Time-dependent CP Violation (tCPV) at Belle -- New results at ICHEP Masashi Hazumi (KEK) October. 10, 2006

2 The Belle (B Factory) Physics Program I.CP Violation in B Decays II.Fundamental SM Parameters (Complex Quark Couplings) III.Beyond the SM (BSM) IV.Unanticipated New Particles I.CP Violation in B Decays II.Fundamental SM Parameters (Complex Quark Couplings) III.Beyond the SM (BSM) IV.Unanticipated New Particles W±W± qiqi qjqj V ij Cabibbo-Kobayashi- Maskawa (CKM) matrix tCPV measurements at the heart of I, II and III !!

3 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)

4 New results shown at ICHEP2006 (0,0)(0,1) _ _ ( ,  ) 1()1() 3()3() 2()2() B0  K0B0  K0 B0  K0B0  K0 B 0   ’K 0 vs. B0  KSKSKSB0  KSKSKS B0  KSKSKSB0  KSKSKS B 0  f 0 K S B 0  K  K  K S B0  KSB0  KS B0  KSB0  KS B0  KSB0  KS B0  KSB0  KS B 0  J/  K 0 Tree 1 b  s Penguins 2 Right-handed current search B 0  K S    3 B   B   4 hep-ex/ hep-ex/ hep-ex/ hep-ex/ hep-ex/

5 Still new results but not covered in this talk (0,0) 1()1() 3()3() 2()2() (0,1) _ _ ( ,  )

6 Still new results but not covered in this talk (0,0) 1()1() 3()3() 2()2() (0,1) _ _ ( ,  ) sin(2  1  3 ) from B 0  D (*)    PRD 73, (2006).  2 from B   PRL 96, (2006) cos2  1 from B 0  D(      K S )h  PRL 97, (2006).

7 Integrated Luminosity KEKB for Belle /fb as of Oct. 4, /fb as of Oct. 4, 2006 year Integrated luminosity (/fb) Data set for ICHEP M BB on Upsilon(4S) Data set for ICHEP M BB on Upsilon(4S)

8  1 with trees - Results -

9 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 00 _ hep-ex/

10 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 background subtracted hep-ex/

11 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 hep-ex/

12 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 _ _ hep-ex/

: BaBar + Belle

14  1 with penguins

15 b  s tCPV: One of the best probes New CP-violating phase can enter New CP-violating phase can enter SUSY as an example O(1) effect allowed even if SUSY scale is above 2TeV.

16 3 theoretically-clean modes  Ks,  ’Ks, 3Ks

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

18 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 ! hep-ex/

19 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 hep-ex/

20 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 hep-ex/

21 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 hep-ex/

22 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 hep-ex/

:  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

24 Standard penguin (bird), or something else (rabbit may be) ? More statistics crucial for mode-by-mode studies A comment ( ) from Jonathan L. Rosner: If one can see a rabbit in the Moon, why not in a penguin diagram?

25 b  s Penguin : Radiative Signals: well established (BF~SM) Preliminary _ 232M BB B  K S    tCPV New approach for NP Yield = 176+/ M BB M( K s  0 ) < 1.8 GeV (  C) hep-ex/

26  2  1 “beam”  2 “banana”

27 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: 

28 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 _ 535M BB 1464±65 signal events hep-ex/

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

30 The results support the expectation from SU(3) symmetry that 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 (Belle 2006: 4.7  )

31  :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

32 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]

33  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 

34 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 _ 449M BB hep-ex/

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

36  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 –subtleties in statistical analyses with small statistics –uncertainty in background modeling, unknown phases etc.  /  2 : Discussions

37 CKM Global Fit Very good overall agreement. O(1) new physics unlikely. Need to be able to detect O(0.1) effects. Roughly speaking; O(0.1) ~(M top /M NP ) 2 or ~(M top /M NP ), therefore a reasonable target if TeV new physics exists. Roughly speaking; O(0.1) ~(M top /M NP ) 2 or ~(M top /M NP ), therefore a reasonable target if TeV new physics exists.

38 What have we learned ? Large CP violation observed  large CPV phase establishedLarge CP violation observed  large CPV phase established –approximate CP symmetry, which can be consistent with small CPV (e.g. seen in Kaons), is ruled out. Only with B factories, we have succeeded to overconstrain the quark flavor sector for the first time in the history.Only with B factories, we have succeeded to overconstrain the quark flavor sector for the first time in the history. The Kobayashi-Maskawa model of CP violation is now a tested theory.The Kobayashi-Maskawa model of CP violation is now a tested theory. This is a great historic achievement !

