Measurements of  1 /  and  2 /  Masashi Hazumi (KEK) July 31, 2006 XXXIII International Conference on High Energy Physics (ICHEP’06) Many thanks to many people, in particular to: T. Aushev, T. Browder, P. Chang, R. Faccini, K. George, T. Gershon, K. Hara, H. Ishino, A. Lazzaro, S. Olsen, Y. Sakai, O. Tajima and K. Trabelsi

2 New Results from BaBar and Belle for Stringent Tests of the Kobayashi-Maskawa Model of CP Violation

3 Main New Results Covered in This Talk (all results are preliminary)  1 with tree diagram (b  ccs)  1 with tree diagram (b  ccs) BaBar: sin2  in B 0  J/    (2S)K S,  c K S,  c1 K S, J/  BaBar: sin2  in B 0  J/    (2S)K S,  c K S,  c1 K S, J/   Belle: sin2  1 in B 0  J/  Belle: sin2  1 in B 0  J/    1 with penguin diagram (b  sqq)  1 with penguin diagram (b  sqq) BaBar: B 0  K + K  K 0,  ’K 0, K S K S K S,  K S,  K S,  0 K SBaBar: B 0  K + K  K 0,  ’K 0, K S K S K S,  K S,  K S,  0 K S Belle: B 0   ’K 0,  0 K SBelle: B 0   ’K 0,  0 K S Belle: B 0   K 0, K + K  K S, K S K S K S, f 0 K S,  K SBelle: B 0   K 0, K + K  K S, K S K S K S, f 0 K S,  K S  2  2 BaBar: , , BaBar: , ,  Belle: Belle:  Belle: Belle:  K.Hara K.George A. Lazzaro O. Tajima This talk H. Ishino S. Telnov

4 Some other new results and recently published results also mentioned but very briefly.  /  3 -related  R.Kowalewski (next speaker) My apologies if your favorites are not included Remarks

5 25 th Anniversary of Time-dependent CP Violation (tCPV)

6 Tony, are you nuts? Look at this. We need millions of B and use them to search for mixing and CP violation This took us six months! Tribute from S. Olsen 5 B mesons

7 PEP-II at SLAC KEKB at KEK Belle BaBar 9GeV (e  )  3.1GeV (e + ) peak luminosity: 1.12  cm  2 s  1 Two Asymmetric-energy B Factories 8GeV (e  )  3.5GeV (e + ) peak luminosity: 1.65  cm  2 s  1 world record 11 nations, 80 institutes, 623 persons 13 countries, 57 institutes, ~400 collaborators

8 Integrated Luminosity PEP-II for BaBar As of July 24, 2006 KEKB for Belle KEKB + PEP-II

9 Far beyond the design luminosities of both proposals Triumph in accelerator science reached on July 13, 2006 ~ 1 Billion BB pairs

10 Motivation Q. What is the main source of CP violation ? A. Kobayashi-Maskawa phase IS the dominant source ! Two promising approaches 1)Overconstrain the unitarity triangle: precise measurements of  and  needed 2) Compare sin2  in tree diagram and penguin diagram (e.g. b  s) sin2  history ( ) Q. Are there deviations from the CKM picture ? (e.g. new CP-violating phases) Paradigm shift !

11  1

12 Time-dependent CP violation (tCPV) “ double-slit experiment ” with particles and antiparticles b c d c s d J/  KSKS b d c KSKS b c s ddt t + Quantum interference between two diagrams tree diagram box diagram + tree diagram Vtd You need to “wait” (i.e.  t  0) to have the box diagram contribution.

