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Validation of DC3 fully simulated W → e ν samples (NLO, reconstructed in 11.0.42)

Validation of DC3 fully simulated W → e ν samples (NLO, reconstructed in 11.0.42). Laura Gilbert 01/08/06. W → e ν from MC@NLO, full sim. Original sample submitted for generation in December, some of the one million W → e - ν now fully simulated on the grid, in batches of 10k events.

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Validation of DC3 fully simulated W → e ν samples (NLO, reconstructed in 11.0.42)

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  1. Validation of DC3 fully simulated W→eν samples (NLO, reconstructed in 11.0.42) Laura Gilbert 01/08/06

  2. W→eνfrom MC@NLO, full sim • Original sample submitted for generation in December, some of the one million W→e-ν now fully simulated on the grid, in batches of 10k events. • 47800 events available (using CBNTs) • Lepton generator level filter efficiency (10Gev, |η|<2.7) was ~63.3% • Generated cross section is 8.4nb (cf. 30nb for W→l-ν: TDR). Luminosity for 10k events is 1.9pb-1. • Cuts applied at any stage are listed on top right of slide. • ALL truth plots are normalised to weighting of simulated data EXCEPT multiplicity plots.

  3. ELECTRONS Sanity plots: multiplicity - truth - full sim

  4. Electron Selection Cuts • At least one electron with transverse energy > 25GeV. (Use ET rather than pT since brem recovery not properly implemented yet0 • Electron candidate has at least one associated track matched (exclude photons) • η < 2.4. This cuts out dubious candidates at the end of the electromagnetic calorimeter. • IsEM flag = 0, electron isolation cut. This should now be tuned correctly but I need to look into the bitwise cuts in more detail to check.

  5. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 ELECTRONS Sanity plots: multiplicity of electrons that pass selection cuts - truth - full sim Almost always only one electron candidate per event passes cuts.

  6. ELECTRONS Checking cuts with truth info: Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 Initially tracks of candiadates entered into egamma container include kaons, pions, muons. After cuts only electrons remain. - before cuts - after cuts

  7. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 ELECTRONS Sanity plots: phi - truth - full sim

  8. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 ELECTRONS Sanity plots: eta - truth - full sim

  9. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 ELECTRONS Identifying electrons with their partner in truth containers, matching (η,φ) space: If (ΔR<0.1) match is found

  10. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 ELECTRONS Sanity plots: ET - truth - full sim

  11. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 ELECTRONS Difference between simulated and truth ET distributions: PROBLEM? No overall difference between simulated and truth ET shapes!

  12. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 • ΔR<0.1 (matching sim to truth) ELECTRONS Electron ET resolution: (sim-truth)/truth for matched sim:truth electron pairs. Resolution looks roughly ok though…

  13. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 ELECTRONS "Wrong sign" electrons found from associated track q/p, AFTER cuts: Wrong sign Correct sign *PROBLEM*

  14. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 ELECTRONS ET distribution of "wrong sign" electron candidates: - +ve charge electrons (from track q/p) - all electron candidates (for shape comparison)

  15. Cuts: • ET (ele truth) > 25GeV ELECTRONS Consider truth information: just cut on ET > 25GeV There are positrons present in egamma truth, but none pass ET cut. - before cuts - after cuts

  16. ELECTRONS • What are the wrong sign electrons? • Not generated positrons • Don't have high pT tracks, so probably not electrons mis-reconstructed. • Possibly wrong track-cluster combinations. Needs further investigation.

  17. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • η(ele) < 2.4 ELECTRON ISSUES • Further investigation needed: • E over p always 0! → needs to be fixed in future. • Where do the "positrons" come from? • Need to look into IsEM flags in detail.

