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CDF Results for ICHEP 2008

CDF Results for ICHEP 2008. Chris Hays, Oxford University Fermilab Wine and Cheese July 25, 2008. Tevatron Run II. Studying the Standard Model at an unprecedented scale Measurements build up the Standard Model Searches probe for cracks. CDF Run II. 145 publications in Run II

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CDF Results for ICHEP 2008

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  1. CDF Results for ICHEP 2008 Chris Hays, Oxford University Fermilab Wine and Cheese July 25, 2008

  2. Tevatron Run II Studying the Standard Model at an unprecedented scale Measurements build up the Standard Model Searches probe for cracks C. Hays, Fermilab Wine and Cheese

  3. CDF Run II 145 publications in Run II 52new results since Moriond Analyses with up to 3 fb-1 of data Thanks to the accelerator division! C. Hays, Fermilab Wine and Cheese

  4. Building the Standard Model:Light Quarks and Gluon C. Hays, Fermilab Wine and Cheese

  5. 2.7 fb-1 Proton-Antiproton Collisions Non-perturbative QCD in every collision Probe by studying underlying event Separate underlying event from perturbative process using Drell-Yan production Define regions relative to boson pT : toward, transverse, away pTZ "toward" "transverse" "away" PYTHIA tune "AW" models underlying event well Standard HERWIG underestimates multiplicity Compare charged particle observables to model predictions C. Hays, Fermilab Wine and Cheese

  6. 0.5 fb-1 Differential Cross Sections Measure momentum & multiplicity distributions from inelastic collisions Unfold detector response and correct for diffractive background C. Hays, Fermilab Wine and Cheese

  7. p p P W,Z p 0.6 fb-1 Diffractive W and Z Production Focus on clean process of pomeron radiation from antiproton Study pomeron structure function using weak boson production Roman pots measure outgoing antiproton momentum Directly measure pz of neutrino from W boson decay Single diffraction cross section / total cross section: W's: 0.95 ± 0.05 ± 0.11% Z's: 0.85 ± 0.20 ± 0.11% C. Hays, Fermilab Wine and Cheese

  8. Building the Standard Model:Bottom Quark C. Hays, Fermilab Wine and Cheese

  9. 1.0 fb-1 B-meson Lifetime Measurements Lifetimes predicted using heavy quark expansion GF2mb5 Bc J/ ) QCD ) QCD [ ( ( |Vcb|2A0 + A2 + A3 ] 3 2  = mb mb 192 3 Bc lifetime in J/ l New CDF method accounts for trigger bias using data Trigger requires tracks with large impact parameters Applied to B± → D0± Use per-event acceptance function when calculating likelihood Can reduce systematic uncertainties Bc c= 142.5 +15.8-14.8 ± 5.5 m B± c= 498.2 ± 6.8 ± 4.5 m World average c= 137.7 ± 11.0 m C. Hays, Fermilab Wine and Cheese

  10. 1.1 fb-1 b Lifetime Measurement Lifetime ratios predicted to O(1/mb4):(b0)/(B0) = 0.88 ± 0.05 Longstanding tension between prediction and measurements World average (2006): 0.804 ± 0.049 Recent CDF measurement in J/ 2above world average New CDF measurement usesc+- decay - b c b c= 422.8 ± 13.8 ± 8.8 m (b0)/(B0) = 0.922 ± 0.039 World's most precise measurement C. Hays, Fermilab Wine and Cheese

  11. 2.8 fb-1 s Measurement Complex Higgs-q-q Yukawa couplings give rise to CKM matrix Wolfenstein parametrization Unitarity requires combinations of different columns to sum to zero Triangles in the complex plane Not SM s (= 0.02 in SM Winter conferences: DØ (2.8 fb-1): 2s = (-0.06, 1.20) at 90% CL (6.6% consistency with SM) CDF (1.4 fb-1): 2s = [0.32, 2.82] at 68% CL (15% consistency with SM) UTfit: "This is a first evidence of physics beyond the Standard Model" 0802.4258 PRL 100, 161802 0803.0659 C. Hays, Fermilab Wine and Cheese

