1. General EWK Meeting 20-01-09 Christopher Rogan California Institute of Technology V+jets m/e studies with 21X: Status and plans for Marcella Bona, Emanuele Di Marco, Ran Feldesh, Joseph D. Lykken, Paolo Meridiani, C.R., Chiara Rovelli, Maurizio Pierini, Ilaria Segoni, Maria Spiropulu, Thiago Tomei, Lukas Vanelderen, Marco Zanetti

2. ◉ goal of the analyses: ◎ candle with the Z mass: validate e and m reconstruction ◎ application examples: ◍ MC tuning with the dN/dnjets and dN/dp T (Z)‏ ◍ check and correction of MET ◍ ratios good for start-up: systematics cancel ◉ references for 16X analyses: ◎ CMS notes ◉ Z+jets & W+jets Alpgen Validation: CMS AN-2008/091 ◉ Z(ee)+jets Candle Analysis: CMS AN-2008/092 ◉ Z(mm)+jets Candle Analysis: CMS AN-2008/095 ◉ W(en)/Z(ee)+jets Ratio Analysis: CMS AN-2008/096 ◉ W(mn)/Z(mm)+jets Ratio Analysis: CMS AN-2008/105 ◎ previous EWK talks on 16X analysis: ◉ summary by M.Pierini Nov 11 th 2008 ◉ note release: E. Di Marco, C. Rogan, and I. Segoni: Oct 17 th 2008 ◎ V+jets talks: ◉ e and m analyses: I. Segoni and M.Zanetti: Nov 14 th 2008 ◉ m selection: M. Bona: Nov 28 th 2008

3. Christopher Rogan - EWK Meeting 20-01-09 3 V+j so far

4. ◉ samples: 2.1.X and Fall09 ◎ signals, other Z/W decays and  tt events: MADGRAPH ◎ QCD: “InclusiveMu15” sample (muon enriched QCD)‏ ◉ general strategy for the analyses ◎ single non isolated muon trigger ◎ muon selection: optimization in the next slides ◎ Z mass window [60, 120] GeV/c 2 ◎ closest-to-the-leading-muon PV selection ◎ jet clustering (calo jets and track jets: SisCone with 0.5)‏ with E/p T and h cuts (30/15 GeV and 3/2.4, respectively)‏ ◎ 2D maximum likelihood fit: Z mass and sin(angle MET, MHT )‏ for Z+jets; transverse mass and sin(angle TS-jet )‏ ◎ floating the shape parameters for low jet multiplicities and fixing for the high multiplicities ◎ sPlots for verify shapes on data

5. ◉ muon selection in 16X ◎ only global muons ◎ p T > 15 GeV/c ◎ vertex variables and isolation variables simultaneous optimization: ◉ vertex variables: Dxy/s(Dxy) and Dz(m-PV)‏ ◉ isolation variables: tracking isolation  i p i T /p m T ECAL isolation  R<0.35 E T ECAL HCAL isolation  R<0.5 E T HCAL ◍ extensive study to select the variables and to establish the optimization procedure: done in 16X and now repeated in 21X production, the PV is displaced in x so we can calculate the distance wrt the PV but the error is calculated wrt (0,0,0)‏ so we started looking at: Dxy better for the electrons that have typically poorer tracking resolution about the same discrimination for muons (wrt the significance)‏ in 21X production, the PV is displaced in x so we can calculate the distance wrt the PV but the error is calculated wrt (0,0,0)‏ so we started looking at: Dxy better for the electrons that have typically poorer tracking resolution about the same discrimination for muons (wrt the significance)‏ Hcal isolation: H0 excluded and zero suppression introduced Hcal isolation: H0 excluded and zero suppression introduced

6. Christopher Rogan - EWK Meeting 20-01-09 6 Cut variables  i p i T /p m T  R<0.35 E T ECAL  R<0.5 E T HCAL Dz(m-PV)‏ Dxy

7. Christopher Rogan - VecBos + jets 15-01-09 7 Optimization on the W selection  Optimize the Punzi Significance:  Consider all backgrounds and scan over all cut values simultaneously, with rates normalized to 100 pb -1  Consider only events in ML fit ‘signal region’

8. Christopher Rogan - VecBos + jets 15-01-09 8 Optimization scans requiring:  R<0.35 E T ECAL  R<0.5 E T HCAL  i p i T /p m T <0.15 <2.25 GeV <2.8 GeV

