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CPV in B → D (*) K (*) ( and B → D K  ) in BaBar and Belle

CPV in B → D (*) K (*) ( and B → D K  ) in BaBar and Belle. Outline: CPV in B → D (*) X s theoretical ideas experimental issues experimental results B ∓ → D (*) 0 K (*) ∓ B 0 → D (*) 0 K (*)0 some other approaches summary. Φ 2 ( α ). V td V * tb. V ud V * ub.

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CPV in B → D (*) K (*) ( and B → D K  ) in BaBar and Belle

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  1. CPV in B → D(*) K(*)(and B → D K  )in BaBar and Belle • Outline: • CPV in B→D(*)Xs • theoretical ideas • experimental issues • experimental results • B∓→ D(*)0K(*)∓ • B0→ D(*)0K(*)0 • some other approaches • summary HEP2003 Europhysics Conference –Aachen, July 18th

  2. Φ2(α) VtdV*tb VudV*ub interference between B →D(*)0 K(Xs)⊕ B→D(*)0 K(Xs) f Φ3(γ) Φ1(β) VcdV*cb experimentally challenging: sensitive to CPV in B → DXs B → DXs is a good place to look Φ3(γ )≡ arg(-VudV*ub/ VcdV*cb) CPV in interference between b→c & b→u theoretically clean: only tree diagrams HEP2003 Europhysics Conference –Aachen, July 18th

  3. PROBLEMS: • r = A(B-→D0K-)/A(B-→D0K-)~ 0.1(0.2) • A(B-→D0K-)difficult to measure directly δ 2A(B-→DCPK-) A(B-→D0K-)= A(B+→D0K+) 2Φ3 A(B-→D0K-) A(B+→D0K+) 2A(B+→DCPK+) δ Ways to measure Φ3 in B→DXs D→fCP ( Gronau, London & Wylermethod) amplitude triangles extensions and modifications various f various Xs,(D) many observables ... statistics required: ∼ 0.5 ab-1 δ - relative strong phase HEP2003 Europhysics Conference –Aachen, July 18th

  4. Experimental issues Use beam constraints to reconstruct B: Mbc(GeV) ΔE (B-→D0h-) K/ separation Babar : dE/dx in SVT & DCH, DIRC Belle: dE/dx in CDC, TOF, ACC ≥2.5 (K/) separation up to 3.5 GeV Apply tight K-ID cut: E  -49 MeV for DK- HEP2003 Europhysics Conference –Aachen, July 18th

  5. Experimental issues Continuum suppression:multidimensional cuts exploiting event topology (Fox-Wolfram moments, thrust...)angle of B-flight direction... Background suppression from other Bdecays depends on specific final states: veto for some B-decays, .... Signal extraction: Maximum likelihood fits with signal shapefrom MC and data control samples, background from side bands and off-resonance data (combinatorial),MC (B-decays) HEP2003 Europhysics Conference –Aachen, July 18th

  6. (7.7 ± 0.9 ± 0.6 )% (8.31 0.35 ± 0.2)% ± (9.9 1.3 ± 0.7)% 56 fb-1 B- → D0 h-measurements Preliminary D0 →K D0 →K0 D0 →K Signal extracted witML fit to the DE,Mbc,PID(p/K) h-identified as K E(GeV) E(GeV) E(GeV) Belle,PRL 87,111801(2001) 10.4 fb-1 ± Babar, hep-ex/0207087 56 fb-1 CLEO, hep-ex/0302026 15.3 fb-1 For other B→D(*)K- modes see Belle, PRL 87,111801(2001) HEP2003 Europhysics Conference –Aachen, July 18th

  7. D1 = KK B D1K D1 =  E(GeV) = 0.17 ± 0.23(stat) ± 0.08(sys) = 1.06 ± 0.26(stat) ± 0.17(sys) B-→DCPK- 81.2 fb-1 Preliminary D1DCP=+ D2DCP=- Observables: asymmetries branching ratios 3 independent equations with 3 unknowns (Φ3,r, ) 24.27.2 HEP2003 Europhysics Conference –Aachen, July 18th

