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The Truth The Top Quark is Hiding

Andrew Ivanov University of California, Davis. The Truth The Top Quark is Hiding. Fermilab Joint Experimental – Theoretical Seminar December 0 5 , 2008. Andrew Ivanov University of California, Davis. SEARCHES FOR NEW PHYSICS IN THE TOP QUARK SECTOR AT CDF. Fermilab

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The Truth The Top Quark is Hiding

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  1. Andrew Ivanov University of California, Davis The Truth The Top Quark is Hiding Fermilab Joint Experimental – Theoretical Seminar December 05, 2008

  2. Andrew Ivanov University of California, Davis SEARCHES FOR NEW PHYSICS IN THE TOP QUARK SECTOR AT CDF Fermilab Joint Experimental – Theoretical Seminar December 05, 2008

  3. Tevatron Accelerator Complex Chicago CDF DØ Tevatron Ring ( ~4 miles) Booster Main Injector CDF Integrated Luminosity pp collisions at √s = 1.96 TeV ~ 4 fb-1 recorded Expect to collect 6 fb-1by the end of 2009 ( 8 fb-1by the end of 2010 ) A. Ivanov, UC Davis

  4. Fundamental Building Blocks of Matter A. Ivanov, UC Davis

  5. Fundamental Building Blocks of Matter I.I. Rabi (1936) A. Ivanov, UC Davis

  6. Fundamental Building Blocks of Matter • Top Quark≅ Truth Quark (Fermilab, 1995) • Mass ~ 175 GeV • Extraordinarily large! • similar to a gold nucleus! • ~40 times heavier than its partner- the bottom quark • ~ 350, 000 times heavier than electron! • The Truth is heavy! A. Ivanov, UC Davis

  7. Fundamental Building Blocks of Matter Why is top so heavy ? • Top Quark≅ Truth Quark (Fermilab, 1995) • Mass ~ 175 GeV • Extraordinarily large! • similar to a gold nucleus! • ~40 times heavier than its partner- the bottom quark • ~ 350, 000 times heavier than electron! • The Truth is heavy! A. Ivanov, UC Davis

  8. Facing the Truth ``Believe those who are seeking the truth; doubt those who find it.” - Andre Gide A. Ivanov, UC Davis

  9. Top Production and Decay BR( t->Wb) ≈100% A. Ivanov, UC Davis

  10. Top Production and Decay BR( t->Wb) ≈100% A. Ivanov, UC Davis

  11. Top Production and Decay Highest Statistics Dominant Background W+jets, S:B ≈ 1:1 BR( t->Wb) ≈100% Cleanest channel High S:B ≈ 3:1 Backgrounds: W/Z + jets A. Ivanov, UC Davis

  12. W- d p t b u p t b W+ e e+ Grasping the TruthTop Quark Physics at Tevatron tt Cross Section A. Ivanov, UC Davis

  13. W- d p t u b p t b W+ e e+ Grasping the TruthTop Quark Physics at Tevatron tt Cross Section Production Mechanism Forward-Backward Asymmetry tt Cross Section A. Ivanov, UC Davis

  14. W- d p t u b p t b W+ e e+ Grasping the TruthTop Quark Physics at Tevatron Top Mass, Width/Lifetime, Charge tt Cross Section Production Mechanism Forward-Backward Asymmetry tt Cross Section A. Ivanov, UC Davis

  15. W- d p t u b p t b W+ e e+ Grasping the TruthTop Quark Physics at Tevatron Top Mass, Width/Lifetime, Charge Spin Correlations tt Cross Section Production Mechanism Forward-Backward Asymmetry tt Cross Section A. Ivanov, UC Davis

  16. W- d p t b u Branching Ratio p t b W+ e e+ Grasping the TruthTop Quark Physics at Tevatron Top Mass, Width/Lifetime, Charge Spin Correlations tt Cross Section Production Mechanism Forward-Backward Asymmetry tt Cross Section A. Ivanov, UC Davis

