CP Violation in B decays 1 Y.Sakai KEK Jan. 9, 2005  experimental review  KEKB/BellePEP-II/BaBar

CP Violation in B decays 2 CP Violation CPV: difference in behavior of particle and anti-particle Universe: almost “matter” only (no anti-matter) Big-Bang  N(particles) = N(anti-particles) Sakalov: 1. baryon number violation 2. CP violation 3. existence of non-equiblium 1964: CPV discovered in K 0 (J.Cronin et. al); O(10 -3 ) 1973: Kobayashi-Maskawa model 3- generation q uark -m ixing : c omplex phase  CPV 1980: Sanda et. al; large CPV in B-meson 1964: CPV discovered in K 0 (J.Cronin et. al); O(10 -3 ) 1973: Kobayashi-Maskawa model 3- generation q uark -m ixing : c omplex phase  CPV 1980: Sanda et. al; large CPV in B-meson

CP Violation in B decays 3 Kobayashi-Maskawa Scheme CPV : due to a complex phase in the quark mixing matrix CKM matrix Wolfenstein representation  1   2   3  V td V tb V cd V cb V ud V ub * * * Unitarity triangle djdj ukuk W-W- V kj

CP Violation in B decays 4 CPV in Decay: 3 types in Decay (Direct CPV) in Mixing (Indirect CPV) in Mixing-Decay Interference _ _ |A(P  f )|  | A(P  f )| _ _ R(P 0  P 0 )  R(P 0  P 0 ) |q/p|  1 WW d b t t b d B 0d0d B 0d0d V td V tb   ’’ Re(  ) Im(  ) K system

CP Violation in B decays 5 made by H. Miyake ( A =  C ) Mixing-induced CPVDirect CPV Mixing-Decay: Time-dependent CPV Sanda Bigi Carter B0B0 B0B0 ｆ ｃｐ B0B0 B0B0 A A  = mixing tt

CP Violation in B decays 6 CPV & UT angles ) fB()B( ) fB() fB( A CP 0 d 0 d 0 d 0 d    f = S sin(  m  t) + A cos (  m  t) 2Im   S =       A = qpqp =  f AAAA Mixing induced CPVDirect CPV  1   2   3  V td V tb V cd V cb V ud V ub * * * ( A =  C ) CPV measurements UT angles Determination of UT

CP Violation in B decays 7 Asymmetric B Factories PEP-II BaBar ~1 km in diameter Mt. Tsukuba KEKB Belle 8 GeV e - x 3.5 GeV e +  11mrad crossing 9 GeV e - x 3.1 GeV e + Head-on collision KEKB PEP-II

CP Violation in B decays 8 Peak Luminosity

CP Violation in B decays 9 Integrated Luminosity 232M BB KEKB/Belle PEP-II/BaBar 386M BB ~530 fb -1 Summer 2005 ~310 fb -1 [as of 26-Dec-2005]

CP Violation in B decays 10 Belle and BaBar Detectors Si Vertex detector Drift Chamber (small cell) CsI(Tl) EM calorimeter  /K L detector (RPC+Fe) SC solenoid (1.5T) TOF counter & Aerogel Cherenkov DIRC

CP Violation in B decays 11  1 Measurement _ d b _ c c s d _ w B0B0 J/  K0K0  CP : CP eigenvalue V* td __ t d t b b d _ w w B0B0 B0B0 _ = -  cp sin2  1 sin(  m  t) + A cos (  m  t) A CP Mixing induced CPVDirect CPV A  0  1   2   3  V td V tb V cd V cb V ud V ub * * * First observed CPV in B (2001)

CP Violation in B decays 12 Time-dep CPV Measurement Flavor-tag (B 0 or B 0 ?) J/  (  ’) KSKS ee ee zz t=0 f CP Vertexing Reconstruction Extract CPV fit same analysis method applied for all modes B0B0 B0B0 B 0 -tag  t   z/c   eff ~30%   t ~140ps

