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New Results from D Ø

New Results from D Ø. John Hobbs (Stony Brook) For the DØ Collaboration. This summer (since mid May) >30 preliminary results 12 papers submitted >42 TOTAL from all physics areas : B physics, EW, Higgs, New Phenomena searches, QCD, top physics

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New Results from D Ø

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  1. New Results from DØ John Hobbs (Stony Brook) For the DØ Collaboration

  2. This summer (since mid May) >30 preliminary results 12 papers submitted >42 TOTAL from all physics areas: B physics, EW, Higgs, New Phenomena searches, QCD, top physics Some have improved techniques, some with increased luminosity, some new topics, (and some a combination of these) FNAL Wine and Cheese, DØ/Hobbs

  3. Discuss a subset of results all results deserve fuller treatment no discussion for results in recent W&Cs: also see DØ results area for full list and notes and papers Thanks to my DØ colleagues for all their hard work… First Observation of a New b-baryon Ξb, June 15 Measurements of the Lb Lifetime @DØ, July 13 Top Quark Physics @DØ as a probe for new Physics, July 20 www-d0.fnal.gov/Run2Physics/WWW/results.htm FNAL Wine and Cheese, DØ/Hobbs

  4. Data Taking and Performance In ’06 shutdown, installed Layer 0 silicon L1 calorimeter trigger upgrade Since then 1.7 fb-1, delivered lumi 1.5 fb-1, recorded 87% operating efficiency Reprocessed all data using improved reco by end May Thank you, accelerator division! FNAL Wine and Cheese, DØ/Hobbs

  5. In this talk • Foundation Physics from EW & QCD • Building blocks supporting other results • Anomalous Couplings • The top program • Beyond-the-Standard-Model searches • B Physics • Higgs Searches FNAL Wine and Cheese, DØ/Hobbs

  6. EW & QCD Results • s(W+c-jets)/s(W+jets) • ds/dpT(Z) • s(WZ) and anomalous couplings • Zg Production and anomalous couplings‡ • s(pp->Z)*B(Z->tt) • Measurement of U(1S) & U(2S) polarization ‡publication FNAL Wine and Cheese, DØ/Hobbs

  7. 1 fb-1 Foundation I: W+(c-jets) • boson + heavy flavor is crucial for continued improvement in Higgs search • Want full program W/Z+c, cc, b, bb • 1st measurement of W+c-quark production • Method • Charge correlation between a lepton from charm decay and W lepton • W + m-tagged jet(s) Dominant modes shown FNAL Wine and Cheese, DØ/Hobbs

  8. Shape consistency illustration Light vs. heavy A PLOT s(W+c-jet) s(W+jet) b vs. c = 0.071 ± 0.017 Jets, pT>20 GeV, |h| < 2.5, (no unfolding) Alpgen+DØ sim predicts = 0.040 Foundation I: W+c Charge symmetric background subtracted by SS vs. OS comparison FNAL Wine and Cheese, DØ/Hobbs

  9. 1 fb-1 Foundation II: pT(Z) • Test of theory • both soft and hard QCD • Generators for W mass, width, … • Previous: limited yZ • Now, up to |yZ|=3 • Z -> ee final state Low pT(Z): tests resummation (Collins, Soper, Sterman) pT(Z) FNAL Wine and Cheese, DØ/Hobbs

  10. pT(Z) Melnikov, Petriello PRD 74, 114017, )2006) pT(Z) FNAL Wine and Cheese, DØ/Hobbs

  11. en mn hadronic 1 fb-1 Foundation III: Z->tt • A number of results use hadronic t decays • Measuring s(pp->Z) in Z->tt cross checks our ability to identify hadronic t decays Obvious physics benefit from cleanly identifying hadronic decays t Branching Fractions FNAL Wine and Cheese, DØ/Hobbs