13 tCPV in B 0 decays ( A =  C a la BaBar) Mixing-induced CPVDirect CPV e.g. for J/  Ks S =  CP sin2  1 = +sin2  1 A = 0 to a good approximation (  CP : CP eigenvalue) e.g. for J/  Ks S =  CP sin2  1 = +sin2  1 A = 0 to a good approximation (  CP : CP eigenvalue)

14 R : detector resolution w : wrong tag fraction (misidentification of flavor)  (1-2w) quality of flavor tagging They are well determined by using control sample D * l  D (*)  etc… S = 0.65 A = 0.00 B 0 tag _ _ -  CP sin2  1 Mixing of D * l Good tag region (OF-SF)/(OF+SF)  t| (ps)

15  1 with trees - Results -

16 B 0  J/  K 0 : 535 M BB pairs B 0  J/  K S B 0  J/  K L Nsig = 7482 Purity 97 % CP odd Nsig = 6512 Purity 59 % CP even p KL information is poor  lower purity Belle preliminary 00 _ BELLE-CONF-0647 O. Tajima

17 B 0  J/  K S B 0 tag _ 0 B 0  J/  K L B 0 tag _ 0 Asym. = -  CP sin2  1 sin  m  t sin2  1 = ±0.038 A = ±0.028 sin2  1 = ±0.057 A = ±0.033 stat error BELLE-CONF-0647 O. Tajima background subtracted

18 B 0  J/  K S B 0 tag _ 0 B 0  J/  K L B 0 tag _ 0 _ B 0  J/  K 0 : combined result Asym. = -  CP sin2  1 sin  m  t sin2  1 = ±0.038 A = ±0.028 sin2  1 = ±0.057 A = ±0.033 stat error BELLE-CONF-0647 O. Tajima

19 B 0  J/  K 0 : combined result sin2  1 = ±0.031 (stat) ±0.017 (syst) A = ±0.021 (stat) ±0.014 (syst) previous measurement sin2   =  (388 M BB pairs) B 0 tag _ 535 M BB pairs _ _ Belle preliminary BELLE-CONF-0647 O. Tajima

20 K.George A =  0.07   BaBar2006: sin2  in b  ccs B 0  J/     (2S)K S,  c K S,  c1 K S,  J/  

: BaBar + Belle Consistency with V ub,  3 /   R. Kowalewski (next speaker)

22  (not sin2  ) measurements B 0  D* + D*  Ks Time-dependent Dalitz analysis (T.Browder, A. Datta et al. 2000)  cos2  > 0 (94%CL, model-dependent) B 0  Dh 0 (h 0 =  0 etc.) Time-dependent Dalitz analysis  cos2  > 0 Belle: 98.3%CL (hep-ex/ , accepted by PRL) BaBar 87% CL (BABAR-CONF06/017) K.George

23  1 with penguins

24 3 theoretically-clean modes  Ks,  ’Ks, 3Ks

25 Results for 3 theoretically-clean modes  K 0,  'K 0, KsKsKs

26 Belle 2006: B 0   K 0 signal B 0 mass B 0 momentum _ 535M BB (bkg subtracted)   K  K , K S        K  K , K S        K S K L, K S      114  17  K L signal 114  17  K L signal 307  21  K S signal 307  21  K S signal Three modes New ! BELLE-CONF-0647

27 Belle 2006: tCPV in B 0   K 0 “sin2  1 ” =  0.50  0.21(stat)  0.06(syst) A =  0.07  0.15(stat)  0.05(syst) “sin2  1 ” =  0.50  0.21(stat)  0.06(syst) A =  0.07  0.15(stat)  0.05(syst)   K S and  K L combined  background subtracted  good tags   t  –  t for  K L  t distribution and asymmetry _ 535M BB Consistent with the SM (~1  lower) Consistent with Belle 2005 (Belle2005: “sin2  1 ” =  The most precise measurement now Consistent with the SM (~1  lower) Consistent with Belle 2005 (Belle2005: “sin2  1 ” =  The most precise measurement now unbinned fit SM BELLE-CONF-0647

28 BaBar 2006: tCPV in B 0      K 0 Obtain CP parameters for 2-body and 3-body modes simultaneously by time-dependent Dalitz fit _ 347M BB KKKSKKKSKKKLKKKSKKKSKKKL 1516  65 K  K  K 0  signal 1516  65 K  K  K 0  signal

