1. Recent Results from the Tevatron Mary Convery Fermilab for the CDF and DØ Collaborations ALCPG11 – Linear Collider Workshop of the Americas Eugene, Oregon March 19-23, 2011

2. Mary Convery (Fermilab)ALCPG112 Outline Introduction Recent Tevatron highlights –New particles observed –CP violation –Precision measurements –Higgs searches Conclusions

3. Main Injector / Recycler Tevatron ( ~4 miles circumf) CDF DØ Antiproton source Chicago Proton source The Fermilab Tevatron Collider Run II Proton-antiproton collisions at √s=1.96 TeV Mary Convery (Fermilab)ALCPG113

4. The Fermilab Tevatron Collider Run II Mary Convery (Fermilab)ALCPG114 year Integrated luminosity (pb -1 ) / 10 13 antiprotons Tevatron has performed well the last few years Optimized use of antiprotons

5. Luminosity performance and projections Mary Convery (Fermilab)ALCPG115 real data for FY02-FY08 7.8 fb -1 Integrated luminosity (fb -1 ) - - - - - - - - - FY04 FY05 FY06 FY07 FY08 FY09 FY10 FY11 ~12 fb -1 9.305 fb -1 delivered thru FY10 have achieved design parameter goals of Run II on track for ~12 fb -1 through FY11, experiments would acquire ~10 fb -1 9.3 fb -1 currently ~10.5 fb -1

6. Mary Convery (Fermilab)ALCPG116 CDF and DØ Run II detectors L2 trigger on displaced vertices Excellent tracking resolution Excellent muon ID and acceptance Excellent tracking acceptance |  | < 2-3 Both detectors Silicon microvertex tracker Solenoid High rate trigger/DAQ Calorimeters and muons

7. The Tevatron research program Precision, New Research Discoveries Mixing, CKM Constraints and CP Violation Heavy Flavor Spectroscopy New Heavy Baryon States Tests of Quantum Chromodynamics Precise measurement of Top- quark and W-boson Masses Top Quark Properties Di-Boson production and SM Gauge Couplings New Exclusive/Diffractive Processes Unique Window into the unknown Searches for Supersymmetry, Extra Dimensions, Exotica Probing the Terascale as the luminosity increases Standard Model Higgs Boson is within reach! Mary Convery (Fermilab)7ALCPG11

8. 8 Observation of new heavy baryons ddb uub dsb 2006 2007 2009 Mary Convery (Fermilab)ALCPG11 ddb uub dsbssb

9. 9 With more data: emergence of a new particle (CDF) 2009 Y (4140) unknown composition These new discoveries yield a few events/fb -1  new areas of research @ 10 fb -1 Mary Convery (Fermilab)ALCPG11 m = 4143.4 +2.9 -3.0 (stat) ± 0.6(syst) MeV/c 2  = 15.3 +10.4 -6.1 (stat) ± 2.5(syst) MeV/c 2 statistical significance > 5 

10. CP violation Charge-conjugation – Parity conservation: a process in which all particles are exchanged with their antiparticles is equivalent to the mirror image of the original process The weak interaction does not conserve C, P, or CP, so the Standard Model predicts CP violation Cabibbo-Kobayashi-Maskawa matrix contains information on the strength of flavor-changing weak decays, important in the understanding of CP violation CKM matrix unitary in the SM Mary Convery (Fermilab)ALCPG1110 SM levels of CP violation do not explain apparent matter-antimatter asymmetry of the universe

11. CP violation in B s → J/  The mass eigenstates are a superposition of B s and B s Width difference between mass eigenstates  is correlated with  s –Measure simultaneously CP violation in the interference between decay w/ and w/o B s - B s mixing Measure by statistical determination of CP even and odd contribution using angular analysis New physics can have large effect on CP violation Mary Convery (Fermilab)ALCPG1111 Bs0Bs0 Bs0Bs0 _ J/    Bs0Bs0,t’ B s 0 =sb _ _ _ _ _ _

