XXXVI International Meeting on Fundamental Physics

1. Physics at the Tevatron XXXVI International Meeting on Fundamental Physics From IMFP2006 → IMFP2008 Rick Field University of Florida (for the CDF & D0 Collaborations) 2nd Lecture Bosons, Top, and Higgs Palacio de Jabalquinto, Baeza, Spain CDF Run 2 Rick Field – Florida/CDF/CMS

2. 23 tt-pairs/month! Tevatron Performance The data collected since IMFP 2006 more than doubled the total data collected in Run 2! IMFP 2008 ~3.3 fb-1 delivered ~2.8 fb-1 recorded ~1.6 fb-1 IMFP 2006 ~1.5 fb-1 delivered ~1.2 fb-1 recorded Integrated Luminosity per Year • Luminosity records (IMFP 2008): • Highest Initial Inst. Lum: ~2.92×1032 cm-2s-1 • Integrated luminosity/week: 45 pb-1 • Integrated luminosity/month: 165 pb-1 • Luminosity Records (IMFP 2006): • Highest Initial Inst. Lum: ~1.8×1032 cm-2s-1 • Integrated luminosity/week: 25 pb-1 • Integrated luminosity/month: 92 pb-1 Rick Field – Florida/CDF/CMS

3. Many New Tevatron Results! Some of the CDF Results since IMFP2006 • Observation of Bs-mixing: Δms = 17.77 ± 0.10 (stat) ± 0.07(sys). • Observation of new baryon states: Sb and Xb. • Observation of new charmless: B→hh states. • Evidence for Do-Dobar mixing . • Precision W mass measurement: Mw = 80.413 GeV (±48 MeV). • Precision Top mass measurement: Mtop = 170.5 (±2.2) GeV. • W-width measurement: 2.032 (±0.071) GeV. • WZ discovery (6-sigma): s = 5.0 (±1.7) pb. • ZZ evidence (3-sigma). • Single Top evidence (3-sigma) with 1.5 fb-1: s = 3.0 (±1.2) pb. • |Vtb|= 1.02 ± 0.18 (exp) ± 0.07 (th). • Significant exclusions/reach on many BSM models. • Constant improvement in Higgs Sensitivity. I cannot possibility cover all the great physics results from the Tevatron since IMFP 2006! I will show a few of the results! Rick Field – Florida/CDF/CMS

4. Z-boson Cross Section (CDF) L = 72 pb-1 IMFP2006 QCDDrell-Yan • Impressive agreement between experiment and NNLO theory (Stirling, van Neerven)! Rick Field – Florida/CDF/CMS

5. Z-boson Cross Section (CDF) IMFP2006 L = 337 pb-1 • Impressive agreement between experiment and NNLO theory (Stirling, van Neerven)! Rick Field – Florida/CDF/CMS

6. New since IMFP2006 Zcc Zcp Zpp Z-Boson Rapidity Distribution • Measure ds/dy for Z→e+e-. Use electrons in the central (C) and plug (P) calorimeter. • Parton momentum fractions x1 and x2 determine the Z boson rapidity, yZ. • Production measurement in high yZ region probes high x region of PDF’s. • Plug-plug electrons, ZPP, are used to probe the high x region! Plug-Plug electrons! 1.1fb-1 91,362 events 66 < MZ < 116 GeV Rick Field – Florida/CDF/CMS

7. New since IMFP2006 Z-Boson Rapidity Distribution • CDF measured ds/dy for Z/g* compared with an NL0 calculation using CTEQ6.1M PDF. • The NLO theory is scaled to the measured s(Z)! • No PDF or luminosity uncertainties included. NLO + CTEQ6.1 PDF NLO + MRST PDF NLL0 + NNL0 MRST PDF Rick Field – Florida/CDF/CMS

8. Channel for Z→ττ: electron + isolated track One t decays to an electron: τ→e+X (ET(e)> 10 GeV) . One t decays to hadrons: τ → h+X (pT > 15GeV/c). Remove Drell-Yan e+e- and apply event topology cuts for non-Z background. Signal cone Isolation cone The Z→tt Cross Section (CDF) • Taus are difficult to reconstruct at hadron colliders • Exploit event topology to suppress backgrounds (QCD & W+jet). • Measurement of cross section important for Higgs and SUSY analyses. • CDF strategy of hadronic τ reconstruction: • Study charged tracks define signal and isolation cone (isolation = require no tracks in isolation cone). • Use hadronic calorimeter clusters (to suppress electron background). • π0 detected by the CES detector and required to be in the signal cone. • CES: resolution 2-3mm, proportional strip/wire drift chamber at 6X0 of EM calorimeter. Rick Field – Florida/CDF/CMS

