1. Donatella Lucchesi1 B Physics Review: Part II Donatella Lucchesi INFN and University of Padova RTN Workshop The 3 rd generation as a probe for new physics Bratislava, 4 – 6 July, 2003  Review of Tevatron measurements: o B and  b lifetimes and masses o B s Mixing  New CDF results: o B s and  b yields o J/  cross section o D 0 branching ratio and CP asymmetries

2. Donatella Lucchesi2 How do we collect b? Old style: o Di-muon trigger: - 2 muons P t > 1.5 GeV (RunI Pt > 2 GeV) - charmonium physics - B lifetime, B mass, rare decays B s  New era:  Multi-bodies Hadronic trigger (SVT): - 2 tracks P t >2 GeV, |d|>120  m,  P t >5.5 GeV, L xy >200  m - All you can imagine with B  X where X>2 A combination of Old and New  Lepton P t >4 GeV (Run I P t >8 GeV)+ track P t >2 GeV |d|>120  m - B  lDX decays, flavor tagging optimization

3. Donatella Lucchesi3 D0: Results from J/  trigger

4. Donatella Lucchesi4 D0: Results from J/  trigger

5. Donatella Lucchesi5 B Mesons Mass Measurements The current results: Decay modes: Best in the world

6. Donatella Lucchesi6 b Hadrons Lifetime Measurements Is it still interesting? Several decays channels are available at Tevatron good test of the theory

7. Donatella Lucchesi7 b Hadrons Lifetime Measurement  Inclusive b lifetime: b  J/  X Experimental needs:  calibrate resolution  understand the alignments   correction if not fully reconstructed decays CDF result:  = 1.527  0.033  0.033 ps

8. Donatella Lucchesi8 Inclusive B  J/  X Lifetime at D0MC D0 Result:  = 1.561  0.024  0.074 ps D0 Run II Preliminary First time at D0 Use the same technique of CDF PDG 2003  = 1.564  0.014 ps

9. Donatella Lucchesi9 b Hadrons Lifetime Measurement  Exclusive lifetime with J/  :  well measured Simultaneous fitting of M B : Extract signal fraction ct: Extract the lifetime B+B+ 1.57  0.07  0.02 (ps) BdBd 1.42  0.09  0.02 (ps) BsBs 1.26  0.2  0.02 (ps) CDF Results: = 0.89  0.15 = 1.11  0.09

10. Donatella Lucchesi10 News about  b  Exclusive  b lifetime (pre-blessed)  Mass measurement (pre-blessed)  b  J/  

11. Donatella Lucchesi11 News about  b cont’d  b   c l  [pK  ] l Difficult to disentangle from decays through excited baryons  Semi-exclusive lifetime  Branching ratio And dE/dX

12. Donatella Lucchesi12 B Lifetime measurement: semi-leptonic decays Useful to optimize B mixing and flavor tagging

13. Donatella Lucchesi13 Flavor tagging  Lepton (muon and electron) tagging: under optimization in the huge sample of B  lDX  Same Side Tagging (SST): B 0 (B 0 ) accompanied by  - (  + ) bdduubdduu B0B0 ++ A(t)= N RS (t) – N WS (t) N RS (t) + N WS (t) B 0 : A(t)= Dcos(  m·t) B ± : A(t)= cost

14. Donatella Lucchesi14 B s Lifetime measurement: semi-leptonic decays Signal to noise ratio better than expected ! Observed yield: RunI  5 Muons Electrons

15. Donatella Lucchesi15 Lifetime  and  Perspectives  CDF lifetime expectation in 2 fb -1 are:  B s  J/  and B s  lD s X combined   (  /  )  few % for both CDF and D0  CP asymmetry in B s  J/  expected small in S. M. If bigger  new physics  If  m s larger:  difficult to measure also with high statistics sample   sizeable  easy to measure   m s =  ·C where C can be calculated inside the S. M. Semi-leptonic decaysFully reconstr. decays  (c  )/c  2%0.5%

16. Donatella Lucchesi16 X s =  m s  B s measurement: semi-leptonic decays Decays included: B s  D s  l, D s *  l (D s   , K* 0 K ,    +   ) ~40K events in 2 fb -1 Proper time resolution:  t = 60 fs  t   K/K  K/K ~ 14% Tagging:  D 2 = 11.3 % (all taggers) Sensitive up to x s  30 CDF Current limit X s > 20.6

17. Donatella Lucchesi17 D 0 :B s mixing in fully hadronic decays Decays included: B s  D s   , D s        (D s   , K* 0 K , K*  K 0 ) B s  J/  K *0 Proper time resolution: 0.40 ps Tagging:  D 2 = 3.1 % Jet Charge  D 2 = 4.7 % Lepton S/B: 1:2 Fully reconstructed decays D0 CDF sensitive up to x s  60 old (Y.B.) prediction

18. Donatella Lucchesi18  Offline Trigger confirmation  3D Vertex for D and B vertices  1.013<m(KK)<1.028 GeV  D s Mass constraint   R(D s -  )<1.5   xy B < 15 and  xy D < 10  P D s > 4 GeV and P t B >6 GeV  L xy D >400  m  L xy B >100  m  |d B |<100  m B s Yield Study: the cuts applied  DsDs  BsBs

19. Donatella Lucchesi19 B s Yield Study: the signal Can we measure the yield? fs/fd: discrepancy LEP - CDF Branching Fraction: unknown Cross section: big uncertainty First observation !

