ≡ 1 Breit-Wigner ≡ n/40 Gaussian θ φ

E-CAL: Energy in cell vs cell density MIP signal at 8 MeV cell density n/40 cell energy (GeV)

MIP signal at 36 MeV what’s this? cell energy (GeV) cell density n/40 H-CAL: Energy in cell vs cell density Soft stuff in Scintillator???

HCAL: analog E fraction only sum up if E cell ≥ 1 MIP ΣE/10 GeV Some losses… Effect on energy resolution to be investigated…

HCAL: Cell Density (in 40 cell window) 31% single cell windows mean ~ 4 cells

Seed Cell Distribution defined as cell w/ cell density > 1/40 In most cases number of seed cells = 0 Number of seed cells

D-weights: comparison with event display Blue – all Red – density > 1/40 Green – density > 3/40

T rack E xtrapolation/ S hower L ink A lgorithm 1. Pick up all seed cells close to extrapolated track - Can tune for optimal seed cell definition - For cone size < 0.1 (~6 o ), get 85% of energy 2. Add cells in a cone around each seed cell through n layers 3. Linked seed cells in subsequent cones form the reconstructed shower 4. Discard all cells linked to the track

Hadronic Z decays at √s = 91 GeV… To develop Photon finder

Cuts to select photon clusters and reject anything else I. EM clusters rejected within 0.03 of extrapolated track within 0.01 if track MIP in all 30 layers II. EM clusters required to have shower maximum energy > 30 MeV (SME is sum of layers 8,9 and 10) still needs fine tuning III. Require E cluster /p track > 0.1, if EM cluster within 0.1 of track Definition of EM cluster Cluster of calorimeter energies within a cone of 0.04 No requirement on E ECAL /E HCAL or E HCAL

Small loss of EM clusters I. Cut on distance to track Probability of overlap of γ and track 0.1% within ΔR < % within ΔR < % within ΔR < 0.2 Reject EM clusters if ΔR < 0.03 < 0.01 if MIP in all 30 layers of ECAL

2 GeV e - 2 GeV  - MeV II. Cut on energy at shower maximum MeV Require SME > 30 MeV

ΔR from EM Cluster to Track EM Cluster Energy/Track E III. Energy – momentum ratio Clusters left after previous cuts 10 GeV π - Require E cluster /p track > 0.1 for ΔR <0.1

Hadronic Z Decays at  s = 91 GeV Total Hadron Level Photon Energy (GeV) Total Photon Candidate Energy After all cuts…

μ EM = 0.25 GeV σ EM = 2.8 GeV Hadronic Z Decays at  s = 91 GeV Total Photon Energy - Total Monte Carlo Photons (GeV) Perfect EFA Goal σ EM = 1.4 GeV Compare to h 0 σ h = 2.9 GeV

Simulation of different active media Gas Electron Multipliers J Li, A White, J Yu: University of Texas in Arlington Simulation of both detailed and simple GEM geometries Resistive Plate Chambers L Xia: Argonne National Laboratory Single π Resolution

Summary 1.Continuing work on implementation of algorithm 2.Tune to single particles first, then to particles in jets 3.Implement photon finder 4.Deal with neutral hadron energy 5.Compare performance to analog version (SNARK) 6.Use EFA to optimize transverse cell size of DHCAL 7.Compare performance with different active media: Scintillator, GEMs and RPCs