1. Chunhui Chen, University of Maryland PASCOS 2006 1 CP Violation in B Physics Chunhui Chen University of Maryland The 12 th International Symposium on Particles, Strings and Cosmology September 12 th, 2006 Columbus, Ohio

2. Chunhui Chen, University of Maryland PASCOS 2006 2 Most recent Results from BaBar and Belle for Stringent Tests of the SM & Search for New Physics using CP Violation in B Physics

3. Chunhui Chen, University of Maryland PASCOS 2006 3 PEP-II for BaBar 391 fb -1 As of Aug. 18 th, 2006 KEKB for Belle 630 fb -1 KEKB + PEP-II Performances of Two B Factories Far beyond the design luminosities for both experiments  1 Billion BB pairs !!

4. Chunhui Chen, University of Maryland PASCOS 2006 4 Why Study CP Asymmetry 0ne of conditions to generate matter dominated Universe: Sakharov conditions (1967): Violation of charge conjugation C & parity P asymmetries Baryon number violation, e.g., proton decay Deviation from thermal equilibrium CP violation allowed in Standard Model (SM): Common origin as the quark mass and their mixing Spontaneous electroweak symmetry breaking due to Higgs coupling Probing the EW scale as well, complementary to other studies at energy frontier, e.g.: high P T Physics at Tevatron & LHC Excellent probe for new Physics beyond SM Constraint on the possible new Physics beyond SM

5. Chunhui Chen, University of Maryland PASCOS 2006 5 CKM Matrix & Unitarity Triangle  3x3 complex unitary matrix  4 free parameters 3 angles 1 phase, change sign under CP  complex phase: Origin of CP violation in SM weak eigenstates ≠ mass eigenstates, related by CKM matrix

6. Chunhui Chen, University of Maryland PASCOS 2006 6 Methods to search for New Physics  Direct search for Physics beyond SM: CP violation in mixing, CPT violation in B decay …  Compare sin2  in tree and penguin modes: B 0  J/  K s v.s. B 0  K s  (b  ul ) Radiative penguin decays B 0 d and B 0 s mixing  2 )  1 )  3 ) CP asymmetries in: b->ccs modes. E.g.: B 0  J/  K s, etc. CP asymmetries in: B  , , . CP asymmetries in: B  DK, D , etc.  Overconstarint of the unitarity triangle: Indirect constraint: V ub,  m d,  m s … (not in this talk) Direct Measurement of CKM angles using CP violation

7. Chunhui Chen, University of Maryland PASCOS 2006 7  CPV through interference of decay amplitudes  (B  f) Direct CP Violation in B System Difficult to extract CKM information due to strong phase BaBar: hep-ex/0608003 E.g.: B  K +  - /K -  + A CP =-0.108  0.024  0.007 A CP =-0.093  0.018  0.008 BaBar: ICHEP06

8. Chunhui Chen, University of Maryland PASCOS 2006 8  CPV through interference between mixing and decay amplitudes Time-dependent CP asymmetry Mixing Induced CP Violation For simple case shown with single decay mechanism: S fcp =Im fcp and C fcp =0 S fcp directly related to CKM angles Theoretically clean way to extract CKM angles = ¡ A CP

9. Chunhui Chen, University of Maryland PASCOS 2006 9 Current Measurement of  (  1 ) More detail: talk in parallel session: A. Kreisel Reference: hep-ex/0607107,hep-ex/0608039 hep-ex/0608016, hep-ex/0607105 hep-ex/0605023

10. Chunhui Chen, University of Maryland PASCOS 2006 10 Interference of b  c tree decay with mixing CP Violation in Charmonium Modes Decay dominated by Single Tree diagram: C=0 and S=sin2  Theoretically clean way to measure sin2 

11. Chunhui Chen, University of Maryland PASCOS 2006 11 Measure sin2  B 0  (cc)K (*)0 Modes B 0  J/  K 0,  (2S)K S,  c K S,  c1 K S, J/  K *0 (    S   ) sin2  =0.710  0.034  0.019 C=0.070  0.028  0.018 sin2  =0.642  0.031  0.017 C=-0.018  0.021  0.014 B 0  J/  K 0 only CP-odd CP-even CP-odd

12. Chunhui Chen, University of Maryland PASCOS 2006 12 Combined Results hep-ex/0608039 hep-ex/0607107  sin2  : Consistent between Babar & Belle Precision measurement, error ~ 4%  C: Slight difference between BaBar and Belle More data needed to understand difference

13. Chunhui Chen, University of Maryland PASCOS 2006 13 B 0  D* + D*  Ks Time-dependent Dalitz analysis (T.Browder, A. Datta et al. 2000)  cos2  > 0 BaBar 94%CL (hep-ex/0608016,model-dependent) B 0  D (*)0 h0 (D 0  K S  & h0 =  0 etc.) Time-dependent Dalitz analysis  cos2  > 0 Belle: 98.3%CL (hep-ex/0605023, accepted by PRL) BaBar 87% CL (hep-ex/0607105) From sin2  to  : cos2  Measurement Sign of cos2  Solve  and  /2-  ambiguity

