1. 1 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 1 Analysing first D0 data  Real Data with:  Jets  Missing Et  Electrons  Muons  Taus And from there up to:  Electroweak Bosons W/Z  B cross section And then: top, Higgs, … Silke Duensing, KU Nijmegen

2. 2 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 2 Using R=0.7 Cone Algorithm with Run 1 corrections 2-jet event E T jet1 ~230GeV E T jet2 ~190GeV 3-jet event E T jet1 ~310GeV E T jet2 ~240GeV E T jet3 ~110GeV E T ~8GeV Real data - Jets     Red: EM towers Blue: Had towers  : -log(  /2)

3. 3 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 3 Jets – cone algorithm Ex: Improved Legacy Simple cone preclustering (  seeds)  collect energy in  cone  Midpoint seeds added in for each pair of jets within R <  R < 2R  Jet axis recalculated until stable  geometric centre = enery centriod  Splitting and merging after all stable protojets have been found seeds midpoints approximates seedless algorithm

4. 4 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 4 Jets  pT distribution  Jets using 0.7 cone with preliminary Run II corrections  Dijet invariant mass Alexander Kupco, Prague

5. 5 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 5 Jets - NADA and Missing E T

6. 6 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 6 Ia Iashvili, Riverside DØ  jet DØ E' = E T   x  cosh(  jet ) Jets – Energy scale Response in the central calorimeter EM fraction = 0.48 E T Jet =24GeV EM fraction >0.9 Isolation < 0.2 E T Jet =27GeV

7. 7 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 7 Electrons – the Z 2 EM objects, E T > 20 GeV, isolation and shower shape cuts (uncalibrated energy scale) Leo Chan, Rochester ee L ~1.2pb -1

8. 8 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 8 Electrons – energy scale

9. 9 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 9 Electrons – trigger L1: Frank Filthaut Jet E T EM clusters, p T > 10 GeV Isolated, EM fraction > 0.9 |  | < 1.1 failed (prescaled) pass Volker Buescher, Mainz L3: failed (prescaled) pass

10. 10 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 10 Electrons – the W EM cluster with track Vishnu Zutshi, NIU Leo Chan, Rochester e ETET  Kinematics: pT >22.5 GeV, |  <0.6  Shower characteristics: EM fraction (0.95<emf<1.05) Isolation (-0.05<iso<0.1)  widths, H-Matrix  Event characteristics: Large Missing ET (>25 GeV) No back-to-back jet, roughly back-to-back MET

11. 11 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 11 Electrons – the W – data data - bkg Back to back jet Low missing Et Fit =  [  Signal+(1-  )Bckg] W  e MC data

12. 12 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 12 Electrons – the W – m T Fit =  [  Signal+(1-  )Bckg] m T (e, ) L ~0.7pb -1 (uncalibrated energy scale)

13. 13 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 13 Muons observed - in Jets Muon in jet (b candidate) Hits in A,B,C layers Onne Peters, NIKHEF Back to back calorimeter jets

14. 14 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 14 Muons - J/   id:  Require wire hits in B/C layer  Require hits in A + B/C scintillators Frederic Deliot, Saclay  Events:  6846 events from 5.8 M pre- shutdown events

15. 15 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 15 Muons – b cross section vs pT Data Sample  3.2 M data events  Total exposed luminosity: 750 nb -1  Events passing L1  +jet trigger: 800k · Require  1 jet +  1  |n jet | < 0.6, |n  | < 0.8 pT  > 6 GeV, dR ( , jet) < 0.7 Run 1 Integrated Cross Section Jet p T > 20 GeV: 12.9 nb Jet p T > 30 GeV: 4.27 nb Run 2 Integrated Cross Section Jet p T > 20 GeV: 9.31 nb (39% low) Jet p T > 30 GeV: 2.77 nb (54% low)

16. 16 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 16 Muons – b tagging Fit -> signal fraction 65%, Fit error 10% P T Rel E jet pp Run II data Run I BG templ Run I Signal templ

17. 17 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 17 b tagging – Impact Parameter MC D. Wijngaarden, F. Fithaut

18. 18 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 18 Tracking – K S Combination of oppositely charged tracksAfter cuts on de/dx and the decays lengthAfter cuts on DCA and decay*momentum vector Requiring K S pT between 0.4-7 &  2 < 10

19. 19 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 19 Taus – decays and reconstruction Cluster with simple cone algorithm, cone 0.3 + 0.5 in    e  e 17.8 %     17.4 %        48 %        15.2 %  ‘s are narrow jets SMT ECAL HCAL  CFT and:  ’s have 1 or 3 tracks with the right invariant mass or E cal /E track but: not yet

20. 20 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 20 Taus – Variables and background The Jet Width –  ‘s are narrow jets

21. 21 Silke Duensing DØ Analysis Status NIKHEF Annual Scientific Meeting 2001 21 Outlook and status - Moriond Physics:  W/Z:  in electrons and muons, Z’ to ee  QCD:  jet pT spectrum+dijets  B:  K S, J/   B tag with  and IP,SV  Higgs, top:  W/Z plus jets Tools:  Energy scale:  in electrons  for jets: with  /jet  Comparison with MC  Trigger commissioning  ID – cuts, efficiencies