  12. Foundation III: Z->tt +5.0 -12 compare to prediction 252 pb Method Use Z -> tt -> m+th Signal prediction Instrumental Bkg (from OS, SS) s(pp->Z)*B(Z->tt) = 247 ±8(stat) ±13(sys) ±15(lumi) pb Increases confidence in our th results FNAL Wine and Cheese, DØ/Hobbs

  13. 1 fb-1 Look at processes pp -> WZ -> eee eem mme mmm Anomalous Couplings • WWZ trilinear coupling (recently also, ZZg/Zgg) Assume an effective Lagrangian, and look for deviation from SM coupling values (SM diagrams) FNAL Wine and Cheese, DØ/Hobbs

  14. Anomalous Couplings Fit number of events and Z pT spectrum Model independent and 2x better than previous best (LEP) FNAL Wine and Cheese, DØ/Hobbs

  15. The Top Program Mass, mt Expected B(t->lvb) Other states Production rate, s Couplings Look for other particles masquerading in production or decay (all tt all the time?) W in-decay properties, e.g. helicity FNAL Wine and Cheese, DØ/Hobbs

  16. Top Mass mt, dilepton MWT and combination mt from s(tt) Cross sections s(tt) in l+trk s(tt) in l+th s(tt), dilep combinition B(t->Wb)/B(t->Wq) & s† Dilepton cross section‡ l+jets cross section‡ New Physics in Prod/Decay Search for stop in ttbar† ttbar Charge Asymmetry† W helicity in top decay ttbar resonance search† s(tt; l+jets)/s(tt; ll) Single top update Top Physics: New Results †prev. W&C ‡publication FNAL Wine and Cheese, DØ/Hobbs

  17. Top Program dilepton (e/µ) 6% 's 14% all jet 46% lepton + jets Top decay - final states this discussion primarily dileptons dilepton lepton + jets e/µ + jet 34% FNAL Wine and Cheese, DØ/Hobbs

  18. 1 fb-1 Top Program: Improvements Mass, mt • Update result w/matrix weighting method. • Added ee and mm to existing em and improved selection, … • Combine with result from n weighting method Use template methods for mt in dilepton final states => Compensate for underconstrained kinematics FNAL Wine and Cheese, DØ/Hobbs

  19. Top Mass DØ Preliminary FNAL Wine and Cheese, DØ/Hobbs

  20. Correlation n weighting mass DØ Preliminary Matrix weighting mass (GeV) Top Mass • Combine Matrix weighting result with neutrino weighting result (same data set) Ensemble studies mt = 173.7 ± 5.4 ± 3.4 GeV FNAL Wine and Cheese, DØ/Hobbs

  21. Top Cross Section • Recover lost acceptance in dilepton final states: l+track • Use leptons which fail identification by finding a high-momentum, isolated track • Orthogonal to standard ll Gain additional 30% acceptance l+track only +0.9 +0.8 -0.9 -0.7 • = 6.2 (stat) (syst) ±0.4 (lumi) FNAL Wine and Cheese, DØ/Hobbs

  22. Top Program 's 14% all jet 46% lepton + jets dilepton lepton + jets e/µ + jet 34% dilepton (e/µ) 6% Top decay - final states Note historical situation: t’s aren’t considered leptons for top…  Focus on an unexplored region,l+t FNAL Wine and Cheese, DØ/Hobbs

  23. Top Program: s(tt)*B(tt -> ltbb) • Further expanding the program • Look for deviation in t modes (from, e.g. H+) • About 2/3 of selected “tt -> lt” is really from tt-> l+jets or tt -> ll • Consider cross-talk from other ttbar channels (e.g l+jets with t fake) as background. • Recompute cross section, moving other top contributions into background category s(tt)*B(tt->ltbbnn) = 0.19 ± 0.08(stat) ± 0.07(syst) ± 0.01 (lumi) pb SM, sB = 0.126 pb FNAL Wine and Cheese, DØ/Hobbs