14. Chunhui Chen, University of Maryland PASCOS 2006 14 Current Measurement of  (  2 ) More detail: talk in parallel session: C. Chavez Reference: hep-ex/0607092,hep-ex/0607098 hep-ex/0607106,hep-ex/0608002 hep-ex/0608035,hep-ex/0609003

15. Chunhui Chen, University of Maryland PASCOS 2006 15 If Interference of suppressed b  u tree decay with mixing only: C=0 and S=sin2  3 rd component: sizable Penguin diagram CP Violation in Charmless Modes C  0 S  sin2  “Penguin pollution” can be removed by isospin analysis  Clean measurement of  [Gronau-London 1990]

16. Chunhui Chen, University of Maryland PASCOS 2006 16 2.3  diff. btw. Belle and BaBar More data needed to solve the difference between BaBar a& Belle CP Violation B 0  +  - hep-ex/0607106 hep-ex/0608035 Mixing inducted CP violation observed: BaBar (3.6  ), Belle (5.6  ) Direct CP violation: BaBar (No Evidence), Belle (5.5  )

17. Chunhui Chen, University of Maryland PASCOS 2006 17 inputs B (  +  0 ) = (5.75  0.42) B (  +  - ) = (5.20  0.25)  10 -6 B (  0  0 ) = (1.30  0.21) C (  0  0 ) =  0.35  0.33 S (  +  - ) =  0.59  0.09 C (  +  - ) =  0.39  0.07 inputs B (  +  0 ) = (5.75  0.42) B (  +  - ) = (5.20  0.25)  10 -6 B (  0  0 ) = (1.30  0.21) C (  0  0 ) =  0.35  0.33 S (  +  - ) =  0.59  0.09 C (  +  - ) =  0.39  0.07 No stringent constraint obtained with  system alone Extract  with B 

18. Chunhui Chen, University of Maryland PASCOS 2006 18 Similar Isospin analysis approach to extract  with B  Branching fraction of B0  0  0 /B 0  +  - is smaller than B  Small penguin pollution Extract  with B  New  0  0 branching fraction Isospin triangle now closed (new  0  + )  constraint on  becomes less stringent.  need to solve multiple solution 2005 Now B (  +  - ) = (23.5  2.2  4.1)  10 -6 B (  0  0 ) = (1.16  0.37  0.27)  10 -6 B (  +  - ) = (23.5  2.2  4.1)  10 -6 B (  0  0 ) = (1.16  0.37  0.27)  10 -6

19. Chunhui Chen, University of Maryland PASCOS 2006 19 Extract  with B  B0B0 B0B0   Interference  info. on strong phase difference (no constraint at 2  ) Dalitz + Isospin (Pentagon) analysis

20. Chunhui Chen, University of Maryland PASCOS 2006 20 consistent with a global fit without  Combined: BaBar(  /  /  )+Belle(  /  )

21. Chunhui Chen, University of Maryland PASCOS 2006 21 Current Measurement of  (  3 ) More detail: talk in parallel session: V. Azzolini Reference: hep-ex/0607065,hep-ex/0607104 etc

22. Chunhui Chen, University of Maryland PASCOS 2006 22 Interference of color-allowed and color-suppressed tree decays Effect depends on ratio of two diagrams Measurement of  (  3 )

23. Chunhui Chen, University of Maryland PASCOS 2006 23 Combined Results of  (  3 ) Not including the most recent BaBar & Belle ICHEP06 results: See Virginia’s talk in this conference for detail

24. Chunhui Chen, University of Maryland PASCOS 2006 24 Now: looking for New Physics as correction to CKM Overconstrained: growing set of independent measurements are consistent with CKM picture UT from CKM angle and indirect Constraints Preliminary: Including the most recent BaBar & Belle ICHEP06 results:

25. Chunhui Chen, University of Maryland PASCOS 2006 25 New B Factory milestone: Comparable UT precision from CPV in B decays alone Overconstrained: subsets of measurements can be used to test for new physics UT from CKM Angle Measurement alone Preliminary: Including the most recent BaBar & Belle ICHEP06 results:

26. Chunhui Chen, University of Maryland PASCOS 2006 26 Interference of color suppressed b  s Penguin decay with mixing Another implication of overconstrained: redundant approaches to same CKM parameter CP Violation in Penguin Modes Dominated by Single penguin diagram: C=0 and S=sin2  but ……

27. Chunhui Chen, University of Maryland PASCOS 2006 27 Possible New Physics Effect 3 theoretically-clean modes  Ks,  ’Ks, 3Ks “Internal Penguin” E.g.: SUSY contribution with new phases New physics in loops?

