1. CP violation at Belle Kenkichi Miyabayashi for Belle collaboration (Nara Women’s University) 2003/Oct./14th BEAUTY2003

2. KM unitarity triangle and CPV parameter convention

3. Topics to be covered… sin2   (sin2  ) related (140/fb) ; –CPV golden mode; B 0 J/  K S –CPV in B 0 J/   0  2 (  ) related (78/fb); –CPV in B 0  +  -

4. Time dependent CP asymmetry

5. CP eigenstate reconstruction M bc (GeV)  E(GeV) Two key variables; M bc = { (E CM /2) 2 - (  P i ) 2 } 1/2 B mass(5.28GeV)  E =  E i - E CM /2 0 Note; These are for full-reconstructable case. For the mode having missing or K L, different variables are used. Example; B 0 J/  K S

6. Vertex recon. to measure  t BB system is boosted  =0.425 ;  t obtained by  z Require consistent with run-dep. IP profile (  r  =21  m). CP side vertex ·reconstructed by dilepton from J/ ,  +  - pair, etc. Tag side vertex ·Impact parameter w.r.t CP side vertex < 500  m ·K S veto ·If reduced  2 > 20 … remove the track having largest  2 Resolution function ·including charmed meson lifetime, motion of B meson, ·Validation by lifetime measurement.

7.  Inclusive Leptons:  high-p l  b  c l   intermed-p l + s l    Inclusive Hadrons:  high-p  + B 0  D (*)   +, D (*)   +, etc.  intermed-p K + K + X,      low-p   D 0   Flavor tagging by other B decay products Based on the calculated likelihood, q =+1 for B 0, -1 for B 0 (Tag side) r = from 0(no flav. info.) up to 1(perfectly confident tag).

8. Validation of flavor tagging B 0 D* - l + decay is self tagging; reconstructed with high purity Good tag Poor tag OF-SF asymmetry ~ (1-2w)cos(  m  t)  w is also investigated. 1-2w

9. CP fit : unbinned max. likelihood fit Signal probability density function(PDF) is; P sig (  t, q, w l,  w l ) = exp(-|  t|/  B )/4  B {1-q  w l +q(1-2w l )[S fCP sin(  m  t)+A fCP cos(  m  t)]} here, l is flavor tagging class(1,2,…6). For i-th event, likelihood value is; P i (  t i, S fCP, A fCP ) =(1-f ol )[f sig P sig (  t, q, w l,  w l ) X R sig (  t i ) + f bg P bg X R bg (  t i )] + f ol P ol (  t i ) Free parameters : S fCP and A fCP Proper resolution func. : R ** B life and mixing : PDG values Fraction of each component : f **

10. sin2  1 (-  CP S ccs )measurement B 0 charmonium + K recon. Mode  CP NeventsPurity J/  K S (  +  - ) 19970.98 J/  K S (  0  0 ) 2880.82  ’(l + l - ) K S 1450.93  ’(J/  ) K S 1630.88  c1 K S 1010.96  c (K S K  )K S 1230.72  c (KK   )K S 740.70  c (pp) K S 200.91 J/  K *0 (K S  0 ) +1*1740.93 J/  K L +123320.60 * 81%.

11. B 0 J/  K L (for sin2  1 measurement) Only K L direction known. In Upsilon(4S) rest frame, B has ~340MeV/c. Reconstruct it with two-body kinematics assumption.

12. CPV in B 0 charmonium+K 0 :sin2  1 sin2  1 = 0.733±0.057(stat)±0.028(syst) If is free in the fit, | |=1.007±0.041(stat) consistent with 1 Now precision measurement!

13. CPV in B 0 J/   0 Decay caused by b ccd transition  CP = +1 Tree has no complex phase if it dominates S J/  = -sin2  1 and A J/  = 0

14. Reconstruction of B 0 J/   0 103events reconstructed. Relatively clean; purity=86±10% Backgrounds are separately est. for B J/  X and combinatorial.

15. Results for S J/  and A J/  After ftag and vtx, 91 events are used. S J/  = -0.72±0.42(stat)±0.08(syst) A J/  = -0.01±0.29(stat)±0.07(syst) B0B0 B0B0

16. CPV in B 0  +  - If only tree contributes, V ub interferes V td (in mixing) extract  2 ! However, penguin looks significantly large (B 0  0  0, listen T.Higuchi’s talk) so that effect on CP asymmetry is there.

17. Event selection of  +  - LR>0.825  enhanced LR<0.825 = K  enhanced To suppress cont. bg, Likelihood Ratio(LR) is calculated by event shape and B’s flight direction. Correlation with flav. tag is taken into account in the CP fit. 760 candidates; (163+24/-23 signals) are obtained by 78/fb.

18. Results for S  and A  S  = -1.23±0.41(stat)+0.08/-0.07(syst) A  = +0.77±0.27(stat)±0.08(syst)

19. Results for S  and A   (cont.) Our result is 3.4  away from CP conservation (i.e. S  =A  =0).

20. Conclusions and future sin2   =0.733±0.057(stat)±0.028(syst) –Moving into the precision measurement regime. –Relevant modes(b ccd) making progress. B 0  +  - is away from CP conserv.(3.4  ) –Analysis using 140/fb is in progress. Now going to resume physics run with new SVD and smaller radius beampipe.

21. Backup slide

22. sin2  1 :charmonium + K S and J/  K L Opposite asymmetry by diff. CP eigenvalue is clearly seen!

23. B ± D CP K ± D1K-D1K- D1K+D1K+ D2K-D2K- D2K+D2K+ B DK decay can be caused via Vcb and Vub, if D decays into CP eigenstate(D 1 (K + K -,  +  - ), D 2 (K S  0, K S , K S , K S , K S  ’)), possibility to access  3 A 1 =0.06±0,19(stat)±0.04(sys) A 2 =-0.19±0.17(stat)±0.05(syst)