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B Physics at CDF

B Physics at CDF. Shin-Hong Kim (University of Tsukuba) October 9 , 2003 ICFP2003 at KIAS, Seoul. Tevatron pp Collider at Fermilab. RunI (1992 ～ 1996) s = 1.8 TeV RunII （ 2001 ～） s = 1.96 TeV + Main Injector. CDF. √. Tevatron Ring. √. Main Injector. Tevatron Status. 2002.

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B Physics at CDF

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  1. B Physics at CDF Shin-Hong Kim (University of Tsukuba) October 9 , 2003 ICFP2003 at KIAS, Seoul

  2. Tevatron pp Collider at Fermilab RunI (1992～1996) s = 1.8 TeV RunII（2001～） s = 1.96 TeV + Main Injector CDF √ Tevatron Ring √ Main Injector

  3. Tevatron Status 2002 2001 Initial Luminosity Run I（1992～1996）: • Record Luminosity 2x1031 cm-2sec-1 • Integrated Luminosity 110 pb-1 on Tape Run II（2001～）: • 5 x1031 cm-2sec-1（August 2003） • Integrated Luminosity 330 pb-1 • 270 pb-1on Tape • 120 pb-1analyzed Schedule: • 2 fb-1 (by the end of 2005) • 9 fb-1 (by the end of 2009) Now 2001 2002 330 pb-1 Integrated Luminosity Delivered 270 pb-1 On tape

  4. Drift Chamber Muon System Central Calor. New Solenoid Old Partially New Time-of-Flight Plug Calor. Muon Silicon Microstrip Tracker Front End Electronics Triggers / DAQ (pipeline) Online & Offline Software

  5. SVT incorporates silicon info in the Level 2 trigger… select events with large impact parameter! Uses fitted beamline impact parameter per track System is deadtimeless: ~ 25 sec/event for readout + clustering + track fitting 35mm  33mm resol  beam  s = 48mm Secondary Vertex B Lxy PT(B)  5 GeV Primary Vertex <Lxy>～450m -500 -250 0 250 500 SVT impact parameter (mm) d = impact parameter Silicon Vertex Trigger (SVT)

  6. Advantage Enormous cross-section ~100 b total ~ 4 b “reconstructable” At 4x1031cm-2s-1  ~150Hz of reconstructable BB!! All B hadrons produced Bu,Bd,Bs,Bc,b,… Disadvantage Large inelastic background Triggering and reconstruction are challenging B Physics at Hadron Colliders b’s produced by strong interaction, decay by weak interaction

  7. Tevatron B cross sections measured at √s =1.8TeV (Run I:1992-1996) consistently higher than NLO calculation Theoretical work is ongoing Fragmentation effects Small x, threshold effects Proposed beyond SM effects What can experiments do? Measure more cross sections √s =1.96 TeV go to lower pT(B) Look at bb correlations Measure the charm cross section Heavy Flavor Cross Sections (RunI) Integrated cross sections X X

  8. Observation of Bc meson(RunI) Cross section times Branching ratio vs Lifetime Invariant mass of J/ψ＋l in Bc→J/ψlν decay mode N（Bc）＝　20.4＋6.2ー5.6

  9. Anomalous J/ψDirect Production (RunI) ●Cross section of J/ψ andψ(2s) direct production is larger than QCD theoretical prediction by a factor of 50. PRL 79 (1997) 572, PRL 79 (1997) 578 ● Polarization of J/ψ andψ(2s)disfavors the color octet model.

  10. J/ψ production cross section ( RunⅡ) CDF measured the J/ψ cross section from PT > 0GeV/c by lowering the trigger threshold. Consistent with Run I Measurement in PT > 5GeV/c region. Need a comparison between this result and theoretical prediction in the PT < 5GeV/c region.