  12. 2.8 fb-1 s Measurement in J/ Bs mixing: Flavor eigenstates oscillate (Bs0↔ Bs0) with frequencym = 17.77 ps-1 Measure lifetime difference () and CP asymmetry (∝ sin2s) in J/ decays CP violation due to interference with and without mixing Complication:J/ not a CP eigenstate Use angular distributions to separate longitudinal, parallel, transverse polarizations Combine with decay time and Bs0/Bs0tagging to obtain likelihood for, ands PRL 97, 242003 3166 Bs0 candidates 7% consistency with SM C. Hays, Fermilab Wine and Cheese

  13. Building the Standard Model:Top Quark C. Hays, Fermilab Wine and Cheese

  14. 2.8 fb-1 Top Quark Cross Section Measurements in "lepton + jets" decay mode with and without b-jet tagging BR(lepton + jets) = 30% (lepton = e,) No tagging:Neural network separates tt from W + jets b-jet tagging:Based on either long b-hadron lifetimes or semi-leptonic b-hadron decays No tagging: Lifetime-based b-jet tagging: tt = 6.8 ± 0.4 (stat) ± 0.6 (sys) ± 0.4 (lum) pb tt = 7.2 ± 0.4 (stat) ± 0.5 (sys) ± 0.4 (lum) pb b → X tagging (2.0 fb-1): tt = 8.7 ± 1.1 (stat) +0.9-0.8 (sys) ± 0.6 (lum) pb b → eX tagging (1.7 fb-1): tt = 7.8 ± 2.4 (stat) ± 1.5 (sys) ± 0.5 (lum) pb C. Hays, Fermilab Wine and Cheese

  15. 2.8 fb-1 Top Quark Cross Section Measurements in "dilepton + jets" decay with and without lifetime-based b-jet tagging BR(dilepton + jets) = 5% (lepton = e,) Combine with lepton + jets measurements No tagging: tt = 6.7 ± 0.8 (stat) ± 0.4 (sys) ± 0.4 (lum) pb With tagging: tt = 7.8 ± 0.9 (stat) ± 0.7 (sys) ± 0.5 (lum) pb 9% precision 8% theory uncertainty C. Hays, Fermilab Wine and Cheese

  16. 2.8 fb-1 Top Quark Mass Top quark loops contribute to the W & Z boson masses mt2-dependent correction drowns ln(mH/mZ) Higgs loop correction Need precise top mass measurement to constrain Higgs mass Winter conferences: mt = 172.6 ± 1.4 GeV, mH = 87+36-27 GeV (Tevatron, 0803.1683) Measurement in lepton + jets channel most precise (winter conferences:mt = 172.7 ± 2.1 GeV) Integrate matrix element over resolutions and unknowns to obtain unbinned likelihood Function of top mass and jet energy scale Neural network separates signal from background mt= 172.2 ± 1.0 (stat) ± 0.9 (JES) ± 1.0 (sys) GeV = 172.2 ± 1.7 GeV Also: Updated measurement in dilepton + jets channel Uses likelihood based on weighting events in 1-2 plane mt = 165.1+3.3-3.2 (stat) ± 3.1 (sys) GeV C. Hays, Fermilab Wine and Cheese

  17. 1.9 fb-1 Top Quark Mass Jet energy scale dominates systematic uncertainty in top mass reconstruction Pursue alternative mass measurements largely independent of energy scale b-jet lifetime:proportional to b-quark pT lepton pT:dependent on WpT Lifetime: mt = 176.7+10.0-8.9 (stat) ± 3.4 (sys) GeV Lepton pT: mt = 173.5+8.9-9.1 (stat) ± 4.2 (sys) GeV Combination: mt = 175.3 ± 6.2 (stat) ± 3.0 (sys) GeV C. Hays, Fermilab Wine and Cheese