39 What’s next ? Deeper, more fundamental questions !

40 General Effective Lagrangian and Flavor Symmetries for Quark Flavor Physics

41 General Effective Lagrangian and Flavor Symmetries for Quark Flavor Physics Big question 2) Is there flavor symmetry yet to be discovered ? Big question 2) Is there flavor symmetry yet to be discovered ? Big question 1) What does the flavor structure of TeV new physics look like ? (How does it taste ?) Subquestions 1-1) Are there new CP-violating phases ? 1-2) Are there new right-handed currents ? 1-3) Are there effects from new Higgs fields ? 1-4) Are there new flavor violation ? Big question 1) What does the flavor structure of TeV new physics look like ? (How does it taste ?) Subquestions 1-1) Are there new CP-violating phases ? 1-2) Are there new right-handed currents ? 1-3) Are there effects from new Higgs fields ? 1-4) Are there new flavor violation ? TeV New physics for EWSB, DM etc.

42 Big question 2) Is there flavor symmetry yet to be discovered ? Big question 2) Is there flavor symmetry yet to be discovered ? Big question 1) What does the flavor structure of TeV new physics look like ? (How does it taste ?) Subquestions 1-1) Are there new CP-violating phases ? 1-2) Are there new right-handed currents ? 1-3) Are there effects from new Higgs fields ? 1-4) Are there new flavor violation ? Big question 1) What does the flavor structure of TeV new physics look like ? (How does it taste ?) Subquestions 1-1) Are there new CP-violating phases ? 1-2) Are there new right-handed currents ? 1-3) Are there effects from new Higgs fields ? 1-4) Are there new flavor violation ?

43 1-1) tCPV in B 0   K 0,  ’K 0, KsKsKs 1-2) (t)CPV in b  s  1-3) B  , , , ee, D  1-4)    1-1) tCPV in B 0   K 0,  ’K 0, KsKsKs 1-2) (t)CPV in b  s  1-3) B  , , , ee, D  1-4)    Big question 2) Is there flavor symmetry yet to be discovered ? Big question 2) Is there flavor symmetry yet to be discovered ? Unitarity triangle with 1% precision Big question 1) What does the flavor structure of TeV new physics look like ? (How does it taste ?) Subquestions 1-1) Are there new CP-violating phases ? 1-2) Are there new right-handed currents ? 1-3) Are there effects from new Higgs fields ? 1-4) Are there new flavor violation ? Big question 1) What does the flavor structure of TeV new physics look like ? (How does it taste ?) Subquestions 1-1) Are there new CP-violating phases ? 1-2) Are there new right-handed currents ? 1-3) Are there effects from new Higgs fields ? 1-4) Are there new flavor violation ?

44 Near Future (till ~2008) Room for some surprise if new physics energy scale is still close to the present limit !Room for some surprise if new physics energy scale is still close to the present limit ! –e.g. 4  deviation from SM in b  s tCPV –At least 1 ab -1 from each B factory experiment is a MUST. In the LHC era (i.e. 2010’s), however, obviously needed is a major upgrade for much higher statistics !In the LHC era (i.e. 2010’s), however, obviously needed is a major upgrade for much higher statistics ! At least one Super B factory needed !

45 Conclusion Time-dependent CP violation measurements were, are, and will be,Time-dependent CP violation measurements were, are, and will be, exciting !

47 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.

48  = (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/ 

49  = (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 _

50 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 !

51 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)

52 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

53 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

54  2 constraints from B 0 →  +  − decay New     branching fraction Isospin triangle now closed (new     )  constraint on  2 becomes less stringent.

55 CKM Matrix: Enigmatic Hierarchy This is correct, but is very strange ! =

56 Flavor symmetry ? Ex: Q6 (with SUSY) –9 independent parameters to describe 10 observables (6 quark masses + 4 CKM parameters) Ex: Q6 (with SUSY) –9 independent parameters to describe 10 observables (6 quark masses + 4 CKM parameters) Babu-Kubo 2004 Testable (falsifiable) if sufficient precision obtained ! Precise  3 measurements may play an essential role to be free from theory uncertainties Testable (falsifiable) if sufficient precision obtained ! Precise  3 measurements may play an essential role to be free from theory uncertainties Many proposals, not conclusive at the moment. (Observed pattern consistent with many models) 1% “spot”