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Mixings, Lifetimes, Spectroscopy and Production of b -quarks

Mixings, Lifetimes, Spectroscopy and Production of b -quarks. ( mostly hadron collider results ). Kevin Pitts University of Illinois. Lepton-Photon 2003 Fermilab August 12, 2003. Outline. Notation: B d = B 0 = | bd  B u = B + = | bu  B s = | bs 

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Mixings, Lifetimes, Spectroscopy and Production of b -quarks

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  1. Mixings, Lifetimes, Spectroscopy and Production of b-quarks (mostly hadron collider results) Kevin Pitts University of Illinois Lepton-Photon 2003 Fermilab August 12, 2003

  2. Outline Notation: Bd = B0 = |bd Bu = B+ = |bu Bs = |bs Bc = |bc b = |udb • Introduction- B physics at hadron machines • Heavy flavor production • charm cross section • Lifetimes • B hadron masses • Branching ratios • BsK+K-, bc-, BsDs+ • Mixing • Bd ,Bs • Summary

  3. Enormous cross-section ~100 barn total ~3-5 barn “reconstructable” At 4x1031cm-2s-1  ~150Hz of reconstructable BB!! All B species produced Bu,Bd,Bs,Bc,b,… Production is incoherent Measure of B and B not required Large inelastic background Triggering and reconstruction are challenging Reconstruct a B hadron, ~20-40% chance 2ndB is within detector acceptance pT spectrum relatively soft Typical pT(B)~10-15 GeV for trigger+reconstructed B’s …softer than B’s at LEP! B Physics at Hadron Machines b b g g b g q b b b b b q g g g q q Flavor Excitation Flavor Creation (gluon fusion) Flavor Creation (annihilation) Gluon Splitting b’s produced by strong interaction, decay by weak interaction Production: Pros Cons Disclaimer: acceptance comments relevant to “central” detectors like DØ and CDF

  4. Both detectors silicon microvertex detectors axial solenoid central tracking high rate trigger/DAQ system calorimeter & muon systems Detectors CDF silicon detector installation • DØ • Excellent electron & muon ID • Excellent tracking acceptance • CDF • Silicon vertex trigger • Particle ID (TOF and dE/dx) • Excellent mass resolution DØ fiber tracker installation

  5. Collider Run IIA Integrated Luminosity ~220 pb-1 on tape per experiment data for physics April 2001 Feb 2002 Jul 2002 first data for analyses commissioning Typical detector efficiency ~85-90% Luminosity used for HF analyses 6140 pb-1

  6. Tevatron B Cross sections measured at sqrt(s)=1.8TeV (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 sqrt(s)=1.96 TeV go to lower pT(B) Look at bb correlations Measure the charm cross section Heavy Flavor Cross Sections Integrated cross sections X X

  7. 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 CDF Silicon Vertex Tracker (SVT) 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

  8. Trigger on displaced tracks, accepts both bottom & charm. Reconstruct large samples of charm hadrons >85% prompt charm! CDF charm yields Yields shown for 5.8pb-1

  9. Prompt charm cross section result submitted to PRLhep-ex/0307080 See poster by Chunhui Chen Calculations shown are Cacciari & Nason hep-ph/0306212 Observations: Data on the “upper edge” of theory for D0 (shown), D+ and D*. Trend similar to that seen in B cross section measurements. CDF Prompt charm Cross Section data/theory for D0 data/theory for B

  10. Large yield, clean signals Acceptance down to pT =0 GeV! c signals also observed Inclusive lifetime shows BJ/X fraction to be 15-20%(>80% direct charm) See Tomasz Skwarnicki’s quarkonia talk Inclusive J/ Inclusive lifetime also important for understanding lifetime systematics

  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 LEP

  12. Belle B+ & B0 Lifetime • 29 fb-1 fully reconstructed decays • 7863 B0 • 12047 B+ • Lifetime measured in t (see Tom Browder’s talk) • Results: (B0)=1.5540.030(stat.)0.019(syst.)ps (B+)=1.6950.026(stat.)0.015(syst.)ps (B+)/(B0)=1.0910.023(stat.)0.014(syst.)ps • Tails are well-modeled

  13. Yields in BJ/X Modes B 0 J/Ks B + J/K+ b J/ • Trigger on low pTdimuons (1.5-2GeV/) • Fully reconstruct • J/, (2s)+ • B+ J/K+ • B0  J/K*, J/Ks • Bs J/ • b J/ B 0 J/K* B + J/K+

  14. DØ1.51 (stat.)  0.2 (syst.) ps CDF 1.51  0.06(stat.)  0.02 (syst.) ps B+, B0 Lifetimes in J/ Modes 115pb-1 (B0) Proper decay length: DØ 1.65  0.08(stat.) (syst.) ps CDF 1.63  0.05(stat.)  0.04 (syst.) ps (B+)

  15. BsLifetime  primary K Lxy K+ + BsJ/, with J/+ and K+K DØ(115pb-1):(shown here) (Bs)=1.19 (stat.) 0.14(syst.) ps (Bs)/(B0) =0.790.14 CDF (138pb-1): (Bs)=1.330.14(stat.) 0.02(syst.) ps (uncorrected for CP composition) Interesting Bs physics: Search for CPV in BsJ/ …sensitive to new physics Width difference  Bs mixing (later in talk)

  16. bLifetime  primary  Lxy p + 5614 signal • Use fully reconstructedbJ/with J/+ and p • Previous LEP/CDF measurements used semileptonic bcl • Systematics different 115pb-1 CDF 469 signal 65pb-1 CDF DØ

