1. 11/3/2005Saverio D’Auria University of Glasgow1 b Physics at the Tevatron Status and prospectives Masses of b-hadrons, rare decays and oscillation measurements at CDF and D0 Saverio D’Auria, University of Glasgow For the CDF and D0 collaborations Chamonix

2. Chamonix 11/3/2005Saverio D’Auria University of Glasgow2 Introduction: b production at the TeVatron CDF, D0: p Collisions: Gluon-gluon Quark-anti-quark Gluon-quark Chicago, 60 km 2 km g g Main contribution to b production at the TeVatron. b Production cross section: 3-level trigger system. XtraFastTrigger (XFT) (L1) SiliconVertexTrigger (L2) Muon Trigger (L1) All b-hadrons are produced: B +,B 0,Y,… B s,  b, B c …  b For “centrally” produced b 360 pb -1 of data analyzed for b-Physics |y| < 1 CDF submitted to PRD hep-ex/0412071

3. Chamonix 11/3/2005Saverio D’Auria University of Glasgow3 Introduction: CDF and D0 detectors CDF: Excellent p T resolution, displaced track trigger  fully hadronic decay modes Tracking: Silicon + Drift Chamber dE/dx, ToF particle ID D0: Excellent muon trigger Tracking coverage |  | < 2 Tracking: Silicon + SciFib, Great b-physics capabilities

4. Chamonix 11/3/2005Saverio D’Auria University of Glasgow4 Introduction: TeVatron performance CDF to tape: 1.1 fb -1 Luminosity record: 1.5  10 32 cm -2 s -1 Highest luminosity ever reached at Hadron collider (including ISR) Results presented here 1/10 of initial LHC (2008) Efficiency: 85-90% per store (fill) L (TeVatron) will reach  4 fb -1 /experiment

5. Chamonix 11/3/2005Saverio D’Auria University of Glasgow5 Inelastic cross section:  60 mb  factor 1/1000 trigger. Compare with b-factories:  is 10 3 higher, L is pb  (TeVatron) vs. fb  (Y(4S))  b  L cm  s  Integrated Lb-events Tevatron29 1.5  10  1000 pb   229  10 9 KEK0.001 1.58  10  471 fb  0.47  10 9 BaBar0.001 0.95  10  256 fb  0.25  10 9 Main Triggers for b-Physics: 2  from J/ , soft lepton, (soft lepton+non prompt track) 2 non-prompt tracks (CDF…) e,e, P.V. (Track) Introduction: Trigger issues

6. Chamonix 11/3/2005Saverio D’Auria University of Glasgow6 Introduction: general issues b-hadron decays can be studied depend on: Production mechanism Detector features Trigger features Environment All b-hadrons are produced: B +,B 0,Y,… B s,  b, B c …  b Good tracking  charged final products Purely hadronic final states available Very large QCD background  no neutrals detected Only decay final states with charged particles studied to now at CDF (+ semileptonic decays !) D0 has detected  c1  c2  J/ ,via conversions.  No  0,  +, etc … CDF Di-muon triggers

7. Chamonix 11/3/2005Saverio D’Auria University of Glasgow7 B  h + h’  CDF has simultaneous access to both B 0 /B 0 s  h + h'  decays PENGUIN R. Fleischer PLB459:306-320, 1999 - constrain hadronic unknowns with SU(3) symmetry. Use approximated s  d quark symmetry (i.e. measure jointly B 0 and B 0 s ) Measure angle . Method needs: time-dependent asymmetries in b-flavor tagged samples, size of SU(3) breaking, sin(2  ) and  m s CDF ultimate long term goal. TREE B s  K  K  almost pure CP even state Measure lifetime and  s

8. Chamonix 11/3/2005Saverio D’Auria University of Glasgow8 B  h + h’  B 0   +  - + c.c. B 0 s  K + K - + c.c. B 0  K -  + B 0  K +  - B 0 s  K +  - B 0 s  K -  + MC   -mass vs. signed momentum imbalance:  =(1- p min /p max )q min discriminates among modes (and flavors in K  modes). 

