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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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**B CP asymmetries**Tree diagram: Penguin diagram: Rt /Rc Ru /Rc g b need |P/T| and =arg(P/T)**Theoretical frameworks**strong isospin symmetry SU(2) (GL) CP-averaged Br(B) only (00 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(B0K+-) 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**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**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:**Constraints in the (r,h) plane:**SU(3) BABAR Belle no significant constraints Charles 99**Constraints in the (r,h) plane:**|P+–| from K0- BABAR Belle**Constraints in the (r,h) plane:QCD Factorisation**BABAR Belle BABAR Belle Negative C and small positive negative **What about ?**BABAR Belle At present, significant theoretical input needed to extract **QCD Factorisation:**uncertainty from hard spectator interaction and annihilation diagram BABAR Belle no zoom Non-factorisable power-suppressed contribution parameters free**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 ( ,)**Predicting C andS using ,from standard**CKM fit Only predictive approach: QCD Factorisation. poor knowledge of sin2 large uncertainty in S**Constraint on Br(B 00)**Inputs = C, Br(B +-), Br(B +0) Moriond’02 Belle measurements ! ! Gronau-London-Sinha-Sinha 01**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 00**Conclusion**• Various strategies to interpret time-dependent asymmetry measurements C, Sstudied: • 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(00) stays large, isospin analysis probably cannot be performed by first generation B factories

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