29  K 0 : sin2  eff = ± 0.31(stat) ± 0.10 (syst) BaBar 2006: tCPV in B 0      K 0  measurement (not sin2  ) Rejected (within SM) 4.6 

30 Belle 2006: B 0   'K 0 signal 1421  46  'K S signal 1421  46  'K S signal 454  39  'K L signal 454  39  'K L signal _ 535M BB (bkg subtracted) B 0 mass B 0 momentum

31 Belle 2006: tCPV in B 0   'K 0 “sin2  1 ” =  0.64  0.10(stat)  0.04(syst) A =  0.01  0.07(stat)  0.05(syst) “sin2  1 ” =  0.64  0.10(stat)  0.04(syst) A =  0.01  0.07(stat)  0.05(syst) _ 535M BB First observation of tCPV (5.6  in a single b  s mode Consistent with the SM Consistent with Belle 2005 (Belle 2005: “sin2  1 ” =  First observation of tCPV (5.6  in a single b  s mode Consistent with the SM Consistent with Belle 2005 (Belle 2005: “sin2  1 ” =   t distribution and asymmetry ''   'K S and  'K L combined  background subtracted  good tags '   t  –  t for  'K L BELLE-CONF-0647

32 BaBar 2006: tCPV in B 0   'K 0 Cf. BaBar 2005: “sin2  ” =  0.13  0.03 “sin2  ” =  0.55  0.11(stat)  0.02(syst) A =  0.15  0.07(stat)  0.03(syst) “sin2  ” =  0.55  0.11(stat)  0.02(syst) A =  0.15  0.07(stat)  0.03(syst) “sin2  ” 4.9  from zero. _ 347M BB

33 Belle 2006: tCPV in B 0  K S K S K S “sin2  1 ” =  0.30  0.32(stat)  0.08(syst) A =  0.31  0.20(stat)  0.07(syst) “sin2  1 ” =  0.30  0.32(stat)  0.08(syst) A =  0.31  0.20(stat)  0.07(syst) 185  17 K S K S K S signal 185  17 K S K S K S signal B 0 mass _ 535M BB  t distribution and asymmetry  background subtracted  good tags BELLE-CONF-0647

34 “sin2  ” =  0.66  0.26(stat)  0.08(syst) A =  0.14  0.22(stat)  0.05(syst) “sin2  ” =  0.66  0.26(stat)  0.08(syst) A =  0.14  0.22(stat)  0.05(syst) BaBar 2006: tCPV in B 0  K S K S K S 176  17 K S K S K S signal 176  17 K S K S K S signal  t distribution and asymmetry _ 347M BB

35 Results for other b  s modes (~20sec/result)

36 Belle 2006: tCPV in B 0  f 0 K S “sin2  1 ” =   0.23(stat)  0.11(syst) A =   0.15(stat)  0.07(syst) “sin2  1 ” =   0.23(stat)  0.11(syst) A =   0.15(stat)  0.07(syst) _ 535M BB 377  25 f 0 K S signal Raw  symmetry B 0 mass good tags     mass BELLE-CONF-0648

37 BaBar 2006: tCPV in B 0    K S “sin2  ” =  0.33  0.26(stat)  0.04(syst) A =  0.20  0.16(stat)  0.03(syst) “sin2  ” =  0.33  0.26(stat)  0.04(syst) A =  0.20  0.16(stat)  0.03(syst) 425  28  0 K S signal 425  28  0 K S signal _ 347M BB

38 Belle 2006: tCPV in B 0    K S “sin2  1 ” =   0.35(stat)  0.08(syst) A =   0.14(stat)  0.05(syst) “sin2  1 ” =   0.35(stat)  0.08(syst) A =   0.14(stat)  0.05(syst) _ 535M BB 515  32  0 K S signal 515  32  0 K S signal Raw  symmetry B 0 mass good tags BELLE-CONF-0648