CP Violation in B decays 13 B-meson Reconstruction Energy difference: Beam-constrained mass:  Utilize special Kinematics at Y(4S) M bc Nsig = 5264 Purity 98 % CP odd 386M BB B 0  J/  K S

CP Violation in B decays 14 B 0  J/  K L : Signals Nsig = 4792 Purity 60 % CP even p KL information is poor  lower purity 386M BB   KLKLKLKL K L direction + 2-body decay kinematics

CP Violation in B decays 15 sin2  1 measurement 386M BB   sin2   =   M BB CP-even CP-odd Preliminary Good tags B 0 tag _ consistent w/ SM expectation WA: sin2  1 = 0.69 ±0.03 < 5% accuracy ! ( A =0.03  0.04 )

CP Violation in B decays 16 New physics Search : b d s d Xs s  KSKS b d s d ts s  KSKS _ B 0 + b  sqq New Physics with New Phase S bs  S bc, A can  0 - SM: b  s Penguin phase = (cc) K 0 - “b  ccs: sin2  1 ” (SM reference) deviation (H.N.Li, W.H.Hou)

CP Violation in B decays 17 b  sqq decay modes - - SM expectation “pure” b  sss Golden mods - b  sdd - f + = 0.91  0.07 [HFAG: Belle(isospin)+BaBar(moment)] * *

CP Violation in B decays 18 B 0   K 0 : result S J/  K 0 fit Good tags - 386M BB Preliminary “sin2  1 ”=+0.44  0.27  0.05 A =+0.14  0.17  0.07 “sin2  1 ”=+0.44  0.27  0.05 A =+0.14  0.17  0.07 “sin2  1 ”=+0.50  0.25  A =  0.23  0.05 “sin2  1 ”=+0.50  0.25  A =  0.23  M BB [PRD71,091102(05)] [hep-ex/ ] Theoretically clean mode 180  16  K s 78  12  K L 114  12  K s 98  18  K L K s                    

CP Violation in B decays 19 B 0   ’  K 0 : result S J/  K 0 fit Good tags Av  0.09: First established b  sqq Penguin CPV ! (>5  ) - 386M BB Preliminary “sin2  1 ”=+0.62  0.12  0.04 A =+0.04  0.08  0.06 “sin2  1 ”=+0.62  0.12  0.04 A =+0.04  0.08  0.06 “sin2  1 ”=+0.36  0.13  0.03 A =  0.09  0.02 “sin2  1 ”=+0.36  0.13  0.03 A =  0.09  M BB [hep-ex/ ] [hep-ex/ ] highest statistics mode 830  35  ’K s 187  18  ’K L 805  67  ’K s 440  54  ’K L _ Preliminary

CP Violation in B decays 20 Summary: Naïve average sin2  1 eff =0.5  0.09 (2.6  from sin2  1 ) b  sqq CPV - - (C f =  A f )

CP Violation in B decays 21  2 measurement  1   2   3  V td V tb V cd V cb V ud V ub * * * mixing Penguin d b d _ d u u W B 0d0d  -  + V ud  V ub Tree B 0d0d d b d u u W g  +  - V td  V tb t d S   sin  2

CP Violation in B decays 22 Effect of Penguin on  2 M. Gronau and D. London, PRL 65, 3381 (1990) Isospin relation EW Penguin neglected (isospin breaking)

CP Violation in B decays 23 B 0   +   Signals candidates 467±33 signals 1606±51 K  events Loose cuts  fit with Shape variable in PDF 227M BB 2820 candidates 666±43 signals 247±31 K  events 275M BB (LR>0.86) (<0.86) BBqq Total number of events used for the fit LR [PRL95,101801(05)] [PRL95,151803(05)]

CP Violation in B decays 24 Results good tag A  =  0.12  0.06 S  =  0.67  0.16  0.06  t (ps) 275M BB 227M BB  t (ps) B 0 tagged _ A  =  0.09  0.15  0.04 S  =  0.30  0.17  0.03 Total background [PRL95,101801(05)] [PRL95,151803(05)]