  17. 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 B0 consistent with world average. Bs and bmeasurements are world’s best. B Hadron Masses CDF result: M(Bs)=5365.50 1.60 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

  18. Outline • Introduction- B physics at hadron machines • Heavy flavor production • charm cross section • Lifetimes • B hadron masses • Branching ratios • BsK+K-, bc-, BsDs+ • Mixing • Bd ,Bs • Summary

  19. a charmless two-body decays longer term Bs modes help extract unitarity angle (see Hassan’s talk) 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) CDF Bh+h tree g b  Vub 28026 events • = 5.252(4) GeV/c2  = 41.0(4.0) MeVc2 penguin M() } (4s),Tevatron } Tevatron +hypothesis Did you ever think this physics could be done at a hadron collider?

  20. BR(BsK+K) 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) Fitted contributions: First observation of BsK+K!! Result: includes error on fs/fd see poster by Diego Tonelli

  21. Reflections, Satellites and All That -“horns” coming from D* -Reflection from BD0K (reconstruct K as ) Vertex trigger sample reconstruct: BD0 Clear peak seen, sidebands have interesting structure Work in progress, must understand these contributions to extract BR

  22. CDF bc with cpK Measure: 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) ) 10-3

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

  24. 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 Towards Bs Mixing ms/md a g b t   s b B0 B0 W W+   b s t Vtb~1 Re(Vts)0.04 Combined limit comes from 13 measurements from LEP, SLD & CDF Run I

  25. Measuring Mixing • Bs or Bsat the time of production? • Initial state flavor tagging • Tagging “dilution”: D=1-2w • Tagging power proportional to: D2 • Bs or Bs at the time of decay? • Final state flavor tagging • Can tell from decay products (e.g. ) • Yields • Need lots of decays (because flavor tagging imperfect) • Proper decay time • Need decay length (Lxy) and time dilation factor ( =pT/mB) • Crucial for fast oscillations (i.e. Bs) Typical power (one tag): D2 = (1%) at Tevatron D2 = (10%) at PEPII/KEKB uncertainty

  26. 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. DØ Results: Jet chargeD2=(3.31.1)% Muon tagging D2=(1.60.6)% “same-side” tagging CDF Results: Same-side (B+)D2=(2.10.7)% (B+/B0/Bs correlations different) Muon tagging D2=(0.70.1)%

  27. 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.

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

  29. DØ B Semileptonic Lifetime BD0X with D0K+ 12pb-1 of data taken with single muon trigger. Time dilation factor () must be corrected for missing  (B) = 1.46  0.08(stat.) ps

  30. Bs Sensitivity • From data, now have some knowledge of the pieces that go into measuring ms • Yields S = # signal events • Flavor tagging tagging power = D2 • Signal-to-noise S/B = signal/background • Proper time resolution t = proper time resolution • The sensitivity formula: • Significance (in number of standard deviations) is “average signficance”

  31. 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 2 sensitivity for ms =15ps-1 with ~0.5fb-1 of data • 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) 5 sensitivity for ms =18ps-1 with ~1.7fb-1 of data 5 sensitivity for ms =24ps-1 with ~3.2fb-1 of data • ms=24ps-1 “covers” the expected region based upon indirect fits. • This is a difficult measurement. • There are ways to further improve this sensitivity…

  32. 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 2 sensitivity for ms =15ps-1 with ~0.5fb-1 of data • 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) 5 sensitivity for ms =18ps-1 with ~1.7fb-1 of data 5 sensitivity for ms =24ps-1 with ~3.2fb-1 of data • ms=24ps-1 “covers” the expected region based upon indirect fits. • This is a difficult measurement. • There are ways to further improve this sensitivity…

  33. Estimates based current performance plus modest improvements. Further gain is possible on all of these pieces: t Event-by-event vertex Layer 00 Flavor tagging Kaon tagging (same-side and opposite-side) Yields Other Bs modes (hadronic and semileptonic) Other Ds modes Triggering Improved use of available bandwidth Improve available bandwidth Improve SVT efficiency Work In Progress Matters most for going to ms > 20 ps-1 Trigger improvements matter most for yields It’s doable! It will take time, luminosity and hard work!

  34. Tevatron Bs Sensitivity • We know Bs mixing is a difficult measurement. • Estimate shown is based solely CDF sensitivity for the hadronic modes. • DØ will have sensitivity in hadronic mode(opposite muon) • Semileptonic modes important, especially at lower ms • DØ and CDF will both contribute to Bslepton+Ds • “This is a marathon, not a sprint.” • SM expectation: s ms • Experiments will also attempt to measure s • in untagged samples • by extracting CP even/odd components in BsJ/

  35. Conclusion • New cross sections, lifetime and branching ratio measurements from the Tevatron • Beginning to exploit high yields and upgraded detectors • DØ has a new spectrometer • CDF has a new impact parameter trigger • Babar and Belle continue to provide an amazing breadth of B+ and B0 results • Tevatron will contribute knowledge of heavier B hadrons • Many technical challenges have been overcome • Lots of work to do • Stay tuned! Thanks to: B.Abbott, B.Brau, T. Browder, B.Casey, S.Donati, S.Giagu, V.Jain, D.Kirkby, B.Klima, J.Kroll, N.Lockyer, C. Paus, M.Rescigno, M.Shapiro, M.Tanaka and the experimental collaborations.

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