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e n qq: background and electron id

e n qq: background and electron id. Andrea Venturi. Two normalization discrepancies: After pre-selection, before lepton-id Background simulation has to be as much as possible complete After pre-selection and lepton-id lepton id and background with electron have to be simulated correctly.

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e n qq: background and electron id

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  1. enqq: background and electron id Andrea Venturi enqq background and e-id - Andrea Venturi

  2. Two normalization discrepancies: After pre-selection, before lepton-id Background simulation has to be as much as possible complete After pre-selection and lepton-id lepton id and background with electron have to be simulated correctly Normalization discrepancies Pre-selected after e-id Pre-selected Before e-id qqbar Zee 2 photons hatched: hadrons enqq background and e-id - Andrea Venturi

  3. Missing events before electron-id Distributions of variables like lepton candidate isolation, visible mass, charged multiplicity show that it is not possible to recover the missing events by rescaling one of the background MC component. Background simulation enqq background and e-id - Andrea Venturi

  4. New untagged gg hadrons MC is available in PYTHIA thanks to Brigitte and Alex Finch (tuning) includes better treatment of VDM and non-perturbative processes It seems it is what we were missing PYTHIA vs PHOT02 as gg hadrons enqq background and e-id - Andrea Venturi

  5. PYTHIA recovers almost all the missing events but: is it ok in the selected phase space region (e-id + NN) ? less events with electron in the detector no selected events with the present MC statistics: PHOT02: 10+/-2 fb (at 189 GeV) PYTHIA: 0 (+/- 5 fb) (at 189 GeV) missing events in some distributions after electron-id ? PYTHIA vs PHOT02: a closer look • PYTHIA PHOT02 ud PHOT02 cc enqq background and e-id - Andrea Venturi

  6. Pre-selection + electron-id enqq background and e-id - Andrea Venturi

  7. We have some MC events full 4f ZZ-like (no WW-like) final states 60K at 189 GeV ~130K at 207 GeV ~20K at each other energy They can be used to replace and test other background MC: PYTHIA ZZ (NC8) PYTHIA Zee gg leptons gg hadrons ??? Possible double counting with gg hadrons only perturbative events in KoralW a posteriori it seems that PYTHIA gg could be combined safely Effect on background evaluation PHOT02 + PYTHIA ZZ/Zee PYTHIA gg + PYTHIA ZZ/Zee PYTHIA gg + KoralW 4f enqq 2-1 : 88 – 97 = -10+/-3 fb 3-2 : 111 – 88 = 23+/-4 fb 1-3 : 97 – 111 = -14+/-4 fb mnqq ~3+/- 2 fb tnqq ~5+/-4 fb KoralW vs PYTHIA ZZ/Zee (+2 photons) enqq background and e-id - Andrea Venturi

  8. PHOT02 + ZZ/Zee Pre-selection + electron-id PYTHIA gg + KoralW enqq background and e-id - Andrea Venturi

  9. PHOT02 + ZZ/Zee electron-id + NN cut PYTHIA gg + KoralW enqq background and e-id - Andrea Venturi

  10. Electron estimators are calibrated with electrons (Paolo A.) What about hadrons ? it looks like RI is not properly simulated, after Paolo corrections, for hadrons Electron – id : estimator calibration Pre-selected no electron-id enqq background and e-id - Andrea Venturi

  11. Possible causes: Different resolution different effective e/hadron separation Calibration is not enough smearing is needed Different quality of electron and hadron simulation different calibration for electron and hadrons Absolute ionization of hadrons is well simulated, while electrons are not well reproduced RI for hadrons enqq background and e-id - Andrea Venturi

  12. Applied correction: in MC events RI for hadrons is computed using expected mean value and resolution as in real data only to the wire dE/dx (pads to be investigated) RI correction 3<P<8 GeV 20<P<40 GeV enqq background and e-id - Andrea Venturi

  13. Present electron -id Pre-selection + electron – id NEW electron -id enqq background and e-id - Andrea Venturi

  14. Effect on background enqq: ~2 fb difference tnqq: ~2 fb difference Effect on efficiency matrix tnqq as enqq: (189 GeV) from 3.7% to 4.1% tnqq as tnqq from 65.9% to 65.7% Hopefully, this correction can be applied using next CN version. Correction effect enqq background and e-id - Andrea Venturi

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