1. Recenti Risultati dell’esperimento BaBar Riccardo Faccini Univ. Roma La Sapienza Gruppo I 25 – 26 Marzo, 2002 (1,0)    (,)(,) (0,0)

2. Riccardo Faccini, Univ. Roma12 Outline Introduction B physics Primer PEPII - BaBar Time-dependent CP asymmetries “Other” B physics Conclusions and Perspectives

3. Riccardo Faccini, Univ. Roma13 CP violation generated by complex coupling constant Quark mixing matrix Cabibbo Kobayashi Maskawa matrix 3 quark generations  one non-removable phase CP violation and Standard Model  sin  Cabibbo 

4. Riccardo Faccini, Univ. Roma14 The ‘Triangles’ CKM matrix is unitary phases  angles , , and  B d system CP violation proportional to triangle area: measure sides and angles independently (1,0)    (,)(,) (0,0) V ub * V ud V cb * V cd V tb * V td V cb * V cd

5. Riccardo Faccini, Univ. Roma15 Unitarity Triangle Analyses Measure the sides or the apex position. B d mixing   m d b  ul |V ub |,D*l |V cb | B s mixing   m s /  m d Kaon decays   K Experiment Theory lattice QCD:  B B, f Bd,s  and with B-factories : the angles  IN ADDITION TO  m d,|V ub |, |V cb |

6. Riccardo Faccini, Univ. Roma16 CP violation in mixing and decay Consider B decays to a mode f interference between mixing and decay decay amplitude phase mixing phase CP mixing decay f is not necessarily a CP eigenstate

7. Riccardo Faccini, Univ. Roma17 Experimental Technique 0 tag B B-Flavor Tagging Exclusive B Meson Reconstruction Low BR (10 -5 ) means high luminosity Accurate and unbiased measurement of the vertices

8. Riccardo Faccini, Univ. Roma18 BaBar and PEP-II @ SLAC High luminosity asymmetric B factory @  (4S) 9 GeV e - on 3.1 GeV e +  (4S) boost: 

9. Riccardo Faccini, Univ. Roma19

10. 10 PEP-II performances Off On (~12% off peak) 24 fb -1 in 2000 40 fb -1 in 2001 10 fb -1 so far in 2002 26 fb -1 more by June 30 100 fb -1 by June 30, 2002 Totals to Date (77.5) (73.6) (7.9) 56 fb -1

11. Riccardo Faccini, Univ. Roma111 PEP-II performance  > 97% design 14 months of continuous running, 4 more to go !

12. Riccardo Faccini, Univ. Roma112 PEP-II performance

13. CP violation in oscillations    Well done Medium Rare B   Charmonium K s,K L D * D (*) D (*)  Charmless two-body

14. Riccardo Faccini, Univ. Roma114 The aim of the game: f  output Dilepton mixing B 0  l X~Re(  )~0  M B0 Hadronic mixing B 0  D (*) ,a 1 ~Re(  )~0  M B0 “sin2  ”B 0  J/  k s + … 1 sin2  “sin2  ”B 0   ?!? (~1) sin2  sin(2  )B 0  D (*)+   ~0.02 sin(2  ) Fit for where Examples:

15. Riccardo Faccini, Univ. Roma115 Time-dependent asymmetry Because of correlation of B 0 and B 0 state, need to measure difference in decay times to see asymmetry due to interference between mixing and direct decay:  (B 0  f CP )  e -  t [1 + sin2  sin(  m  t)] asymmetry  sin2  sin(  m  t)  t = t CP - t tag (picoseconds)  (B 0  f CP )  e -  t [1 - sin2  sin(  m  t)] If f CP =J/K s

16. Riccardo Faccini, Univ. Roma116 CP analysis: reconstruct f CP and tag other side as B 0 or B 0. Mixing analysis: tag both sides as B 0 or B 0 ; e.g., fully reconstruct one B decay to a non-CP state; tag other side. From the ideal world to “reality”… B tag = B 0 B 0 B 0 or B 0 B 0 First add dilution due to imperfect tagging. Assume the mistag rate is  = 22%. Time-dependent CP asymmetry is diluted by (1-2  ) = 0.56 Extract  from mixing analysis.