9. Christopher Rogan - VecBos + jets 15-01-09 9 Dxy(PV)‏Dz(m-PV)‏ Optimization scans requiring: <0.11 cm<0.005 cm

10. Christopher Rogan - VecBos + jets 15-01-09 10 Optimized cut values 0.0045 0.005 (n.a.)‏ 0.005 0.11 0.1 0.11 (0.08)‏ 0.1 0.11 4.5 3.1 4.0 (6.0)‏ 4.1 2.8 2.0 2.5 (1.6)‏ 2.75 2.25 0.11 0.2 (0.11)‏ 0.2 0.15 Values used Values used Calo jets Track jets

11. Christopher Rogan - EWK Meeting 20-01-09 11 Optimized cut values Values used Values used 0.15 0.2 0.11 2.25 2.75 2.5 2.0 2.8 2.5 4.5 4.0 2.5 4.5 0.11 0.1 0.11 0.1 0.11 0.0055 0.005 0.0045 Calo jets Track jets

12. Christopher Rogan - EWK Meeting 20-01-09 12 Changing muon pt cut W selection

13. Christopher Rogan - EWK Meeting 20-01-09 13 Changing muon pt cut Z selection

14. Christopher Rogan - EWK Meeting 20-01-09 14 Analysis strategy Common requirements: Single non isolated HLT trigger (HLT_Ele15_LW_L1R) pixel-match GSF electron reconstruction electron identification* electron isolation* electron - PV compatibility calo-jet clustering (SisCone, ΔR=0.5) electron(s) from W(Z) cleaning from calo-jets jet counting W-specific requirements: exactly 1 electron (against Z+j) Z mass veto (decouple W+j dataset from Z+j) MET > 20 GeV (against QCD) m T (W) > 30 GeV (against QCD) Z-specific requirements: ≥2 electrons (against W+j) Z mass range (decouple Z+j dataset from W+j) yields and ratio determination: Maximum Likelihood fit efficiency correction of yields, if needed * for Z, asymmetric id+iso

15. Christopher Rogan - EWK Meeting 20-01-09 15 why re-iteration with 2.1.X ? electron reconstruction details changed w.r.t. 1.6.X. (i.e. CSA07) tracker material changed some electron identification related to tracker - ECAL match can be changed among others, H/E definition changed pre-shower is excluded HO is excluded and zero-suppression in HCAL has been introduced H/E is affected HCAL isolation is affected PV is displaced in x w.r.t. (0,0,0) In this iteration, possibly no new variables w.r.t. the ones used in CSA07 analysis are used. Various new quantities have been developed and released, will be tested in W+j/Z+j @ next round Disclaimer!

16. Christopher Rogan - EWK Meeting 20-01-09 16 Electron identification We use the set of variables from egamma POG, with selection depending on electron classification (based on f brem ) we compare 2.1.X - 1.6.X and re-optimize selection for golden / showering both barrel and endcap this defines the W electron and the first Z electron (i.e. tight) loose egamma identification on the other (asymmetric ID) tracker-ECAL match ECAL-HCAL match ECAL cluster shapes

17. Christopher Rogan - EWK Meeting 20-01-09 17 Efficiency of ele - id Cuts optimized simultaneously to maximize W signal significance against QCD QCD e.m. enriched + b,c→electrons used the optimization is driven by W+j. For Z+j, the highest pT electron is identified with the same criteria to allow efficiency cancelation in Wj/Zj the ID of the second is based on the same variables, but looser selection ε(CSA07) ε(Summer08)- 93.7 +/- 0.1 95.7 +/- 0.1-*- s9s25: 95.7 +/- 0.1 95.9 +/- 0.1-*- deta: 97.6 +/- 0.1 91.2 +/- 0.1-*- dphiIn: 98.4 +/- 0.1 98.6 +/- 0.1-*- sigmaEtaEta: 93.5 +/- 0.1 96.5 +/- 0.1-*- eOverPout: 93.7 +/- 0.1 99.2 +/- 0.1 -*- total eID: 75.5 +/- 0.2 79.0 +/- 0.2 Single electron efficiency on W+≥0j The optimized cuts egamma loose

18. Christopher Rogan - EWK Meeting 20-01-09 18 S and B yields (W+j) yields, normalized in 100 pb -1, up to electron definition. large stat error

19. Christopher Rogan - EWK Meeting 20-01-09 19 S and B yields (Z+j) yields, normalized in 100 pb -1, up to electron definition