  17. W- d p t b u Branching Ratio p t b W+ e e+ Grasping the TruthTop Quark Physics at Tevatron Top Mass, Width/Lifetime, Charge Spin Correlations tt Cross Section Production Mechanism Forward-Backward Asymmetry W helicity tt Cross Section A. Ivanov, UC Davis

  18. W- d p t b u Branching Ratio p t b c? Z? W+ FCNC decays? e e+ Grasping the TruthTop Quark Physics at Tevatron Top Mass, Width/Lifetime, Charge Spin Correlations tt Cross Section Production Mechanism Forward-Backward Asymmetry W helicity tt Cross Section A. Ivanov, UC Davis

  19. Charged Higgs H- ? W- d p t u b Branching Ratio p t b c? Z? W+ FCNC decays? e e+ Grasping the TruthTop Quark Physics at Tevatron Top Mass, Width/Lifetime, Charge Spin Correlations tt Cross Section Production Mechanism Forward-Backward Asymmetry W helicity tt Cross Section A. Ivanov, UC Davis

  20. Top Quark Properties Measurements Top Width Top Lifetime Top Charge top < 12.7 GeV at 95%CL (theory: top = 1.5 GeV ) Q=-4/3 excluded at 87% CL ctop< 52.5 m at 95%CL theory: top = 5 x 10-24s ) FCNC Decays W Helicity Gluon Fraction F0 = 0.65 ± 0.10(stat) ± 0.06(syst) F+ < 0.12 at 95% CL (SM: F0 = 0.70 & F+ = 0.0) (ggtt)/(pptt) = 0.07 ± 0.16 (NLO: gluon~15%, quark~85%) BR(t->Zq) < 10.6 % at 95% CL (SM: BR(t->Zq) ~ 10-14 )

  21. Top Quark Properties Measurements Top Width Top Lifetime Top Charge About a quarter of CDF physics results presented at ICHEP08 are on properties of the top quark Results are mostly consistent with the Standard Model top < 12.7 GeV at 95%CL (theory: top = 1.5 GeV ) Q=-4/3 excluded at 87% CL ctop< 52.5 m at 95%CL theory: top = 5 x 10-24s ) FCNC Decays W Helicity Gluon Fraction F0 = 0.65 ± 0.10(stat) ± 0.06(syst) F+ < 0.12 at 95% CL (SM: F0 = 0.70 & F+ = 0.0) (ggtt)/(pptt) = 0.07 ± 0.16 (NLO: gluon~15%, quark~85%) BR(t->Zq) < 10.6 % at 95% CL (SM: BR(t->Zq) ~ 10-14 )

  22. New Physics Searches Intrinsic Property of Top Top Decay Production Mechanism Rresonant O Charged Higgs Resonance Top Charge e.g. Topcolor-Assisted Technicolor C.Hill, PRL B345, 483 (1995) Hill and Parke, PRD 49, 4454 (1994) Exotic quark with Q= -4/3 D. Chang, W. Chang and E. Ma, PRD 59 (1999) 091503 PRD 61 (2000) 037301 Appears in SUSY and GUT models Within MSSM for low tanb t-> H+b with enhanced branching ratio and subsequent decay H+->cs _ A. Ivanov, UC Davis

  23. New physics admixture in the sample of tops? t’ ``The pure and simple truth is rarely pure and never simple” - Oscar Wilde A. Ivanov, UC Davis

  24. Fourth Generation G. Kribs, T. Plehn, M. Spannowsky, T. Tait hep-ph/0706.3718 Possible 4-th generation quark with mass of few hundreds GeV Consistent with EWK data Oblique corrections drive Higgs Mass to ~ 500 GeV A. Ivanov, UC Davis

  25. Fourth Generation G. Kribs, T. Plehn, M. Spannowsky, T. Tait hep-ph/0706.3718 Almost degenerate b´ and t´ masses: M(t´) - M(b´) < M(W) Decays as top! t´ -> Wb A. Ivanov, UC Davis