17. Riccardo Faccini, Univ. Roma117 From the ideal world to reality... Now add effect of imperfect measurement of  t. Assume double Gaussian  z resolution of 100 microns (80%) and 300 microns (20%). [  c ~ 170 microns/ps] Add background contribution. N S /N B ~ 10:1 for mixing analysis, 50:1 for CP analysis.

18. Riccardo Faccini, Univ. Roma118 First step: get fully reco Bs B 0  D (*) -  , D (*) -  , D (*) - a 1 +,J/  K* 0 B   D (*)0  ,J/  K -,  S  K - Kinematic variables for signal and background estimates  E=E* B -  s /2  ~15 MeV m ES =  (s/4 - p* B 2 )  ~3MeV Neutral B Mesons Charged B Mesons

19. Riccardo Faccini, Univ. Roma119 Tagging power Tagging category Efficiency  (%) Mistag fraction w (%) B 0 /B 0 diff.  w (%) Q =  (1-2w) 2 (%) Lepton 11.1  0.28.6  0.90.6  1.5 7.6  0.4 Kaon 34.7  0.418.1  0.7-0.9  1.114.1  0.6 NT1 7.7  0.222.0  1.51.4  2.32.4  0.3 NT2 14.0  0.337.3  1.3-4.7  1.90.9  0.2 ALL 67.5  0.525.1  0.8  (sin2  )  1/  Q b sc e -,  - K-K- Hierarchical tagging: Lepton, kaon, neural nets exploiting soft pions, misidentified leptons….

20. Riccardo Faccini, Univ. Roma120 Electron ID Electromagnetic calorimeter: ~6500 crystals of CsI ~18 X 0 Typical Tight Electron selection: ~92% efficiency above 500 MeV, with 0.1%  misID

21. Riccardo Faccini, Univ. Roma121 Muon ID Instrumented Flux Return (IFR) with up to 21 RPC’s in 65 cm of iron Typical Tight Muon selection: ~65-70% efficiency above 1.5 GeV, with ~2.5% pion mis ID Efficiency drop reduced in new chambers!!!

22. Riccardo Faccini, Univ. Roma122 KAON ID SYSTEM (DIRC) Reflections in quartz bar e-e- e+e+

23. Riccardo Faccini, Univ. Roma123 KAON ID PERFORMANCES  and K candidates from D 0 decays tagged by soft  from D *+ ; about 11% contamination from backgrounds Performances evaluated on control samples

24. Riccardo Faccini, Univ. Roma124 Vertexing Algorithm One of the two B mesons is fully reconstructed (“CP”), while the other is only partially reconstructed (dropping tracks with bad  2 ) Full power of the SVT and of the kinematic and vertexing constraints exploited Beam spot Interaction Point B REC Vertex B REC daughters B REC direction B TAG direction TAG Vertex TAG tracks, V 0 s  ~70  m  ~180  m ~1cm ~0.1 mm

25. Riccardo Faccini, Univ. Roma125 Silicon Vertex Tracker (SVT) 5 double-sided layers Radiation hard (2 MRad) radius = (32 - 140) mm angular acceptance in lab: 20.1 o to 150.2 o 143k channels (0.94 m 2 ) ~14 cm

26. Riccardo Faccini, Univ. Roma126 sin2     R.F. coordinator

27. Riccardo Faccini, Univ. Roma127 Step II: get CP eigenstates J/ K s (K S   +  - ) J/ K s (K S   0  0 ) J/ K *0 (K *0  K S  0 )  c1 K s (2S) K s J/ K L ModeN tag PurityCP (cc)K s 99594% 11 J/  K L 74257%+1 J/  K *0 11383%+0.68 All CP 1,85079% Bflav 17,63485%Flav. ES 1999-2001 data 62 x 10 6 BB pairs, 56 fb -1 on peak   