20. Christopher Rogan - EWK Meeting 20-01-09 20 m(e + e - ) lineshapes Cruijff = Gaussian + exp tails for signal, parabola for inclusive bkg ≥1 jet≥2 jet≥3 jet Z+jets (MADGRAPH) tt+jets (MADGRAPH) consistent parameters for signal lineshape as a function of jet multiplicity

21. Christopher Rogan - EWK Meeting 20-01-09 21 m T (W) lineshapes Cafu = Crystal ball + Gaussian with same mean ≥1 jet ≥2 jet W+jetstt+jetsZ+jetsQCD decreasing importance

22. Christopher Rogan - EWK Meeting 20-01-09 22 slope correction Yields uncorrectedYields efficiency-corrected W+j Z+j e -Slope =7.5±1.2 e -Slope =6.8±0.5 e -Slope =6.9±1.1 e -Slope =6.8±0.5 W/Z = 1.09±0.20W/Z = 1.01±0.19 ⇒ eff changes the slope, but effect on double ratio is within uncertainty Preliminary

23. Christopher Rogan - EWK Meeting 20-01-09 23 slope correction Yields uncorrectedYields efficiency-corrected W+j Z+j W/Z = 0.91±0.05 ⇒ eff changes the slope, but effect on double ratio is within uncertainty e -Slope =7.32±0.09e -Slope =6.82±0.08 e -Slope =8.0±0.4e -Slope =7.4±0.3 W/Z = 0.93±0.04 Preliminary

24. Christopher Rogan - VecBos + jets 15-01-09 24 ◉ for the candle analysis: ◎ we start from the optimization values obtained for the ratio in the W selection we can afford to loosen the cut to increase efficiency ◉ muon p T > 10 GeV/c ◉ vertex variables: Dxy <0.02 cm & Dz(m-PV) <0.15 cm ◉ isolation:  i p i T /p m T <0.30 (on the second leg)‏ Preliminary

25. Christopher Rogan - EWK Meeting 20-01-09 25 Preliminary ≥1jet Background

26. Christopher Rogan - VecBos + jets 15-01-09 26 ≥1jet ≥2jet ≥3jet ≥4jet Signal

27. Christopher Rogan - VecBos + jets 15-01-09 27 ≥1jet ≥2jet ≥3jet ≥4jet Background

28. Christopher Rogan - VecBos + jets 15-01-09 28 ≥1jet ≥2jet ≥3jet ≥4jet Signal

29. Christopher Rogan - VecBos + jets 15-01-09 29 ≥1jet ≥2jet ≥3jet ≥4jet Background

30. Christopher Rogan - VecBos + jets 15-01-09 30 ◉ for the electron candle analysis: we can afford to loosen the cut to increase efficiency ◉ electron p T > 10 GeV/c ◉ loose electron ID on both legs ◉ Best Z candidate choice (highest pt electrons) ◉ vertex variables: Dxy <0.04 cm & Dz(m-PV) <0.12 cm ◉ isolation:  i p i T /p m T <0.15 (on both legs)‏ Preliminary

31. Christopher Rogan - EWK Meeting 20-01-09 31 ≥1jet ≥2jet ≥1jet ≥2jet Signal

32. Christopher Rogan - EWK Meeting 20-01-09 32 ≥1jet ≥2jet ≥1jet ≥2jet Background

33. Christopher Rogan - EWK Meeting 20-01-09 33 EXTRA SLIDES

34. Christopher Rogan - EWK Meeting 20-01-09 34 Madgraph/Alpgen Production changes  For tt+j  parton pt 20, matched at 30 MADGRAPH – KT MLM matching  x-section 317pb @ 10 TeV, x-section 750 pb @ 14 TeV  Parton pt 70, matched at 20 GeV, ALPGEN –MLM (old, IC) Matching  x-sec 450 pb @14 TeV – if 20 GeV parton pt x-sec 754 pb@14 TeV,  x-section 270 pb@ 10 TeV [15% compared to MAD, MAD>ALPGEN but different scales, PDFs see below]  Scale (m_top)^2 at MADGRAPH  Scale (M_T)^2=sum(m_top^2+P_T^2) ALPGEN  Lower Q^2 pushes the cross section up (MAD>ALPG) (10%)  PDF CTEQ6L NLO and corresponding a_s change in MADGRPAH  PDF CTEQ5L LO ALPGEN  NLO PDF pushes x-section up (MAD>ALPG) (10%)

