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Tevatron Results and Future Prospects

Outline The Tevatron Detectors and data Highlights of the recent Tevatron results Standard Model Higgs searches Future Tevatron experimental program Summary. Tevatron Results and Future Prospects. Russian Academy of Sciences Nuclear Physics Session November 23, 2009 - ITEP

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Tevatron Results and Future Prospects

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  1. Outline The Tevatron Detectors and data Highlights of the recent Tevatron results Standard Model Higgs searches Future Tevatron experimental program Summary Tevatron Results and Future Prospects Russian Academy of Sciences Nuclear Physics Session November 23, 2009 - ITEP Dmitri Denisov, Fermilab Disclaimer: DØ is used for majority of the examples, CDF in most cases has similar results

  2. Tevatron: Proton-antiproton Collider Run I Run IIa Run IIb Bunches in Turn 6  6 36  36 36 36 s (TeV) 1.8 1.96 1.96 Typical L (cm-2s-1) 1.6 1030 9 1031 3 1032  Ldt (pb-1/week) 3 17 50 Bunch crossing (ns) 3500 396 396 Interactions/ crossing 2.5 2.3 8 Run IRun IIa Run IIb 0.1 fb-1 ~1fb-1 ~12 fb-1 World highest energy collider 1.96 TeV center of mass energy Energy and luminosity Nevents (sec-1) = s(E)L Run IIa Run IIb Dmitri Denisov, RAS, November 2009

  3. Tevatron Performance 7.2 fb-1 • Peak luminosity is 3.5.1032 cm-2sec-1 • A lot of anti-protons made! • Reliable operation of very complex accelerators • In stores ~120 hours/week • Total 7.2 fb-1 delivered in Run II • Integration rate is steadily raising Integrated Luminosity vs Fiscal Year Peak Luminosity FY2010 2009 2002 Performance continues to improve! Dmitri Denisov, RAS, November 2009

  4. Tevatron Physics Goals Precision tests of the Standard Model • Weak bosons, top quark, QCD, B-physics… Search for particles and forces beyond those known • Higgs, supersymmetry, extra dimensions…. Fundamental Questions Quark sub-structure? Origin of mass? Matter-antimatter asymmetry? What is cosmic dark matter? SUSY? What is space-time structure? Extra dimensions?… Dmitri Denisov, RAS, November 2009

  5. Tevatron Detectors • Driven by physics goals, the detectors emphasize • Electron, muon andtau identification • Jets and missing transverse energy • Flavor tagging throughdisplaced vertices Dmitri Denisov, RAS, November 2009

  6. The DØ Collaboration DØ is an international collaboration of 510 physicists from 18 nations who have designed, built and operate the DØ detector at the Tevatron and perform data analysis Institutions: 89 total, 38 US, 51 non-US Collaborators: ~ 50% from non-US institutions with strong European involvement ~ 100 postdocs, 110 graduate students Dmitri Denisov, RAS, November 2009

  7. Data Collection • DØ experiment is smoothly recording high quality physics data • Typical week ~50 pb-1 • On average 92% data taking efficiency • As of today DØ has ~6.5 fb-1 on tapes • Was ~4.9 fb-1 on tapes at 2008 RAS meeting • All detectors functioning well Preliminary Results Many results published Most results published 2002 November 2009 2002 November 2009 Dmitri Denisov, RAS, November 2009

  8. Experimental Challenges A zero bias DØ data event at 0.6.1032 cm-2sec-1 ... and at 2.4.1032 cm-2sec-1 Average number of interactions per crossing is reaching ~10 at 3.1032 cm-2sec-1 • Radiation doses of the inner silicon layer are reaching Mrads levels • Carefully monitoring silicone performance • Layer 1 (one out of 5 layers) will become under depleted after ~8 fb-1 • All other layers are far from been affected • No deterioration of tracking performance is expected up to ~12 fb-1 Dmitri Denisov, RAS, November 2009

  9. Triggering Typical store with starting luminosity of 3.5 .1032 cm-2sec-1 All high pt triggers are un-prescaled at all luminosities Dmitri Denisov, RAS, November 2009