  11. B Hadron Lifetimes • All lifetimes equal in spectator model. • Differences from interference & other nonspectator effects • Heavy Quark Expansion predicts the lifetimes for different B hadron species • Measurements: • B0,B+ lifetimes measured to better than 1%! • Bs known to about 4% • LEP/CDF (Run I) b lifetime lower than HQE prediction • Tevatron can contribute to Bs, Bc and b (and other b-baryon) lifetimes. Heavy Flavor Averaging Group http://www.slac.stanford.edu/xorg/hfag/index.html

  12. 1.51  0.06(stat.)  0.02 (syst.) ps B+, B0 Lifetimes in J/ Modes (B0) 1.63  0.05(stat.)  0.04 (syst.) ps (B+) • Trigger on low pTdimuons (1.5-2GeV/) • Fully reconstruct • J/, (2s)+ • B+ J/K+ • B0  J/K*, J/Ks • Bs J/ • b J/ Proper decay length:

  13. Bs lifetime - PDG 1.461 ± 0.057 ps 1.33 ± 0.14(stat) ± 0.02(sys) ps Bs Lifetime Bs→J/ψΦwith J/ψ→μ+μ- and Φ→K+K- B+→ J/ΨK+, B0→J/ΨK*0check technique, systematics

  14.  primary  Lxy p + bLifetime • Use fully reconstructedb J/with J/ + and  p • Previous LEP/CDF measurements used semileptonicb  cl • Systematics different 469 signal First lifetime from fully reconstructed Λb decay!

  15. Measure masses using fully reconstructed BJ/X modes High statistics J/+ and (2s)J/+ for calibration. Systematic uncertainty from tracking momentum scale Magnetic field Material (energy loss) B+and B0consistent with world average. Bsand bmeasurements are world’s best. CDF result: M(Bs)=5365.5 1.6 MeV World average: M(Bs)=5369.60 2.40 MeV CDF result: M(b)=5620.4 2.0 MeV World average: M(b)=5624.49.0 MeV B Hadron Masses

  16. New Particle decaying to J/π+π • Belle observes narror 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 September 20 • final state J/π+π • mostly prompt prodction • 709±86 events

  17. a charmless two-body decays longer term Bs modes help extract unitarity angle  Signal is a combination of: B0+ BR~5x10-6 B0K+ BR~2x10-5 BsK+K BR~5x10-5 Bs+K BR~1x10-5 Requirements Displaced track trigger Good mass resolution Particle ID (dE/dx) tree g b  Vub • 28026 events • = 5.252(4) GeV/c2  = 41.0(4.0) MeVc2 penguin M() Bh+h } (4s),Tevatron } Tevatron +hypothesis

  18. 32060 events • = 5.252(2) GeV/c2  = 41.1(1.9) MeV/c2 Simulation BdK BsKK Bd BsK  M() CDF RunII Preliminary kinematics & dE/dx to separate contributions Sep.~1.3 D*D0, D0K (dE/dx – dE/dx())/(dE/dx) BR(BsK+K) Fitted contributions: First observation of BsK+K!! Result: Measure ACP

  19. Measure: bc with cpK • Backgrounds: real B decays • Reconstruct p as p: BdDp+K+ppp+ • Use MC to parametrize the shape. • Data to normalize the amplitude • Dominant backgrounds are real heavy flavor • proton particle ID (dE/dx) improves S/B Fitted signal: New Result ! BR(Lb Lcp) = (6.0 1.0(stat)  0.8(sys)  2.1(BR) ) x 10-3

  20. Bs Yields: CDF BsDs+ BsDswith Ds + and KK+ BR(Bs Dsp) = ( 4.8 1.2 1.8 0.8 0.6) 10-3 (Stat) (BR) (sys) (fs/fd) New measurement ! Previous limit set by OPAL: BR (Bs Dsp ) < 13% BR result uses less data than shown in plot.