  18. 2.7 fb-1 Single Top Production Top produced weakly in s-channel (tb = 0.9 pb) or t-channel (tq = 2.0 pb) Cross section directly measures Vtb magnitude Unique test of CKM unitarity Single top cross section overwhelmed by W + jets background Advanced techniques required to separate signal from background t-channel likelihood function: 7 (10) input variables for 2- (3)-jet final states s-channel likelihood function: 6 input variables for 2-jet final state C. Hays, Fermilab Wine and Cheese

  19. 2.7 fb-1 Single Top Production Matrix-element probability: Combines s & t channels Boosted decision tree: Four trees: 2 or 3 jets with 1 or 2 tags Neural network: Four networks: 2 or 3 jets with 1 or 2 tags C. Hays, Fermilab Wine and Cheese

  20. Building the Standard Model:Leptons and Electroweak Bosons C. Hays, Fermilab Wine and Cheese

  21. 2.4 fb-1 W Boson Mass W mass precision the primary limitation on indirect Higgs mass constraint Also constrains other scalars with weak charge (e.g., superparticles) Published measurement with 200 pb-1 has 48 MeV uncertainty (world's best) Dominant uncertainties expected to scale with square root of luminosity Now analyzing 12x data: PRL 99, 151801 PRD 77, 112001 W → e Z →  97k Z → ll events 1.4M W → l events Expect total uncertainty < 25 MeV C. Hays, Fermilab Wine and Cheese

  22. Building the Standard Model:The Higgs Boson C. Hays, Fermilab Wine and Cheese

  23. 3.0 fb-1 The Higgs Boson The last unobserved particle in the standard model Only fundamental scalar Gives fermions and weak bosons their masses Responsible for generational mixing Narrow allowed mass region Direct 95% CL limit:mH > 114 GeV Indirect 95% CL limit: mH < 160 GeV Higgs boson at the Tevatron:  (pb) Higgs boson at CDF: All dominant channels updated New channels added All include improvements: scale better than luminosity C. Hays, Fermilab Wine and Cheese

  24. 2.7 fb-1 Higgs Searches (mH≲130 GeV) Use W/Z + H production at low mass Significantly suppresses background Leptonic boson decays provide further suppression Balance loss in cross section with large H → bb BR WH → lbb Matrix element probability + boosted decision tree: ME likelihoods among 21 inputs Neural network approach: Six categories based on lepton type and number of b-tags Added trigger to extend muon coverage mH = 115 GeV:  < 5.0 x SM (5.8 x SM expected) winter conferences: < 7.1 x SM expected  < 5.8 x SM (5.6 x SM expected) C. Hays, Fermilab Wine and Cheese

  25. 2.4 fb-1 Higgs Searches (mH≲130 GeV) ZH → llbb Matrix element probability: 2-dimensional neural network: 13 input variables separate ZH from tt and Z+jets Less data and lepton coverage Better sensitivity for overlap sample mH = 115 GeV:  < 11.6 x SM (11.8 x SM expected) winter conferences: < 16 x SM expected mH = 120 GeV:  < 14.2 x SM (15.0 x SM expected) C. Hays, Fermilab Wine and Cheese

  26. 2.1 fb-1 Higgs Searches (mH≲130 GeV) ZH → bb + WH → lbb WH + ZH → qqbb Added H1 algorithm using charged-particle tracks to improve jet energy resolution Matrix element procedure CDF Run II Preliminary 7 inputs to neural network mH = 115 GeV:  < 7.9 x SM (6.3 x SM expected) winter conferences: < 8.3 x SM expected ME discriminant mH = 120 GeV:  < 38 x SM (40 x SM expected) C. Hays, Fermilab Wine and Cheese

  27. 3.0 fb-1 Higgs Searches (mH≳130 GeV) Traditionally focus on direct Higgs production High branching ratio to WW H → WW → ll low-background final state Additional sensitivity with new modes H → WW qqH WH + ZH + qqH → qqWW mH = 160 GeV:  < 1.6 x SM (2.0 x SM expected) winter conferences: < 2.5 x SM expected  < 6.9 x SM (4.6 x SM expected) Combination:  < 1.6 x SM (1.8 x SM expected) Large boson branching ratio to quarks Provides 30% additional acceptance Neural network: Uses matrix element likelihood as a discriminant in events with no jets Also: WH → WWW → lll  < 33 x SM (33 x SM expected) C. Hays, Fermilab Wine and Cheese

