1. Top Physics at the Tevatron Mike Arov (Louisiana Tech University) for D0 and CDF Collaborations 1

2. Top physics overview Discovered in 1995 by CDF (19 events) and DO (17 events) Has many unique properties: m top ~ gold atom Γ~1.4 GeV>>ΛQCD coupling to Higgs boson ~ 1 Top quark mass is measured with <1% uncertainty 2

3. Top physics Only selected new analyses are presented in this talk! 3

4. Top production Top pair 85% 15% Single top s-channel t-channel 4

5. Top Quark Decays 5

6. Tevatron collider at Fermilab 1.96 TeV p-anti p collider 396 ns between bunches Has delivered ~6 fb-1 of data since 2002, and Running smoothly: expect ~10 fb-1 by end of 2010 6

7. Top Production Cross Section in lepton +jets channel Luminosity uncertainty reduced by normalizing to Z cross section B-tagging is a powerful tool for top physics 7

8. B-tagging Impact Parameter Tagging (IPT) Secondary Vertex Tagging (SVT) Soft Lepton Tagging (SLT) e,  Neural Network Tagging (NNT) 8

9. B-tagging (continue) Good efficiency vs fake rate Works well with top quark 9

10. Top Production Cross Section Summary 10

11. Single Top s-channel t-channel Difiicault W background! Small cross section Was challenging years after top pair discovery B-tagging and multivariate analysis techniques were the key! 11

12. Single Top Multivariate Analysis Boosted Decision Trees (BDT) Neural Networks (NN) No single variable is sufficient! 12

13. Single Top Results Observation ! |V tb f 1 L | = 0.88 ± 0.07 13

14. Single Top Summary 14

15. Top quark mass measurement methods Template method – using MC templates with different masses do fit to top data Matrix method – using probability density: Acceptance Matrix ElementTransfer Function 15

16. Top quark mass results (lepton+jets) 16 Independent Jet Energy Scale (JES) measurement allows in-situ calibration

17. Top Mass Summary 173.1 ±0.6 (stat) ±1.1 (syst) GeV/c 2 17

18. Measurement of the Forward-Backward Charge Asymmetry in Top-Antitop Production N + is the number of events where top has larger rapidity than antitop, while N - is the number of events where it is smaller In LO QCD it is 0, but in NLO it isn't due to interference between diagrams like these 18

19. Asymmetry Results Phys. Rev. Lett. 100, 142002 (2008 ) A fb = 0.193 ±0.065 (stat) ±0.024 (syst) A fb = 12 ±8 (fit) ±1 (stat) 19

20. Spin Correlations  = 0.320 +0.545 –0.775  = -0.17 +0.64 –0.53 20

21. Mass Difference 21 Main motivation – check CPT Using matrix method in l+jets channel Likelihood function modified to allow for different top masses  M t = 3.8 ±3.7 GeV

22. Search for Charged Higgs boson If H+ is lighter than top we can have the following scenarios: 22

23. Search for Charged Higgs boson Leptophobic model 23 Tauonic model

24. Search for ttbar Resonances in the Lepton+Jets (D0) and All Hadronic (CDF) Final State Invariant mass was plotted for candidate events Good agreement was observed and no resonant production signal  4 jets 3 jets 24

25. Search for ttbar Resonances For topcolor-assisted technicolor M Z' > 820 GeV (D0) and M Z' > 805 GeV (CDF) The limit is set using M tt distributions 25

26. Summary Top physics at Tevatron is diverse research field covering both SM and beyond SM physics. In this talk I presented our last combined and most precise measurements of top pair and single cross section. And I also showed latest development on top mass and several properties measurements and searches. Not all analyses could be shown. A lot more info can be found on the webpages of colaborations: http://www-d0.fnal.gov/Run2Physics/top/top_public_web_pages/top_public.html http://www-cdf.fnal.gov/physics/new/top/public_tprop.html More exciting measurements and searches are to come. 26

27. Backup slides 27

28. D0 and CDF Detectors muon system shielding electronics 28

29. Experimental challenges of top quark physics Jet Energy Scale b-tagging Limited statistics (less so as we collect more data) Accurate background modeling (mainly W and QCD) Luminosity measurement uncertainties 29

30. Jet Energy Scale The associated statistical and systematic uncertainty is dominant one in top physics 30

31. Resonance not observed 31

32. Search for W' decaying to top and b Heavy W' can be observed in single top s channel The right-handed W' limit depends on the unknown mass of the right-handed neutrino, since when M(w' R ) <M( R ) only hadronic decays of W are allowed. The following limits were set : M(w' L ) > 731 GeV M(w' R ) > 768 GeV for M(w' R ) <M( R ) M(w' R ) > 739 GeV for M(w' R ) >M( R ) Phys. Rev. Lett. 100, 211803 (2008 ) 32

33. W helicity f 0 = 0.49 ±0.11 (stat) ±0.09 (syst) f + = 0.11 ±0.06 (stat) ±0.05 (syst) f 0 = 0.62 ±0.10 (stat) ±0.05 (syst) f + = -0.04 ±0.04 (stat) ±0.03 (syst) f 0 = 0.697±0.012 f + = 0 33