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 /RcRu /Rcgbneed |P/T| and =arg(P/T)Theoretical frameworksstrong isospin symmetry SU(2) (GL)CP-averaged Br(B) only (00 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(B0K+-) 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 seen32 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 00)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 00Conclusion
Various strategies to interpret time-dependent asymmetry measurements C, Sstudied:Significant constraints on from QCD Factorisation but still need validation from dataQualitative 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 constraintsIf central value of BR(00) stays large, isospin analysis probably cannot be performed by first generation B factories