  26. Electroweak Precision Data • Discrepancy with the SM?! • FB - b-quark forward-backward asymmetry ~ 2.6 away (LEP) • As a result: • sinw,lep is ~ 3.3  away from sinw,had • Assumptions on mistakes in the LEP measurements • Underestimated systematic uncertainty • Systematical shift in the measured value are not satisfactory A. Ivanov, UC Davis

  27. Indirect Bounds on Higgs Higgs = 84 +34-26GeV/c2 A. Ivanov, UC Davis

  28. +AbFB +AcFB Higgs Mass Fit Fits to leptonic data M. Chanowitz, PRL 97 (2001) 231802

  29. +AbFB +AcFB Higgs Mass Fit Fits to leptonic data 95% C.L. M. Chanowitz, PRL 97 (2001) 231802

  30. Beautiful Mirror Quarks Top-less Mirrors Standard Mirrors Perfect for Tevatron searches Might have to wait for LHC New physics in Z->bb? Different coupling of the b-quark to Z? D. Choudhury, T. Tait C. Wagner, PRD 65 (2002) 053002 Mirror quarks of b-quarks improve the fit Two scenarios: with and without top mirror quarks A. Ivanov, UC Davis

  31. Search Using 200 pb-1 A. Ivanov, UC Davis

  32. W- d p t b u p t b W+ e e+ Reconstructing the TruthTop Event Reconstruction m(jj) = mW m (jjb) = m(l b) m(l) = mW A. Ivanov, UC Davis

  33. W- d p t b u p t b W+ e e+ Top Event Reconstruction m(jj) = mW m (jjb) = m(lb) m(l) = mW • Jet combinatorics: • 12 possibilities • Form 2 • Select configuration with lowest 2 jet-parton assignment • Reconstruct mtop A. Ivanov, UC Davis

  34. Variables of Interest Mreco HT Mreco HT Quasi model-independent variables retain sensitivity to other possible beyond SM events Perform a 2-dim binned Likelihood Fit Scan Likelihood as a function of t´ cross section Include systematic effects as nuisance parameters Maximize Likelihood with respect to all them - profiling method A. Ivanov, UC Davis

  35. Search Results Using 760 pb-1 mt’> 256 GeV at 95%CL CDF, PRL 100 (2008) 161803 A. Ivanov, UC Davis

  36. Data Fit for mt´ =350 / 400 GeV A. Ivanov, UC Davis

  37. Data Fit for mt´ =350 / 400 GeV t’ candidates ?! A. Ivanov, UC Davis

  38. CDF Event Display A. Ivanov, UC Davis

  39. Search Results Using 2.8 fb-1 mt’> 311 GeV at 95% C.L. A. Ivanov, UC Davis

  40. Top Mass Measurements • Lepton +Jets Channel: Mt= 164.5 ± 3.9 (stat) ± 3.9 (syst) Mt= 173.4 ± 2.5 (stat) ± 1.3(syst) Dilepton Channel: A. Ivanov, UC Davis

  41. Top Mass Measurements A. Ivanov, UC Davis

  42. Top Mass Measurements Tevatron Combination: 7% chance that LJ and DIL results more discrepant than observed Fermilab-TM-2380-E, TEVEWWG/top 2007/01 A. Ivanov, UC Davis

  43. Top Mass Measurements A. Ivanov, UC Davis

  44. Top Mass Measurements • Stop mass below the • mass of the top quark? • Can the top data have • an admixture of • stop quarks? A. Ivanov, UC Davis

  45. Supersymmetry • One of the first • and well motivated theories beyond • the SM • Pros: • - Naturally cures the hierarchy problem • Cons: • - Doubles the number of elementary particles • SUSY must be broken A. Ivanov, UC Davis

  46. Why Supersymmetry? Electroweak Baryogenesis A. Ivanov, UC Davis

  47. Why Supersymmetry? Dark Matter Electroweak Baryogenesis A. Ivanov, UC Davis

  48. Why Supersymmetry? Dark Matter Electroweak Baryogenesis A. Ivanov, UC Davis

  49. Why Supersymmetry? A. Ivanov, UC Davis

  50. Why Supersymmetry? REPRODUCIBILITY A. Ivanov, UC Davis

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