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Tevatron Run 2 Physics Results

Tevatron Run 2 Physics Results. Dhiman Chakraborty Northern Illinois University for The D0 and CDF collaborations ACFA workshop 15-17 December, 2003 TIFR, Mumbai, India. Outline. Introduction The collider upgrade - Tevatron Run 2 The detector upgrades – CDF & D0 New Physics results

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Tevatron Run 2 Physics Results

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  1. Tevatron Run 2 Physics Results Dhiman Chakraborty Northern Illinois University for The D0 and CDF collaborations ACFA workshop 15-17 December, 2003 TIFR, Mumbai, India

  2. Outline • Introduction • The collider upgrade - Tevatron Run 2 • The detector upgrades – CDF & D0 • New Physics results • QCD • Bottom • W/Z • Top • Higgs • New Phenomena • Summary & Outlook Tevatron Run 2 Physics Results

  3. The Tevatron Collider in Run 2 • Proton-antiproton collisions at s = 1.96 TeV • 36 bunches each of p & p 396 ns between bunch crossings • Increased from 6x6 bunches with 3.5ms in Run 1 • Increased instantaneous luminosity: • Run 2 goal: 30 x 1031 cm–2 s-1 • Current: ~4.5 x 1031 cm–2 s-1 • Projections through FY 2009: • “Base”: 4.4 fb-1 • “Design”: 8.6 fb-1 Tevatron Run 2 Physics Results

  4. Run 2 luminosity profile • Lint~300 pb-1 delivered by the Tevatron • Good quality data since Spring 2002 • D0 & CDF collecting data with 85%-90% eff. Projection for 2004: additional 310-380 pb-1 delivered Tevatron Run 2 Physics Results

  5. 19 countries 83 institutions, 664 physicists The Tevatron Collider Experiments

  6. The upgraded D0 Run 2a detector Multipurpose collider detector: Tracking • silicon vertex detector • fiber tracker • 2T magnetic field Calorimetry - preshowers - U/LAr calorimeters Muon - drift tubes and scintillator Trigger+ Data Acquisition System Tevatron Run 2 Physics Results

  7. The upgraded CDF Run 2a detector • New bigger silicon, new drift chamber • Upgraded calorimeter, muon system • Upgraded DAQ/trigger, esp. displaced-track trigger Tevatron Run 2 Physics Results

  8. 4 H-disks 12 F-disks 6 Barrels The new silicon detectors D0 • Common features: • Coverage of the • luminous regions • Extended acceptance at • large pseudo-rapidity • 3D Tracking capability • Excellent I.P. resolution CDF Tevatron Run 2 Physics Results

  9. QCD Inclusive jet cross section vs. NLO predictions • Theoretical uncertainties dominated by PDF’s • Full Run 2 data set will help reduce this uncertainty • So far the data agrees reasonably well with NLO predictions Tevatron Run 2 Physics Results

  10. QCD Dijet mass vs. NLO predictions • Search for new phenomena, e.g. compositeness (qq, qg, gg) • Sensitive to gluons at large x Tevatron Run 2 Physics Results

  11. Heavy flavor: B hadrons Several new measurements on masses, lifetimes & branching fractions of B hadrons performed by both CDF and D0, many more, such as Bsoscillation, M(Bc), & B(Λb), coming soon. B hadron mass measurements using fully reconstructed decays: Bsand bmeasurements world’s best: CDF result: M(Bs)=5365.5 　1.6 MeV World avg: M(Bs)=5369.60 2.40 MeV CDF result: M(b)=5620.4 2.0 MeV World avg: M(b)=5624.49.0 MeV 1st observation at Tevatron 5.71 ± 0.016 GeV (PDG: 5.698 ± 0.008 GeV) Tevatron Run 2 Physics Results

  12. Bs lifetime - 1.33± 0.14(stat)±0.02(sys) ps PDG: 1.461 ± 0.057 ps Heavy flavor: B hadron lifetimes mass: 5.272 ± 0.005 GeV • Lifetime: • 1.671 ± 0.018 ps (PDG) Bs→J/ψΦwith J/ψ→μ+μ- and Φ→K+K- B+→ J/ΨK+, B0→J/ΨK*0check technique, systematics Tevatron Run 2 Physics Results

  13. Heavy flavor: blifetime  primary  Lxy p + Use fully reconstructedb J/with J/ + and  p Only at the Tevatron ! Tevatron Run 2 Physics Results

  14. Heavy flavor: new particle decaying to J/π+π • Belle observes narrow state • final state J/π+π • exclusive: B+ →J/π+π K+ • 35.7 ±6.8 events • possibly charmonium • mass is unexpected • shown August 12, 2003 • CDF confirms this on • September 20 • final state J/π+π • mostly prompt prodction • 709±86 events Tevatron Run 2 Physics Results

