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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. Analysing first D0 data. Real data - Jets. Using R=0.7 Cone Algorithm with Run 1 corrections. 3-jet event

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Analysing first D0 data

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  1. 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 Analysing first D0 data

  2. Real data - Jets Using R=0.7 Cone Algorithm with Run 1 corrections 3-jet event • ETjet1~310GeV • ETjet2~240GeV • ETjet3~110GeV • ET~8GeV h f Red: EM towers Blue: Had towers h: -log(q/2) 2-jet event • ETjet1~230GeV • ETjet2~190GeV h f

  3. Ex: Improved Legacy Simple cone preclustering (seeds) collect energy in h-q cone Midpoint seeds added in for each pair of jets within R < DR < 2R Jet axis recalculated until stable geometric centre = enery centriod Splitting and merging after all stable protojets have been found Jets – cone algorithm midpoints seeds approximates seedless algorithm

  4. pT distribution Jets using 0.7 cone with preliminary Run II corrections Dijet invariant mass Alexander Kupco, Prague Jets

  5. Jets - NADA and Missing ET

  6. Jets – Energy scale Response in the central calorimeter  jet DØ DØ DØ ETJet=27GeV EM fraction >0.9 Isolation < 0.2 ETJet=24GeV EM fraction = 0.48 E' = ETgxcosh(hjet) Ia Iashvili, Riverside

  7. Electrons – the Z 2 EM objects, ET > 20 GeV, isolation and shower shape cuts L~1.2pb-1 e e Leo Chan, Rochester (uncalibrated energy scale)

  8. Electrons – energy scale

  9. Electrons – trigger L1: EM clusters, pT > 10 GeV Isolated, EM fraction > 0.9 || < 1.1 failed (prescaled) pass Volker Buescher, Mainz L3: failed (prescaled) pass Frank FilthautJet ET

  10. Electrons – the W Kinematics: pT >22.5 GeV, |h| <0.6 Shower characteristics: EM fraction (0.95<emf<1.05) Isolation (-0.05<iso<0.1) h-f widths, H-Matrix Event characteristics: Large Missing ET (>25 GeV) No back-to-back jet, roughly back-to-back MET Vishnu Zutshi, NIU Leo Chan, Rochester EM cluster with track ET e

  11. Electrons – the W – data data data - bkg Back to back jet Low missing Et We MC Fit = a[bSignal+(1-b)Bckg]

  12. Electrons – the W – mT mT(e,n) L~0.7pb-1 (uncalibrated energy scale) Fit = a[bSignal+(1-b)Bckg]

  13. Muons observed - in Jets Onne Peters, NIKHEF Back to back calorimeter jets Muon in jet (b candidate) Hits in A,B,C layers

  14. mid: 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 Muons - J/

  15. Data Sample 3.2 M data events Total exposed luminosity: 750 nb-1 Events passing L1 m+jet trigger: 800k · Require 1 jet + 1m |njet| < 0.6, |nm| < 0.8 pTm > 6 GeV, dR (m, jet) < 0.7 Muons – b cross section vs pT Run 1 Integrated Cross Section Jet pT > 20 GeV: 12.9 nb Jet pT > 30 GeV: 4.27 nb Run 2 Integrated Cross Section Jet pT > 20 GeV: 9.31 nb (39% low) Jet pT > 30 GeV: 2.77 nb (54% low)

  16. Fit -> signal fraction 65%, Fit error 10% PTRel p Ejet Muons – b tagging Run II data Run I BG templ Run I Signal templ

  17. b tagging – Impact Parameter MC D. Wijngaarden, F. Fithaut

  18. Tracking – KS Requiring KS pT between 0.4-7 & c2 < 10 Combination of oppositely charged tracks After cuts on de/dx and the decays length After cuts on DCA and decay*momentum vector

  19. Cluster with simple cone algorithm, cone 0.3 + 0.5 in hf Taus – decays and reconstruction t‘s are narrow jets SMT ECAL HCALm CFT and: t’s have 1 or 3 tracks with the right invariant mass or Ecal/Etrack but: not yet

  20. Taus – Variables and background The Jet Width – t‘s are narrow jets

  21. Physics: W/Z: in electrons and muons, Z’ to ee QCD: jet pT spectrum+dijets B: KS, J/Y B tag with m and IP,SV Higgs, top: W/Z plus jets Tools: Energy scale: in electrons for jets: with g/jet Comparison with MC Trigger commissioning ID – cuts, efficiencies Outlook and status - Moriond

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