  10. Detectable Objects – Particle Identification • Excellent understanding of the detector and algorithms achieved • Took many years… • Certification of additional data for identification methods within a few weeks • Automated software Zmm Muons • Final decay products •  electrons • muons  charged tracks •  jets (b) •  missing Et (n) • Detection and MC optimization using well known objects Zee Electrons Jets ~2% b-tagging Rapidity Dmitri Denisov, RAS, November 2009

  11. Continuing Improvements Tagging of b-jets with Neural Network Optimizing muon acceptance by triggering on jets and missing energy Dmitri Denisov, RAS, November 2009

  12. QCD Studies Inclusive jet cross sections • Use partons scattering to study proton structure •  Quarks sub-structure? Rutherford style experiment • Measure QCD parameters and structure functions • Determine Jet Energy Scale •  Critical for top mass and Higgs searches • Understand the backgrounds to physics beyond Standard Model • Measured in the widest kinematic region • In rapidity and transverse momentum • 8+ orders of magnitude s changes • In agreement with pQCD predictions Pt, GeV Dmitri Denisov, RAS, November 2009

  13. Di-jet Resonances • Di-jet resonances predicted in beyond Standard Model theories • Masses up to 1.2 TeV studied • Tight limits set W’ Talk of N. Skachkov Dmitri Denisov, RAS, November 2009

  14. Top Quark Studies W helicity Top Mass l+ Top Width Anomalous Couplings Production cross-section Top Spin W+ CP violation Top Charge Resonant production p n t b Production kinematics _ b X _ Top Spin Polarization _ q’ t q Rare/ non SM Decays W- _ p Branching Ratios |Vtb| • Heaviest known elementary particle: 173 GeV • Measure properties of the least known quark • mass, charge, decay modes, etc. •  data sets of 1000’s of top quarks exist •  Short life time: probe bare quark Top quark cross sections in multiple channels: top quark identification CDF August 2009 Combination precision is 6.5% Dmitri Denisov, RAS, November 2009

  15. Top Quark Mass Measurement • Top mass is measured using decay products in many different channels • Lepton+jets channel with two jets coming from W is the most precise First measurement of quark-anti quark mass difference: CPT test in quark sector DØ and CDF combined top mass result mt= 173.11.2 GeV 0.7% accuracy Best (of any) quark mass measurement! Dmitri Denisov, RAS, November 2009

  16. Single Top Quark Production – 5s Observed! • EW production of top quark •  direct probe of |Vtb| • similar to hunt for Higgs: (Wb)b • High backgrounds Tevatron (3.2 fb-1, mt=170 GeV): σs+t = 2.76+0.6-0.5 pb |Vtb|> 0.77 @ 95% C.L. Developed and used advanced methods to separate signal events from substantial backgrounds Talks of V. Shary, L. Dudko Dmitri Denisov, RAS, November 2009

  17. Electroweak Physics Indirectly constrain new physics through precision measurements of electroweak parameters Measure single and multi-boson production, W mass, W production asymmetry,… Leptonic decay modes of W/Z are maiunly used as hadronic modes are overwhelmed by QCD Single most precise W mass measurement! World average is now 80.399 ± 0.023 GeV (0.025%) Statistic limited 80.401 ± 0.021(stat.) ± 0.038(syst.) GeV Dmitri Denisov, RAS, November 2009

  18. Studies of di-boson Production Detect very rare SM processes, search for anomalous vector boson couplings and develop experimental methods for Higgs hunting H  WW • ZZ is the smallest SM di-boson cross section: • s(ZZ)=1.6 ± 0.1 pb • On the road to Higgs 2009! Talk of V. Shary Dmitri Denisov, RAS, November 2009

  19. b Quark Studies High b quark cross section: ~10-3stot ~104 b’s per second produced! All b containing species are produced B, B0, Bs, Bc, b… • Large b quark data samples provide • B mesons lifetime studies • Mass spectroscopy (Bc, etc.) • Studies of Bs oscillations • CP violation studies • Search for new b hadrons • Search for rear decays Wb observed! Lb lifetime from CDF now agrees with others Dmitri Denisov, RAS, November 2009