9. 1 and 3 tracks, opposite sign same sign, opposite sign The Z→tt Cross Section (CDF) • CDF Z→ττ (350 pb-1): 316 Z→ττ candidates. • Novel method for background estimation: main contribution QCD. • τ identification efficiency ~60% with uncertainty about 3%! IMFP2006 264 ± 23 (stat) ± 14 (sys) ± 15 (lum) Rick Field – Florida/CDF/CMS

10. Higgs → tt Search (CDF) events IMFP2006 140 GeV Higgs Signal! 1 event • Data mass distribution agrees with SM expectation: • MH > 120 GeV: 8.4±0.9 expected, 11 observed. • Fit mass distribution for Higgs Signal (MSSM scenario): • Exclude 140 GeV Higgs at 95% C.L. • Upper limit on cross section times branching ratio. Rick Field – Florida/CDF/CMS

11. New since IMFP2006 Higgs → tt Search (CDF) events events No Significant Excess of events above SM background is observed! Rick Field – Florida/CDF/CMS

12. W-boson Cross Section (CDF) W Acceptance • Extend electron coverage to the forward region (1.2 < |h| < 2.8)! IMFP2006 48,144 W candidates ~4.5% background overall efficiency of signal ~7% Rick Field – Florida/CDF/CMS

13. New since IMFP2006 W-Boson Mass Measurement • The Challenge: • Do not know neutrino pz. • No full mass reconstruction possible. • Extract from a template fit to PT, MT, and Missing ET. • Transverse mass: MW = 80413 ± 48 MeV/c2 Single most precise measurement to date! Rick Field – Florida/CDF/CMS

14. New since IMFP2006 W-Boson Width Measurement • Model transverse mass distribution over range 50-200 GeV. • Normalize 50-90 GeV and fit for the width in the high MT region 90-200 GeV. • The tail region is sensitive to the width of the Breit Wigner line-shape. Rick Field – Florida/CDF/CMS

15. W+ W- y antiproton proton e+ u W+ p p d u e W Production Charge Asymmetry • There are more u-quarks than d-quarks at high x in the proton and hence the W+ (W-) is boosted in the direction of the incoming proton (antiproton). • Measuring the W± asymmetry constrains the PDF’s! Q2 = 100 GeV2 MRST2004NLO xG(x,Q2) u d d u x u 10-3 10-2 10-1 1 Rick Field – Florida/CDF/CMS

16. New since IMFP2006 W Production Charge Asymmetry • Since the longitudinal momentum of the neutrino, pL(n), is not known the W rapidity cannot be reconstructed. • So previously one looked at the the electron charge asymmetry. • The V-A structure of the W+ (W-) decay favors a backward e+ (forward e-) which “dilutes” the W charge asymmetry! • New CDF measurement performed in W→en channel. • pL(n) is determined by constraining MW = 80.4 GeV leaving two possible yW solutions. Each solution receives a probability weight according to the V-A decay structure and the W cross-section, s(yW). • The process is iterated since s(yW) depends on the asymmetry. Rick Field – Florida/CDF/CMS

17. W + g Cross Sections (CDF) IMFP2006 ET(g) > 7 GeV R(lg) > 0.7 Rick Field – Florida/CDF/CMS

18. New since IMFP2006 W + g Cross Sections (CDF) ET(g) > 7 GeV R(lg) > 0.7 18.03±0.65(stat)±2.55(sys) ±1.05(lum) Rick Field – Florida/CDF/CMS

19. Z + g Cross Sections (CDF) IMFP2006 Note: (W)/(Z) ≈ 4 while (W)/(Z) ≈ 11 ET(g) > 7 GeV R(lg) > 0.7 Rick Field – Florida/CDF/CMS

20. New since IMFP2006 Z + g Cross Sections (CDF) 390 events ET(g) > 7 GeV R(lg) > 0.7 Meeg > 40 GeV/c2 Rick Field – Florida/CDF/CMS

21. The W+W Cross-Section IMFP2006 Campbell & Ellis 1999 Rick Field – Florida/CDF/CMS

22. The W+W Cross-Section (CDF) IMFP2006 L = 825 pb-1 We are beginning to study the details of Di-Boson production at the Tevatron! • WW→dileptons + MET • Two leptons pT > 20 GeV/c. • Z veto. • MET > 20 GeV. • Zero jets with ET>15 GeV and |h|<2.5. Observe 95 events with 37.2 background! Lepton-Pair Mass! Missing ET! ET Sum! Rick Field – Florida/CDF/CMS