  18. ELECTRON JETS W Transverse mass plots look fishy if I apply exclusions on events containing jets with ET>30GeV. Therefore many jets come from electrons. Identify and exclude these electron jets. Can only be one on jets with η<2.5 to make electron matching possible. (Jets reconstructed using cone algorithm with R<0.7, see later)

  19. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • Jet η < 2.5 ELECTRON JETS Matching electrons and jets in (η,φ) space: - truth - full sim Log scale→ Identify jets with electrons if ΔR<0.7

  20. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • Jet η < 2.4 ELECTRON JETS Matching electrons and jets in energy: Trying to match energy as well as (η,φ) distribution (no cut made): Jets are corrected to have more energy than electron candidates so -ve values more likely to be a match. - truth - full sim

  21. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • Jet η < 2.4 ELECTRON JETS A closer look at electron-jet ΔR and energy distributions: simulation Smattering of events here

  22. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • Jet η < 2.4 ELECTRON JETS A closer look at electron-jet ΔR and energy distributions: truth no events here

  23. Cuts: • ET(ele) > 25GeV • At least one track matched • IsEM=0 • Jet η < 2.4 ELECTRON JETS A closer look at electron-jet ΔR and energy distributions: (truth - simulation) Truth - simulated This is the normalised difference of the last two plots! Energy difference (MeV) ΔR

  24. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 JETS • Looking at all jets which have not been matched with electrons: ie. Jets which are isolated from electron candidates by at least 0.7 in (η,φ). • Still looking at jets with η<2.4 for accurate electron matching. • There are three available clustering algorithms: • Kt alorithm: apparently unsuitable for low pT jets. • Cone algorithm with R<0.4. Discounted as produces very low statistics (few jets reconstructed) • Cone algorithm with R<0.7. Use this.

  25. JETS Sanity plots: multiplicity before any selection: - truth - full sim

  26. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 JETS Sanity plots: multiplicity after electron/jet matches removed, jet η<2.4 - truth - full sim Log scale→ Multiplicity greatly reduced

  27. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 JETS Sanity plots: phi - truth - full sim

  28. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 JETS Sanity plots: eta - truth - full sim Shape before η cut

  29. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 • ΔR(jet-truth)<0.5 JETS Matching jets with truth in (η,φ) space: Log scale→ If (ΔR<0.5) match is found

  30. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 JETS Sanity plots: ET - truth - full sim Jets not reconstructed < 10GeV

  31. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 • ΔR(jet-truth)<0.5 JETS ET resolution: (sim-truth)/truth

  32. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 JETS Sanity plots: Energy - truth - full sim

  33. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 • ΔR(jet-truth)<0.5 JETS Energy resolution: (sim-truth)/truth

  34. Cuts: • ΔR (e-jet) > 0.7 • Jet η < 2.4 JETS Sanity plots: ET - truth - full sim Strange: data is shifted down from truth.

  35. JET ISSUES • Jets from electrons are easily identified and removed by an exclusion cut in (η,φ) space. • Not certain this is the best algorithm, but other available algorithms have more problems. • Jet statistics low after removal of electrons, therefore resolutions not well defined. • Meaning of jet “mass” not well understood, left-shift of simulation w.r.t. truth unexpected.

  36. Cuts: • Ptele > 25GeV • At least one track matched • IsEM=0 • Electron η < 2.4 • Jet η < 2.4 • ΔR (e-jet) > 0.7 • MET>25GeV MISSING ENERGY Sanity plots: Missing ET Probably not properly calibrated - truth: calculated from non-interacting particles - full sim: corrected, inc. muons Cut on MET>25GeV

  37. Cuts: • Ptele > 25GeV • At least one track matched • IsEM=0 • Electron η < 2.4 • Jet η < 2.4 • ΔR (e-jet) > 0.7 • MET>25GeV MISSING ENERGY Missing ET Resolution: Asymmetry reflecting right-shift of data w.r.t. truth

  38. Cuts: • Ptele > 25GeV • At least one track matched • IsEM=0 • Electron η < 2.4 • Jet η < 2.4 • ΔR (e-jet) > 0.7 • MET>25GeV MISSING ENERGY Missing ET φ distribution: - truth - full sim

  39. Cuts: • Ptele > 25GeV • At least one track matched • IsEM=0 • Electron η < 2.4 • Jet η < 2.4 • ΔR (e-jet) > 0.7 • MET>25GeV W RECONSTRUCTION W transverse mass reconstructed from Missing ET and highest ET electron: - truth - full sim

  40. Conclusions: • The W looks like TDR (right)! • Electrons are well reconstructed. • The e/p variable in the egamma container should probably be fixed. • Electrons with mis-identified charge not yet understood. • Missing energy doesn’t seem best corrected to match truth. • Insufficient stats for decent jet resolution. • Jet “mass” shift seems strange.

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