1. B decays to charm hadrons at Belle M.-C. Chang Fu Jen Catholic University (On behalf of Belle Collaboration) European Physical Society HEP2007 International Europhysics Conference on High Energy Physics The North of England at Manchester Thursday 19th July to Wednesday 25th July

2. 2 Note. A theory prediction is included 1.Search for decay Double charmed baryonic decay Cabiboo-favored Cabiboo-suppressed Naively, we estimate Br( )~7.7 x 10 -7 Br( )~3.6 x 10 -4 PRL 90, 121802 (2003) PRD 74, 111105 (2006) PRD 48, 4188 (1993) 0.83%

3. 3 Data samples: 479fb -1 Event selections –Mass region of  c (reconstructed by pK): 2.275 ~ 2.295 GeV/c 2 –Selections of tracks, Particle ID, Vertex fit, and Continuum background suppression (shape variables) are all optimized. Data MC

4. 4 Br ( )< 5.7 x 10 -5 @ 90% C.L. ~3 smaller than a na ï ve expectation from assuming a simple Cabbibo-suppression factor of |V cd /V cs | 2 Predicted by ~7.7 x 10 -7 Predicted by ~3.6 x 10 -4 Preliminary discussions

5. 5 Preliminary Discussions: Due to the measurement error of, not sensitive to the assumption of Br corr =Br/(PSx CS); PS: phase space correction factor CS: Cabibbo suppression correction factor ~O(1) Maybe: 1.Strong suppression 2.Large

6. 6 2.Study of decay intermediate two-body decays in We study these 4 kinds of  c in the final state. 357fb -1 Dalitz plots

7. 7 B 0   c ++ (2455) p   B 0   c 0 (2455) p  ＋ M 2 (p   ) M 2 (p   ) 182 events 122 events Significant peak MC 3-body phase space M 2 (  c  p) M 2 (  c  p) M 2 (p   ) M 2 (p   ) We found a significant peak near ~ 1.5 GeV/c 2 in

8. 8 M(p   ) cos  p  M(  c 0   ) M(p   )cos  p  M(  c 0   ) B 0   c 0 (2455) p  ＋ Data MC signals for three decay modes sideband B0c0+pB0c0+p B 0   c 0 N 0 (p  + ) kinematics B 0  X(  c 0  + )p B0c0+pB0c0+pB 0   c 0 N 0 (p  + ) The X( c 0  + ) doesn ’ t correspond to any known  c 0  + resonance. 1. 2.3. Relativistic BW parameters are fitted by a simultaneous fit

9. 9 Fit with S 11 +P 11 (PDG values) S-wave : N(M=1535,  =150) P-wave : N(M=1440,  =300) Fit C.L = 60.4% M 2 (p   )cos  p  M(p   )cos  p  M(  c 0   ) Good C.L. Fit with relativistic S-wave and P-wave Breit-Wigner Preliminary The fitted masses and widths are consistent with PDG. Possibly a mixture of S11(1535) and P11(1440).

10. 10 3.Observation of Decay Hep-ex0704.2652 Submit to PRD(RC) 414fb -1 Signal candidates D s + mass sideband B signal region, in (c) Threshold peaking seems Intrinsic in all multiple baryonic B decays. B sideband region

11. 11 6.6 The first error is statistical, the second is systematic, and the third Error comes from the uncertainty in

12. 12 Cross-check On resonance data with inversed Shape variable requirements. Continuum data Proton with inversed identification We have confidence on our result!

13. 13 4.Improved measurement of & search for PRD75, 091102(R), 2007 More accurate result than the current world average [Ref. to PDG].

14. 14 @90% C.L. misidentification of a pion as a kaon and thus shifted in Delta E distribution. The theoretical predictions range from 8 - 25 x 10^-5 [J.Phys.G31, 273(2005) and Eur.Phys.J.C42,29(2005)]. This result severely challenges above estimations.

15. 15 Summary 1 PreliminaryPreliminary: < 5.7 x 10 -5 @ 90% C.L. ~3 smaller than a na ï ve expectation from "The result is consistent with a logarithmic trend of the branching fraction (corrected for PS and CS) " In three-body decay We observe a broad mass structure and the which is possibly a mixture of S11(1535) and P11(1440). PreliminaryPreliminary: ~5.9

16. 16 Summary 2 Preliminary,Preliminary, we Observe the decay: Threshold peaking in Published, Improved measurement: Upper Limit: Challenge some theory predictions. result is consistent with the factorization hypothesis for non-leptonic exclusive decays of B mesons