CP Violation in B decays 25 Experiments Summary Belle 275M B A B AR 227M A  ~2.3  difference between Belle and B A B AR S  - A  ( C  )

CP Violation in B decays 26 Significance (A,S)=(0,0) 1-C.L.=5.6x10 -8, 5.4  (A,S)=(0,−0.62) 1-C.L.=5.1x10 -5, 4.0  Large CP Violation, Large Direct CPV confirm previous Belle results (153M) both statistical and systematic errors are taken into account. S  A  275M BB Feldman-Cousins Analysis [PRL95,101801(05)] A  ~  3 A CP (     ) 0.37(Av.) [Gronau-Rosner, PLB 335,339(04)]

CP Violation in B decays 27  2 (  ) with isospin analysis HFAG EPS 2005 B (  +  0 ) 5.5  0.6 B (  +  - ) 5.0  0.4 B (  0  0 ) 1.5  0.3 x10 -6 A (  0  0 ) 0.28  0.4 New BaBar B (  +  - ) [hep-ex/ ]

CP Violation in B decays 28 B 0   +   CPV B (  0  0 ) << B (  +   ), B (  +  0 ) <  6 26  6 x10 -6 (HFAG) small Penguin effect (  ) 22 A 00 A +0 A +- / 2 f L ~ 100%  CP  +1 Similar to  +  , but more complicated … Two lucky cards ! B  VV: not CP eigenstate in general  +   +  0 : wide resonance

CP Violation in B decays 29 B 0   +   signal 232M BB f L =   [PRL95,041805(05)]

CP Violation in B decays 30 B = 24.4  2.2  x M BB B 0   +   signal f L =   Preliminary continuum b  c b  u Helicity M  signal continuum  continuum [hep-ex/ ]

CP Violation in B decays 31 Fit Results 232M BB 275M BB S =  0.42  0.08 A = 0.00  0.30   t (ps) S =  0.24  A = 0.03  0.18  Preliminary Good tag signal background [hep-ex/ ] [PRL95,041805(05)] B 0 tagged _

CP Violation in B decays 32  +   Isospin analysis  2 = 96  13 deg. add new Belle  +   : B, S, A Note: Isospin triangle does not close experimental error ?  2 <116 CL

CP Violation in B decays 33 B 0   +   CPV B 0   +   : not CP eigenstate, same diagram as  +   Mixing CPV with 4 amplitudes (complicated) B 0   +    0 : Dalitz [BaBar PRL 91,201802(’03); Belle PRL94,121801(’05)] s  = m(     ) 2 s + =m(     ) 2 A  = f  A  + f  A  + f  A  f i  (s +, s  ) : form factors (Breit-Wigner) A(  i  j ) = A ij =e i  2 T ij + P ij P  =  (P  +P  )/2 Fit to  t, Dalitz dist.   2 w/o discrete ambiguity ! ++ ++ ++

CP Violation in B decays 34  t-Dalitz Fit Results Preliminary m(     ) 2 m(     ) 2 m’ ’’ transformation 232M BB Square Dalitz [hepex/ ]

CP Violation in B decays 35  +   Dalitz: Constraint on  2  2 = 113   6 deg [hepex/ ]

CP Violation in B decays 36 Summary of  2  2 = 99  deg. 13 8

CP Violation in B decays 37  3 measurement  1   2   3  V td V tb V cd V cb V ud V ub * * * u b u u c s W B +d+d  D0D0 V cs  VubVub u b u s u c W B +d+d D0D0 ++ V us  V cb _ f COM interference Simple mixing CPV   3 ( with B d ) + Tree 3 3

CP Violation in B decays 38  3 : GWL & ADS method 1) f COM = D CP Gronau-Wyler-London [PLB 253,483; 265,172(’91)] D 0 /D 0   +  - /  +  - (CP=+1),  S  0 / .. (CP=  1) 2) f COM = D DCSD Atwood-Dunietz-Soni [PRL 91,171801(’03)] ex) B +  D 0 [  -  + ]  + & D 0  -  + ]  + _ _ Measurements have been done, but only give loose constraint on  3 need more data Measurements have been done, but only give loose constraint on  3 need more data

