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

2. W→eν 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. 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) 47800 events available (using CBNTs) Lepton generator level filter efficiency (10Gev, |η|<2.7) was ~63.3% 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. 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. 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. ALL truth plots are normalised to weighting of simulated data EXCEPT multiplicity plots.

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

4. Electron Selection Cuts At least one electron with transverse energy > 25GeV. (Use ET rather than pT since brem recovery not properly implemented yet0 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) 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. 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. 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. ELECTRONS - truth - full sim Sanity plots: multiplicity of electrons that pass selection cuts Cuts: ET(ele) > 25GeV At least one track matched IsEM=0 η(ele) < 2.4 Almost always only one electron candidate per event passes cuts.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

24. JETS Cuts: ΔR (e-jet) > 0.7 Jet η < 2.4 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). 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. Still looking at jets with η<2.4 for accurate electron matching. There are three available clustering algorithms: There are three available clustering algorithms: Kt alorithm: apparently unsuitable for low pT jets. 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<0.4. Discounted as produces very low statistics (few jets reconstructed) Cone algorithm with R<0.7. Use this. Cone algorithm with R<0.7. Use this.

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

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

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

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

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

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

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

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

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

34. JETS Sanity plots: ET Cuts: ΔR (e-jet) > 0.7 Jet η < 2.4 - 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. 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. 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. 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. Meaning of jet “mass” not well understood, left- shift of simulation w.r.t. truth unexpected.

36. MISSING ENERGY - truth: calculated from non- interacting particles - full sim: corrected, inc. muons Sanity plots: Missing ET Probably not properly calibrated 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 Cut on MET>25GeV

37. MISSING ENERGY 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 ET Resolution: Asymmetry reflecting right-shift of data w.r.t. truth

38. MISSING ENERGY - truth - full sim 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 ET φ distribution:

39. W RECONSTRUCTION - truth - full sim 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 transverse mass reconstructed from Missing ET and highest ET electron:

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