  21. Measuring Bs Oscillation • 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

  22. Flavor Tagging • Strategy: use data for calibration (e.g. BJ/K, Blepton) • “know” the answer, can measure right sign and wrong sign tags. Results: • Same-side (B+)D2=(2.10.7)% (B+/B0/Bs correlations different) • Muon tagging D2=(0.70.1)% “same-side” tagging

  23. CDF Bs Sensitivity Estimate hadronic mode only • Current performance: • S=1600 events/fb-1 (i.e.effective for produce+trigger+recon) • S/B = 2/1 • D2 = 4% • t = 67fs surpass the current world average • With “modest” improvements • S=2000 fb (improve trigger, reconstruct more modes) • S/B = 2/1 (unchanged) • D2 = 5% (kaon tagging) • t = 50fs (event-by-event vertex + L00) 　　　　ms=24ps-1 “covers” the expected region based upon indirect fits. • This is a difficult measurement. • There are ways to further improve this sensitivity… • 2 sensitivity for ms =15ps-1 with ~0.5fb-1 of data • 5 sensitivity for ms =18ps-1 with ~1.7fb-1 of data • 5 sensitivity for ms =24ps-1 with ~3.2fb-1 of data

  24. RunII Projected Integrated Luminosity Middle of 2007 ms =24ps-1 (5σ) End of 2005 ms =18ps-1 (5σ) Now

  25. Conclusion • New results of masses, lifetimes and branching ratio • on B physics produced at CDF, especially on • heavier B-hadrons. • New measurements on heavier B-hadrons, such as • Bsoscillation, Bc mass and Λb branching ratio will • come in the near future.

  26. BACKUP SLIDES

  27. TOF counter • TOF time resolution ～100ps(design value) • Φ meson → K+ K- S/N: 0.025 → 0.45 S/N = 1942/4517 TOF S/N = 2354/93113

  28. Add B scale correction Tune missing material ~20% Correct for material in GEANT Raw tracks Material & Momentum Calibration D0 • Use J/y’s to understand E-loss and B-field corrections • s(scale)/scale ~ 0.02% ! • Check with other known signals confirm with gee U 1S 2S 3S mm

  29. J/ψproduction in RunⅡa

  30. DD Possible interpretations y(13D3) y(13D2) h2(11D2) y(13D1) • A y(13D2) state: • Because D-states have negative parity, spin-2 states cannot decay to DD • They are narrow as long as below the DD* threshold • h2(11D2) preferentially decays to hc(11P1). Decays to p+p-J/y would be of magnetic type and are suppressed. • Some models predict large widths for y(13D2) →p+p-J/y • All models predict even larger widths for y(13D2) →g cc (13P2,1) Should easily see y(13D2) →ggJ/y. • Discovery of the signal is very recent. Belle is working on this channel but is not ready to present any results. 14% g g 65% g g g 7% 32% p+p- g 20% Based on: E.J.Eichten, K.Lane C.Quigg PRL 89,162002(2002) J/y

  31. Ds, D+ mass difference 11.6 pb-1 • Ds± - D± mass difference • Both D  fp (fKK) • Dm=99.28±0.43±0.27 MeV • PDG: 99.2±0.5 MeV (CLEO2, E691) • Systematics dominated by background modeling ~2400 events ~1400 events Brand new CDF capability

  32. Bd mixing measured with great precision World average now dominated by Babar and Belle t   d b B0 B0 W W+   b d t Vtb~1 Re(Vtd)0.0071 Bd Mixing Bd fully mixes in about 4.1 lifetimes

  33. Measurement of ms helps improve our knowledge of CKM triangle. Combined world limit on Bs mixing ms>14.4ps-1 @95%CL Bs fully mixes in <0.15 lifetime!!! Bs oscillation much faster than Bd because of coupling to top quark: Re(Vts)0.040> Re(Vtd)0.007 ms/md a g b t   s b B0 B0 W W+   b s t Vtb~1 Re(Vts)0.04 Towards Bs Mixing Combined limit comes from 13 measurements from LEP, SLD & CDF Run I

  34. Semileptonic Bs Yields Plots show: BsDsl with Ds + and KK+ (will also reconstruct Ds K*0K+ and Ds KsK+)

  35. RunIILuminosity

  36. RunIIWeeklyLuminosity

  37. RunIIPhysicsProgram

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