20. Donatella Lucchesi20 B s Yield Study: the technique Big effort in a full detector and trigger simulation optimization “a la LEP” to measure the efficiencies N(B s ) N(B d ) = fsfs fdfd ss dd Br(B s  D s -  + ) Br(D s -  - ) Br(  k + k - ) Br(B d  D -  + ) Br(D -  k +  -  - ) PDG Monte Carlo

21. Donatella Lucchesi21 Same mode for: Similar cuts to signal also visible. B s Yield Study: Normalization mode

22. Donatella Lucchesi22 Uncertainty in due to fit. Uncertainty in B s Yield Study: Systematic

23. Donatella Lucchesi23 B s Yield Study: Result

24. Donatella Lucchesi24 B s Yield Measurement: where we are Signal to noise optimization: S/  B is optimized with  >60%  Offline Trigger confirmation  3D Vertex for D and B vertices  1.010<m(KK)<1.028 GeV (only for B s )  D Mass constraint   R(D-  )<1.5   xy B < 15 and  xy D < 10  P D > 3 GeV (3.5 for B s ) and P t B >6 GeV (5.5 for B s )  L xy D >-150  m  L xy B >250  m (400 for B s )  |d B |<80  m  Pt(  B )>1.6 (1.9 for B s )

25. Donatella Lucchesi25 Bs Yield Measurement: where we are Signal to noise optimization

26. Donatella Lucchesi26  b   c  Relative Yield Measurement  Confirm trigger cuts  Pt(proton)>2 GeV  Pt(  from  b )>2 GeV  Pt(  c )>4.5 GeV  Pt(  b )>7.5 GeV  c  (  b )> 225  m  c  (  c from  b )> -65  m  d0(  b )<85  m  Pt(proton)>Pt(  from  c )  2.269<m(  c )<2.302 GeV   xy (  b )<30   xy (  c )<20 Same technique used for B s

27. Donatella Lucchesi27  b   c  Relative Yield Measurement

28. Donatella Lucchesi28 The Normalization Channel B 0  D -  + same cuts optimized for  b are applied

29. Donatella Lucchesi29  b   c  Relative Yield Measurement

30. Donatella Lucchesi30  b   c  Relative Yield Measurement

31. Donatella Lucchesi31 Many other B decays BD+-BD+- D ±  K s  ±

32. Donatella Lucchesi32 CP violation in Standard Model:  at CDF R. Aleksan et al. Z Phys. C54 653 (1992) proposal: B s  D s  K  time dependent decay rate depends on: sin(  ) and cos(  ) a)Theoretically clean b) Reasonable Branching ratio c) Background B s  D s  d) Need tagging e) Need time dependent analysis ~ 1000 events in RunIIa ~ 3500 events in RunIIb S/B = 1/6 S/B = 1 DsDs Ds*KDs*K Ds*Ds* DsKDsK

33. Donatella Lucchesi33 J/  cross section P t  >1.5  Pt(J/  )  0 First time at Tevatron  (P t >0, |y|<0.6)=240±1(stat) (syst) nb +35 -28

34. Donatella Lucchesi34 CP Asymmetries and Decays Ratios of D 0  h + h - Two Tracks Trigger open CDF to a new field, charm physics Pure D 0 samples are required  D * tag used The charge of the slow pion gives the D 0 flavor

35. Donatella Lucchesi35 CP Asymmetries and Decays Ratios of D 0  h + h -

36. Donatella Lucchesi36 CP Asymmetries and Decays Ratios of D 0  h + h -  (D 0  KK)  (D 0  K  ) = 9.38 ± 0.18 (stat) ± 0.10 (syst) %  (D 0  )  (D 0  K  ) = 3.686 ± 0.076 (stat) ± 0.036 (syst) %  (D 0  f) -  (D 0  f)  (D 0  f) +  (D 0  f) A CP = A CP (  ) = 2.0 ± 1.7 (stat) ± 0.6 (syst) % A CP (KK) = 3.0 ± 1.9 (stat) ± 0.6 (syst) % Results competitive with dedicated experiments and e + e - machines i.e. CLEO FOCUS

37. Donatella Lucchesi37 Summary CDF is starting doing competitive B physics measurements D0 need more time since the new detector In Italy many activities:  B s branching ratio analysis  D 0 branching ratio & CP measurements  No contribution on J/  analysis  Many opportunities for students !