CP Violation in B decays 39 Novel method: Dalitz f COM = D   K S     B+:B+: B-:B-: m + =m(K s  + ), m  =m(K s   ) CPV : Asymmetry in Dalitz dist.: r r |A 2 | |A 1 | r = obtain from tagged D 0 (D *+  D 0  + ) sample

CP Violation in B decays 40 CPV in Dalitz plane MC simulation  3 = 70 deg.  = 0, r = B+B+ BB Sensitivity to  3

CP Violation in B decays 41 Signal yields 232M BB 275M BB D 0 K* D0KD0K D* 0 K [D 0  0 ] 209 signals 58 signals 36 signals 49 signals 90 signals 282 signals [PRL95,121802(05)] [hepex/ ][hepex/ ] EE EE EE

CP Violation in B decays 42 Dalitz Plots: D 0 K 232M BB 275M BB B+B+ BB B+B+ BB

CP Violation in B decays 43  3 Fit Results  3 (deg) rBrB rBrB  3 (deg) D 0 K* D0KD0K D* 0 K [D 0  0 ] r B : different for modes D0KD0K D* 0 K [D 0  0  ]

CP Violation in B decays 44  3 Summary [hepex/ , ]  3 = 63  deg [PRL95,121802(05)]

CP Violation in B decays 45 b u W B 0 ++ VudVud  VcbVcb c d D*D* d d b c W B 0 ++ V cd  V ub u d D*D* d d   (B 0 →D    ) ~ 1 + cos(  mt) – S  sin(  mt)  (B 0 →D    ) ~ 1 + cos(  mt)  S  sin(  mt)  (B 0 →D    ) ~ 1  cos(  mt)  S  sin(  mt)  (B 0 →D    ) ~ 1  cos(  mt)  S  sin(  mt)   Cabibbo favored Cabibbo suppressed CP S  = 2(  1) L R sin(2  1  3  )  : hadronic phase, R = ~0.02 A CF A DCS mixing mixing induced CPV [L=0 (D  ), 1(D   ) R,  not same for D  and D   sin(2  1 +  3 ): B 0  D (*)+  - TCPV 4 2 [I.Dunietz, PLB 427,179(’98)] B0→B0→ mixing A DCS A CF

CP Violation in B decays 46  t Distributions B 0  D   10.6K cand.(96% purity) B0B0 B0B0  152M BB 232M BB partial reconstruction B0B0  B0B0 D    CP Full recon  t(ps) 89.3K signals Good tag Lepton tag background D    D    [hepex/ ][PRL 93,031802(04)] D    D    D   

CP Violation in B decays 47 sin(2  1 +  3 ): Summary D*   DD DD (c~0 if  ~0 or 180 deg.) R D  : estimated form B (B  D s    ) [SU(3) symmetry] No significant constraint on  3 yet !

CP Violation in B decays 48 Solution of sin2  1 Ambiguity sin2  1 : 4-fold ambiguity;  1   /2-  1,  1 +  3  /2-  1 J/  K* 0 : Time-dependent angular analysis interference A // A , A 0 A   cos2  1 BaBar: cos2  1 = 3.32   0.27 (88M BB) Belle: cos2  1 = 0.56  0.79  0.11 (275M BB) _ _ D 0 [K s  +  -  h 0 : Time-dependent Dalitz-plot analysis =  Dh e -i2  1 f (m + 2,m  2 ) / f (m  2,m  2 )  2  1 phase depends on (m + 2,m  2 ) : known 2Im   S = New ! use D (*)  0, D (*) , D ,(309  31 signals)  1 = ( 16  21  12) o 386M BB exclude  1 = 68 o solution >95% CL [PRD71,032005(05)] [PRL95,091601(05)] [hep-ex/ ]

CP Violation in B decays 49  1  2  3 Summary Consistent with  1 +  2 +  3 = 180 o SM constraints

