1. Study of the suppressed decay B-DK- and B-D(*)CPK- decays at Belle
Naoki Kikuchi (Tohoku Univ) on behalf of Belle collaboration

2. Today’s menu CKM model 3 measurement GLW method & B-D(*)CPK- result
ADS method & B-DADSK- result
Summary
Naoki KIKUCHI

3. 1. CKM model Weak interaction Unitarity condition Complex component  
Naoki KIKUCHI

4. 2. 3 measurement B-D0K- B-D0K- Vub X D0f K- W- W- B- K- B- D0f
Penguins can’t enter DK decay!
Vub s b u
D0f K- W- c W- u B- s b c K- B-
D0f u u u u
B-D0K-
B-D0K-
D0 and D0 decay into common final state, f. Determine 3 through interference term.
rB determines the size of interference by 3.
Choice of final state
f=[KS+-] : Dalitz analysis  P.Krokovny's talk
f=D+ [K+K-, - -], D-[KS0, KS, KS…] : GLW method
f=DADS [K+-] / suppressed decay: ADS method
Naoki KIKUCHI

5. 3. GLW method 23 Direct CPV Decay rate average D decay mode Features
M.Gronau and D. London, PLB 253, 483 (1991)
M. Gronau and D. Wyler, PLB 265, 172 (1991)
Direct CPV
Decay rate average
D decay mode
CP=+ mode
K+K-, 
CP=- mode
KS0, KS, KS
Features
Model independent
High statistics
Low sensitivity for rB
3 unknowns 
A(B+D+K+)
A(B+D0K+)
23
A(B+D0K+)=A(B-D0K-)
A(B-D0K-)
A (B-D+K-) 
Naoki KIKUCHI

6. 3.1. Analysis procedure 2 independent kinematic variables
E : Energy difference
Mbc : Beam energy constrained mass Variables with * are evaluated in CM system
D reconstruction
|Mrec-MD|<2.5
PID  dE/dx+TOF+Cherenkov For K, LR(K/)>0.4 For , LR(K/)<0.7
Mbc E
Naoki KIKUCHI

7. 3.1. Analysis procedure (cont’d)
Continuum background suppression
BB:spherical
qq:jet-like
(4S) resonans
Optimized cut based on FOM
s(e+e-hh)
|cosB|
SFW event shape parameter LR + 
Naoki KIKUCHI

8. 3.2. Result on DCPK B-DCPK- w/Belle 274M BB
PRD 73, (2006)
Yield: D+K : 143.321.9 (12.4)
D-K : 149.519.0 (9.2)
Signals are established!
Significant deviations of A~0,R~1 are not seen. DK Dπ
Naoki KIKUCHI

9. 3.2. Result on D*CPK B-D*CPK- w/Belle 274M BB Using D*D0 mode
PRD 73, (2006)
Yield: D*+K : 43.910.2 (5.2)
D*-K : 32.710.0 (3.3)
Signals are established!
Significant deviations of A~0,R~1 are not seen.
Naoki KIKUCHI

10. 4. ADS method Decay mode CP asymmetry Features Low statistics
D. Atwood, I. Dunietz and A. Soni, PRL 78, 3357 (1997) PRD 63, (2001)
Decay mode
CP asymmetry
Features
Low statistics
High sensitivity s s AB K-
ADxrD K+
B-D0 K K+p- u l u b c c d B- D0 l p- u u u u
Color allowed x Doubly-Cabibbo sup.
B-D0 K K+p- u b u u D0 K+ c c s B-
ABxrB s u AD K- p- u u d
Color sup. x Cabbibo allowed
3 unknowns
well measured
Naoki KIKUCHI

11. Favored mode DE-fit events
4.1. Result on DADSK
B-DADSK- w/Belle 386M BB
hep-ex/ (2005)
Favored mode DE-fit 　　　　　　events
ADS mode DE-fit 　　　　　 events
B-K+K-- BG charmless decay
Favored mode
Naoki KIKUCHI

12. Varying 0<φ3,<π, ±2σ for rD,
4.1. Result (cont’d)
Constraint for rB with B-DK- decay
hep-ex/ (2005)
Varying 0<φ3,<π, ±2σ for rD,
rB < 0.18 (90% C.L.)
BABAR Dalitz analysis hep-ex/ (2006)
Belle Dalitz analysis PRD 73, (2006)
BABAR Dalitz analysis(1 limit)
Belle Dalitz analysis
Naoki KIKUCHI

13. 5. Summary
GLW & ADS method are model independent methods to extract 3.
GLW
Measurement for B-DCPK-/D*CPK-
Signals are established
DCPV is not seen yet.
ADS
Search for B-DADSK-
Signal is not seen yet
But we give a constraint on rB.
We need more BBs.
BBs are being mass-produced!
Naoki KIKUCHI

14. Backup
Naoki KIKUCHI

15. How much we need luminocity for DADSK?
Assumptions
rB=0.1 (Dalitz+ADS+Dalitz)
3=55.2 ~ 68.2O
Current our upper limit w/386M BB
Our recorded data w/727M BB
Naoki KIKUCHI

16. D(*)CPK systematics
Naoki KIKUCHI