12. Precision: CP Violation in  s 12 Both CDF and D0 measure the CP violating parameter  s in B s in J/   Mary Convery (Fermilab)ALCPG11

13. Dimuon charge asymmetry (D0) Measure CP violation in mixing using the dimuon charge asymmetry of semileptonic B decays: –N b ++, N b −− : number of events with two b hadrons decaying semileptonically and producing two muons of same charge –One muon comes from direct semileptonic decay b → μ − X –Second muon comes from direct semileptonic decay after neutral B meson mixing Mary Convery (Fermilab)13ALCPG11 Evidence for anomalous like-sign dimuon charge asymmetry A sl is 3.2  from Standard Model predictions First evidence for Beyond the Standard Model CP Violation

14. Double semileptonic decay of BB results in OS lepton pair when no mixing; LS lepton pair when one meson undergoes mixing Use impact parameters of muon pairs with template fits to identify source of muons: b, c, prompt Correct for other sources of dimuons  =0.126±0.008, consistent with LEP average  =0.1259±0.0042, smaller than previous Tevatron measurements (CDF’s used looser silicon-track requirements) Measurement of time-integrated mixing probability of B hadrons Mary Convery (Fermilab)ALCPG1114 _ _ _ μ + μ + μ  μ 

15. Search for new dielectron resonances and Randall-Sundrum gravitons Common approach to search for new particles – look for bump in mass of combined objects No significant excess over SM observed Combined with 5.4 fb -1 diphoton analysis, RS-graviton mass limit for the coupling k/M Pl =0.1 is 1055 GeV/c 2 – strongest limit to date Mary Convery (Fermilab)ALCPG1115 Highest-mass dielectron ever observed (960 GeV/c 2 )

16. Signature-based Search: γ + missing-E T + b-jet + lepton Search for new physics by looking for anomalies in kinematic distributions, rather than limiting search to specific model Leading background is Standard Model tt  No excess observed Measure cross section σ(tt  ) =0.18 ± 0.07 pb R(tt  /tt) = 0.024 ± 0.009 16Mary Convery (Fermilab)ALCPG11

17. Towards the Higgs Mary Convery (Fermilab)ALCPG1117

18. W mass summary M w = 80.399  0.023 GeV Tevatron has world’s best measurement Mary Convery (Fermilab)18ALCPG11

19. Top quark pair production and decay Top quark existence required by the SM, partner of the bottom quark Discovered in 1995 at Tevatron Only SM fermion with mass at the EW scale ~40x heavier than the bottom quark Top decays before hadronization – provides unique opportunity to study a "bare" quark Pair produced via strong interaction Top quark decays ~100% to W+b t-tbar events classified by decay of W’s: –All-hadronic (44%, large background) –Dilepton (5% excl , small background) –Lepton+Jet (30% excl , manageable background) Mary Convery (Fermilab)19ALCPG11

20. Summary of Top Mass We now know the mass of the top quark with better precision (<1%) than any other quark Mary Convery (Fermilab)20ALCPG11 new! updated

21. Constraints from precision top quark mass measurement SM Higgs Mass constrained by M top and M W through loop correction of W mass Precision top quark mass measurement –Predict SM Higgs mass –Constraints for physics beyond standard model X ?? Mary Convery (Fermilab)21ALCPG11

22. Where is the Higgs hiding? M H < 157 GeV at 95% C.L. preferred M H – 87 +35 -26 GeV M w vs M top Mary Convery (Fermilab)22ALCPG11

23. Standard Model Higgs production and decay Higgs are produced in several different ways –gg→H, qq → WH, qq → ZH biggest cross sections –Also qq → qqH, bb → H, gg,qq→ ttH The Higgs decays into different “final states” depending on its mass To find it, we need to look at all these final decay states and combine the results Mary Convery (Fermilab)ALCPG1123

24. The Challenge These are production numbers – trigger, acceptance etc. not yet factored in… # of Events produced/exp in 1 fb -1 Mary Convery (Fermilab)24ALCPG11

25. W/Z + jets Test of perturbative QCD Background for W/Z+H and other new physics –Test Monte-Carlo modeling Mary Convery (Fermilab)ALCPG1125