28. Riccardo Faccini, Univ. Roma128 Sin(2  ) Likelihood Fit Simultaneous unbinned maximum likelihood fit to  t spectra to both flavour and CP samples 35 total free parameters Fit Parameters sin2  1 Mistag fractions for B 0 and B 0 tags8 Signal resolution function8 Empirical description of background  t17 B lifetime fixed to the PDG value  B = 1.548 ps Mixing Frequency fixed to the PDG value  m d = 0.472 ps -1 Global correlation coefficient for sin2  : 14%   

29. Riccardo Faccini, Univ. Roma129 Mixing validation 29.7 fb -1 hep-ex 0112044 All  t and mistag parameters simultaneously extracted from data 44 total free parameters  m d =0.516±0.016±0.010 ps -1    |V td | |V ub /V cb |

30. Riccardo Faccini, Univ. Roma130 “Golden” and J/  K L Background contribution 471 B 0 tags 524 B 0 tags 392 B 0 tags 350 B 0 tags   

31. Riccardo Faccini, Univ. Roma131 Results Goodness of fit: Prob(L max >L obs ) = 27% sin2  = 0.75 ± 0.09 ± 0.04 hepex / 02 03 007 (Mar. 2002: results on data up to Dec. 2001)   

32. Riccardo Faccini, Univ. Roma132 Analysis improvements Still improving faster than statistics ICHEP00 Winter 01 LP01 Winter 02  (sin2  )      Improved track efficiency and vertex resolution Re-optimized selection criteria

33. Riccardo Faccini, Univ. Roma133 Systematic errors Error/SampleKSKS KLKL K *0 Total Statistical0.100.190.560.09 Systematic0.040.060.100.04 Signal resolution and vertex reconstruction 0.014 Resolution model, outliers, residual misalignment of the SVT Factor of 3 smaller compared to last publication  Tagging 0.007  possible differences between B CP and B flavour samples Backgrounds 0.022 (overall) Signal probability, fraction of B + background in the signal region, CP content of background Total 0.05 for J/  K L channel; 0.09 for J/  K *0 Monte Carlo statistics used for validation: 0.014 External parameters (t B and Dm): 0.014 Total: 0.04 for total sample   

34. Riccardo Faccini, Univ. Roma134 Interpretation … Method as in Höcker et al, Eur.Phys.J.C21:225-259,2001 (also other recent global CKM matrix analyses)   

35. Riccardo Faccini, Univ. Roma135 thanks to the hard work of the B community SIX MONTHS AGO 0.79 ± 0.10 (  sin2  BaBar =0.14)    NOW

36. Riccardo Faccini, Univ. Roma136 non charmonium modes : D*D* D * D * is vector-vector decay (L=0,1,2) so mix of CP=+1 and –1. Weak phase for tree decay is same as for b  ccs but watch out for penguins! Ignoring penguins: S = (1-2R T )sin2  With 20/fb: R T =0.22 ± 0.18(stat)± 0.03(syst) With full sample we fit the coefficients: S = -0.05 ± 0.45(stat) ± 0.07(syst) C = 0.12 ± 0.30(stat) ± 0.03(syst) +    Trieste

37. Riccardo Faccini, Univ. Roma137 Non Charmonium modes: D*D    D * D N tag = 85 Purity = 52% D * D S +- = -0.43  1.41  0.20 C +- = 0.53  0.74  0.13 S -+ = 0.38  0.88  0.05 C -+ = 0.30  0.50  0.08 Not a CP eigenstate but CP info can be extracted as well Parametrize time evolution as In the factorization & no penguin limit: C=0 S=sin2 

38. Riccardo Faccini, Univ. Roma138 Charmless two body:    Measure: Branching Ratios, time dependent A CP and Direct CPV Measure: Branching Ratios, time dependent A CP and Direct CPV B ->    ,    ,      – poor signal to noise ratio topological variables global likelihood fits – Kinematically similar     /     /     pion-kaon separation ISOSPIN Analysis G. Cavoto Coordinator Padova,Roma, Torino