39 Belle 2006: tCPV in B 0  K  K  K S “sin2  1 ” =   0.15(stat)  0.03(syst) (CP-even) A =   0.10(stat)  0.05(syst) “sin2  1 ” =   0.15(stat)  0.03(syst) (CP-even) A =   0.10(stat)  0.05(syst) _ 535M BB 840  34     K S signal 840  34     K S signal Raw  symmetry B 0 mass good tags  0.13 BELLE-CONF-0648

40 Belle 2006: tCPV in B 0   K S “sin2  1 ” =   0.46(stat)  0.07(syst) A =   0.29(stat)  0.06(syst) “sin2  1 ” =   0.46(stat)  0.07(syst) A =   0.29(stat)  0.06(syst) _ 535M BB 118  18  K S signal 118  18  K S signal B 0 mass Raw  symmetry good tags BELLE-CONF-0648

41 BaBar 2006: tCPV in B 0   K S “sin2  ” =  0.62 (stat)  0.02(syst) A =  0.43 (stat)  0.03(syst) “sin2  ” =  0.62 (stat)  0.02(syst) A =  0.43 (stat)  0.03(syst)    17  0 K S signal _ 347M BB

42 BaBar 2006: tCPV in B 0    K S “sin2  ” =  0.17  0.52(stat)  0.26(syst) A =  0.64  0.41(stat)  0.25(syst) “sin2  ” =  0.17  0.52(stat)  0.26(syst) A =  0.64  0.41(stat)  0.25(syst) 111  19   K S signal 111  19   K S signal quasi 2-body approach (restricting to the region dominated by  0 ) _ 347M BB

:  1 with b  s Penguins Smaller than b  ccs in all of 9 modes Smaller than b  ccs in all of 9 modes Theory tends to predict positive shifts (originating from phase in Vts) Naïve average of all b  s modes sin2  eff = 0.52 ±  deviation between penguin and tree (b  s) (b  c) Naïve average of all b  s modes sin2  eff = 0.52 ±  deviation between penguin and tree (b  s) (b  c) More statistics crucial for mode-by-mode studies

44 Standard penguin (bird), or something else (rabbit may be) ? More statistics crucial for mode-by-mode studies

45 Other handles to search for new physics with penguin diagrams B 0  KsKs (b  d penguin): even higher statistics needed B   sum rule [Gronau, Rosner 2005] A( K 0  0 ) = A( K    ) + A( K 0  + ) – A( K +  0 ) B 0  Ks  0  (electromagnetic penguin) New physics may lead to right handed currents. This can be investigated using time-dependent CPV measurements of b  s  decays and will be discussed in Barlow's talk. S ~ 0 expected in SM  0.12  0.11  0.16  0.04

46  2  1 “beam”  2 “banana”

47 tCPV and  2 (  ) 11 33 22 V ud V * ub V td V * tb V cd V * cb B0B0 d b – d – bt – t B0B0 – V * tb V td V * tb V td Mixing diagramDecay diagram (tree) B0B0 b – d d u – d – u // // V ud V * ub With the tree diagram only S     = +sin2  2 A     = 0 S     = +sin2  2 A     = 0 3 possibilities: 

48 Belle 2006: B 0 →  +  − decay (CP asymmetry) first error: stat., second: syst. background subtracted  +  − yields  +  − asymmetry Large Direct CP violation (5.5  ) Large mixing-induced CP violation (5.6  ) confidence level contour H. Ishino BELLE-CONF-0649 _ 535M BB 1464±65 signal events

49 S. Telnov BaBar 2006: tCPV in B 0      confidence level contour Evidence for CP violation (3.6  ) Direct CP violation not yet observed

50 History of B 0 →  +  − decay 2.3  diff. btw. Belle and BaBar ( C =  A )

51 The results support the expectation from SU(3) symmetry that HFAG summer 2005 Interpretation: Direct CP violation+SU(3) N.G. Deshpande and X.-G. He, PRL 75, 1703 (1995) M. Gronau and J.L. Rosner, PLB 595, 339 (2004) ICHEP2006 World Average