  15. Heavy flavor: Towards a Measurement of Bs Mixing • Bs reconstruction • e.g. • Flavortagging ( Bs or Bsat the time of production?) • Tagging “dilution”: D=1-2w • Tagging power proportional to: D2 • Proper decay time • Crucial for fast oscillations (i.e. Bs) Typical power (one tag): D2 = O(1%) at Tevatron D2 = O(10%) at PEPII/KEKB uncertainty Tevatron Run 2 Physics Results

  16. Heavy flavor: Towards a Measurement of Bs Mixing opposite side jet charge tagging: • Bs->Ds ln tagging power:1.6% opposite side soft muon tagging: Tevatron Run 2 Physics Results

  17. Electroweak: Z →l+l− • Z→μ+μ−: • CDF Event selection: • Two central tracks: • pT > 20 GeV, opposite charge, MIP trace in CAL • at least one |η| < 0.6, both |η| < 1.0 • 66 < Mμμ < 116 GeV , Cosmic veto (bkg <1%) • CDF: σZ • B(Z→μ+μ−) = 246 ± 6 ± 12 ± 15 pb • stat. syst. lumi. • D0: σZ • B(Z→μ+μ−) = 261.8 ± 5.0 ± 8.9 ± 26.2 pb • stat. syst. lumi. Ncand = 1631 ∫L = 72 pb-1 εtotal = 9% Ncand = 1631 ∫L = 42 pb-1 Z→e+e−: Two isolated electrons, ET > 25 GeV, |η| < 1.1 CDF: σZ•B(Z→e+e−) = 267.0 ± 6.3 ± 15.2 ± 16.0 pb lumi. stat. syst. DØ: σZ•B(Z→e+e−) = 275 ± 9 ± 9 ± 28 pb lumi. stat. syst. Tevatron Run 2 Physics Results

  18. Electroweak: looking for Z→ +− • Look for isolated, high pT e or μ opposite narrow hadronic jet • CDF • DØ • • small numbers of • candidates • • rates consistent • with expectations Tevatron Run 2 Physics Results

  19. Electroweak:(W→l) • pT(e) > 25 GeV, ETmiss > 25 GeV • OR • pT(μ) > 20 GeV, ETmiss > 20 GeV • D0: • σW • B(W→e) • = 2.884 ± 0.021 ± 0.128 ± 0.284 nb • σW • B(W→μ) • = 3.226 ± 0.128 ± 0.100 ± 0.322 nb • CDF: • σW • B(W→e) • = 2.64 ± 0.01 ± 0.09 ± 0.16 nb • σW • B(W→μ) • = 2.64 ± 0.02 ± 0.12 ± 0.16 nb • (all uncertainties are stat. ± syst. ± lumi.) Tevatron Run 2 Physics Results

  20. Electroweak:(ratio & widths) σW• B(W→l) σZ• B(Z→l+l−) R = Indirect measurement of ΓW : Using NNLO calculation of the cross section ratio and the LEP measurement of B(Z→l+l−), one can extract B(W→l). The SM prediction for Γ (W→l) then gives ΓW= Γ (W→l) / B(W→l): • Luminosity, pdf, some expt. sys. uncertainties cancel • R = 10.34±0.35 (stat)±0.48 (sys) Tevatron Run 2 Physics Results

  21. Higgs • D0 & CDF are picking up searches for SM-like Higgs where LEP left it off. • Must look hard despite limited sensitivity. • While LEP expts are now rigorously studying a broad spectrum non-SM scenarios, Tevatron expts. Are focusing on MSSM, with the expectation of a light SM-like Higgs. Tevatron Run 2 Physics Results

  22. Higgs sensitivity at the Tevatron The 1998-99 FNAL study updated in Sep 2003 with • Hit-level simulations • Background modeling based on Run 2 data and improved analysis techniques • Focus on 115 Gev < M(H) < 140 GeV (lowered expectation for int lum) • Focus on pp -> Wh -> lnubb (CDF) and pp -> Zh -> nunubb • Results combined for both channels and experiments. Despite optimistic assumptions in the previous study, the newer study suggests that we can do better than we thought 5 yrs ago. With 4-5 fb**-1, DO+CDF together may be able to exclude M(H)<130 GeV at 95% CL if it isn’t there. Note: systematic uncertainties have not been taken into account. Tevatron Run 2 Physics Results