39. Riccardo Faccini, Univ. Roma139 Background suppression Background dominated by continuum quark- antiquark production (u,d,s,c) Jet-like topology cos(  S ),cosine of the angle between sphericity axis of B and recoil Fisher Discriminant, scalar sum of the momenta of all recoil charged and neutral particles flowing into 9 concentric cones centered on the B candidate’s thrust axis Isotropic topology background signal   

40. Riccardo Faccini, Univ. Roma140 Global Likelihood fit analysis Extended global maximum likelihood fit  signal yields (n sig ) m ES,  E, Fisher,  C,  t Uncorrelated variables each event i : Independent control samples to study Probability Density Function for both BKG and SIG   

41. Riccardo Faccini, Univ. Roma141 B 0                B(    - ) =( 5.4  0.7  0.4) 10 -6 B(K +  - ) =(17.8  1.1  0.8) 10 -6 B(K + K - ) < 1.1 10 -6 (90% C.L.) A K  =(-0.05  0.06  0.01) [-0.14 - +0.05] 90%CL Direct CP violation   

42. Riccardo Faccini, Univ. Roma142 Global fit to B.F. Beneke et al., hep-ex 0104110 (matter of debate…)   

43. Riccardo Faccini, Univ. Roma143 C  and S  fit (technology) Extension of global unbinned max likelihood fit Need to add tagging and  t : same tech as sin(2  ) Yields by tagging category l k NT1 NT2 qq  t resolution fcn (from m ES sideband)   

44. Riccardo Faccini, Univ. Roma144 B 0     Asymmetry S  =-0.01  0.37  0.07 [-0.66, +0.62] 90%CL C  =-0.02  0.29  0.07 [-0.54, +0.48] 90%CL    from M.Beneke et al. Nucl.Phys.B606:245,2001

45. Riccardo Faccini, Univ. Roma145 Starting the isospin analysis we either need : -a triangle with a shape [BR (     ) > a few 10 -6 ] -a tiny (~10 -7 ) BR Our present result: BR (     )< 3.4 10 -6 at 90% CL doesn’t allow any conclusion   

46. Riccardo Faccini, Univ. Roma146 sin(2  + ) in D (*)  Not a CP eigenstate, but you can extract CP information any how. Four different pdfs fitted at the same time: Small expected asymmetry (| |<<1): need a lot of statistics and control over systematics Expect  (sin(2  +  ))~0.6 in 100 fb -1 One majour missing piece:  = A (B   D    ) A (B   D    )    Roma

47. Riccardo Faccini, Univ. Roma147 Observation of B   D s    Reconstructed D s  modes D s      , K *0 K +, K S K +         K *0        K S       Background rejection helicity angle (for D s      , K *0 K + modes) Fisher discriminant cos  thrust D s  vertex probability (  E, m ES ) of the reconstructed B   D  cos 2  C BF (B   D    ) BF (B   D s    )  fD2fD2 f Ds 2 Measurement of the parameter D  signal efficiency  [10 - 17 %] d c d BB DsDDsD  b u s,ds,d    |V td | |V ub /V cb | By-product: very clean V ub transition Roma

48. Riccardo Faccini, Univ. Roma148 B   D s    yield 14.9  4.1 events D    D    Systematic error mostly from uncertainty on BF of secondary decays, peaking background uncertainty, selection criteria BF( B   D s    ) (*) = ( 3.1  1.0  1.0 )  10  5 BF( B   D s    )  BF(D s      ) = ( 1.11  0.37  0.24 )  10  6 BF( B   D s    ) (*) = ( 3.1  1.0  1.0 )  10  5 BF( B   D s    )  BF(D s      ) = ( 1.11  0.37  0.24 )  10  6 (*) 25% uncertainty from PDG BF(D s       ) significance of the signal = 3.5  Evidence of reflected D s   D  background Preliminary    |V td | |V ub /V cb | | |~0.020±0.005(stat.+sys.) ± 0.00? (th.)

