Update on WZ analysis electron channel Zhijun Liang

Update on W/Z analysis (electron channel) Zhijun Liang University of Oxford 1

Introduction • Wgamma production TGC • W measurement can probe WW triple gauge boson coupling (TGC) vertex • Events selected with 1 isolated lepton (e, ) , 1 isolated photon, large ETmiss • Main background: • W+jets (jet fakes as ) • Z+ /jets (one lepton not Id, jet mis-Id as ) • ttbar production ATL-COM-PHYS-2010 -296 • Very interesting physics of TGC couping in high pt region. 2

Data Samples Electron: • Dataset : L 1 Calo stream (period A to D) Egamma stream( E to F 2) • Trigger : L 1_EM 14 for (period A to E) EF_e 15_loose(period F) EF_e 15_medium(period G, H, I) • Ntuple : Standard model D 3 PD • GRL : from W/Z (electron) observation group , from period A to I • Zee GRL: L=36. 55 pb-1 • Wenu GRL : L=36. 4 pb-1 3

Event Selection Electron: • W( e ) selection cuts • Egamma GRL, MET Clean-up • L 1_EM 14(A~E) or EF_e 10_medium(F), EF_e 15_medium(period G, H 1) • n. Vtx>=1 (n. Trk>=3) • Electron selection : • Pt>20 Ge. V, | |<2. 5(no crack), OTX cut, Is. EM robuster tight • MET>25 Ge. V, MT(e, )>40 Ge. V • Z veto: no second medium electron • Photon selection: • | |<2. 5 (no crack 1. 37 -1. 52) , d. R( , )>0. 7 • Pt>15 Ge. V, pass OTX cut • Loose Photon • Isolation : Et. Cone 40 < 3 Ge. V 4

W Data Cut Flow Electrons GRL, Trigger, Primary Vtx cut, MET Clean, At least one Electron Pt>20 Ge. V, | |<2. 5(no crack) At least one electron pass Robuster tight 528481 Z veto (no second medium electron) 517181 MET>25 Ge. V 125742 MT>40 Ge. V 118173 Photon: | |<2. 5 (no crack), d. R( , )>0. 7 Pt( )>15 Ge. V OTX cut 2014 Loose photon (is. EM loose) 350 Robust tight photon 122 5

Signal and Background Prediction Using MC (electron channel) • Number of signal and background events normalized to L=36. 4 pb-1 Cuts W(enu)+ W(taunu) J +J W(+)g W(-)g Wg robuster tight+GRL+Trigger+…. 186. 16 111. 31 297. 45 142470. 76 142422. 293. 13 50 117358. 227. 86 67 Zveto 183. 48 109. 67 MET>25 140. 51 87. 35 MT>40 138. 39 84. 55 222. 16 29. 56 21. 60 27. 80 Robust Tight photon Ph d. R(e, ph)<0. 7, eta-pt cut, OTX Is. EM loose photon Photon Isolation<3 Ge. V Zee ttbar Total MC Data 22011. 3 844. 55 171709 528481 9 11705. 4 6083. 17 801. 12 161305 517181 6 6085. 59 3264. 79 345. 06 682. 88 121879 125742 116236. 62 2861. 82 304. 04 567. 06 120191 118173 51. 16 1227. 64 40. 06 21. 84 172. 96 1513 2014 20. 56 48. 36 213. 79 7. 36 12. 50 18. 34 300. 35 350 21. 45 16. 26 37. 72 40. 66 2. 12 5. 57 3. 19 89. 26 122 19. 12 14. 79 33. 91 8. 21 2. 91 0. 97 47. 23 59 1. 23 Observe more events in Data Need k factor for MC ? 6

W Plots Isolated Tight photon Et. Cone 40 < 3 Ge. V 7

Isolated Tight photon Et. Cone 40 < 3 Ge. V W Plots 8

W Plots Isolated Tight photon Et. Cone 40 < 3 Ge. V More high pt photon In data 9