  23. Doubly charged Higgs • appear in left-right symmetric models • for M(H±±) < 160 GeV, dilepton decay modes dominate • 107 pb-1 • M(H±±) > 95 GeV @ 95% c.l. (right-handed) • M(H±±) > 115 GeV @ 95% c.l. (left-handed) • world’s best limit Tevatron Run 2 Physics Results

  24. top-antitop production • mainly quark-antiquark annihilation • W and b-quark decays specify final states • isolated high PT leptons • soft leptons in jets • detached vertices in jets Top Tevatron Run 2 Physics Results

  25. Top: tagging high-pT b jets Soft Lepton Tag • Exploits presence of e/m in semileptonic decays • On average, hese leptons have lower pT than those from W/Z, • and are not as isolated • Silicon Vertex Tag • Signature of a b decay is a displaced vertex: • Long lifetime of b hadrons (c ~ 450 m)+ boost • B hadrons travel Lxy~3mm before decay with large charged track multiplicity • B-tagging at hadron machines established: • crucial for top discovery in RunI • essential for RunII physics program Tevatron Run 2 Physics Results

  26. Top: Run 2 cross section (l+jets) • 1 high pT lepton(e,m) • Large Missing ET • 3 central jets This signature suffers from large W+jets background. Isolate signal using: SVX B-tag and/or kinematics D0 Run II preliminary - L=45 pb-1 Tevatron Run 2 Physics Results

  27. Top: Run 2 cross section summary (pair production) Tevatron Run 2 Physics Results

  28. Top: Mass Measurement (Run 1) • Template method: • Kinematic fit under the tt hypotesis • Combinatorial issues • best c2 combination chosen • Likelihood fit • Dynamical method: • Event probability of being signal or background as a function of m(t) • Better use of event information  increase statistical power • Well measured events contribute more • New D0 Run 1 result: factor of 2.5 improvement on the statistical uncertainty! D0 l+jets Tevatron Run 2 Physics Results

  29. Top: Mass Measurement (Run 2) D0 Run 2 preliminary A precise measurement of the top mass combines cutting edge theoretical knowledge with state of the art detector calibration CDF Run 2 preliminary, 108 pb-1 CDF Run 2 preliminary, 126 pb-1 Mass in l+jets channel with a b-tagged jet Mass in dilepton channel Tevatron Run 2 Physics Results

  30. New Phenomena: SUSY • Multitude of choices for models/params • generic MSSM • vs. • SUGRA, cMSSM, RPV, GMSB, AMSB, … • There is no absolute exclusions in SUSY • Use theories only as guides and • Concentrate on experimental signatures • rather than individual models • After all, he real goal and hope is to find • something… • CDF has searched for in Run 2 • and D0 for • A lot of emphasis also on signatures with • photons and t’s. Tevatron Run 2 Physics Results

  31. New Phenomena: leptoquarks • Appear in several extensions • to the SM: GUTs, RPV SUSY, TC, … • Carries both lepton & baryon numbers • Pair production most likely at Tevatron • Assume coupling to l & q of same • generation only, to avoid FCNCs • Most combinations of charged & neutral • leptons of the 1st two generations analyzed. • Run 2 data so far consistent with expected • background mm ee Tevatron Run 2 Physics Results

  32. New Phenomena: Z’ to dileptons • Look for narrow resonance beyond M(Z) in dilepton mass spectrum • No significant excess over expected background in Run 2 data yet Z’(ee) Z’(mm) Tevatron Run 2 Physics Results

  33. New Phenomena: small & large EDs Analysis similar to Z’ search CDF: m_g>600 GeV at 95% CL for Small (warped) ED (Randall-Sundrum) D0: MS(GRW) > 1.37 TeV @ 95% CL (incl. Run 1) for Large (flat) EDs (Arkani-Hamed, Dimopoulos, Dvali) Tevatron Run 2 Physics Results

  34. New Phenomena: other results • D0 has performed a model-independent search for deviations in data from SM predictions for emevents (a la Sleuth) SM background: Ztt, WW, ttbar, fake isolated leptons Data: • em: 1.8 ± 0.1 expected, 2 obs. • emj: 0.1 evt expected, 0 obs. CDF has searched for in windows about the B meson masses: best limits, still O(100) above SM predictions, but near SUSY enhancement scenarios. Tevatron Run 2 Physics Results

  35. Summary & Outlook • Run 2 of the Tevatron has already produced many new results on b, electroweak, Higgs, top, & New Phenomena - Most have already superceded Run 1 results, - Several measurements are world’s best. • Many many more are on their ways: stay tuned as theintegrated luminosity grows and our understanding of the detectors’ performance improves. • We’ve entered a new territory in discovery potential for physics beyond the SM. Tevatron Run 2 Physics Results

  36. X ? Tevatron Run 2 Physics Results

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