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Energy Flow Studies

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

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Energy Flow Studies

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  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 • Reject EM Clusters if within Delta-R<0.03 from Track (0.2% loss of real photons) • Shower Max Energy > 30 MeV (MIP=8 MeV) • 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 Photon Candidate Energy Total Hadron Level Photon Energy (GeV)

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

  8. Energy Fragments from a Single 10 GeV -

  9. Current Photon Work • Reject EM Clusters if within Delta-R<0.03 from Track (0.2% loss of real photons) • Shower Max Energy > 30 MeV (MIPS=8 MeV) • 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=4.35 Neutrons/K0L, Mean E=4.4 GeV

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

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

  14. Study of >2 GeV Neutron/K0L overlapping >2 GeV Tracks Separation between Track and Closest N/K0L Separation between N/K0L and Closest Track Overflow bin Overflow bin Angular Separation (radians) Angular Separation (radians) 10% overlap within Sep<0.2 48% overlap within Sep<0.2 23% overlap within Sep<0.4 77% overlap within Sep<0.4

  15. Overlapping Showers from Other Tracks Separation between random >2 GeV Track and Closest >2 GeV Track Angular Separation (radians) 16% overlap within Sep<0.1 59% overlap within Sep<0.3 41% overlap within Sep<0.2 72% overlap within Sep<0.4

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

  17. Single 10 GeV Charged Pions: Means and Widths

  18. Single 10 GeV Charged Pions: All Hits Cone<0.2 EM+HAD Energy (GeV) EM+HAD Energy (GeV) 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 No overlap from particle list Overlapping Neutron/K0L Cal Energy/Track P

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

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

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

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

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

  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 • Easy to recognize MIP • Easy to determine 1st layer of pion shower Energy deposited in last EM layer (within 0.60 of track) Interactions Zeros Overflows Tail Single 2 GeV - Single 2 GeV Muon

  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 EM Cluster Energy/Track E Delta-R from EM Cluster to Track

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