Time-dependent CP Violation (tCPV) at Belle -- New results at ICHEP2006 --

1. Time-dependent CP Violation (tCPV) at Belle-- New results at ICHEP2006 -- Masashi Hazumi (KEK) October. 10, 2006

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

3. tCPV in B0 decays e.g. for J/ Ks S = -CPsin2f1 = +sin2f1 A = 0 to a good approximation (CP : CP eigenvalue) Mixing-induced CPV Direct CPV (A = -C a la BaBar)

4. 3 Right-handed current search B0g KSp0g 2 b g s Penguins f2(a) B gpp 4 B grp f3(g) f1(b) 1 Tree B0g J/K0 New results shown at ICHEP2006 hep-ex/0608017 hep-ex/0608039 B0gfK0 hep-ex/0609006 B0gh’K0 B0gKSKSKS _ _ (r, h) B0g f0KS hep-ex/0608035 B0g K+K-KS vs. B0gp0KS B0gwKS hep-ex/0609003 (0,0) (0,1) hep-ex/0608039

5. _ _ (r, h) f2(a) f3(g) f1(b) (0,0) (0,1) Still new results but not covered in this talk

6. cos2f1 from B0g D(gp+p-KS)h0 PRL 97, 081801 (2006). f2 from B grr PRL 96, 171801 (2006) _ _ (r, h) f2(a) f3(g) f1(b) sin(2f1+f3) from B0g D(*)-p+ PRD 73, 092003 (2006). (0,0) (0,1) Still new results but not covered in this talk

7. Data set for ICHEP2006 535M BB on Upsilon(4S) Integrated Luminosity KEKB for Belle 640.578 /fb  as of Oct. 4, 2006  Integrated luminosity (/fb) year

8. b/f1 with trees- Results -

9. _ B0 J/y K0 : 535 M BB pairs B0 J/y KS 0 B0 J/y KL 0 Nsig = 7482 Purity 97 % CP odd Nsig = 6512 Purity 59 % CP even pKL information is poor  lower purity hep-ex/0608039

10. _ B0 tag B0 tag _ B0 tag background subtracted B0 J/y KS 0 B0 J/y KL 0 B0 tag Asym. = -xCPsin2f1sinDmDt hep-ex/0608039 sin2f1= +0.643 ±0.038 A = - 0.001 ±0.028 sin2f1= +0.641 ±0.057 A = +0.045 ±0.033 stat error stat error

11. _ B0 tag B0 tag B0 tag _ _ B0 tag B0 tag B0 J/y K0 : combined result B0 J/y KS 0 B0 J/y KL 0 B0 tag Asym. = -xCPsin2f1sinDmDt hep-ex/0608039 sin2f1= +0.643 ±0.038 A = - 0.001 ±0.028 sin2f1= +0.641 ±0.057 A = +0.045 ±0.033 stat error stat error

12. _ 535 M BB pairs B0 tag New ! _ B0 tag B0 J/y K0 : combined result previous measurement sin2f1= 0.652  0.044 (388 M BB pairs) _ sin2f1= 0.642 ±0.031 (stat) ±0.017 (syst) A = 0.018 ±0.021 (stat) ±0.014 (syst) hep-ex/0608039

13. 2006: BaBar + Belle

14. b/f1 with penguins

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

16. 3 theoretically-clean modes fKs, h’Ks, 3Ks

17. Results for 3 theoretically-clean modes fK0, h'K0, KsKsKs

18. _ 535M BB Belle 2006: B0gfK0 signal Three modes 11417 fKLsignal fgK+K-, KSgp+p- fgK+K-, KSgp0p0 fgKSKL, KSgp+p- 30721 fKS signal B0 momentum New ! (bkg subtracted) B0 mass hep-ex/0608039

19. _ 535M BB New ! Belle 2006: tCPV in B0gfK0 “sin2f1” = +0.50  0.21(stat)  0.06(syst) A = +0.07  0.15(stat)  0.05(syst) Dt distribution and asymmetry • Consistent with the SM (~1s lower) • Consistent with Belle 2005 (Belle2005: “sin2f1” = +0.440.270.05) • The most precise measurement now • fKS and fKL combined • background subtracted • good tags • Dt g –Dt for fKL unbinned fit SM hep-ex/0608039

20. _ 535M BB Belle 2006: B0gh'K0 signal 142146 h'KS signal 45439 h'KL signal B0 momentum B0 mass (bkg subtracted) hep-ex/0608039

21. _ 535M BB New ! Belle 2006: tCPV in B0gh'K0 “sin2f1” = +0.64  0.10(stat)  0.04(syst) A = -0.01  0.07(stat)  0.05(syst) Dt distribution and asymmetry • First observation of tCPV • (5.6s) in a single bgs mode • Consistent with the SM • Consistent with Belle 2005 (Belle 2005: “sin2f1” = +0.620.120.04) • h'KS and h'KL combined • background subtracted • good tags • Dt g –Dt for h'KL hep-ex/0608039

22. _ 535M BB New ! Belle 2006: tCPV in B0gKSKSKS “sin2f1” = +0.30  0.32(stat)  0.08(syst) A = +0.31  0.20(stat)  0.07(syst) Dt distribution and asymmetry B0 mass 18517 KSKSKS signal • background subtracted • good tags hep-ex/0608039

