1. Energy Flow Studies Steve Kuhlmann Argonne National Laboratory for Steve Magill, U.S. LC Calorimeter Group

2. Introduction/Outline Detector is the “Small” Detector (Si-W EM Cal, 5 mm X 5mm, R=127 cm, 17%/  E) (Fe-Scint HAD Cal, 1 cm X 1cm, R=144cm, 60%/  E) Software is JAS2 and GIZMO simulation Conversion to Geant4 “soon” Real Track Pattern Recognition Included Will Discuss: Brief Photon Review and Plans Initial work on the Real Challenge: Neutrons/KLongs

3. Resolution components of Hadronic Z Decays at  s = 91 GeV Assuming Perfect Identification in this Detector Configuration Neutrons+KLong 2.9 GeV Photons 1.4 GeV Tracks 0.25 GeV Put together in Tesla TDR in Energy Flow algorithm

4. Hadronic Z Decay

5. Simple 3 cut analysis 1.Reject EM Clusters if within Delta-R<0.03 from Track (0.2% loss of real photons) 2.Shower Max Energy > 30 MeV (MIP=8 MeV) 3.Reject EM Cluster if Delta-R< 0.1 AND E/P<0.1 Java code is available at: www.hep.anl.gov/stk/lc/uta/ Will be put in CVS Server “soon”

6. Hadronic Z Decays at  s = 91 GeV Total Hadron Level Photon Energy (GeV) Total Photon Candidate Energy

7. Mean=0.25 GeV, Width=2.8 GeV, Perfect EFLOW Goal is 1.4 GeV. Hadronic Z Decays at  s = 91 GeV Total Photon Energy - Total Monte Carlo Photons (GeV)

8. Energy Fragments from a Single 10 GeV  -

9. Current Photon Work 1.Reject EM Clusters if within Delta-R<0.03 from Track (0.2% loss of real photons) 2.Shower Max Energy > 30 MeV (MIPS=8 MeV) 3.Reject EM Cluster if Delta-R< 0.1 AND E/P<0.1 Replace these two cuts with SLAC NNet-based ClusterID package. (Worked on technical difficulties with Bower after UTA, not solved)

10. Neutron/K0L Content of Hadronic Z Decays at  s = 91 GeV

11. Neutron/K0L Energies in Hadronic Z Decays at  s = 91 GeV Neutrons/K0L, Mean E=4.4 GeV Neutrons/K0L, Mean E=4.35

12. Study of >2 GeV Neutron/K0L overlapping >2 GeV Tracks

14. Angular Separation (radians) Separation between Track and Closest N/K0L Separation between N/K0L and Closest Track Overflow bin 10% overlap within Sep<0.2 23% overlap within Sep<0.4 48% overlap within Sep<0.2 77% overlap within Sep<0.4 Overflow bin

15. Overlapping Showers from Other Tracks 41% overlap within Sep<0.272% overlap within Sep<0.4 Separation between random >2 GeV Track and Closest >2 GeV Track Angular Separation (radians) 16% overlap within Sep<0.159% overlap within Sep<0.3

16. Single 10 GeV Charged Pions: Basic Shower Widths Angular Separation (radians)

17. Single 10 GeV Charged Pions: Means and Widths MeanWidth All Hits8.3 GeV19%60%/sqr(E) Cone<0.48.1 GeV21%67%/sqr(E) Cone<0.37.9 GeV22%68%/sqr(E) Cone<0.27.5 GeV22%70%/sqr(E) Cone<0.16.4 GeV25%80%/sqr(E) Cone<0.0755.8 GeV28%88%/sqr(E)

18. Single 10 GeV Charged Pions: EM+HAD Energy (GeV) All HitsCone<0.2 These plots are with analog hadron cal, very similar with digital

19. Select Charged Pions isolated from other tracks in Z Decays, look for Neutron Overlap Cal Energy/Track P No overlap from particle list Overlapping Neutron/K0L

20. Two approaches being investigated: 1) Put calorimeter and track properties into neural net. List of calorimeter variables put into ClusterID Net: Tesla TDR approach 2) Careful removal of track depositions from Calorimeter. Used in European package called “Snark”. Results similar to Tesla TDR, but larger resolution tails.

21. Reminder, the Questions we eventually need to Answer Detector Size and Hadron Calorimeter Resolution? Digital or Analog Hadron Calorimeter? Optimized segmentation for physics/costs?

22. Backup Slides

23. Question from Jeju and Calor2000: Will Hadronization or Jet Clustering Ruin Resolutions? No, at least if backgrounds are small

24. Particle Energies in Hadronic Z Decays at  s = 91 GeV Charged, Mean E=2.85 Photons, Mean E=1.0 Neutrons/K0L, Mean E=4.35

25. Tracking cannot be assumed to be perfect, forward tracking and “curlers” are issues Effect of ignoring charged particles below certain thresholds Tesla TDR, is fine if achieved

26. Track Reconstruction Efficient Down to Pt=0.5 GeV in Barrel Region

27. Single 10 GeV  - Delta-R from EM Cluster to Track EM Cluster Energy (GeV) EM Clustering -- Cone 0.04

28. Reduce charged particle fragments with 3-layer shower max energy > 30 MeV 2 GeV Electron 2 GeV  - ddd MeV Also reduces neutron/K0L clusters

29. Single 10 GeV  - Delta-R from EM Cluster to Track EM Cluster Energy (GeV) Now With Shower Max Cut, will be improved with more detailed information on lateral/longitudinal profile

30. Effect of possible Photon threshold on Hadronic Z Decays at  s = 91 GeV Sum of all Hadron Level energy except photons < 0.2 GeV. Won’t apply such a cut (yet). Photons are soft, Mean E=1.0

31. Hadronic Z Decays at  s = 91 GeV Simple photon finder: Remove EM Clusters within 0.03 of Track, unless track was MIP in all 30 layers. Then remove if within 0.01.

32. Hadronic Z Decays at  s = 91 GeV Probability of Overlapping Photon Close to a Track, 0.1% within DR<0.02, 3.3% within DR<0.1, 11% within DR<0.2

33. Determining Charged Particle Depositions Energy deposited in last EM layer (within 0.6 0 of track) Easy to recognize MIP Easy to recognize MIP Easy to determine 1 st layer of pion shower Easy to determine 1 st layer of pion shower Interactions Single 2 GeV  - Single 2 GeV Muon Tail OverflowsZeros

34. Determining Charged Particle Depositions Single 2 GeV  - Energy weighted

35. Effect of Neutrinos in Hadronic Z Decays

36. One more cut motivated by Single 10 GeV  -, now either an Energy Ratio Delta-R from EM Cluster to Track EM Cluster Energy/Track E