9. Chamonix 11/3/2005Saverio D’Auria University of Glasgow9 B  h + h’  Results will be updated soon with larger luminosity. Expected (2fb -1 ) accuracy:  (  ) =±10  (stat) ±3  (syst) (syst: SU(3) breaking)

10. Chamonix 11/3/2005Saverio D’Auria University of Glasgow10 Efficiency Dilution D Reconstruct signal(s) flavor specific (selection cuts) Measure decay time for each candidate Establish flavor ( ) at production (  tagging) Mixing Asymmetry Need high statistics sample, well measured lifetime. Tagging production flavor Statistics reduced by a factor  D 2 : N tagged events =  D 2 N useful events  m s : lower statistics B s larger  m s s.l.decays larger  t Production Vertex Mixing Measurements

11. Chamonix 11/3/2005Saverio D’Auria University of Glasgow11 Opposite side Soft-Lepton tag Flavor from the sign of the lepton (e or  ) in semileptonic decays of accompanying b-meson. Source of dilution: charm semi-leptonic cascade decays, oscillation in the opposite side. Kaon Tag: Sign of the kaon in cascade decay b  c  s Jet Charge Sign of the momentum-weighted average charge of opposite jet. Same side B s has preferentially a K  “close by”, B s has a K , B 0 has a  , B 0 has a   Flavour Tagging

12. Chamonix 11/3/2005Saverio D’Auria University of Glasgow12 B  D + hadrons Other decays very useful for increasing statistics for mixing. Example in B 0 Two 4-track vertices Symultaneous mass-lifetime fits

13. Chamonix 11/3/2005Saverio D’Auria University of Glasgow13 B  D + hadrons Exercise for the B +,0 : 10 hadronic decay modes. Aim: test machinery, measure OST dilution scale factors.

14. Chamonix 11/3/2005Saverio D’Auria University of Glasgow14 B  D + hadrons ParameterValue Ct (B+) [  m] 495.0 5.2(stat) Ct (B0) [  m] 468.1 4.8(stat)  m d (ps -1 ) 0.536 0.028 0.006 Dsst0.209

15. Chamonix 11/3/2005Saverio D’Auria University of Glasgow15 B  l + D + X Semileptonic decays have larger statistics, but larger ct uncertainty (not a problem for B0). Same exercise as before, using semileptonic decays in hadronic trigger.

16. Chamonix 11/3/2005Saverio D’Auria University of Glasgow16  m d measurements NEW since la Thuile ‘05 Exp’t (pb  ) channelTag Result D0250s.l. combined 0.456 ± 0.034 (stat.) ± 0.024 (syst.) D0460s.l.o.s.t. 0.558 ± 0.048 (stat.) ± x.xxx (syst.) CDF355s.l.o.s.t. 0.497 ± 0.028 (stat) ± 0.015 (syst.) CDF355f.r.o.s.t. 0.503 ± 0.063 (stat) ± 0.015 (syst.) Main purpose: tagging and fitting test preparing for  m s Best measurement HFAG  m d = (0.506 ± 0.006 ± 0.008) ps  460 pb 

17. Chamonix 11/3/2005Saverio D’Auria University of Glasgow17 Amplitude scan Fourier-transform method Fix frequency (  m) Fit for the oscillation amplitude. Limit at 95%: lowest value  m lim P( A (  m lim )  1) = 5% Sensitivity: lowest value of  m with error compatible with 1 (at 5%) Measurement: (range of) amplitude(s) compatible with 1 and not compatible with 0…..value of  m from asymmetry fit ! Advantage: easier to combine results semileptonic

18. Chamonix 11/3/2005Saverio D’Auria University of Glasgow18  m s CDF sensitivity studies World average Limit:  m s > 14.5 ps  Sensitivity for  m s < 18.3 ps  PDG 2004 & HFAG CDF 2 CDF Semileptonic: B s  D s l X, D s   , K*K,       CDF hadronic B s  D s , D s   , K*K,         D0 Semileptonic: B s  D s l X,  7000 D s   

19. Chamonix 11/3/2005Saverio D’Auria University of Glasgow19  m s D0 Preliminary results Semi leptonic decays L = 460 pb , opposite side tag  m s > 5.0 ps  at 95% CL Limit < world average, but this is a first step in the full analysis Tagged 376  31 D = 0.47 ± 0.01

20. Chamonix 11/3/2005Saverio D’Auria University of Glasgow20

21. Chamonix 11/3/2005Saverio D’Auria University of Glasgow21 Bs  l + Ds + X 8 GeV electron trigger

22. Chamonix 11/3/2005Saverio D’Auria University of Glasgow22 Bc  J/  + X Lifetime of Bc Measured in Semileptonic channel

23. Chamonix 11/3/2005Saverio D’Auria University of Glasgow23 B c  J/  Mass = 6287.0 ± 4.8(stat.) ± 1.1(syst.) MeV/c 2 18.9 ± 5.7 candidates 10.0 ± 1.4 evts Background Theory in very good agreement. Potential models, NRQCD, LQCD Mass measured using fully Reconstructed mode. Evidence for decay B c  J/  5-  observation soon.

