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Study of the suppressed decay B -  DK - and B -  D ( * ) CP K - decays at Belle

Study of the suppressed decay B -  DK - and B -  D ( * ) CP K - decays at Belle. Naoki Kikuchi (Tohoku Univ) on behalf of Belle collaboration. Today ’ s menu. CKM model  3 measurement GLW method & B -  D ( * ) CP K - result ADS method & B -  D ADS K - result Summary.

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Study of the suppressed decay B -  DK - and B -  D ( * ) CP K - decays at Belle

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  1. Study of the suppressed decay B-DK-andB-D(*)CPK- decaysat 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. B-D0K- Penguins can’tenter DK decay! c u X u u u u 2. 3 measurement • 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 Vub s b u K- D0f W- W- B- c s b B- D0f K- B-D0K- Naoki KIKUCHI

  5. 3 unknowns 3. GLW method 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  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 massVariables with * are evaluated in CM system • D reconstruction • |Mrec-MD|<2.5 • PID  dE/dx+TOF+CherenkovFor K, LR(K/)>0.4For , LR(K/)<0.7 Mbc E Naoki KIKUCHI

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

  8. 3.2. Result on DCPK • B-DCPK- w/Belle 274M BB PRD 73, 051106 (2006) Yield: D+K : 143.321.9 (12.4) D-K : 149.519.0 (9.2) • Signals are established! • Significant deviations ofA~0,R~1 are not seen. DK Dπ Naoki KIKUCHI

  9. 3.2. Result on D*CPK • B-D*CPK- w/Belle 274M BBUsing D*D0 mode PRD 73, 051106 (2006) Yield: D*+K : 43.910.2 (5.2) D*-K : 32.710.0 (3.3) • Signals are established! • Significant deviations ofA~0,R~1 are not seen. Naoki KIKUCHI

  10. 3 unknowns well measured 4. ADS method D. Atwood, I. Dunietz and A. Soni, PRL 78, 3357 (1997) PRD 63, 036005 (2001) • Decay mode • CP asymmetry • Features • Low statistics • High sensitivity s s K+ K- AB ADxrD B-D0 K-K+p- u u l d c b c l B- D0 p- u u u u Color allowed x Doubly-Cabibbo sup. B-D0 K-K+p- u b u u K+ D0 c s c B- ABxrB u s AD K- p- d u u Color sup. x Cabbibo allowed Naoki KIKUCHI

  11. 4.1. Result on DADSK • B-DADSK- w/Belle 386M BB hep-ex/0508048(2005) Favored mode DE-fitevents ADS mode DE-fitevents B-K+K-- BGcharmless decay Favored mode Naoki KIKUCHI

  12. 4.1. Result (cont’d) • Constraint for rB with B-DK- decay hep-ex/0508048(2005) Varying 0<φ3,<π, ±2σ for rD, rB < 0.18(90% C.L.) BABAR Dalitz analysis hep-ex/0607104(2006) Belle Dalitz analysis PRD 73, 112009(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 limitw/386M BB Our recorded dataw/727M BB Naoki KIKUCHI

  16. D(*)CPK systematics Naoki KIKUCHI

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