23. New since IMFP2006 WW+WZ Cross-Section NLO Theory σWW × Br(W→ln, W→jj) = 12.4 pb × 0.146 = 1.81 pb σWZ × Br(W→ln, Z→jj) = 3.96 pb × 0.07 = 0.28 pb Rick Field – Florida/CDF/CMS

24. W+Z → trileptons + MET The Z+W, Z+Z Cross Sections IMFP2006 Observe 2 events with a background of 0.9±0.2! Upper Limits Rick Field – Florida/CDF/CMS

25. New since IMFP2006 The W+Z Cross Section Strategy • Search for events with 3 leptons and missing energy. • Small cross-section but very clean signal. • Anomalous cross-section sensitive to non SM contributions. 3.0 σ significance! Rick Field – Florida/CDF/CMS

26. New since IMFP2006 The Z+Z Cross Section Strategy: • Search for events with either 4 leptons or 2 leptons and significant missing ET. • Calculate a Prob(WW) or Prob(ZZ) based on event kinematics and LO cross section. • Construct a likelihood ratio. • Fit to extract the llnn signal. ZZ decaying into 2 leptons + MET ZZ decaying into 4 leptons 3.0 σ significance! Rick Field – Florida/CDF/CMS

27. New since IMFP2006 Higgs → W+W • We are within a factor of two of the standard model Higgs (160 GeV) → WW! Rick Field – Florida/CDF/CMS

28. Heavy Quark Production at the Tevatron • Total inelastic stot ~ 100 mb which is 103-104 larger than the cross section for D-meson or a B-meson. • However there are lots of heavy quark events in 1 fb-1! • Want to study the production of charmed mesons and baryons: D+, D0, Ds , lc , cc , Xc, etc. • Want to studey the production of B-mesons and baryons: Bu , Bd , Bs , Bc , lb , Xb, etc. with 1 fb-1 ~1.4 x 1014 ~1 x 1011 ~6 x 106 ~6 x 105 ~14,000 ~5,000 • Two Heavy Quark Triggers at CDF: • For semileptonic decays we trigger on m and e. • For hadronic decays we trigger on one or more displaced tracks (i.e. large impact parameter). CDF-SVT Rick Field – Florida/CDF/CMS

29. New since IMFP2006 B-Baryon Observations (CDF) The Tevatron is excellent at producing particles containing b and c quarks(Bu, Bd, Bs, Bc, b, b,b) b b bc Rick Field – Florida/CDF/CMS

30. Top Decay Channels • mt>mW+mb so dominant decay tWb. • The top decays before it hadronizes. • B(W  qq) ~ 67%. • B(W ln) ~ 11% l = e, m, t. Rick Field – Florida/CDF/CMS

31. New since IMFP2006 s(tt) =  6.16 ± 1.05 (stat) ± 0.72 (syst) + 0.37 (lumi) pb s(tt) =  8.3 ± 1.5 (stat) ± 1.0 (syst) + 0.5 (lumi) pb Dilepton Channel (CDF) • Backgrounds: • Physics: Drell-Yan, WW/WZ/ZZ, Z tt • Instrumental: fake lepton • Selection: • 2 leptons ET > 20 GeV with opposite sign. • >=2 jets ET > 15 GeV. • Missing ET > 25 GeV (and away from any jet). • HT=pTlep+ETjet+MET > 200 GeV. • Z rejection. IMFP2006 84 events 65 events 20 events background Rick Field – Florida/CDF/CMS

32. s(tt) =  8.2 ± 0.5 (stat) ± 0.8 (sys) ± 0.5 (lum) pb s(tt) =  8.2 ± 0.6 (stat) ± 1.1 (syst) pb s(tt) =  8.8 ± 0.8 (stat) ± 1.2 (sys) ± 0.5 (lum) pb Lepton+Jets Channel (CDF) b-Tagging • Require b-jet to be tagged for discrimination. Tagging efficiency for b jets~50% for c jets~10% for light q jets < 0.1% 1 b tag IMFP2006 2 b tags ~70 events HT>200GeV ~180 events ~150 events ~45 events Small background! Rick Field – Florida/CDF/CMS

33. New since IMFP2006 Tevatron Top-Pair Cross Section CDF Run 2 Preliminary Theory Bonciani et al., Nucl. Phys. B529, 424 (1998) Kidonakis and Vogt, Phys. Rev. D68, 114014 (2003) Rick Field – Florida/CDF/CMS

34. New since IMFP2006 Top Quark Mass Leptons+Jets Channel Dilepton Channel Mt=170.4 ± 3.1(stat) ± 3.0(sys)GeV/c2 Rick Field – Florida/CDF/CMS