  28. Breaking the Standard Model:Supersymmetry ± C. Hays, Fermilab Wine and Cheese

  29. 2.7 fb-1 Stop and Sbottom Production Supersymmetry solves the hierarchy problem, predicts coupling unification, has a dark matter candidate, and is required by string theory Superpartners of every particle, differing in spin by 1/2 Searches for stop and gluino-mediated sbottom production mgluino - msbottom = 20 GeV C. Hays, Fermilab Wine and Cheese

  30. 2.0 fb-1 Chargino + Neutralino and Sneutrino Production Chargino + neutralino search Spin 1/2 partners of gauge and Higgs bosons mix to form charginos and neutralinos Sneutrino search Resonant production if R-parity violated e, e, final states Limits set in m0-m1/2 plane of constrained SUSY m > 586 GeV (e) 487 GeV (e) 484 GeV () for couplings 0.05-0.1  C. Hays, Fermilab Wine and Cheese

  31. Breaking the Standard Model:Neutral Resonances ' C. Hays, Fermilab Wine and Cheese

  32. ' 2.5 fb-1 Resonance Decays to Dimuons New U(1) symmetry ubiquitous in models: versions of supersymmetry, unified theories Excited graviton states predicted in warped extra dimension theories Both predict resonances decaying to dileptons, likely at Electroweak mass scale Winter conferences: dielectron search showed excess at mass around 240 GeV 0.6% probability to be a background fluctuation New search in dimuon channel: similar sensitivity to a resonance with this mass Probe 1/m spectrum: resolution constant vs 1/m Most significant excess at 103 GeV 6.6% probability to be due to background Set mass limits on Z' and gravitons C. Hays, Fermilab Wine and Cheese

  33. Breaking the Standard Model:A Fourth Generation ' ' C. Hays, Fermilab Wine and Cheese

  34. ' 2.8 fb-1 Fourth Generation Top Quark t' can lead to large s and D0 mixing (Hou, Nagashima, and Soddu, PRD 76, 016004) Search for t' in lepton + jets final state Reconstruct hypothesized t' mass and search in plane of mass vs total transverse energy 1% consistency between data and SM at this mass mt' > 311 GeV C. Hays, Fermilab Wine and Cheese

  35. CDF Run II:ICHEP 2008 Reaching the peak of the physics Broad program with many exciting results New results not shown today: Z + jets cross section Inclusive photon cross section X(3872) mass measurement Search for narrow resonances below the  Search for Bs/d → e Gluon fusion fraction of top production W helicity measurement combination Limits on top decay to non-SM final states Anomalous single top production Search for charged Higgs in top decays Anomalous ZZZ couplings Search in photon + missing pT + jet Search in photon + missing pT + b-jet Search in photon + missing pT + b-jet + lepton Maximal-flavor-violation in same-sign top production Technirho production Leptoquark production See http://www-cdf.fnal.gov/physics/S08CDFResults.html for more details C. Hays, Fermilab Wine and Cheese

  36. The Standard Model at ICHEP 2008 Closing in on the final piece Are we seeing a new wrinkle? C. Hays, Fermilab Wine and Cheese

  37. Backup C. Hays, Fermilab Wine and Cheese

  38. 2.0 fb-1 Top Quark Pair Production Standard Model predicts 85% qq annihilation and 15% gluon fusion J = 0 J = 1 Top quark decays via W+: left-handed top decays to right handed l+ t spin: t spin: Leptons go in same direction when J = 0 l+ momentum: l- momentum: Measure gluon fusion fraction through lepton azimuthal correlation Distribution sculpted by event selection gluon fusion qq annihilation gluon fusion fraction: 53+36-38% C. Hays, Fermilab Wine and Cheese

  39. 1.9 fb-1 Anomalous ZZZ Couplings C. Hays, Fermilab Wine and Cheese

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