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Strategy for TTbar systematic analysis

Strategy for TTbar systematic analysis. Andrey Khoroshilov. Bergische Universitaet Wuppertal. 16. Aug 2012. Introduction. The decay of pair produces 2 b-jets Some of systematic errors have different impacts on 1-b and 2-b tagged samples. 2-b tag sample has almost no background.

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Strategy for TTbar systematic analysis

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  1. Strategy for TTbar systematic analysis Andrey Khoroshilov Bergische Universitaet Wuppertal 16. Aug 2012

  2. Introduction • The decay of pair produces 2 b-jets • Some of systematic errors have different impacts on 1-b and 2-b tagged samples. • 2-b tag sample has almost no background. • Sensitivity of the analysis can be improved by splitting analyzed data by 1 and 2 b-tagged samples. 2

  3. Control plots for 4.7 fb-1 3

  4. QCD fit Muons Electrons I have few events difference in number events with other groups. That should be fixed in next iteration. QCD fit works properly. 4

  5. Control plots for electron channel 5

  6. Control plots for muon channel 6

  7. List of systematics • IFSR (ttbar) ← AcerMC+Pythia • Btagging (ttbar, wjets, …, Zprime) • JES (ttbar,wjets, …, Zprime) • Ptjmin10, iqopt3 (Wjets) • Parton Shower & Fragmentation (ttbar): MC@NLOHerwig ± |PowhegHerwig - MC@NLOHerwig| MC@NLOHerwig ± |PowhegHerwig - PowhegPythia| • Need to implement MC_truth for detailed study of systematic behavior • Add all systematics used by TTbar group 7

  8. BtagSyst (electron channel, ttbar) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 8

  9. BtagSyst (muon channel, ttbar) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 9

  10. Relative Btag systematic • 2-b tags • 1-b tags • Inclusive ATLAS work in progress Almost no Btag relative uncertainty for 1-tag (2÷3%), large effect for 2-tag (22÷27%)! Slight systematic error dependence from mtt for 2-b sample 10

  11. JES (electron channel, ttbar) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 11

  12. JES (muon channel, ttbar) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 12

  13. IFSR (electron channel, ttbar) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 13

  14. IFSR (electron channel, ttbar) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 14

  15. BtagSyst (electron channel, Wjets) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 15

  16. BtagSyst (muon channel, Wjets) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 16

  17. JES (electron channel, Wjets) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 17

  18. ptjmin10 (electron channel, Wjets) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 18

  19. ptjmin10 (muon channel, Wjets) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 19

  20. iqopt3 (electron channel, Wjets) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 20

  21. iqopt3 (muon channel, Wjets) 1..2 b-tags 1..2 b-tags 0..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 2 b-tags 1 b-tags 21

  22. 0..2 b-tags 1..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags MC@NLOHerwig ± |PowhegHerwig - MC@NLOHerwig|Electron channel 0..2 b-tags 1..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 22

  23. MC@NLOHerwig ± |PowhegHerwig - MC@NLOHerwig|Muon channel 0..2 b-tags 1..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 23

  24. MC@NLOHerwig ± |PowhegHerwig - PowhegPythia|Electron channel 0..2 b-tags 1..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 24

  25. MC@NLOHerwig ± |PowhegHerwig - PowhegPythia|Muon channel 0..2 b-tags 1..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 25

  26. IFSR ← AcerMC+Pythia (electron channel, ttbar) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 26

  27. IFSR (muon channel, ttbar) 1..2 b-tags 0..2 b-tags • Up • Default • Down 0 b-tags 1 b-tags 2 b-tags 27

  28. Limit settings results Zprime: no systematicsttbar: JES, PS, IFSR, Frag, btagW+jets: btag, JES, ptjmin10, iqopt3 28

  29. Conclusion • Limit settings results from Markus look promising • Need one more production round with latest version of Kolophon • Need MC_truth tool • Include all systematics in analysis • Make the same analysis for boosted. 29

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