CP Violation in B decays 50 CKM Global Fit  1   2   3  V td V tb V cd V cb V ud V ub * * *  m d b  d  b  c l b  u l

CP Violation in B decays 51 A CP   (B  f)  (B  f)  (B  f)  (B  f) = A 1 A 2 sin(  1  2 )  1  2 ) A 1 2  A 2 2  A 1 A 2 cos(  1  2 )  1  2 ) 2 2 Direct CPV: B   Penguin d b d _ s/d u u W B 0d0d --  + V us/d  V ub Tree Key prediction of Kobayashi-Maskawa model Strong support of KM B 0d0d d b d u u W g  + -- V ts/d  V tb t s/d Observation in B Tree-Penguin interference Direct CP Violation

CP Violation in B decays 52 A CP (B 0  K    ) A CP =    significance ! Signal: 3042  M BB386M BB Signal: 1601  51 A CP =   (4.2  World Average (+CDF/Cleo) [HFAG] A CP =  [hepex/ ] [PRL 93,131801(05)]

CP Violation in B decays 53 A CP for Charmless B decays

CP Violation in B decays 54 A CP : 3-body Dalitz alnaysis 386M BB  (770) 0 K   (782) 0 K  f 0 (980) K  f 0 (1370) K  f 2 (1275) K   c0 (782) K  Non-res.   (892) 0     (1430) 0    =  1 for B  ]

CP Violation in B decays 55 DCPV: B    0 K  [hepex/ ] A CP =30  11  2 % (3.9  ) +11  4 [A CP =34  13  6 % ] BaBar +15  20 1 st DCPV in Charged particle ! [PRD72,072003(05)]

CP Violation in B decays 56 CPV in Mixing  A SL (t)     (B 0   X) B 0   (B 0   X) B 0   (B 0   X) B 0   (B 0   X) B 0  |p/q| 2  |q/p| 2 |p/q| 2 +|q/p| 2 SM: O(10 -3 ) t-independent Belle: A CP =  0.1  0.79  0.70 % 85M BB Babar: A CP =  0.5  1.2  1.4 % 23M BB [PRL 88,321801(02)] World Average (+LEP/Cleo) [HFAG] A LS =  0.30  0.78 % Large A SL  New Physics Not yet observed: only missing peace of SM CPV in B still far away from SM [hepex/ ]

CP Violation in B decays 57 Summary CP Violation in B decays Large CPV [O(1)~O(0.1)] established in Mixing-Decay Interference & Direct CPV not yet in Mixing [O(10 -3 ) in SM] UT angle measurements with CPV  1 = ( 21.7  ) o  1 = ( 99  ) o  1 = ( 63  ) o Great success of KM scheme ! New Physics Search More precision, b  s penguins, new modes… New Physics Search More precision, b  s penguins, new modes… Excitement with more data Now

CP Violation in B decays 58 Future Prospect ~10 10 BB/year !! 1.6x fb -1 5x10 34 ~1 ab -1 5x ~50 ab -1 L peak L int Crab cavities Crab cavities Major upgrade of KEKB & Belle World Highest Luminosity ! (cm -2 s -1 )

CP Violation in B decays 59 backup

CP Violation in B decays 60 Physics Reach SuperKEKB 5ab -1 50ab -1 LHCb Physics at Super B Factory (hep-ex/ ) 2fb -1

CP Violation in B decays 61 b  ccd: J/  , D  D  -

CP Violation in B decays 62 B 0   K 0 386M BB KSKS Nsig=180  16 purity 0.57 Nsig= 78  13 KLKL purity 0.12 Preliminary Event Shape

CP Violation in B decays 63 B 0   ’ K 0 386M BB  ’K S Nsig=830  35 purity 0.61 Nsig= 187  18  ’K L purity 0.66 highest statistics mode Preliminary Event Shape

CP Violation in B decays 64 Extraction of  3 ? estimated form B (B  D s    ) [SU(3) symmetry] No significant constraint yet ! R