49. Riccardo Faccini, Univ. Roma149 Other B physics Well done Medium Rare B Mixing, B  s  B   Semileptonic end point, recoil of fully reco Bs DK    |V ub /V cb | |V td | D * l + more charmonium/ charmless + B lifetimes

50. Riccardo Faccini, Univ. Roma150 B  DK Pisa This Branching fraction is an ingredient of a number of methods proposed to extract the value of  in CKM matrix in a theoretically clean way   

51. Riccardo Faccini, Univ. Roma151  E separation (Monte Carlo) B -  D 0  - D 0 is selected in the modes: D 0  K , D 0  K3 , D 0  K  0 B -  D 0 K - D 0  K -  + The presence of the signal B  D 0 K - is evident when a Kaon PID requirement is applied to the prompt track (“h”) R=(5.5 ± 1.4 ± 0.5)% CLEO R=(7.9 ± 0.9 ± 0.6)% Belle Averaging over the three D 0 modes:   

52. Riccardo Faccini, Univ. Roma152 BaBar B 0 lifetime measurements New preliminary lifetime measurements using partial reconstruction. (not in average) BaBar measurements accepted by PRL Lifetime measurements validate t measurement techniques Padova

53. Riccardo Faccini, Univ. Roma153  m d =0.493±0.012±0.009 ps -1 BaBar  m d measurements BaBar mixing in dilepton B 0 decays (stat)(syst) BaBar measurements Mixing measurements validate time-dependent asymmetry measurement techniques. 30 fb -1    |V td | |V ub /V cb | C. Bozzi Coordinator Ferrara, Roma

54. Riccardo Faccini, Univ. Roma154 Charmonium results Deep investigation of QCD and quarkonium dynamics Alternative samples for sin2  determination BF(B   J/  K  ) = ( 4.4  1.4  0.7 )  10  5 BF(B   J/  K  ) = (10.2  3.8  1.8 )  10  5 BF(B   J/  )  0.95  10  5 @ 90% C.L. BF(B   J/  )   2.7  10  5 @ 90% C.L. BF(B   J/  )  6.4  10  5 @ 90% C.L. BF(B   J/  K  ) = ( 4.4  1.4  0.7 )  10  5 BF(B   J/  K  ) = (10.2  3.8  1.8 )  10  5 BF(B   J/  )  0.95  10  5 @ 90% C.L. BF(B   J/  )   2.7  10  5 @ 90% C.L. BF(B   J/  )  6.4  10  5 @ 90% C.L. BF(B   J/     )  = ( 5.0  0.7  0.6 )  10  5 BF( B    c  K  ) = ( 1.50  0.19  0.15  0.46 )  10  3 BF( B    c  K  ) = ( 1.06  0.28  0.11  0.33 )  10  3 BF(B   J/   ) / BF(B   J/  K  ) = (3.91  0.78  0.19)  10  2 A CP (J/    0.22  0.01 BF( B    c  K  ) = ( 1.50  0.19  0.15  0.46 )  10  3 BF( B    c  K  ) = ( 1.06  0.28  0.11  0.33 )  10  3 BF(B   J/   ) / BF(B   J/  K  ) = (3.91  0.78  0.19)  10  2 A CP (J/    0.22  0.01 50.9 fb -1 on-peak 51.7 fb -1 on-peak 20.7 fb -1 on-peak + start looking for Charmonium  hadrons to search for unseen particles (Hc) to add to the sin2  sample    R.F. Coordinator Napoli, Genova