W Plots Isolated Tight photon Et. Cone 40 < 3 Ge. V Visible signal! 10

Isolated Tight photon Et. Cone 40 < 3 Ge. V W Plots 11

Isolated Tight photon W Plots Robust Tight photon: 12

W photon purity( reverse 3 variable in tight) W data Isolated Non-isolated Non-tight 5 12 Tight 59 30 Non-iso: etcone 40>7 Ge. V Iso: etcone 40<3 Ge. V Non-tight: reversing robuster tight on four variables weta 1, F_side, E_ratio, W_tot 13

W photon purity(reverse 4 variable in tight) W data Isolated Non-isolated Non-tight 9 21 Tight 59 30 Non-iso: etcone 40>7 Ge. V Iso: etcone 40<3 Ge. V Non-tight: reversing robuster tight on four variables weta 1, F_side, E_ratio, W_tot 14

W photon purity(reverse 5 variable in tight) Non-iso: etcone 40>7 Ge. V Iso: etcone 40<3 Ge. V Non-tight: reversing robuster tight on five variables weta 1, F_side, E_ratio, W_tot, delata_E W data Isolated Non-isolated Non-tight 17 52 Tight 59 30 15

W photon purity(reverse 5 variable in tight) Non-iso: etcone 40>7 Ge. V Iso: etcone 40<3 Ge. V Non-tight: reversing robuster tight on five variables weta 1, F_side, E_ratio, W_tot, delata_E W data Isolated Non-isolated Non-tight 17 52 Tight 56 31 16

Correction for signal leakage C 1=112/897= 0. 12+-0. 01 C 2=4/897=4. 5 e-3+-2. 2 e-3 C 3=2/897=2. 2 e-3+-1. 54 e-3 W signal Monte Carlo Isolated Non-isolated Non-tight 112 2 Tight 897 4 Non-iso: etcone 40>7 Ge. V Iso: etcone 40<3 Ge. V Non-tight: reversing robuster tight on five variables weta 1, F_side, E_ratio, W_tot, delata_E 17

Correcting signal leakage into purity measurement Assume: Can be neglected Then : More information http: //bit. ly/cye. MWU 18

NA NB NC ND Corrected purity Reverse 3 variable 59 30 5 12 82. 9+12. 2% Reverse 4 variable 59 30 9 21 82. 4+-8. 7% Reverse 5 variable 59 30 17 52 86. 8+-6. 0% Corrected purity Etcone 40>6 Ge. V -1. 5% Etcone 40>7 Ge. V Central value Etcone 40>8 Ge. V -2. 6% 19

Summary on Wgamma study • Photon purity 86. 8+-6. 0%(stat) • Systematic from non-tight background template: 3. 9% • Systematic from non-iso background template: 2. 6% 20

Z(ee) Data Cut Flow Electrons GRL, Trigger, Primary Vtx cut, At least two medium Electron Pt>20 Ge. V, | |<2. 5(no crack) 11973 opposite charge , M(ee)>40 Ge. V 10088 Photon: | |<2. 5 (no crack), d. R( , )>0. 7 Pt( )>15 Ge. V OTX cut 200 Loose photon (is. EM loose) 54 Loose photon + Isolation : Et. Cone 40<5 Ge. V 39 Robust tight photon 24 21

Signal and Background Prediction Using MC (electron channel) • Number of signal and background events normalized to L=36. 55 pb-1 Cuts Zg Zee+J Total MC Data 69. 50 10717. 92 10787 11973 65. 15 10378. 48 10443 10088 19. 81 144. 26 164. 07 200 18. 49 22. 98 41. 47 54 18. 01 8. 03 26. 04 39 14. 88 4. 50 19. 38 24 2 robuster medium +GRL+Trigger + pt(e)>20 Ge. V +|eta|<2. 5 Mee>40, oppsite charge Ph d. R(e, ph)<0. 7, eta-pt cut, OTX Is. EM loose+Et. Cone 40<5 Is. EM Robuster Tight Observe more events in Data Need k factor for MC ? 22

• Number of signal and background events normalized to L=36. 55 pb-1 Z (electron channel) after tight photon cut 23

Z (electron channel) after tight photon cut 24