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Pass 6 Topology (TKR) Analysis

TKR (Topology) Schematic. Create variables for use in this analysis. Veto the Interrupted Shower Topology. Use ToT to kill Range-outs & Heavy Ions. Divide up into 3 Topological groups and apply PreFilters and CTs. Pass 6 Topology (TKR) Analysis. What's new in Pass 6 Global IST Veto

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Pass 6 Topology (TKR) Analysis

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  1. TKR (Topology) Schematic Create variables for use in this analysis Veto the Interrupted Shower Topology Use ToT to kill Range-outs & Heavy Ions Divide up into 3 Topological groups and apply PreFilters and CTs Pass 6 Topology (TKR) Analysis • What's new in Pass 6 • Global IST Veto • Global Heavies & Range-outs Veto

  2. A New Background Class Identified (Robert Johnson) Incoming e+ and e- can interact in the first few layers going to an all-neutral state. The resulting gammas can then pair convert particularly in the thick layers.

  3. Interrupted Shower Cut AcdTileEventEnergyRatio > max(.003, (6 - TkrUpstreamHC)* .006) & AcdTileEventEnergyRatio > (-.015 - .00002*AcdTkr1ActiveDistENorm) & TkrUpstreamHC > 0 Events in RED - Vetoed Note: This cut could be broken out as a separate stand-alone cut to improve efficiency for some Event Classes What's Killed What's Left Max loss: ~ 7% around 500-1000 MeV

  4. Heavy Ions & Range outs from Below MIP Range Outs Tracker ToTs give a dE/dX meas. Plotting Tkr1ToTFirst vs CTBBestLogEnergy suggested that scaling the ToT to energy had merit: ScaledToT = Tkr1FirstTot * 2.5/CTBBestLogEnergy Decoding by Source Type Heavies & Range Out Cut Tkr1ToTFirst < .2 & CTBBestEnergy < 25000) | Tkr1ToTFirst * 2.5/CTBBestLogEnergy > 6.5

  5. Totals Totals Which Sources are Effected by these new vetos Heavy Ion / Range-out Veto Interupted Shower Veto The IS Veto seems to take out more then just e+/e- The HR Veto does its job well

  6. Topology Classes VTX Tkr1CoreHC is the number of extra hits close to the first track. Electrons/positrons like to make lots of delta-rays. You can use this variable directly or as a ratio to the number of hits on the first track

  7. Another good discriminator is the track-dispersion. This variable measure how spread out the various found tracks are in the detector. EM showers make bundles of closely packed tracks VTX Topology Veto Tkr1CoreHC > 1 & TkrDispersion < 400

  8. TKR VTX CT NodeSplit/Remainder: 30/10 6 Trees 2k/Tree

  9. 1Tkr Front Again it’s a question of which to use: the scaled Core Hit Count or 1Tkr Front Veto Tkr1CoreHC < 2 This seems like a big hit, except there are not a lot of Gammas in this class

  10. TKR 1Tkr Front CT Node Split/Remainder: 30/10 5 Trees 2k/Tree

  11. Note: The numbers in various parts here are not the same due to different data samples that were used over time to do this: v13r7, v13r9, and partial and full samples 1Tkr Back 1 Tkr Back Veto Tkr1CoreHC < 1 This is more serious. There are just very few handles on these events. They are dirty

  12. TKR 1Tkr Back CT Node Split/Remainder: 30/10 20 Trees 2.5k/Tree

  13. nTKR Topology nTkr Topology Veto Tkr1CoreHCRatio > .1 & CTBBestEnergy > 50 & TkrDispersion < 300

  14. TKR nTkr CT Node Split/Remainder: 30/10 20 Trees 3k/Tree

  15. Pass 5 - Pass 6 PreFilter Comparison Pass 6 sacrofices 3.5% Gamma efficiency for a 1.5x improvement in background rejection power

  16. Pass 5 - Pass 6 CT Comparison Pass 5 Pass 6

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