Measurements of  1 /  Flavor Physics and CP Violation 2010, May 25, 2010, Torino, Italy, K. Sumisawa (KEK)

V* td __ t d t b b d _ w w B0B0 B0B0 _ V* td =| V td |e i1i1 pqpq ~e +i2  1 mixing induced CP violation Time-dependent CP Violation in B 0 decays KM ansatz: CPV is due to a complex phase in the quark mixing matrix B0B0 B0B0 f CP B0B0 B0B0 A A  = A A  qpqp ~e -i2  1 B-B mixing _ Unitarity Triangle  1  2  3

Time-dependent CP Violation in B 0 decays Mixing-induced CPV Direct CPV e.g. for B 0  J/  Ks S = -  CP sin2  1 = +sin2  1 A ~ 0 (  CP : CP eigenvalue  1) e.g. for B 0  J/  Ks S = -  CP sin2  1 = +sin2  1 A ~ 0 (  CP : CP eigenvalue  1) B0B0 A f CP B0B0 A tt Decay time difference between B meson pairs We can measure CPV (asym.) as a function of proper time diff (  t). (A= -C)

Principle of Measurement in B-factories Reconstruct B  f CP ( b  c ) decays Measure proper-time difference:  t Determine flavor of B tag Evaluate CP asymmetry from  t and flavor of B tag ee ee B CP zz B tag  (4 S )  ~ 0.43(Belle) ~0.56(BABAR) f CP ( b  c )  z  c  B ~ 200  m(Belle) ~ 250  m(BABAR) Flavor tag ( ) z c t     ≈

8  3.5GeV 2.1×10 34 cm -2 s -1 2 B-factories PEP-II 9GeV(e - ),3.1GeV(e + ) 1.2  cm -1 s -1 BABAR Detector 4 lyr.

Success of the B-factories Stopped in April 2008

sin2  1 with charmonium K 0 modes N sig =7482 Purity=97% N sig =6512 Purity=59% N sig =8733 Purity=93% N sig =5813 Purity=56% E B - E CM /2 535MBB 465MBB _ _

sin2  1 with charmonium K 0 modes sin2  1 =0.642±0.031±0.017 A f =0.018±0.021±0.014 PRL98,031802(2007) sin2  1 =0.687±0.028±0.012 A f =-0.024±0.020±0.016 PRD79,072009(2009) (cc)K S J/  K L

error in  1 < 1  but ambiguities exist. sin2  1   1 agreement between two experiments

B 0  D[K S  +  - ]h 0 (h 0 =  0, ,  ) _ Time dependent Dalitz analysis gives sin2  1 and cos2  1 cos2  1 >0 at 86% C.L cos2  1 >0 at 98.3% C.L. smaller  1 (<45  ) solution is favored. consistent with b  ccs sin2  1 describe Dalitz variables. _

constraint for  1 /  other measurement using J/  K* 0 (K* 0  Ks  0 ) D* + D* - Ks can also contribute.

b  ccd J/  0 : constrain penguin contribution in Golden mode(J/  K 0 ) without model dependence. D ( * )+ D ( * )- : penguin contribution is expected to be small. tree + (penguin)

b  ccd J/  0 : constrain penguin contribution in Golden mode(J/  K 0 ) without model dependence. D ( * )+ D ( * )- : penguin contribution is expected to be small. Belle A=-C=0.91  0.23  0.06 (3.2  significance A≠0)

14 b  sqq TCPV _ d b _ c c s d _ w B0B0 J/  K0K0 d b _ _ s s s d _ gt B0B0 K0K0 ,  ’... w Extra CPV phase from New Physics Time-Dependent CP asymmetry in B 0 decays S =sin2  1 A ~ 0 S =sin2  1 eff A ~ 0 Many two-body and quasi-two body analyses have been done. Since  → K + K -, f 0 → K + K - and non-resonant contributions overlap invariant mass(as do  0 →  +  - and f 0 →  +  - ), recently time-dependent Dalitz analyses have been performed in three-body decays such as B 0 → (K + K - )K S and B 0 → (  +  - )K S.