24. Chamonix 11/3/2005Saverio D’Auria University of Glasgow24  s

25. Chamonix 11/3/2005Saverio D’Auria University of Glasgow25  s

26. Chamonix 11/3/2005Saverio D’Auria University of Glasgow26 Bs   Other channels will be added in future: Also Bs   (2S) 

27. Chamonix 11/3/2005Saverio D’Auria University of Glasgow27 B d,s      Flavour-Changing Neutral Currents. BR = (3.4 ±0.54)    place to look for new Physics mSUGRA models enhanced 10 to 100  (Dedes, Dreiner, Nierste, hep-ph/0108037) SO(10) models 100  (Dermisek, Rabi et al. hep-ph/0304101) MSSM models enhanced 1000  D0 updated measurement to include 300 pb  CDF uses 171 pb  Mass resolution 27 MeV/c 2 Limits on both B d and B s Both analyses blind BR ( B s      BR ( B d     ) D0   ---------- CDF      % CL D0 looking for BR (B s      Closed box Attainable Sensitivity = 1.2 10  (95% CL) CDF/D0 Rare decays   b s 300 pb -1

28. Chamonix 11/3/2005Saverio D’Auria University of Glasgow28 Conclusions The Tevatron can produce unique results in B Physics and confirm/complement B factories.

29. Chamonix 11/3/2005Saverio D’Auria University of Glasgow29 Backup Slides Aurora Borealis at Fermilab 9 th November 2004, 3 a.m. 42°N

30. Chamonix 11/3/2005Saverio D’Auria University of Glasgow30

31. Chamonix 11/3/2005Saverio D’Auria University of Glasgow31

32. Chamonix 11/3/2005Saverio D’Auria University of Glasgow32 Summary of cut values used: 1.p T (  ) > 1.8 GeV/c 2.L xy /  (L xy ) > 4.4 3.  2 (3D) < 9.0 4.d 0 (B c ) < 65  m 5.pointing angle  < 0.4 radians 6.  2 vtx (  ) < 2.6 7.ct < 750  m CutMC Efficiency N-1 data entries Background rejection L xy /  (L xy ) 42.0%1193096.7% p T (  ) 62.3%304387.1%  2 (3D) 80.5%76248.4% Pointing angle 85.4%76848.8%  2 vtx (  ) 92.7%56530.4% d 0 (B c ) 97.5%44812.3% ct  98.7%4104.1% CDF Fully reconstructed B c Maximized S = number of signal events from MC B = average number of background events (data) from whole region in a window ±2-   wide (60.4 MeV/c 2 ).

33. Chamonix 11/3/2005Saverio D’Auria University of Glasgow33 Flavor tagging D0 use “any”  for tagging, use opposite side fully reconstructed decays, semileptonic decays for high statistics Opposite side tagging is the same as for B s mixing: use Dilution from B d to fix this parameter for B s.  D ² (%) CDF s.l.D0 s.l.CDF had SST (B d ) 1.04 ± 0.35 ± 0.061.00 ± 0.36 ---- Soft  0.56 ± 0.05 1.00 ± 0.38 0.46 ± 0.11 ± 0.03 Soft e0.29 ± 0.03--0.18 ± 0.06 ± 0.02 Jet Qpt 0.16 ± 0.03 ± 0.03 11 0.24 ± 0.09 ± 0.01 Jet Qjp 0.150 ± 0.03 ± 0.02 0.11 ± 0.06 ± 0.02 Jet Qvtx 0.26 ± 0.03 ± 0.02 0.14 ± 0.07 ± 0.01 Combined 1.429 ± 0.093 1.12 ± 0.18 ± 0.04 Overall fitter

34. Chamonix 11/3/2005Saverio D’Auria University of Glasgow34 CDF Fully reconstructed B c

35. Chamonix 11/3/2005Saverio D’Auria University of Glasgow35 CDF Partially reconstructed hadronic B c No pointing cuts Relax vertex chi2

