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Z τ+τ Analysis

Z τ+τ Analysis. Joshua Swanson. Action Items. Use single electron and single muon triggers.  Add trigger matching This was done last week. plot genET-ET(SC) with statistical information. Look at cuts to eliminate background. Electron Reconstruction.

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Z τ+τ Analysis

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  1. Z τ+τ Analysis Joshua Swanson Joshua Swanson

  2. Action Items • Use single electron and single muon triggers.  Add trigger matching • This was done last week. • plot genET-ET(SC) with statistical information. • Look at cuts to eliminate background Joshua Swanson

  3. Electron Reconstruction • Most events are reconstructed within 1 GeV of their actual Et. • It is slightly skewed towards the high side but this is expected. Joshua Swanson

  4. Electron ID Variable • The Tight ID is clearly the best with a significance of 12.45, it kills 93.2% of the bkgd and only 47.6% of the signal. Joshua Swanson

  5. Inclusive Z τ(electron)+ τ(hadron) Search. Joshua Swanson Joshua Swanson

  6. Details • Dataset: /Ztautau/Summer08_IDEAL_V11_redigi_v2/GEN-SIM-RECO • CMS Version: CMSSW_2_2_13. • Analysis done using PAT v2 and PF2PAT. • Analysis is normalized to a luminosity of 1 fb-1. • This analysis is done in preparation for my preliminary examination at UW next Spring. Joshua Swanson

  7. Background • The major sources of background for Z->τ(e)+τ(h). • QCD (Pythia EM Enriched sample Pt bins 20-30, 30-80, and 80-170) • W+Jets (Madgraph) • Photon+Jets (Pythia using Pt bins up to 800) Joshua Swanson

  8. Pre-Selection • Require event to pass HLT-Ele15-LW-L1R • Require reconstruction of a PAT e and PF τ • Impose a 5 GeV visible invariant mass cut. • Require that particles are visible within the detector (abs(η)<2.5). Joshua Swanson

  9. Initial Cuts • Require the electron to pass the version 1 tight ID. • Require either 1 or 3 tracks in the signal cone. • Require the sum of the charge (τ+e) equals zero. • Apply e and μ discrimination for the τ. Joshua Swanson

  10. Ecal Isolation Reject Joshua Swanson

  11. Track Isolation Reject Joshua Swanson

  12. Tau Pt Reject Joshua Swanson

  13. Transverse mass of the e & PF MET. Reject Joshua Swanson

  14. Require the τ and e are back to back. Reject Joshua Swanson

  15. Cut on Invariant Mass of the τ and e Reject Joshua Swanson

  16. Final Results • Still need to cut out some more QCD possibly cut a little tighter. • Significance = 37.7 • Signal/Bkgd = 0.58 Joshua Swanson

  17. Next steps • Move to 3_1_X and use new Summer09 samples when available. • Work on better τ reconstruction efficiency. Joshua Swanson

  18. Back Up Slides Joshua Swanson

  19. Electron efficiency using a V01 Tight ID • Gen Electrons (passing tight ID and matched) divided by all gen electrons. Joshua Swanson

  20. Tau Efficiencies • Gen taus (matched) divided by all gen taus. Joshua Swanson

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