  20. Bs Mixing Parameters Bs meson allows to probe the entire matrix: Mass difference between mass eigenstates P-value(SM)=3.4% Hint of physics beyond Standard Model?! Very sensitive to New Physics Talk of N. Skachkov Dmitri Denisov, RAS, November 2009

  21. Search for New Phenomena One of the most natural studies is to look for New Phenomena at energy frontier machine: SUSY, leptoquarks, Technicolor, new exotic particles, extra dimensions… Recipe: search for irregularities in effective mass spectra or other kinematic parameters looking for events not described by the SM WZ resonances search Z’ decays to electron pair search SUSY A. Popov talk Dmitri Denisov, RAS, November 2009

  22. “Ghost” Muons In November 2008 CDF reports observation of excess of di-muons with large decay distances • DØ has substantially thicker muon system and magnetized iron toroid • Punchthrough is much less • Excellent time resolution of trigger counters in all layers of the muon system • Rejection of cosmic muons CDF Preliminary ~20% excess observed New Physics?! • Two lessons • Importance of two experiments • Time scale to perform new analysis could be ~4 months • DØ repeated similar study in March 2009 • No excess found within ~1% uncertainty Dmitri Denisov, RAS, November 2009

  23. Standard Model Higgs Search • Available experimental limits • Direct searches at LEP: MH >114 GeV at 95% C.L. • Precision EW fits Light Higgs favored – in the Tevatron energy range! MH 157 GeV (95%) or <185 GeV with direct LEP limit LEP Tevatron provides: Precision mtop and Mw measurements Direct searches Dmitri Denisov, RAS, November 2009

  24. SM Higgs Production and Decays at the Tevatron Production cross sections  in the 1 pb range for gg  H  in the 0.1 pb range for associated vector boson production Decays  bb for MH < 130 GeV  WW for MH > 130 GeV Search strategy: MH <130 GeV associated production and bb decay W(Z)H  ln(ll/nn) bb Backgrounds: top, Wbb, Zbb… MH >130 GeV gg  H production with decay to WW Backgrounds: electroweak WW production… Dmitri Denisov, RAS, November 2009

  25. Major Experimental Challenges Low cross sections and high backgrounds • Inclusive production • at 115 GeV ~5 inclusive Higgs bosons would be produced per day • QCD backgrounds too high… Cross section x BR for key Higgs modes Required - highest acceptance, use of modern analysis tools Dmitri Denisov, RAS, November 2009

  26. SM Higgs Search: WH lnbb (MH<130 GeV) • One of the most sensitive channels in the ~110-130 GeV mass range • Consider 8 independent channels • e+jets, m+jets • 2, 3 jets • 1, 2 b-tags (NN-based) • Main background: W+b/c jets, tt • Dijet mass  multivariate discriminant Limits are used for DØ combination Talk of I. Razumov Dmitri Denisov, RAS, November 2009

  27. SM Higgs Search: H  WW lnln(MH >130 GeV) e+ n W+ n W- e- Search strategy:  2 high Pt leptons and missing Et  WW pair comes from spin 0 Higgs: leptons prefer to point in the same direction H Dmitri Denisov, RAS, November 2009

  28. Setting Limits on Standard Model Higgs Using Neural Network plots limits on Higgs cross section set in each individual channel and normalized to Standard Model Higgs cross section at a given mass H  WW Limit at 165 GeV : 1.36 (expected) and 1.55(observed) Dmitri Denisov, RAS, November 2009

  29. Combining Multiple Channels Similarly, DØ uses 58 sub-channels Dmitri Denisov, RAS, November 2009

  30. Standard Model Higgs Search Combining multiple search channels Tevatron sets Standard Model Higgs limits When ratio equals to one – specific Higgs mass is excluded at 95% CL Ratio to SM observed(expected): 2.70 (1.78) at 115 GeV, 0.94 (0.89) at 165 GeV Dmitri Denisov, RAS, November 2009

  31. Confidence Level Combined Plot • SM Higgs excluded in the range 163-166 GeV at 95% CL • Expected exclusion range 159-168 GeV Tevatron demonstrated sensitivity to Higgs and will continue to increase exclusion region or… find the Higgs Dmitri Denisov, RAS, November 2009

