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

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

3. Tevatron Status Run I （ 1992 ～ 1996 ） : Record Luminosity 2x10 31 cm -2 sec -1 Integrated Luminosity 110 pb -1 on Tape Run II （ 2001 ～） : 5 x10 31 cm -2 sec -1 （ August 2003 ） Integrated Luminosity 330 pb -1 –270 pb -1 on Tape –120 pb -1 analyzed Schedule: 2 fb -1 (by the end of 2005) 9 fb -1 (by the end of 2009) Initial Luminosity Now Integrated Luminosity Delivered On tape 330 pb -1 270 pb -1 2002 2001

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

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 -500 -250 0 250 500 35  m  33  m resol  beam   = 48  m SVT impact parameter (  m) Silicon Vertex Trigger (SVT) d = impact parameter Primary Vertex Secondary Vertex B Lxy ～ 450  m P T (B)  5 GeV

6. B Physics at Hadron Colliders Advantage Enormous cross-section –~100  b total –~ 4  b “reconstructable” –At 4x10 31 cm -2 s -1  ~150Hz of reconstructable BB!! All B hadrons produced –B u,B d,B s,B c,  b,… Disadvantage Large inelastic background –Triggering and reconstruction are challenging b’s produced by strong interaction, decay by weak interaction

7. Heavy Flavor Cross Sections (RunI) 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 p T (B) –Look at bb correlations –Measure the charm cross section Integrated cross sections X X

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

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

11. B Hadron Lifetimes All lifetimes equal in spectator model. lDifferences from interference & other nonspectator effects Heavy Quark Expansion predicts the lifetimes for different B hadron species Measurements: lB 0,B + lifetimes measured to better than 1%! lB s known to about 4% lLEP/CDF (Run I)  b lifetime lower than HQE prediction Tevatron can contribute to B s, B c and  b (and other b-baryon) lifetimes. Heavy Flavor Averaging Group http://www.slac.stanford.edu/xorg/hfag/index.html

12. B +, B 0 Lifetimes in J/  Modes 1.51  0.06(stat.)  0.02 (syst.) ps 1.63  0.05(stat.)  0.04 (syst.) ps (B+)(B+) (B0)(B0) Proper decay length: l Trigger on low p T dimuons (1.5-2GeV/  ) l Fully reconstruct J/ ,  (2s)  +   B +  J/  K + B 0  J/  K*, J/  K s B s  J/   b  J/ 

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

14.  b Lifetime Use fully reconstructed  b  J/  with J/   +   and  p   –Previous LEP/CDF measurements used semileptonic  b   c l Systematics different 46  9 signal L xy ++ p   primary First lifetime from fully reconstructed Λ b decay!

15. B Hadron Masses 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 B 0 consistent with world average. B s and  b measurements are world ’ s best. CDF result: M(B s )=5365.5  1.6 MeV World average: M(B s )=5369.60  2.40 MeV CDF result: M(  b )=5620.4  2.0 MeV World average: M(  b )=5624.4  9.0 MeV

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. 280  26 events  = 5.252(4) GeV/c 2  = 41.0(4.0) MeVc 2 M(  ) charmless two-body decays –longer term B s modes help extract unitarity angle  Signal is a combination of: –B 0  +   BR~5x10 -6 –B 0  K +   BR~2x10 -5 –B s  K + K  BR~5x10 -5 –B s  + K  BR~1x10 -5 Requirements –Displaced track trigger –Good mass resolution –Particle ID (dE/dx) Bh+h Bh+h }  (4s),Tevatron } Tevatron tree V ub     pengui n  +   hypothesis

