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Top and Electroweak Results from CDF

Top and Electroweak Results from CDF. Igor Volobouev LBNL for the CDF Collaboration. Top / Electroweak Program. Measurement of fundamental parameters Calibration ( e.g ., M Z ) Precision measurements of M top , M W , V tb , etc . Tests of Standard Model predictions

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Top and Electroweak Results from CDF

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  1. Top and Electroweak Results from CDF Igor Volobouev LBNL for the CDF Collaboration

  2. Top / Electroweak Program • Measurement of fundamental parameters • Calibration (e.g., MZ ) • Precision measurements of Mtop, MW, Vtb, etc. • Tests of Standard Model predictions • Cross sections, branching fractions, kinematical distributions, lepton universality • Top quark properties: unique to CDF/D0 • Searches for new phenomena • Higgs • Anomalous couplings, new particles and resonances, rare and forbidden decays • Discovery potential exists in all areas

  3. =1 TOF =2 =3 CDF Run 2 Upgrade • Improved Si coverage • |h| < 2 • up to 8 layers • New central tracker • 96 layers • Time of Flight • Expanded muon system • Forward calorimeter • Trigger and electronics h = -ln(tan(/2))

  4. Run 2 Data Sample • Total current sample on tape: 175 pb-1 • “Winter analyses” sample: 56-91pb-1 • 4-9 pb-1/week • 90% efficiency “Winter” sample Total Luminosity (pb-1) Commissioning Delivered On Tape Store Number

  5. We Z Electroweak Measurements • Unambiguous predictions from the Standard Model, world averages, Run 1 measurements • W, Z production cross sections • Lepton universality • Forward-backward asymmetry • Di-boson production • “New physics” reach at a few hundred pb-1 • Data analysis infrastructure • Lepton and photon identification • W and Z signatures • Calibrations • Luminosity monitoring

  6. Clean signature Isolated lepton Missing ET High s and S/B 72 pb-1 sB(Wll) Wm

  7. Wtand Lepton Universality • Narrow, isolated hadronic jet from t • Missing ET > 25 GeV • Electrons removed • Relatively low background ( 26%) sB(Wtn) = 2.62 ± 0.07stat ± 0.21sys ± 0.16lum nb

  8. Two leptons: negligible background (< 1%) Used for calibrations: energy scale, resolutions sB(Zll) l =e: 267±6stat±15sys±16lum pb l =m: 246±6stat±12sys±15lum pb

  9. Forward-backward asymmetry: AFB with Z0/g*  e+e- • Probes g/Z interference, sensitive to new physics • High mass reach is unique to Tevatron • Measurement is consistent with the SM prediction

  10. pp  Wg, Zg, WW Depend on trilinear gauge couplings (s-channel): Events found / expected Wg 81 / 83.1 Zg 25 / 23.2 WW 2/ 4.3 Results are statistics-limited, consistent with the SM predictions g q W W q' Di-boson Cross Sections 81 events

  11. Main question: is top quark adequately described by the Standard Model? Run 2 results so far: Cross section Top mass Many precision tests of top to come with more data SM: tt production cross section at 1.96 TeV is 30% larger than at 1.8 TeV Top spin polarization Production Cross Section Resonance production ? Production kinematics Top Quark Measurements

  12. tt =13.2 ± 5.9stat ± 1.5sys pb Dilepton Cross Section • Signature: 2 leptons, 2 jets, missing ET • Backgrounds: WW, Z tt, Drell-Yan, fake leptons • Event selection: signature and • Scalar transverse energy > 200 GeV • Background rejection: photon conversion veto, Z veto, lepton isolation,  for missing ET • Found 5 candidates, expected 0.3 background events

  13. tt = 5.3 ± 1.9stat ± 0.8sys pb Lepton + Jets Cross Section Control Signal 15 candidate events with b tags, 3.8 background

  14. tt = 5.3 ± 1.9stat ± 0.8sys pb Lepton + Jets Cross Section Control Signal 15 candidate events with b tags, 3.8 background

  15. tt Cross Section Summary hep-ph/0303085 (M. Cacciari et al)