26. Mary Convery (Fermilab)ALCPG1126

27. Di-bosons WW, WZ, ZZ Background to Higgs searches: W/Z H, H->WW, H->ZZ Similar techniques as used for Higgs searches –dijet mass, matrix element, neural networks –Discrimination in kinematics of final state (???) Mary Convery (Fermilab)ALCPG1127

28. Using m jj and matrix element techniques with 4.3-4.6fb -1 Observed with >5  significance WW/WZ → lepton + jets 5.2 σ 5.4 σ σ = 18.1 ± 3.3 stat ± 2.5 sys pb σ = 16.5 +3.3-3.0 ± 3.5 sys pb SM = 15.1 ± 0.9 pb Mary Convery (Fermilab)28ALCPG11

29. WZ→lll, ZZ→ll Using neural networks Mary Convery (Fermilab)ALCPG1129 3.7±0.6(stat.). +0.6-0.4 (syst.)

30. ZZ → eeee, ee ,  10 events σ = 1.35 +0.50 -0.40 (stat) ± 0.15(syst) pb SM prediction 1.4±0.1 pb Mary Convery (Fermilab)ALCPG1130

31. 31 Single top Test s vs t channel [new physics] Direct measurement of V tb [precision] Lifetime [new physics] Wbb similar final state as Higgs –Similar tools Test s vs t channel [new physics] Direct measurement of V tb [precision] Lifetime [new physics] Wbb similar final state as Higgs –Similar tools Mary Convery (Fermilab)ALCPG11

32. SM Higgs: H  WW (high mass channel) H  WW  l l - signature: Two high p T leptons and MET –Primary backgrounds: WW and top in di-lepton decay channel –Key issue: Maximizing signal acceptance –Excellent physics-based discriminants Most sensitive Higgs search channel at the Tevatron H H μ+μ+ ν W-W- W+W+ e-e- ν W-W- W+W+ Spin correlation: Charged leptons go in the same direction Mary Convery (Fermilab)32ALCPG11

33. Limits from H  WW First time CDF and D0 independently exclude mass range for Standard Model Higgs at 95% CL D0 excludes M H =165 GeV/c 2 CDF excludes 158<M H <168 GeV/c 2 Mary Convery (Fermilab)ALCPG1133

34. Combine experiments Factor away in sensitivity from SM Neither experiment has sufficient power to span the entire mass range using the luminosity we expect to acquire in Run II SM Higgs Excluded: m H = 163-166 GeV Mary Convery (Fermilab)34ALCPG11

35. We are making steady progress… Some projected improvements: Combine all channels Maximize signal acceptance Improve b-tagging to reduce W/Z+jets background Improve dijet mass reconstruction (resolution) Improve di-tau mass reconstruction Improve signal vs background separation (neural networks, boosted decision trees, matrix element methods, combining different kinematic variables Mary Convery (Fermilab)ALCPG1135

36. How well can we do? Mary Convery (Fermilab)36ALCPG11

37. Forward-backward tt production asymmetry QCD t-tbar production symmetric at leading order, positive and negative contributions to asymmetry at next-to-leading order Asymmetry seen in previous measurements by CDF and D0 and dilepton channel New CDF measurements show 2  excess in both lepton+jets and dilepton channel Mary Convery (Fermilab)ALCPG1137 low masshigh mass l - high mass l + _

38. Evidence for mass dependence of A fb Significant asymmetry at large  y, M tt Consistent with CP conservation ( l + vs l - = t vs t) Mary Convery (Fermilab)ALCPG1138 low masshigh mass l - high mass l + _

39. Conclusions The Tevatron has a broad program –Precision measurements Mixing, CKM Constraints and CP Violation Precise measurement of top-quark and W-boson masses –Searches for Higgs and beyond SM physics –B hadron spectroscopy Once new particles observed, studies of their properties –Tests of Quantum ChromoDynamics Stay tuned as the Tevatron continues to produce important results in many areas of HEP Mary Convery (Fermilab)ALCPG1139