Interferences in B decays with K ＋ K - Ks final state B0B0   K S CP= -1 A1A1 K+K-KSK+K-KS f 0 (980)K S CP= 1 A2A2 ANAN Non-resonant CP=+0.86±0.20  K S f 0 (980)K S Non-resonant Dalitz-plot ⇒ distinguish the intermediate states considering interferences Opposite CP eigenvalue from  Ks ⇒ State-by-state CP measurement Dalitz-plot

Time-dependence of Dalitz plot in B 0 →K ＋ K - Ks B0B0  K S A A K+K-KSK+K-KS f 0 (980)K S B0B0 CP asymmetry (  1,eff, A CP ) of B   K S using Time-dependent Dalitz plot analysis in B  K + K - Ks B0B0 A K+K-KSK+K-KS B0B0 A c.f. Time-dependence Interference in B 0 B 0 (  1,eff )+ intermediate states (Dalitz phase) Time-dependenceDalitz-plot

updated Belle result (B 0  K + K - Ks ) Decay amplitude resonanceForm factorSpinCP eigenvalue f 0 (980)Flatté01  (1020) RBW1 f x (1500)RBW01  c0 RBW01 ( KsK - ) K ＋ exp(-  s - ) 01 ( KsK + ) K - exp(-  s + ) 01 ( K ＋ K - )Ks exp(-  s 0 ) 01 RBW: Relativistic Breit Wigner 19 free parameters 12: isobar model 6: CPV parameters. 1:  for NR Belle 657MBB to be submitted to PRD.

Multiple solution 4 preferable solutions External information from B 0 →  +  - Ks f 0 (980) B.F.(f 0 (980)→  +  - )/B.F.(f 0 (980)→K + K - ) and compare with PDG solutions with low f 0 (980)Ks fraction preferred f x (1500) If f x (1500)=f 0 (1500) for both decays B.F.(f 0 (1500)→  +  - )/B.F.(f 0 (1500)→ K + K - ) and compare with PDG solutions with low f x (1500)Ks fraction preferred Decay mode fractions Solution 1 preferred.

fit result (Dalitz plot)  (1020)  c0 f x (1500) D veto J/  veto background Solution 1

fit result (  t plot) proper time distribution and raw asymmetry plot in  mass region Belle 657MBB to be submitted to PRD. background Solution 1 the third error: Dalitz plot model uncertainty SM expectation

(7.7  7.7  0.9)  (8.5  7.5  1.8)  BABAR K + K - Ks result whole regionlow mass region BABAR 465MBB arXiv:

average in B   Ks, B  f 0 (980) Ks Consistent with the Standard Model prediction at current sensitivity  1(b  ccs) = (21.0 ± 0.9)° (7.7  7.7  0.9)  (8.5  7.5  1.8) 

result using  +  - Ks Belle 657MBB PRD79(2009) BABAR 383MBB PRD80(2009)

Compilation of effective sin2  1 Still precision is statistically dominated. ↓ To obtain sensitivity in effective sin2  1 of O(10 -2 ), we need O(10ab -1 ) of integrated luminosity.

Summary  1 /  = (21.1  0.9)  in B-factories sin2  1 from b  ccs modes. resolve the quadratic ambiguity by measuring cos2  1 with Dalitz analysis, etc. penguin modes are good probes of new physics. We need more data. Belle is now updating its result with the full data sample. J/  K 0 full data: 535M  771MBB (factor 1.44) improved tracking software: 20% gain for J/  Ks yield : factor 1.61  (2S)Ks,  c1 Ks,  c Ks, and combined analysis last update with150MBB (657MBB for  (2S)Ks) (statistical error for sin2  1 )~0.02 etc.. _ __

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27 background Combined result:

Resonances considered in the KsKK signal model 28/38

29/38 Signal PDF = 1. Dalitz amplitude and phases 2. CP-violating amplitude and phases (  Ks, f 0 Ks, others) 3. Kinematics (Dalitz plot)  for NR Decay amplitude Time-dependence Dalitz-plot × B0:B0: B0:B0: q 2 q ⇒ 19 fit parameters

30/38 Event selection B 0 →KsK + K - reconstruction Ks selection K ± selection by PID (K/  ) Continuum suppression Efficiency: ~16% Unbinned ML fit to  E and M bc distributions B 0 →KsK + K ±51evts. Purity~50% Background Continuum ~47% Other B decays ~3% Event-by-event signal probability f sig (  E, M bc ) for CP measurement Reconstructed B 0 →KsK + K - candidates Signal Continuum M bc EEEE Other B decays Time-dependent Dalitz plot fit to the selected B 0  KsK + K - candidates.

plots for K + K - Ks signal background  mass region A CP (  t) raw asymmetry plot in  mass region Belle 657MBB ICHEP2008 preliminary

BABAR K + K - Ks result whole regionlow mass region BABAR 465MBB arXiv: (7.7  7.7  0.9)  (8.5  7.5  1.8)  (8.?  8.?)  (197  11) 