35. Christopher Rogan - VecBos + jets 15-01-09 35 Comparison of isolation variables: CSA07 - FALL08

36. Christopher Rogan - VecBos + jets 15-01-09 36 Comparison of vertex variables: CSA07 - FALL08 significance

37. Christopher Rogan - VecBos + jets 15-01-09 37 ◉ isolation variables: tracking isolation normalized:  i p i T /p m T ECAL isolation:  R<0.35 E T ECAL HCAL isolation:  R<0.5 E T HCAL tracking isolation: tracks within DR < 0.5 ◈ at least 5 associated hits ◈ | Dz(track-PV)| < 0.1 cm ◈ |Dxy/s(Dxy)| < 5 ◈ 500 MeV/c < p T < 500 GeV/c ECAL isolation: EM calotowers in the 0.35 cone around the m m energy is not subtracted HCAL isolation: hadronic calotowers in the 0.5 cone

38. Christopher Rogan - VecBos + jets 15-01-09 38 W selection efficiencies Preliminary

39. Christopher Rogan - VecBos + jets 15-01-09 39 Z selection efficiencies Preliminary

40. Christopher Rogan - EWK Meeting 20-01-09 40 E seed /P out Major point: track p out estimation depends by the tracker material knowledge barrelendcap

41. Christopher Rogan - EWK Meeting 20-01-09 41 Δη vtx GSF-track - ECAL supercluster match larger tails for non-showering non-showering endcap bumps for η>0, η<0: tilt changed in the geometry? barrelendcap

42. Christopher Rogan - EWK Meeting 20-01-09 42 ΔΦ vtx GSF-track - ECAL supercluster match barrelendcap

43. Christopher Rogan - EWK Meeting 20-01-09 43 H/E CSA07: H/E = sum(H rechits) / supercluster energy in cone ΔR=0.1 no HCAL zero-suppression Summer08: H/E = max (H rechit / basic cluster ), the H rechit is the one above the ECAL basic cluster HCAL zero - suppression barrelendcap

44. Christopher Rogan - EWK Meeting 20-01-09 44 s 9 /s 25 Cluster shape variable barrelendcap

45. Christopher Rogan - EWK Meeting 20-01-09 45 σ ηη Cluster shape variable (cluster width) changed thresholds? barrelendcap

46. Christopher Rogan - VecBos + jets 15-01-09 46 Optimization scan requiring: Dz(m-PV)‏ Dxy(PV)‏  R<0.35 E T ECAL  i p i T /p m T  R<0.5 E T HCAL

47. Christopher Rogan - VecBos + jets 15-01-09 47  R<0.35 E T ECAL  i p i T /p m T  R<0.5 E T HCAL Dz(m-PV)‏ Dxy(PV)‏ Optimization scan requiring:

48. Christopher Rogan - VecBos + jets 15-01-09 48 Optimization scan requiring:  R<0.35 E T ECAL  i p i T /p m T  R<0.5 E T HCAL Dz(m-PV)‏ Dxy(PV)‏

49. Christopher Rogan - EWK Meeting 20-01-09 49 Optimization  Some comments:  Currently we are not including a sphericity cut or MET cut in the optimization (we will include this once I finish the W MET calibration using the Z candle)  As a result, we are cutting more tightly on these five variables relative to what we will do when including MET or sphericity - I anticipate that the signal efficiency will go up with  Ultimately, we will also do the optimization in the signal region of the ‘angular variable’ which we use in the fit - we can’t do this until we have the W MET calibration.  Hence these are probably not the ‘final’ values, but they demonstrate the procedure/philosophy of the optimization

50. Christopher Rogan - EWK Meeting 20-01-09 50 what looks different Most of the electron ID variables looks very similar to CSA07. (see backup) larger differences in: H/E, σ ηη H/E: definition changed, was H/E in a cone ΔR=0.1, now is H over- ECALseed /E seed σ ηη : noise threshold for covariance matrix calculation changed (w 0 =4.2 → 4.7): expected larger width H/E barrel σ ηη barrel

51. Christopher Rogan - EWK Meeting 20-01-09 51 what’s looks different: Δη vtx double peak for golden (i.e. when the super-cluster = 1 basic cluster) in the endcap peak>( )0 true also evaluating Δη=η clus -η genele it is a cluster problem difference 1.6.X - 2.1.X: 2.1.X has not the preshower: the cluster position (depth in crystal) accounts for it with a parameter hypothesis check. In 3.0.X preshower is back the double peak disappears η clus -η genele η Δη vtx (3.0.X)