23. Smaller than bgccs in all of 9 modes Theory tends to predict positive shifts (originating from phase in Vts) 2006: f1 with bgs Penguins Preliminary Naïve average of all b g s modes sin2beff = 0.52 ± 0.05 2.6 s deviation between penguin and tree (b g s) (b g c) More statistics crucial for mode-by-mode studies

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

25. 535M BB _ 232M BB New ! b s Penguin : Radiative New approach for NP Signals: well established (BF~SM) B KSp0g tCPV M(Ks p 0) < 1.8 GeV Yield = 176+/- 18 Preliminary (-C) hep-ex/0608017

26. f1 “beam” f2 “banana” a/f2

27. – – – – – – t Vud u b d u b With the tree diagram only d p/r V*ub – Sp+p- = +sin2f2 Ap+p- = 0 B0 B0 t b d p/r B0 d d Mixing diagram Decay diagram (tree) tCPV and f2 (a) f2 VtdV*tb VudV*ub f3 f1 VcdV*cb V*tb Vtd Vtd V*tb 3 possibilities: pp, rr, rp

28. _ 535M BB New ! Belle 2006: B0→p+p− decay (CP asymmetry) hep-ex/0608035 1464±65 signal events p+p− yields first error: stat., second: syst. Large Direct CP violation (5.5s) Large mixing-induced CP violation (5.6s) Preliminary p+p− asymmetry confidence level contour background subtracted

29. History of B0→p+p− decay (C = -A) 2.3s diff. btw. Belle and BaBar

30. Interpretation: Direct CP violation+SU(3) The results support the expectation from SU(3) symmetry that N.G. Deshpande and X.-G. He, PRL 75, 1703 (1995) M. Gronau and J.L. Rosner, PLB 595, 339 (2004) (Belle 2006: 4.7s) ICHEP2006 World Average

31. W V*tb t d g p+ u u 0 d B p- d d b Vtd pp :tough bananas • App world average  observation of large direct CPV • Large penguin diagram (P) ~ Tree diagram (T) • Large strong phase difference between P and T

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

33. inputs B(p+p0) = (5.75 0.42) B(p+p-) = (5.20 0.25)  10-6 B(p0p0) = (1.30 0.21) A(p0p0) = +0.35 0.33 S(p+p-) = -0.59  0.09 A(p+p-) = +0.39  0.07 f2 constraints from B0→p+p− decay No stringent constraint obtained with pp system alone  need rr and rp

34. _ 449M BB New ! a/f2 = [83 ] +12 -23 Belle 2006: f2 from B grpDalitz analysis + isospin (pentagon) analysis • 26(Dalitz) + 5(Br(rp), Br(r+p0), Br(r0p+), A(r+p0), and A(r0p+)) r+p- r-p+ r0p0 Preliminary Results mass helicity 1-CL (1s) (no constraint at 2s) f2 (degree) will be included in the world average hep-ex/0609003

35. +5 -19 aGlobal Fit = [ 98 ] º a/f2 = [93 ] +11 - 9 ICHEP2006: BaBar(pp/rp/rr) + Belle(pp/rr) consistent with a global fit w/o a/f2

36. a/f2: Discussions • rr sets a “window” around 90 • pp chooses the correct position inside the window: revival of pp ! • rp essential to suppress f2~ 0 or 180 • Good agreement b/w the CKM fit (a 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.

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) ~(Mtop/MNP)2 or ~(Mtop/MNP), therefore a reasonable target if TeV new physics exists.

38. What have we learned ? • Large 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. • 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 TeV New physics for EWSB, DM etc. 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 ?

42. 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 ?

43. 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 ? 1-1) tCPV in B0gfK0, h’K0, KsKsKs 1-2) (t)CPV in b g sg 1-3) B gtn, mn, mm, ee, Dtn 1-4) tgmg Big question 2) Is there flavor symmetry yet to be discovered ? Unitarity triangle with 1% precision

44. Near Future (till ~2008) • Room for some surprise if new physics energy scale is still close to the present limit ! • e.g. 4s 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 ! At least one Super B factory needed !

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

46. Backup Slides

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

48. Principle of tCPV measurement CP-side m+ J/y m- (4S) resonance B1 electron KS/L positron B2 bg = 0.425 (Belle) 0.56 (BaBar) • Fully reconstruct one B-meson which decays to CP eigenstate

49. _ B0 Principle of tCPV measurement CP-side m+ J/y m- (4S) resonance B1 electron KS/L B0 positron nm B2 p- bg = 0.425 (Belle) 0.56 (BaBar) K+ p- Flavor tag and vertex reconstruction Dz ~ 200mm (Belle) m+ • Fully reconstruct one B-meson which decays to CP eigenstate • Tag-side determines its flavor (effective efficiency = 30%) • Proper time (Dt) is measured from decay-vertex difference (Dz)

50. Motivation sin2b history (1998-2005) Q. What is the main source of CP violation ? A. Kobayashi-Maskawa phase IS the dominant source ! Paradigm shift ! Q. Are there deviations from the CKM picture ? (e.g. new CP-violating phases) • Two promising approaches • Overconstrain the unitarity triangle: precise measurements of • a and b needed • 2) Compare sin2b in tree diagram and penguin diagram (e.g. b g s)