  16. Lepton + jets channel: Run 1 CDF result was 176.1 ± 6.6 GeV/c2 Statistical error is mainly due to jet combinatorics. Mtop with b tags will be presented at the summer conferences. Systematic errors will dominate the uncertainty Jet energy reconstruction MC top decay modeling Background Top Quark Mass 33 events

  17. Electroweak Drell-Yan at high mass (PDFs, new physics) W charge asymmetry Direct W width pp WZ, ZZ, trilinear couplings MW with 40 MeV/c2 precision (400 pb-1 are needed if 1/L scaling holds) Top Analysis of production and decay kinematics Resonant production W helicity Spin correlations Single top production Vtb Rare and forbidden decays Mt with 3 GeV/c2 precision Future Run 2 Measurements Many of these measurements are already in the works

  18. Higgs Constraint Current SM Higgs fit: MH = 81+52–33 GeV LEP 2 direct search limit: MH > 114.4 GeV at 95% CL

  19. Summary • A variety of Run 1 results have been reestablished • We are confident that CDF components are working as expected and the system integration was a success • Our understanding of the CDF detector is improving. We have already developed many building blocks needed for taking on really challenging physics problems. • So far, top and electroweak results are consistent with the Standard Model predictions • Most measurements are statistics limited, and will benefit from larger datasets • Expect many new and improved Run 2 results this summer and during the next few years

  20. Backup Slides

  21. Electron Identification • CEM transverse energy ET > 20 GeV • Track pT > 10 GeV/c • Track |z0| < 60 cm • ET/pT < 2.0 when ET < 50 GeV • Cluster EHAD/EEM < 0.055 + 0.00045 * E • Track-to-shower match  3 cm • Fractional calorimeter energy isolation < 0.1 • Shower profile consistent with electron • Fiducial to CES

  22. Muon Identification • Track pT > 20 GeV/c • Track |z0| < 60 cm • Cosmic ray veto • EEM < 2 + max(0, 0.0115 * (p - 100)) GeV • EHAD < 6 + max(0, 0.0280 * (p - 100)) GeV • Fractional calorimeter energy isolation < 0.1 • Track match to a muon chamber stub: 3, 5, and 6 cm for CMU, CMP, and CMX, respectively

  23. B Jet Tagging with SVX • At least two well-reconstructed tracks with  3 silicon hits • Secondary vertex LXY significance at least +3s • Efficiency in tt events: 45  1  5 % for “taggable” jets

  24. Weekly Delivered Luminosity

  25. Downtime and Deadtime • Downtime – much better when we keep taking data… • HV Trips (COT, Silicon, muon, etc.) (not so often these days) • L3/EVB/CSL/L2, etc. (comes/goes in wave. Right now, it is good) • HRRs (bunch counter errors, TDC done timeout, etc.) • Trigger table tests, 2 SRC tests, XFT tests… (future investment) • Startup time, waiting to bring up HV at beginning of the store • Silicon D-mode calibration and other odds and ends • Downtime due to operator errors are very small • Dead time – much easier when lumi is low and trigger rates low, but… • L1/L2 busy dead time (much work in progress, eg. 2SRC readout) • Hitting CSL output limit -- design 20Mb/sec. This current problem should be solved by: • Tightening (wisely) trigger filters, limiting L3 output rates • Dropping L3 reconstruction banks and other diagnostic banks • Compressing silicon/COT raw data banks, etc. • However, at the same time, we are also reviewing/studying the possibility/consequence of extending the current CSL 20Mb/sec limit

  26. Wg, electron channel Cross section for ET(g) > 7 GeV, DR > 0.7 : s(Wg) = 17.2  3.8(stat.)  2.8(sys.)  1.0(lum.) pb SM: s(Wg) = 18.7 1.3 pb Wg, muon channel s(Wg) = 19.8  4.5(stat.)  2.4(sys.)  1.2(lum.) pb SM: s(Wg) = 18.7 1.3 pb Zg, combined s = 5.8  1.3(stat.)  0.7(syst.)  0.3(lum.) pb SM:s = 5.3  0.4 pb Di-boson Run 2 Results WW: expected 2.8 signal and 1.5 background events (SM), found 2

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