52  :tough bananas A  world average  observation of large direct CPV Large penguin diagram (P) ~ Tree diagram (T) Large strong phase difference between P and T B 0d0d d b d u u W g ++ -- V td V * tb t d

53 Isospin analysis: flavor SU(2) symmetry Model-independent (symmetry-dependent) method SU(2) breaking effect well below present statistical errors “Penguin pollution” can be removed by isospin analysis [Gronau-London 1990]

54  2 constraints from B 0 →  +  − decay inputs B (  +  0 ) = (5.75  0.42) B (  +  - ) = (5.20  0.25)  B (  0  0 ) = (1.30  0.21) A (  0  0 ) =  0.33 S (  +  - ) =  0.59  0.09 A (  +  - ) =  0.07 inputs B (  +  0 ) = (5.75  0.42) B (  +  - ) = (5.20  0.25)  B (  0  0 ) = (1.30  0.21) A (  0  0 ) =  0.33 S (  +  - ) =  0.59  0.09 A (  +  - ) =  0.07 No stringent constraint obtained with  system alone  need  and 

55 tCPV with B 0       Even worse on first sight... –Dirty final state:              –Mixture of CP = +1 and  1: need to know each fraction (A + +A - )/√2 A || (A + -A - )/√2 A⊥A⊥ A0A0 + + A0A0 A+A+ A-A-     +1  1  1 CP vector

56 Isospin analysis with B   Branching fraction for B 0      is larger than     Branching fraction for B 0      is small (<1.1x10 -6 ) –small penguin pollution ~100% longitudinally polarized (~pure CP-even state) –no need for elaborate angular analysis No significant 3-body/4-body contamination Dirty final states including  0 –OK in the clean e + e  environment the best mode as of summer 2005 the best mode as of summer 2005

57 BaBar2006: tCPV in B  

58 BaBar2006: B   (cont.) B 0      branching fraction: indication at 3.0  B +      branching fraction

59  2 constraints from B 0 →  +  − decay New     branching fraction Isospin triangle now closed (new     )  constraint on  2 becomes less stringent.

60 BaBar2006: B   Dalitz analysis Preliminary result in 2004 (16 parameters ignoring     ) is superseded. Interference  info. on strong phase difference B0B0 B0B0  

61 ICHEP2006: BaBar(  /  /  ) + Belle(  /  )  Global Fit = [ 98 ] º  /  2 = [93 ]  +11  9 consistent with a global fit w/o  /  2

62  sets a “ window ” around 90   chooses the correct position inside the window: revival of  !  essential to suppress  2 ~ 0  or 180  Good agreement b/w the CKM fit (  determined by others) and the direct measurements Still a lot to do –solution around 0 or 180 , which requires |P/T|~1, can/should be much more suppressed e.g. Model-independent constraint using  K* (robust against SU(3) breaking) [Beneke-Gronau-Rohrer-Spranger 2006] –subtleties in statistical analyses with small statistics –uncertainty in background modeling, unknown phases etc.  /  2 : Discussions

63 Belle 2006:  2 from B   Dalitz analysis + isospin (pentagon) analysis 26(Dalitz) + 5(Br(     ), Br(     ), Br(     ), A (     ), and A (     ))  2 (degree) 1-CL Results             mass helicity  /  2 = [83 ]  +12  (1  ) (no constraint at 2  will be included in the world average BELLE-CONF-0650 _ 449M BB