35. Top Cross-Section vs Mass Tevatron Summer 2005 CDF Winter 2006 CDF combined Cacciari, Mangano, et al., hep-ph/0303085 Rick Field – Florida/CDF/CMS

36. Tevatron Run I + LEP2 Constraining the Higgs Mass • Top quark mass is a fundamental parameter of SM. • Radiative corrections to SM predictions dominated by top mass. • Top mass together with W mass places a constraint on Higgs mass! Summer 05 114 GeV Higgs very interesting for the Tevatron! Rick Field – Florida/CDF/CMS

37. Strongly Produced tt Pairs g g Other Sources of Top Quarks • Dominant production mode NLO+NLL = 6.7  1.2 pb • Relatively clean signature • Discovery in 1995 ~85% ~15% ElectroWeak Production: Single Top • Larger background • Smaller cross section s≈ 2 pb • Not yet observed! Rick Field – Florida/CDF/CMS

38. Single Top Production tW associated production s-channel t-channel (mtop=175 GeV/c2) Run I 95% C.L. B.W. Harris et al.:Phys.Rev.D66,054024 T.Tait: hep-ph/9909352 Z.Sullivan Phys.Rev.D70:114012 Belyaev,Boos: hep-ph/0003260 Rick Field – Florida/CDF/CMS

39. Single Top at the Tevatron IMFP2006 95% C.L. limits on single top cross-section (2.9 pb) (0.9 pb) (2 pb) • The current CDF and DØ analyses not only provide drastically improved limits on the single top cross-section, but set all necessary tools and methods toward a possible discovery with a larger data sample! • Both collaborations are aggressively working on improving the results! Theory! Single Top Discovery is Possible in Run 2 !!!! - R. Field (IMFP2006) Rick Field – Florida/CDF/CMS

40. New since IMFP2006 Single Top Production DØ Combination 3.6s! Single Top Signal! 3.4s! Expected sensitivity: 2.1 s+t= 4.9 ±1.4 pb s= 1.0, t =4.0 pb First direct measurement of Vtb 0.68 <|Vtb|< 1 @ 95%CL or |Vtb| = 1.3± 0.2 PRL 98 18102 (2007) Rick Field – Florida/CDF/CMS

41. New since IMFP2006 Single Top Production 3.1s! s+t= 3.0 ± 1.2 pb s= 1.1, t =1.9 pb s+t= 2.7 ± 1.2 pb s= 1.1, t =1.3 pb Expected sensitivity: 3.0 Expected sensitivity: 2.9 Observed significance: 2.7 Rick Field – Florida/CDF/CMS

42. CDF Run II Preliminary L=1.5 fb-1 s-channel t-channel Z. Sullivan, Phys.Rev. D70 (2004) 114012 Measurement of |Vtb| (CDF) • Using the Matrix Element cross section measurement, CDF determines |Vtb| assuming |Vtb| >> |Vts|, |Vtd|! |Vtb|= 1.02 ± 0.18 (exp) ± 0.07(thy) DØ |Vtb|>0.68, |Vtb| = 1.3 ±0.2 Rick Field – Florida/CDF/CMS

43. Jet1 Lepton Jet2 Single Top Candidate Event • t-channel single top production has a kinematic peculiarity. • Distinct asymmetry in lepton charge Q times the pseudo-rapidity of the untagged jet! t-channel single top! EPD > 0.9 Central Electron Candidate Charge: -1, Eta=-0.72 MET=41.6 GeV Jet1: Et=46.7 GeV Eta=-0.6 b-tag=1 Jet2: Et=16.6 GeV Eta=-2.9 b-tag=0 Q×h = 2.9 (t-channel signature) EPD=0.95 CDF Run: 211883, Event: 1911511 Rick Field – Florida/CDF/CMS

44. New since IMFP2006 Single Top at the Tevatron Single top cross-section measurements! • Single top has (almost) been seen at the Tevatron at the expected rate! If you think 3.5s is enough to claim discovery? Rick Field – Florida/CDF/CMS

45. Top-AntiTop Resonances CDF Run 1 Excess is reduced! Phys.Rev.Lett. 85, 2062 (2000) • CDF observed an intriguing excess of events with top-antitop invariant mass around 500 GeV! Rick Field – Florida/CDF/CMS

46. New since IMFP2006 Top-AntiTop Resonances • The excess has disappeared! Excess is gone! Rick Field – Florida/CDF/CMS

47. Tevatron Measurements Jets b-quarks We are getting very close to the Higgs and/or new physics! W Z W+g Single top Z+g W+W tt W+Z Z+Z Rick Field – Florida/CDF/CMS