55. Riccardo Faccini, Univ. Roma155 More rare charmless B decays Milano    More penguin dominated modes for sin2 

56. Riccardo Faccini, Univ. Roma156 B  s , exclusive semi- leptonic, leptonic results BF(B   K *0  ) = ( 4.23  0.40  0.22 )  10  5 BF(B   K *+  ) = ( 3.83  0.62  0.22 )  10  5 -0.170<A CP <0.082 @ 90% C.L. BF(B   K *0  ) = ( 4.23  0.40  0.22 )  10  5 BF(B   K *+  ) = ( 3.83  0.62  0.22 )  10  5 -0.170<A CP <0.082 @ 90% C.L. Handle on V td Sensitive to new physics Probes b quark dynamics inside the B meson BF(B    0  ) < 1.5 10  6 @ 90% C.L. BF(B    +  ) < 2.8 10  6 @ 90% C.L. BF(B    0  ) < 1.5 10  6 @ 90% C.L. BF(B    +  ) < 2.8 10  6 @ 90% C.L.    |V td | |V ub /V cb | Handle on Vub Are the exclusive B.F. better or worse than the inclusive ones from the theoretical point of view? BF(B    + l ) = ( 3.26±0.65 +0.63 –0.65 ±0.44 ) 10 -4 sys sper. sys theo => |V ub | = ( 3.57±0.36 +0.33 –0.38 ±0.60 ) 10 -3 sys sper. sys theo BF(B   e + e - ) < 3.3 10  7 @ 90% C.L. BF(B    + l ) = ( 3.26±0.65 +0.63 –0.65 ±0.44 ) 10 -4 sys sper. sys theo => |V ub | = ( 3.57±0.36 +0.33 –0.38 ±0.60 ) 10 -3 sys sper. sys theo BF(B   e + e - ) < 3.3 10  7 @ 90% C.L.    |V td | |V ub /V cb |

57. Riccardo Faccini, Univ. Roma157 Physics on the recoil The high luminosity and the high number of fully reconstructed B’s opens a brand new world in B physics In 100 fb-1 (July 2002) : 300 K fully reco B 100 K semi-leptonic B (one missing) Will be able to reconstruct single B in modes with BF ~10 -4 - 10 -5 Ferrara,Napoli,Roma

58. Riccardo Faccini, Univ. Roma158 Semi-leptonic physics on the recoil Require a lepton on the recoil (B  l X) Fully reconstruct the X system: Study the b  c transitions in detail Measure the rate of the b  u transition Will allow the search for B     |V td | |V ub /V cb |

59. Riccardo Faccini, Univ. Roma159 Semileptonic branching fractions of B + and B 0 BF(B +  Xe ) (10.3  0.6  0.5)% BF(B 0  Xe ) (10.4  0.8  0.5)% = = 0.99  0.10  0.04 Direct lepton yields ~ 600 each for B +, B 0 [but >2000 available now] Systematic errors: - semileptonic decay model - B + / B 0 cross-feed - hadron misidentification - electron ID efficiency - … Averaging these, BF(B  Xe ) = (10.4  0.5  0.5)% Preliminary    |V td | |V ub /V cb |

60. Riccardo Faccini, Univ. Roma160 BTW, we also do Charm Physics Bari Dalitz analysis: strong interactions and CP symmetries Available modes: D0  K s h + h - Ds  K s K s  + + D mixing:

61. Future and summary

62. Riccardo Faccini, Univ. Roma162 PEP-II luminosity projections Get the picture, numbers are revised often !

63. Riccardo Faccini, Univ. Roma163 By 2005: the error on sin2  eff will be ~0.15 B     will be seen if B.F.>few 10 -7 the error on sin2  in D * D * will be ~0.30 the stat error on V ub will be ~5% B  will have been seen if BF>~few 10 -5 And … Some projections … the world will know sin2 at the ~0.03 Current data sample

64. Riccardo Faccini, Univ. Roma164 Conclusion and Outlook  is becoming a precision measurement we are expanding into the non charmonium land  is a tough challenge, need L and brain (  too) A great variety of studies are still to be pursued: THIS IS JUST THE START OF THE FUN!!!! sin2  = 0.75 ± 0.09 ± 0.04