  24. 1 fb-1 Top Program: Reinterpreting s • Use recent cross section measurements for additional information • From measured values compute • For a H+, if MH≈ MW and if B(H+ -> cs) = 1 s(tt), lj s(tt), ll +0.27 -0.26 R = = 1.21 (stat+sys) e.g. in MHDM, radiative corrs. w/in MSSM,… B(t->Hb) < 0.35 (95% CL) expected, B < 0.25 (95% CL), if B=0 FNAL Wine and Cheese, DØ/Hobbs

  25. Top Program: Reinterpreting s Looking at methods of measuring mt with different implicit assumptions? Extract the mass from the cross section s(tt) from l+jets channel Measured mt = 166.9 (exp)(th) +5.9 +3.7 -5.2 -3.8 FNAL Wine and Cheese, DØ/Hobbs

  26. BSM Searches: New Results • t -> c + c0 • q search in th + jets + ET • c±c0 in trileptons, eel • b’ -> Z+b, “Long Lived Parents of Z’s” • 3rd generation LQ in ttbb • GMSB in gg • t pairs in dileptons + ET + b-jets‡ • H -> gg • H±± -> m+m-m+m- • LQ3 in b-tagged jets + ET‡ ‡publication FNAL Wine and Cheese, DØ/Hobbs

  27. 1 fb-1 SUSY: t-> c + c0 • R-parity implies stop pair production • For c0 as LSP, and . mc < Mt-mc0 < mW + mb • 2 (charm) jets plus MET in the final state t -> c + c0 FNAL Wine and Cheese, DØ/Hobbs

  28. 2 jets, pT > 40(20) GeV df(jj) < 165 lepton, track vetos ET > 60 GeV SUSY: t-> c + c0 Basic Preselection (partial list) then flavor tag (>= 1 jet) mass dependent optimization HT (GeV) FNAL Wine and Cheese, DØ/Hobbs

  29. SUSY: t-> c + c0 Composition* W->ln+jets 20.6 ± 2.3 Z ->nn+jets 13.2 ± 1.8 W->ln+HF 11.9 ± 1.1 Z ->nn+HF 11.6 ± 0.8 other 7.0 ± 0.4 Total 64.3 ± 3.2 Data 66 *use Z->ee+jets to normalize Z->vv+jets FNAL Wine and Cheese, DØ/Hobbs

  30. 1 fb-1 Predicted Final Yields Signal (80,160)* 4.7 ± 0.4 Signal (100,150) 7.1 ± 0.6 Bkg 1.7 Data 2 +0.6 -0.4 q Search in th + jets + ET 1 or 2 t’s in final state *(m0,m1/2) here are t’s again FNAL Wine and Cheese, DØ/Hobbs

  31. q Search in th + jets + ET LEP2 excluded B(c1+-->c10tn) LEP2 excluded tan(b)= 15, A0=-2m0, m<0 FNAL Wine and Cheese, DØ/Hobbs

  32. Run IIb data 0.9–1.7 fb-1 SUSY Chargino/Neutralino ->trileptons • New result in eel After initial selection After partial selection Pred. Bkg 208± 7 Data 182 FNAL Wine and Cheese, DØ/Hobbs

  33. SUSY trileptons After full selection Signal 1-2 evts* Pred Bkg 1 ± 0.3 Data 0 Limit moves from m>140 GeV (all channels) to m>146 GeV *Depending on SUSY parameters FNAL Wine and Cheese, DØ/Hobbs

  34. B Physics: New results • Bs Mixing Update • Search for Bs–> m+m- Decay (1 fb-1‡; 2 fb-1†) • Lb lifetime in semileptonic decay‡† • 1st Observation of Xb ‡† • Direct CP violation in B+ -> J/y K+ • Search for FCNC in D mesons‡ • Observation of B**‡ †prev. W&C ‡publication FNAL Wine and Cheese, DØ/Hobbs