18. BR(B s  K + K  ) Simulation B d  K  B s  KK B d   B s  K  320  60 events  = 5.252(2) GeV/c 2  = 41.1(1.9) MeV/c 2 M(  ) Sep.~1.3  CDF RunII Preliminary (dE/dx – dE/dx(  ))/  (dE/dx) D*  D 0 , D 0  K  kinematics & dE/dx to separate contributions First observation of B s  K + K  !! Result: Measure A CP modeYield (65 pb -1 ) B0KB0K 148  17(stat.)  17(syst) B 0  39  14(stat.)  17(syst) BsKKBsKK 90  17(stat.)  17(syst) BsKBsK 3  11(stat.)  17(syst) Fitted contributions:

19.  b  c  with  c  pK  Backgrounds: real B decays Reconstruct  as p: B d  D   +  K +      +  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: BR(  b   c   ) = (6.0  1.0 (stat)  0.8 (sys)  2.1 (BR) ) x 10 -3 New Result ! Measure:

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

21. Measuring B s Oscillation B s reconstruction –e.g. Flavor tagging ( B s or B s at the time of production?) –Tagging “ dilution ” : D=1-2w –Tagging power proportional to:  D 2 Proper decay time –Crucial for fast oscillations (i.e. B s ) uncertainty Typical power (one tag):  D 2 = O(1%) at Tevatron  D 2 = O(10%) at PEPII/KEKB

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 + )  D 2 =(2.1  0.7)% (B + /B 0 /B s correlations different) Muon tagging  D 2 =(0.7  0.1)% “same-side” tagging

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

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

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 B s oscillation, B c mass and Λ b 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 TOF S/N = 2354/93113 S/N = 1942/4517

28. Material & Momentum Calibration Use J/  ’s to understand E-loss and B-field corrections –  (scale)/scale ~ 0.02% ! Check with other known signals Raw tracks Correct for material in GEANT Tune missing material ~20% Add B scale correction D0D0  1S 2S 3S confirm with  ee 

29. J/ψproduction in Run Ⅱ a

30. Possible interpretations A  (1 3 D 2 ) state: –Because D-states have negative parity, spin-2 states cannot decay to DD –They are narrow as long as below the DD* threshold –  2 (1 1 D 2 ) preferentially decays to h c (1 1 P 1 ). Decays to     J/  would be of magnetic type and are suppressed. –Some models predict large widths for  (1 3 D 2 ) →     J/  –All models predict even larger widths for  (1 3 D 2 ) →  c (1 3 P 2,1 ) Should easily see  (1 3 D 2 ) →  J/  Discovery of the signal is very recent. Belle is working on this channel but is not ready to present any results.  2 (1 1 D 2 )  (1 3 D 2 )  (1 3 D 3 )  (1 3 D 1 ) DD  J/       7% 65% 14% 32% 20% Based on: E.J.Eichten, K.Lane C.Quigg PRL 89,162002(2002)

31. D s, D + mass difference D s ± - D ± mass difference –Both D   (   KK) –  m=99.28±0.43±0.27 MeV PDG: 99.2±0.5 MeV (CLEO2, E691) –Systematics dominated by background modeling 11.6 pb -1 ~1400 events ~2400 events Brand new CDF capability

32. B d Mixing B d mixing measured with great precision –World average now dominated by Babar and Belle B0B0 bd d WW t W+W+ t b B0B0    V tb ~1 Re(V td )  0.0071 B d fully mixes in about 4.1 lifetimes

33. Towards B s Mixing Measurement of  m s helps improve our knowledge of CKM triangle. Combined world limit on B s mixing –  m s >14.4ps -1 @95%CL –B s fully mixes in <0.15 lifetime!!! B s oscillation much faster than B d because of coupling to top quark: Re(V ts )  0.040 > Re(V td )  0.007 B0B0 bs s WW t W+W+ t b B0B0    V tb ~1 Re(V ts )  0.04 Combined limit comes from 13 measurements from LEP, SLD & CDF Run I    ms/mdms/md

34. Semileptonic B s Yields Plots show: B s  D s l  with D s  + and  K  K + (will also reconstruct D s  K* 0 K + and D s  K s K + )

35. RunII Luminosity

36. RunII Weekly Luminosity

37. RunII Physics Program