36. Chamonix 11/3/2005Saverio D’Auria University of Glasgow36 D0 combined taggers, semileptonic decays, 250 pb  :  m d = 0.456 ± 0.034 (stat.) ± 0.024 (syst.) ps  D0 combined opposite side taggers, semileptonic decays, 460 pb  :  m d = 0.558 ± 0.048 (stat.) ± x.xxx (syst.) ps  CDF combined opposite side taggers, semileptonic decays, 355 pb  :  m d = 0.497 ± 0.028 (stat) ± 0.015 (syst.) ps  CDF combined opposide side taggers, fully reco. decays, 355 pb  :  m d = 0.503 ± 0.063 (stat) ± 0.015 (syst.) ps 

37. Chamonix 11/3/2005Saverio D’Auria University of Glasgow37 Mixing Control sample: B u

38. Chamonix 11/3/2005Saverio D’Auria University of Glasgow38 Other  b-physics results: CP Asymmetry in B +   K PRL, hep-ex/0502044 Evidence for the decay B s   PRL, hep-ex/0502044 CP Asymmetry in B  hh (h=  ,K  ) ICHEP’04 ICHEP 04 A CP (B +   K) B s penguin-diagram decay ICHEP 04 Penguins at Fermilab

39. Chamonix 11/3/2005Saverio D’Auria University of Glasgow39 Only meson to have 2 spectator-model weak decays with comparable amplitudes (b and c decays). Possible contamination for B s decays Perfect source of flavour-tagged B s Measure angle  in self-tagged decays Relevance of mass measurements Relevance of B c Spectroscopy of heavy-light quark system, to complement quarkonia Verify detailed calculation and hypothesis (potential, NRQCD ….) Validation of Lattice QCD Spectroscopy of heavy-heavy mesons: quarkonia vs. B c. [Masetti, Fleischer-Wyler,Kiselev]

40. Chamonix 11/3/2005Saverio D’Auria University of Glasgow40 Fully reconstructed modes using J/  trigger D0 more candidates CDF better mass resolution (11 MeV, J/  mass constrained) Calibration using J/  mass, checked against the Y, systematics sub-MeV b hadron masses

41. Chamonix 11/3/2005Saverio D’Auria University of Glasgow41 Systematics below 1 MeV for high statistics channels Best single measurements of b-hadron masses b hadron masses B+B+ B0B0 B s mass  b mass

42. Chamonix 11/3/2005Saverio D’Auria University of Glasgow42 Tevatron best place to measure B c mass precisely CDF: Search for fully reconstructed mode Trigger: 2  ’s from J/  p T > 1.5 GeV/c 2-body topology, reference mode B +  J/  K + Blind search: range: semileptonic mass ± 2  m. Experimental issues: lifetime, small BR, small  prod. expected 10-50 events, based on Run I rate.   P.V. Background: Prompt J/  associated to random prompt track  require lifetime Secondary J/  with prompt track Secondary J/  with non prompt track  require good vertexing B+B+ B0B0   CDF Fully reconstructed B c

43. Chamonix 11/3/2005Saverio D’Auria University of Glasgow43 Hypothesis test set up before opening the box. After box open: scan search region with binned likelihood fit: mass fixed (scanned), Gaussian width fixed (resolution), S,B fit parameters CDF Fully reconstructed B c Score function Threshold value From “toy Monte Carlo”, P  1/1000 false positive

44. Chamonix 11/3/2005Saverio D’Auria University of Glasgow44 D0 Semi-leptonic B c decay Inclusive measurement B c  J/  X Same strategy, require 3 rd track be a . Inclusive measurement, no pointing constraint. No lifetime cut  mass and lifetime measurement Depends on Monte Carlo for Probability Density Function and “k-factor” Control sample:  ( 2S )  X  X (expected low BR ) Signal: 95±12±11 candidates, Significance likelihood ratio 60 Mass = MeV/c² D0 ICHEP 04 5.4 5.6 5.8 6.0 6.2 6.4 6.6 6.8 Mass (GeV/c²) Systematic uncertainties from MC sample composition and decay model; background fraction. Larger than stat. -2 log(Likelihood)

45. Chamonix 11/3/2005Saverio D’Auria University of Glasgow45 b and c-mesons excited states Evidence for the decay B s  D s1 (2536)  X Signal: 18 ± 5.5 candidates, 3.5  ICHEP 04 435pb  Studies of excited b-mesons for Same Side tagging & MC tuning Soft  from fragmentation and decay

46. Chamonix 11/3/2005Saverio D’Auria University of Glasgow46 B-hadrons mass summary New for Moriond EW 05