52. Christopher Rogan - EWK Meeting 20-01-09 52 electron isolation Comparison of the variables used in the CSA07 notes Traker: sum(p T tracks )/p T ele, with internal cone veto internal cone veto found to be good and robust external cone ΔR=0.4: all similar, chosen the intermediate one ECAL: sum(E T 5x5 crystals -E T super-cluster )/E T super-cluster in a cone ΔR=0.4 electron footprint E T super-cluster not optimal, move to rechits isolation soon HCAL: sum(E T rechits )/E T super-cluster in a cone ΔR=0.4 ECAL rechits removal tracker veto cone See summary from M. Le Bourgeois: http://indico.cern.ch/contributionDisplay.py?contribId=4&confId=4 3146 http://indico.cern.ch/contributionDisplay.py?contribId=4&confId=4 3146

53. Christopher Rogan - EWK Meeting 20-01-09 53 isolation: distributions trackerECAL HCAL isolation ε(CSA07) ε(Summer08) - *- tracker: 91.8 +/- 0.4 89.025 +/- 0.2- *- ECAL: 90.3 +/- 0.4 94.748 +/- 0.2- *- HCAL: 93.6 +/- 0.4 91.989 +/- 0.2

54. Christopher Rogan - EWK Meeting 20-01-09 54 vertexing variables Used to suppress events not coming from Primary Vertex (PV): dz = z ele -z PV dxy = distance in transverse plane w.r.t. PV RMS=210μmRMS=66μm

55. Christopher Rogan - EWK Meeting 20-01-09 55 jet multiplicity dependency (1) efficiency variations in different multiplicities change the slope V+(n-1)j / V+(n)j but mostly cancels out in double ratio W+nj / Z+nj (W ele and 1 st ele of Z have the same selection) Z+jets: no variations at all re-estimate on Fall08 samples with HLT

56. Christopher Rogan - EWK Meeting 20-01-09 56 jet multiplicity dependency (2) W+jets: 2% drop at each added jet re-estimate on Fall08 samples with HLT

57. Christopher Rogan - EWK Meeting 20-01-09 57 maximum likelihood fit signal, backgrounds yields extracted on data with extended, maximum likelihood fit for Z+≥1jet also Z lineshape parameters extracted on data Z+jets: 1dim fit: P=PDF(m ee ) W+jets: 1dim fit: P=PDF(m T W ) N i =signal and backgrounds yields Z+jets: i=signal, tt W+jets: i=signal, tt+QCD, Z+jets total number of events entering the fit (i.e. extended likelihood)

58. Christopher Rogan - VecBos + jets 15-01-09 58 Tracking Isolation  i p i T /p m T comparison wrt the jet bin

59. Christopher Rogan - VecBos + jets 15-01-09 59 ECAL Isolation  R<0.35 E T ECAL comparison wrt the jet bin

60. Christopher Rogan - VecBos + jets 15-01-09 60 HCAL Isolation  R<0.5 E T HCAL comparison wrt the jet bin

61. Christopher Rogan - VecBos + jets 15-01-09 61 vertex variable: Dz(m-PV)‏ comparison wrt the jet bin

62. Christopher Rogan - VecBos + jets 15-01-09 62 vertex variable: Dxy comparison wrt the jet bin

63. Christopher Rogan - VecBos + jets 15-01-09 63 W selection results Calo jets Preliminary 16X numbers: CAVEAT different cuts and different energy!

64. Christopher Rogan - VecBos + jets 15-01-09 64 W selection results Track jets Preliminary

65. Christopher Rogan - VecBos + jets 15-01-09 65 Z selection results Calo jets Preliminary 16X numbers: CAVEAT different cuts and different energy!

66. Christopher Rogan - VecBos + jets 15-01-09 66 Z selection results Track jets Preliminary

67. Christopher Rogan - EWK Meeting 20-01-09 67 W slopes Calo jets

68. Christopher Rogan - EWK Meeting 20-01-09 68 W slopes Track jets

69. Christopher Rogan - EWK Meeting 20-01-09 69 Z slopes Calo jets

70. Christopher Rogan - EWK Meeting 20-01-09 70 Z slopes Track jets

71. Christopher Rogan - EWK Meeting 20-01-09 71 Calo jets Track jets

72. Christopher Rogan - EWK Meeting 20-01-09 72 W/Z Ratio