  32. Future Accelerator Schedule Dmitri Denisov, RAS, November 2009

  33. Tevatron Luminosity Projections • Projections are based on extrapolations of the current performance • Improvements are still coming • We expect 12 fb-1 delivered by 2011 • Excellent physics program • Many studies are statistically limited Tevatron SM Higgs Exclusion With data accumulated by the end of 2011 95% exclusion over entire allowed mass range Dmitri Denisov, RAS, November 2009

  34. Tevatron Standard Model Higgs Projections Good chance with 2011 data to see Hints of the Higgs boson! Dmitri Denisov, RAS, November 2009

  35. Progress with SM Higgs limits at the Tevatron Steady progress with increase in data set and analysis experience Factor of 1.78 from SM prediction at Higgs mass 115 GeV Dmitri Denisov, RAS, November 2009

  36. Tevatron Reach Projections D0 Run 2 (e) W Boson Mass 10 pb-1 10 fb-1 • 15 MeV error on W boson mass and no changes in mean value means SM Higgs exclusion of MH <117 GeV! Many other exciting studies progressing! Dmitri Denisov, RAS, November 2009

  37. Russian Groups Participation at the Tevatron JINR, IHEP, ITEP, MSU, PNPI – 10% of the DØ Collaboration • Muon system design, construction and operation: IHEP, JINR, PNPI, ITEP • Silicon detector: MSU • Key contributions to physics analysis in • B-physics • Top quark studies • New Phenomena searches Talks later today! Without contributions from Russian groups none of the results presented in this talk would be possible Dmitri Denisov, RAS, November 2009

  38. Tevatron Physics Highlights: Summary DØ Publications per year Tevatron is performing extremely well: 12 fb-1 by 2011 • Experiments are collecting and analyzing data from the energy frontier collider smoothly •  Many discoveries and precision measurements • ~200+ studies in progress publishing 2 papers a week No significant deviations from the Standard Model observed… yet  Although there are a few “~2 sigma” discrepancies…  Data samples analyzed are to increase by 2-10 times • Many legacy measurements in progress •  Precision electroweak and other sectors •  Will be in the text books for a while! •  Some results from ppbar collider are unique SM Higgs search is in a very active stage  Excluded at 95% CL Higgs with mass around 165 GeV  Proceeding to exclude wider mass range or… to see the Higgs! Looking with excitement forward for continuing exciting physics results from the Tevatron experiments! Dmitri Denisov, RAS, November 2009

  39. Comparing March and November 2009 Results Dmitri Denisov, RAS, November 2009

  40. Russian Groups Participation in CDF JINR and ITEP Major JINR’s contributions • Creation and maintenance of the scintillation complex for CDF m-trigger for c,b,t – physics study • Creation and maintenance of the Silicon Vertex Trigger for secondary vertex detection • Top mass analysis • Search for the Very High Multiplicity processes using CDF data Excellent contributions! Dmitri Denisov, RAS, November 2009

  41. CDF and DØ Experiments in Run II CDF DØ Silicon Detector Central Drift Chamber Calorimetry Extended muon coverage Fast electronics Silicon Detector 2 T solenoid and central fiber tracker Large coverage muon system Fast electronics Driven by physics goals detectors are becoming “similar”: silicon, central magnetic field, hermetic calorimetry and muon systems Dmitri Denisov, RAS, November 2009

  42. DØ Detector Silicon Detector Fiber Tracker 5 barrel layers, 800k channels 12 fb-1 capable! 8 axial, 8 stereo fibers double layers - 77,000 fibers with VLPC readout Muon System Uranium Liquid Ar Calorimeter scintillators shielding All detectors are running very well! Dmitri Denisov, RAS, November 2009

  43. Search for New Physics in Top Quark Sector • In the Standard Model top decays before hadronization • Theories beyond Standard Model predict existence of resonances • In top-colour assisted technicolourleptophobic heavy boson couples mainly to 3rd generation • Search for narrow resonance optimised at high masses • Using reconstructed 4-momenta of two top quarks Heavy t’ quark search in the top samples in t’t’WqWq Lepton + jets Excess?! Dmitri Denisov, RAS, November 2009

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