64 Summary tCPV allows a direct access to fundamental EW parameters with small hadronic uncertainties in spite of large hadronic uncertainties in branching fractions !tCPV allows a direct access to fundamental EW parameters with small hadronic uncertainties in spite of large hadronic uncertainties in branching fractions ! sin2  1 now determined with 4% accuracysin2  1 now determined with 4% accuracy tCPV in b  s: interesting (and tantalizing) hint of deviation from SM expectations: only an order of magnitude more data will resolve the issuetCPV in b  s: interesting (and tantalizing) hint of deviation from SM expectations: only an order of magnitude more data will resolve the issue With improved statistics and sophisticated analyses, it has become clear that  2 is harder to determine than we thought at ICHEP2004; however, statistics are still the main obstacle.With improved statistics and sophisticated analyses, it has become clear that  2 is harder to determine than we thought at ICHEP2004; however, statistics are still the main obstacle. My talk is just a status report ! The best of two B factories is yet to come ! My talk is just a status report ! The best of two B factories is yet to come ! tCPVBeautyin

66 Both  1 /  and  2 /  Determined from Measurements of Time-dependent CP Asymmetries in the B Meson System

67 Belle 2006: Systematic errors of B 0  J/  K 0 Sin2  1 A Vertexing Flavor tagging  t Resolution Physics parameters Possible fit bias BG fractions (J/  K S ) BG fractions (J/  K L ) BG  t Tag-Side interference total

68 J/  K 0 J/  K S J/  K L q=+1 q=-1 SVD1 SVD2 ntrk tag >=6 ntrk tag =5 ntrk tag =4 ntrk tag =3 ntrk tag =2 ntrk tag =1 r

69 KEKB Integrated luminosity B 0  J/  K S 0 B 0  J/  K L 0

: World Average  0.026

: BaBar + Belle No direct CPV in the SM: will see with more data ~2  difference b/w BaBar and Belle

72 BaBar: statistical error: More precise measurements possible with more data ! More precise measurements possible with more data ! K.George

73 Belle 2006: B 0   K S helicity _ 532M BB Consistent with the model used in the analysis [P-wave (  ) + small non P-wave component obtained from Dalitz analysis] Consistent with the model used in the analysis [P-wave (  ) + small non P-wave component obtained from Dalitz analysis]

74 Belle 2006: tCPV in B 0   K 0 _ 532M BB KSKS KSKS KLKL KLKL “sin2  1 ” =  0.23(stat) “sin2  1 ” =  0.56(stat)

75 Belle 2006: tCPV in B 0   'K 0 _ 532M BB 'KS'KS 'KS'KS 'KL'KL 'KL'KL “sin2  1 ” =  0.11(stat) “sin2  1 ” =  0.24(stat)

76 Belle 2006: tCPV in B 0   'K 0 “sin2  1 ” with subsamples Errors are statistical only

77 Belle 2006: tCPV in B 0   'K 0 Significance of tCPV S = 0 ruled out with >5.6  at any A

78

79

80 B 0 →  +  − decay C =−A 2.3  diff. btw. Belle and BaBar

81

82

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84 (1.4  b/w BaBar and Belle)

85

86

87

88 UTfit:  from , ,  All combine d 

90 The Kobayashi-Maskawa weak phase (0,0)(0,1) _ _ ( ,  ) 1()1() 3()3() 2()2() Normalized with |VcdVcb*|  =  (1  2 /2)  =  (1  2 /2) In particular, V td = |V td |exp(  i  1 ) V ub = |V ub |exp(  i  3 ) A 3 3 generations  CP-violating phase

91 What ’ s CP violation ? It is a partial rate asymmetry ! |B  |f   1 = |  1 |e is e i   2 = |  2 |e is’ e i  ’ |B  |f   1 = |  1 |e is e  i   2 = |  2 |e is’ e  i  ’ CP  ’: weak phase diff. : previous slide s  s’: static phase diff. : FSI, Resonance,  m  ’: weak phase diff. : previous slide s  s’: static phase diff. : FSI, Resonance,  m