65. Riccardo Faccini, Univ. Roma165 Backup Slides

66. Riccardo Faccini, Univ. Roma166 sin2  from the run1 data sample Result sin2  Signal evts.Purity Old 0.45  0.20 43080% New 0.60  0.15 54073% (uncorrected) m d result stable Old: 0.493  0.024 ps -1 New: 0.502  0.023 ps -1 Event-by-event Change in t RMS  0.9  t Fitted change in t resolution Reprocessed data with significantly better SVT internal alignment. Event-by-event change in t  0.9  t Fitted t resolution shows the improvement. Investigated change in sin2 in common events (old vs. reprocessed) Estimated size of statistical spread of sin2 with toy MC, full MC, and data. Observed change is about 2 sigma in this estimated spread.

67. Riccardo Faccini, Univ. Roma167 Analysis improvements Detector improvements Improved tracking impacts  t resolution for reprocessed Run1 data: Improved usage of the first SVT hit. Improved SVT alignment Improved track finder Published Run2a data already had the improved tracking Improved PID impacts tagging Better DIRC alignment and K selector Better  selector Analysis changes Re-optimized selection criteria to improve yield Wider K S mass window results in 7% increase in J/  K S yield Looser  id,  0 veto results in 15% J/  K L yield with purity 60%  54%. B 0  J/  K* 0 Full angular analysis Reduce feed-across by vetoing B +  J/  K* + results in 60% background rejection with 0.5% signal loss.   

68. Riccardo Faccini, Univ. Roma168 Check ‘null’ control sample (B flav ) Treat B flavour sample as CP Expect no asymmetry See no asymmetry Sample “sin2  ” B o flavour 0.00 ± 0.03 B+B+ -0.02 ± 0.03 Analysis doesn’t create artificial asymmetries

69. Riccardo Faccini, Univ. Roma169 Consistency and more Subsamples Different vtx reco Fit without | |=1 constraint (CP=-1 only) | | = 0.92  0.06 (stat)  0.03 (syst) 2Im /(1+| | 2 ) = 0.76  0.10     sin2 

70. Riccardo Faccini, Univ. Roma170 Measuring the angles:  u u d b tree diagram V ub C   0, S  = - sin2  V ud

71. Riccardo Faccini, Univ. Roma171... but there are penguins isospin analysis d u b u Im ( )  sin2   need to relate asymmetry to  C   0, S  = - sin2  eff penguin diagram V td V* tb weak phase(s)strong phase

72. Riccardo Faccini, Univ. Roma172     asymmetry [Belle – BaBar]

73. Riccardo Faccini, Univ. Roma173 and if you believe to the Blue Fairy we might be even in the game BTW: I don’t from M.Beneke, G.Buchalla, M.Neubert, and C.T.Sachrajda, Nucl.Phys.B606:245-321,2001

74. Riccardo Faccini, Univ. Roma174 PEP-II improving luminosity

75. Riccardo Faccini, Univ. Roma175 PEP-II ; a possible scenario

76. Riccardo Faccini, Univ. Roma176  E PDF 0.15 GeV -0.15  E with pion mass hypothesis ~45 MeV shift for each Kaon  signal MC B -  D 0   ; signal MC, h  h  sideband  MeV marginal separation help in BKG suppression G4

77. Riccardo Faccini, Univ. Roma177 PDF shapes : m ES ARGUS function B -  D o  - fully reconstructed h+h-  E sideband x = m ES /E* beam Gaussian   2.6 MeV.... by far the most discriminating

78. Riccardo Faccini, Univ. Roma178 Fisher separation B -  D 0   ; h  h  sideband,MC signal background h  h   E sideband ( dots ) continuum h  h  MC ( histo ) ( dots ) B -  D 0   ( histo )  h  h  MC Fisher sensitive to rest of event only

79. Riccardo Faccini, Univ. Roma179 Two checks (using     )  =1.66  0.09 ps  m d =0.517  0.062 ps -1

80. Riccardo Faccini, Univ. Roma180 OPR Processing keeps up with data taking