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Interpreting CP asymmetries in

Interpreting CP asymmetries in. B   CP asymmetries. Tree diagram:. P enguin diagram:. R t / R c. . R u / R c. g. b. need | P / T | and  =arg( P/T ). Theoretical frameworks. strong isospin symmetry SU(2) (GL) CP-averaged Br(B   ) only (  0  0 not seen yet)

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Interpreting CP asymmetries in

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  1. Interpreting CP asymmetries in

  2. B CP asymmetries Tree diagram: Penguin diagram: Rt /Rc  Ru /Rc g b need |P/T| and =arg(P/T)

  3. Theoretical frameworks strong isospin symmetry SU(2) (GL) CP-averaged Br(B) only (00 not seen yet) EW penguins neglected 1 + SU(3) flavour symmetry(BF,Ch) OZI-suppressed annihilation penguins neglected No correction of SU(3) breaking 1 + |P| from K0- (GR,BBNS) Rth from QCD factorisation Neglect annihilation diagram in K0-  remains unconstrained QCD factorisation(BBNS) Use the prediction of both |P/T| and  Non-factorisable 1/mb contributions fixed to default value use Br(B0K+-) and |P| = |PK| GL: Gronau, London, Phys.Rev.LettD65:3381,1990 BF: Buras,Fleisher, Phys.Lett.B360:138,1995 Ch: Charles, Phys.Rev.D59:054007,1999 GR: Gronau, Rosner, Phys.Rev.D65:013004,2002 BBNS: Beneke et al., Nucl.Phys.B606:245-321,2001

  4. Experimental inputs Global CKM fit using standard constraints (referred as standard CKM fit in this talk) ICHEP02 Aspen03 sign convention changed! ICHEP’02 Branching fractions (x10-6) WA = BaBar + Belle + CLEO not seen 32 CL range: CKMFitter: Hoecker et al., Eur.Phys.J.C21,225,2001 and http://ckmfitter.in2p3.fr

  5. Constraints in the (r,h) plane from isospin analysis BABAR Belle BABAR Belle no significant constraints Grossman-Quinn 98; Charles 99; Gronau-London-Sinha-Sinha 01 Gronau,London,Sinha,Sinha bound:

  6. Constraints in the (r,h) plane: SU(3) BABAR Belle no significant constraints Charles 99

  7. Constraints in the (r,h) plane: |P+–| from K0- BABAR Belle

  8. Constraints in the (r,h) plane:QCD Factorisation BABAR Belle BABAR Belle Negative C and small positive  negative 

  9. What about ? BABAR Belle At present, significant theoretical input needed to extract 

  10. QCD Factorisation: uncertainty from hard spectator interaction and annihilation diagram BABAR Belle no zoom Non-factorisable power-suppressed contribution parameters free

  11. Constraints/predictions on |P/T| and  (C,S ) and ( ,) from standard CKM fit non-factorisable contributions fixed • non-factorisable contributions free • theoretical parameters varied within a given range • uncertainty from ( ,)

  12. Predicting C andS using  ,from standard CKM fit Only predictive approach: QCD Factorisation. poor knowledge of sin2  large uncertainty in S

  13. Constraint on Br(B  00) Inputs = C, Br(B  +-), Br(B  +0) Moriond’02 Belle measurements ! ! Gronau-London-Sinha-Sinha 01

  14. How about More Statistics? Isospin analysis for present central values, but 500 fb–1 (BaBar C,,S and WA branching fractions) • and even more... The only hope for BaBar and Belle is not to observe B0 00

  15. Conclusion • Various strategies to interpret time-dependent asymmetry measurements C, Sstudied: • Significant constraints on  from QCD Factorisation but still need validation from data • Qualitative information when constraining the penguin amplitude using Br(B-K0-) • Mild assumption frameworks based on SU(2) and SU(3) do not lead to significant constraints • If central value of BR(00) stays large, isospin analysis probably cannot be performed by first generation B factories

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