28. Chunhui Chen, University of Maryland PASCOS 2006 28 Theory tends to predict positive shifts (originating from phase in V ts ) Naïve average of all b  s modes sin2  eff = 0.52 ± 0.05 2.6  deviation between b  s penguin and b  c tree mode Naïve average of all b  s modes sin2  eff = 0.52 ± 0.05 2.6  deviation between b  s penguin and b  c tree mode More statistics crucial for mode-by-mode studies Combined Results Observation of CP violation in B 0  ’ K 0 S=+0.55  0.11  0.02 (BaBar, 4.9  ) S=+0.64  0.10  0.04 (Belle, 5.6  ) Measured sin2  eff in all b  s modes are smaller than the measured sin2  in b  c tree mode

29. Chunhui Chen, University of Maryland PASCOS 2006 29 CP Violation in Mixing W-W- W-W- B 0 mass eigenstate: If mass eigenstate  CP eigenstate (|q/p|  1): CP Violation Expected deviation in SM ~ 10 -3 Most recent results: |q/p|-1 = (-0.8  2.7(stat.)  1.9(syst.))  10 -3, BaBar PRL96 (2006) 251802 |q/p|-1 = (+6.5  3.4(stat.)  2.0(syst.))  10 -3, Babar hep-ex/0607091 |q/p|-1 = (+0.5  4.0(stat.)  3.5(syst.))  10 -3, Belle Phys.Rev. D73 (2006) 112002

30. Chunhui Chen, University of Maryland PASCOS 2006 30 Summary and Outlook UT constraint from direct measurement of CKM angles sin2  determined at 4% level in Charmonium modes cos2  determined to be positive with > 98% confidence  /  /  Precise  measurement feasible by combining  /  /  Precision ~ 10  at present, need more statistics Methods to extract  well established in experiment Current UT constraint agree with SM Sin2  eff in penguin mode ~ 2  deviated from SM expectation interesting hint? Need more statistics No evidence of CP violation in B mixing Consistent with SM expectation More data expected in next 2 years! The best of two B factories is yet to come ! More data expected in next 2 years! The best of two B factories is yet to come !

31. Chunhui Chen, University of Maryland PASCOS 2006 31 Additional Slides for Reference

32. Chunhui Chen, University of Maryland PASCOS 2006 32 V is unitarity  geometric representation: triangle in complex plane Im Re V i1 V * k1 V i2 V * k2 V i3 V * k3 There are 6 triangles Kaon UT Beauty UT flat n.b. these triangles are rescaled by one of the sides The Unitarity Triangle

33. Chunhui Chen, University of Maryland PASCOS 2006 33 Located at the Stanford Linear Accelerator Center PEPII B Factory at SLAC L = 1.21 x 10 34 /cm 2 /sec

34. Chunhui Chen, University of Maryland PASCOS 2006 34 DIRC ( PID) 144 quartz bars 11000 PMs 1.5T solenoid EMC 6580 CsI(Tl) crystals Drift Chamber 40 layers Instrumented Flux Return Iron / Resistive Plate Chambers or Limited Streamer Tubes (muon / neutral hadrons) Silicon Vertex Tracker 5 layers, double sided strips e + (3.1GeV) e - (9GeV) Collaboration founded in 1993 Detector commissioned in 1999 BaBar Detector

35. Chunhui Chen, University of Maryland PASCOS 2006 35 e + source Ares RF cavity Belle detector L = 1.65 x 10 34 /cm 2 /sec SCC RF(HER) ARES(LER) 8 x 3.5 GeV 22 mrad crossing angle ~1 km in diameter Mt. Tsukuba KEKB Belle since 1999 The KEKB Collider

36. Chunhui Chen, University of Maryland PASCOS 2006 36 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 - Belle Detector

37. Chunhui Chen, University of Maryland PASCOS 2006 37 For exclusive B reconstruction, two nearly uncorrelated * kinematic variables are used: B candidate (energy, 3-momentum) and beam energy in  (4S) frame Signal at  E ~ 0  (  E)  10-40 MeV Signal at m ES ~ m B  (m ES )  2.6 MeV “Energy- substituted mass” Reconstruction of B Decays E.g.: B 0  J/  K S

38. Chunhui Chen, University of Maryland PASCOS 2006 38 Background Rejection Ratio of second-to-zero th order Fox-Wolfram moments (R 2 ): Angle of thrust axis of “rest of the event” wrt B candidate direction (  T ) E.g.: B decays Continuum

39. Chunhui Chen, University of Maryland PASCOS 2006 39 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 ~ 260  m (BaBar) B0B0 B0B0 _ Principle of tCPV Measurement  = 0.56 (BaBar) 0.425 (Belle) produces coherent B pair