  35. 2.4 fb-1 Mixing: What’s in the Update? • More data: 2.4 fb-1 (2x previous) • Better detector: Layer 0 silicon • Track-by-track IP resolution uncertainty • Same side flavor tagging (SST) • Additional channel: hadronic decays • Better boost description Experimentally demanding FNAL Wine and Cheese, DØ/Hobbs

  36. Mixing: Two of the Improvements Bs hadronic decays Improved flavor tagging Tag eD2 Old OST 2.5 ± 0.2% SST 1.7 ± 0.6% New OST 4.5 ± 0.9% (evt charge) m trigger Dse, Dsp 22 ± 5% FNAL Wine and Cheese, DØ/Hobbs

  37. Mixing -logL 3.1s Dms Channels: mfp efp mK*K pfp 2.4 fb-1 (Data thru end May) FNAL Wine and Cheese, DØ/Hobbs

  38. B± -> J/yK± using asymmetry A = N(B+ -> J/yK+) – N(B- -> J/yK- ) N(B+ -> J/yK+) + N(B- -> J/yK- ) B Physics: Direct CPV, B+ -> J/y K+ • Compare rates of opposite charge states + FNAL Wine and Cheese, DØ/Hobbs

  39. B Physics: Direct CPV, B+ -> J/y K+ • Possible at DØ, magnet polarity flipping • Detector effects largely cancel A = +0.0067 ± 0.0074 (stat) ± 0.0026 (sys) 1% sensitivity, 2x better than PDG FNAL Wine and Cheese, DØ/Hobbs

  40. Higgs Searches: What’s New? • Improved techniques (WH, ZH) • NN in analysis and input to limit • Separate into n-tags and k-jets • Increased lepton acceptance (30%, e) • … and more … • More luminosity: • WH, WW(partial) channels both with IIa+IIb data samples. • WH -> WWW* with IIa (1 fb-1) FNAL Wine and Cheese, DØ/Hobbs

  41. 1–1.7 fb-1 Higgs Searches: New Results • Low Mass (MH < 135 GeV) • WH -> lnbb • ZH -> llbb • Intermediate Mass • WH -> WWW* • High Mass (MH > 135 GeV) • H->WW -> mth • H -> WW -> em FNAL Wine and Cheese, DØ/Hobbs

  42. 1-1.7 fb-1 Higgs Searches: Low Mass WH -> lnbb, Preselection FNAL Wine and Cheese, DØ/Hobbs

  43. Higgs Searches: Low Mass ≈Variables: pT,j1, pT,j2 DR(jj), pT,dijets, MJJ, pT(l,MET) Now using a NN for final stage. Fit NN output for final result NN output =1 b-tag No tag >= 2 b-tag FNAL Wine and Cheese, DØ/Hobbs

  44. 1-1.7 fb-1 High Mass: H->WW->em Basic preselection then multivariate for final stage NN output FNAL Wine and Cheese, DØ/Hobbs

  45. Higgs: WH Limit WH -> lnbb FNAL Wine and Cheese, DØ/Hobbs

  46. FNAL Wine and Cheese, DØ/Hobbs

  47. Conclusions • DØ running well • IIb average efficiency, 87% • using new Layer 0, L1 Cal trig. • >42 new results • All major physics areas • Broadening the program • Improved techniques • Up to 2.4 fb-1 in analysis • Yet essentially all are statistics limited FNAL Wine and Cheese, DØ/Hobbs

  48. BACKUP FNAL Wine and Cheese, DØ/Hobbs

  49. Top Mass FNAL Wine and Cheese, DØ/Hobbs

  50. l+jets 1 fb-1 Top Program: Cross Section & Decay • Simultaneous measurement of s(tt) and R=B(t->bW)/B(t->qW) in l+jets channel • Predict b-jet multiplicity as function of R • Use l+jets channel • Overall yield and • 0, 1 and 2-tag yields Fit yields as function of sand R FNAL Wine and Cheese, DØ/Hobbs

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