Interpreting CP asymmetries in

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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)
Interpreting CP asymmetries in B CP asymmetriesTree diagram:Penguin diagram:Rt /RcRu /Rcgbneed |P/T| and =arg(P/T)Theoretical frameworksstrong isospin symmetry SU(2) (GL)CP-averaged Br(B) only (00 not seen yet)EW penguins neglected1 + SU(3) flavour symmetry(BF,Ch)OZI-suppressed annihilation penguins neglectedNo correction of SU(3) breaking1 + |P| from K0- (GR,BBNS)Rth from QCD factorisationNeglect annihilation diagram in K0- remains unconstrainedQCD factorisation(BBNS)Use the prediction of both |P/T| and Non-factorisable 1/mb contributions fixed to default valueuse Br(B0K+-) and |P| = |PK| GL: Gronau, London, Phys.Rev.LettD65:3381,1990 BF: Buras,Fleisher, Phys.Lett.B360:138,1995Ch: Charles, Phys.Rev.D59:054007,1999GR: Gronau, Rosner, Phys.Rev.D65:013004,2002BBNS: Beneke et al., Nucl.Phys.B606:245-321,2001 Experimental inputsGlobal CKM fit using standardconstraints (referred as standard CKM fit in this talk)ICHEP02 Aspen03sign convention changed!ICHEP’02 Branching fractions (x10-6)WA = BaBar + Belle + CLEOnot seen32 CL range:CKMFitter: Hoecker et al., Eur.Phys.J.C21,225,2001 and http://ckmfitter.in2p3.frConstraints in the (r,h) plane from isospin analysisBABARBelleBABARBelleno significant constraintsGrossman-Quinn 98; Charles 99; Gronau-London-Sinha-Sinha 01Gronau,London,Sinha,Sinha bound: Constraints in the (r,h) plane: SU(3)BABARBelleno significant constraintsCharles 99Constraints in the (r,h) plane: |P+–| from K0-BABARBelleConstraints in the (r,h) plane:QCD FactorisationBABARBelleBABARBelleNegative C and small positive  negative What about ? BABARBelleAt present, significant theoretical input needed to extract QCD Factorisation:uncertainty from hard spectator interaction and annihilation diagramBABARBelleno zoomNon-factorisable power-suppressed contribution parameters free Constraints/predictions on |P/T| and (C,S ) and ( ,)from standard CKM fitnon-factorisable contributions fixed
  • non-factorisable contributions free
  • theoretical parameters varied within a given range
  • uncertainty from ( ,)
  • Predicting C andS using  ,from standard CKM fitOnly predictive approach: QCD Factorisation.poor knowledge of sin2 large uncertainty in S Constraint on Br(B  00)Inputs = C, Br(B  +-), Br(B  +0)Moriond’02 Belle measurements !!Gronau-London-Sinha-Sinha 01How 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0Conclusion
  • 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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