92 Wolfenstein parameterization

93 Inclusive e ’ s at the ϒ (4S) Belle CLEO result in ~1980 Tribute from S. Olsen

94 Back to the Future 1981  2006

95 PEP-II KEKB Belle BaBar 9GeV (e  )  3.1GeV (e + ) peak luminosity: 1.12  cm  2 s  1 Two Asymmetric-energy B Factories 8GeV (e  )  3.5GeV (e + ) peak luminosity: 1.65  cm  2 s  1 world record ! Charged tracking/vertexing SVD: SVD: (-7/03) 3-layer DSSD Si µstrip (-7/03) 3-layer DSSD Si µstrip (8/03-) 4-layer (8/03-) 4-layer CDC: 50 layers (He-ethane) CDC: 50 layers (He-ethane) Hadron identification CDC: dE/dx CDC: dE/dx TOF: time-of-flight TOF: time-of-flight ACC: Threshold Cerenkov ACC: Threshold Cerenkov(aerogel)Electron/photon ECL: CsI calorimeter ECL: CsI calorimeter Muon/K L KLM: Resistive plate KLM: Resistive platecounter/iron Charged tracking/vertexing 5-layer DSSD Si µstrip 5-layer DSSD Si µstrip 40 layers (He-isobutane) 40 layers (He-isobutane) Hadron identification tracker: dE/dx tracker: dE/dx DIRC imaging Cerenkov DIRC imaging CerenkovElectron/photon CsI calorimeter CsI calorimeter Muon/K L Instrumented flux return Instrumented flux return

96 PEP-II & BaBar L max = 1.12 X cm – 2 s – 1  L dt = 371 fb – Υ (4S)+off(~10%)} (>3.7x10 8 B events) Charged tracking/vertexing 5-layer DSSD Si µstrip 5-layer DSSD Si µstrip 40 layers (He-isobutane) 40 layers (He-isobutane) Hadron identification tracker: dE/dx tracker: dE/dx DIRC imaging Cerenkov DIRC imaging CerenkovElectron/photon CsI calorimeter CsI calorimeter Muon/K L Instrumented flux return Instrumented flux return 11 nations, 80 institutes, 623 persons

97 e + source Ares RF cavity Belle detector World record: L = 1.6 x /cm 2 /sec SCC RF(HER) ARES(LER) The KEKB Collider 8 x 3.5 GeV 22 mrad crossing angle ~1 km in diameter Mt. Tsukuba KEKB Belle since 1999

98 Belle detector K L  detector 14/15 layer RPC+Fe Electromagnetic Calorimeter CsI(Tl) 16X 0 Aerogel Cherenkov Counter n = 1.015~1.030 Si Vertex Detector 4-layer DSSD TOF counter 3.5 GeV e + Central Drift Chamber momentum, dE/dx 50-layers + He/C 2 H 6 charged particle tracking K/  separation B vertex Muon / K L identification ,  0 reconstruction e +-, K L identification 8.0 GeV e -

99  = (Belle) 0.56 (BaBar) Principle of tCPV measurement CP-side 1.Fully reconstruct one B-meson which decays to CP eigenstate electron positron  (4S) resonance B1B1 B2B2 ++ -- K S/L J/ 

100  = (Belle) 0.56 (BaBar) Principle of tCPV measurement CP-side Flavor tag and vertex reconstruction 1.Fully reconstruct one B-meson which decays to CP eigenstate 2.Tag-side determines its flavor (effective efficiency = 30%) 3.Proper time (  t) is measured from decay-vertex difference (  z) electron positron  (4S) resonance B1B1 B2B2 ++ -- K+K+ --  ++ -- K S/L J/   z ~ 200  m (Belle) B0B0 B0B0 _

101 b g s modes and their “ cleaness ” in SM taken from a review “CP violation” in PDG2005 (D.Kirkby, Y.Nir) pure tree b  cud D CP  0 D CP Ks (Vcb*Vud)T + (Vub*Vcd)T 2 + ucd

102 Experimental Challenge B 0  J/  K S B0  KSB0  KS Tree Penguin We need 1) large number of BB pairs 2) additional background rejection Event Shape (Jet-like) (Spherical) Mbc Signal Likelihood

103 Signal Likelihood (LHR) projection Mbc projection LHR Mbc Clear separation between signal and background Clear separation between signal and background B 0   Ks   Ks signal   Ks signal