  8. =0.06 ± 0.19(stat) ± 0.04(sys) = 1.21 ± 0.25(stat) ± 0.14(sys) = -0.19 ± 0.17(stat) ± 0.05(sys) = 1.41 ± 0.27(stat) ± 0.15(sys) sin2(Φ3)≤ r 1/4 || 78 fb-1 B-→DCPK- hep-ex/0304032 Signal yields extracted with a likelihood fit to the DE 179.615 165.414.5 D1=KK, pp 25.06.5 22.16.1 D2=Ksp0, Ksf, Ksh, Ksw, Ksh’ 29.96.5 20.55.6 HEP2003 Europhysics Conference –Aachen, July 18th

  9. D1=K+K-, p+p- 13.14.34.4.3 D2=Ksp0, Ksf, Ksw 7.23.6 2.4 = -0.02 ± 0.33(stat) ± 0.07(sys) = 0.19 ± 0.50(stat) ± 0.04(sys) Similar analysis can be performed with K*- replacing K- 88 fb-1 B-→DCPK*- Preliminary D0 → K, K,K 0 MK*- coshel from P→PV No indication for non-resonant DK (6.1 ± 1.6(stat) ± 1.7(sys)) x 10-4CLEO HEP2003 Europhysics Conference –Aachen, July 18th

  10. 81.2 fb-1 B→V V can be also used, angular analysis required, B- → D*0 K*- Preliminary B → D*0 K*-ALL D*0 → D00 D*0 → D0 (8.0 ± 1.0(stat) ± 1.2(sys)) x 10-4 (7.7 ± 2.2(stat) ± 2.6(sys)) x 10-4CLEO HEP2003 Europhysics Conference –Aachen, July 18th

  11. B0→ D0 K(*)0 both amplitudes are color suppressed r ~ 0.4 isospin relations ⇒ extract Φ3 and  B0→ D0 K*0 , K*0 → K+- (kaon tags B0 flavour) rates and asymmetriesB0→ D1,2K*0⇒Φ3 B0→ D0 K0s , B0 – B0 mixing time dependent asymmetries (B0-decay vertex needed) HEP2003 Europhysics Conference –Aachen, July 18th

  12. 27.07.3 41.08.4 E M(D0) sidebands 78 fb-1 B0→ D0 K(*)0 PRL 90, 141802 (2003) 90% CL Vub. HEP2003 Europhysics Conference –Aachen, July 18th

  13. | | | | | | Summary of Br’s, event yields, ..... 347±20 @ 78 fb-1 D  K 360±20 @ 56 fb-1 D  K 70±10 @ 88 fb-1 D  K 10±4 @ 78 fb-1 D  K 15±5 @ 78 fb-1 D  K PDG HEP2003 Europhysics Conference –Aachen, July 18th

  14. uu us cu us b c b u u u u u Some other approaches • Atwood,Dunietz, Soni (ADS): use doubly Cabibbo-suppressed D decays • Dalitz plot analysis of BDK • BDK, Dalitz plot analysis of multibody D decays ( e.g. DKs+-) • ................ r ~ 1, Br~ 10-7 Both amplitudes are color allowed HEP2003 Europhysics Conference –Aachen, July 18th

  15. Summary and outlook No direct CPV observed in B→DXs, no direct constraints on Φ3 yet, but there is a steady progress: • new relevant decay modes observed: • B-→ DK(*)- D→fCP, CP=+,- • B0→ DK(*)0 • other analyses in progress • accelerator performance • KEKB: Lpeak>1034cm-2 s-1 PEP-II: Lpeak>61033cm-2 s-1 • Belle and BaBar aiming for ≈ 0.5 ab-1 in 2005 • some meaningful constraints on Φ3 possible by that time • new theoretical ideas • precise measurements in D sector ........ HEP2003 Europhysics Conference –Aachen, July 18th

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