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Rare Hadronic B decays

Rare Hadronic B decays. Selected results from Babar, Belle, Cleo. Outline. Introduction Analysis method B u and B d decays to mesonic final states (results and discussions) Conclusion. Introduction (1). Rare B decays branching fractions (BF) less than 10 -5

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Rare Hadronic B decays

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  1. Rare Hadronic B decays Selected results from Babar, Belle, Cleo

  2. Outline • Introduction • Analysis method • Bu and Bd decays to mesonic final states (results and discussions) • Conclusion Liliana Teodorescu

  3. Introduction (1) • Rare B decays • branching fractions (BF) less than 10-5 • do not involve CKM favoured b->c transitions • Theoretical mechanism • CKM suppressed tree b->u transitions (T) • loop (penguin) b->s or b->d transitions (P) • interference between T and P => direct CP violation Direct CP violation observable weak phase diff. strong phase diff. ACP sizeable when and Liliana Teodorescu

  4. Introduction (2) Physics interest • Standard Model • Precise tests of the theoretical predictions (small amplitude processes) • Potential evidence for CP violation • Constraints on CKM parameters – extraction of UT angles through • direct measurements of the time-dependent asymmetries • branching fraction dependence on the UT angles • New Physics • New particles hidden in the loops • Constraints on theoretical models SM non-SM Higgs SUSY Observables • BF • time-integrated CP asymmetry • time-dependent CP asymmetry Covered in this talk BFs and ACP (time-integrated)(Babar, Belle, Cleo) Liliana Teodorescu

  5. Analysis method Babar, Belle, Cleo • exploit production at threshold and small energy released in Signal isolation • identification of reconstructed B with 2 almost uncorrelated kinematical var. beam-energy substituted mass (beam constrained mass – Mbc ) Signal: mES= mB energy difference Signal: E = 0 Background suppression • “continuum” events - non-resonant • event shape variables: used • independently, in a Fisher • discriminant or in a Neural Network B decays: spheric Continuum: jet-like • other B decays – decay angles, helicity angles etc. Signal extraction • 1dim. or multidim. fit of E, mES(Mbc), shape var., PID var. • cont. bkg. - modeled with a phase-space function with kinematical threshold - studied with events of sidebands in E, mES(Mbc) outside the signal region off-resonance data, MC etc. Liliana Teodorescu

  6. Wealth of rare hadronic B decays! Presented in this talk • In this talk • used HFAG averages • rely on HFAG references • referenced explicitly only new results HFAG – Heavy Flavor Averaging Group http://www.slac.stanford.edu/xorg/hfag Liliana Teodorescu

  7. B -> h h' ( h,h'=K, ) p Physics interest • provide information used in CKM angles  (2) and  (3) determination • extraction of angles suffers from hadronic uncertainties in the theoretical calculations • BFs give limits of these hadronic uncertainties • ACP used to establish the direct CP violation in SM or indicate New Physics Liliana Teodorescu

  8. B -> (1) p p B ->+- b->u tree dominated +- 78fb-1 82fb-1 signal B ->+0 b->u tree dominated BF (10-6) 15fb-1 B ->00 4.2 140fb-1 3.4 142fb-1 • contributions from color-suppressed • tree and gluonic penguin amplitudes • theoretical predictions: BF < 1·10-6 • observation of significant signal Liliana Teodorescu

  9. B -> (2) p p BF’s ratios PR D65, 013004, 2002 • expectations • significant penguin contribution to +- mode => penguin pollution • complicates the extraction of  (2) from time-dependent CP asymmetries CP Asymmetries Preliminary 82fb-1 140fb-1 Direct CP violation in B0 -> + - Obsevation (in time-dependent analysis) Do not observe CP violation 140fb-1 PRL, hep-ex/0401029 (time-dependent analysis) Cross check time-integrated asymmetry Liliana Teodorescu

  10. B -> K (1) p • b->u tree and b->s penguin transitions • penguin amplitude dominates 82fb-1 B ->K+ • no b->u transition, only b->s penguin trans. • good case to determine penguin’s contrib. B ->K0+ B ->K00 • dominated by color suppressed tree BF (10-6) 82fb-1 78fb-1 15fb-1 Significant penguin contribution isospin relations the 3 ratios = 1 Liliana Teodorescu

  11. B -> K (2) and B -> K K p CP Asymmetries B ->K • could be significant due to interference between T and P amplitudes Preliminary • no evidence of direct CP violation in K decay modes B ->KK BFs • give information about the rescattering processes (FSI) • rescattering can modify BF and ACP for   and K modes • KK more sensitive to rescattering effects 82fb-1 BF (10-6) 140fb-1 9.13fb-1 • BF limits in agreement with pQCD predictions (PR D63, 014003 (2000)) • no evidence of rescattering yet Liliana Teodorescu

  12. B ->( ´)(K,K *, ) h,h r,p Physics interest • provide information for understanding the relative contribution of tree and penguin amplitudes in B decays • have potential for establishing the direct CP violation Liliana Teodorescu

  13. B ->( ´)(K,K *) h,h PL B254(1991)247 destructive interference and /’ mixing flavor-singlet (important for ´K*) CKM suppressed agreement with NLO QCD NP B651(2003)225 ACPexpected (20-40)% for the suppressed modes K0, K*0 modes - no external tree BF (10-6) Preliminary Belle: -0.020.070.01 Cleo: +0.030.120.02 Liliana Teodorescu

  14. B ->( ´)( ) h,h r,p CKM suppressed • Expectations: • BF’s: (0.1-1.0) 10-6 • ((’)+ the highest) • ACP: large for , small for  color suppressed hep-ph/0307395 ACP dominant 0, 0 modes - no external tree BF (10-6) Preliminary Liliana Teodorescu

  15. B -> h ( h = K, ) r p Physics interest • provide methods for extracting CKM angle  ( 2 ) e.g. decay amplitude isospin analysis of • decay amplitudes are extracted from BFs and ACP asymmetries • test the theoretical models with the BF’s ratio (large range of predictions) Liliana Teodorescu

  16. B-> 0 0 r p • needed for the isospin analysis for extraction using the decay modes: • give limits on the contribution of penguin ampl. • BF predictions around or below 10-6 signal cont.+ B bkg. cont. bkg. 140fb-1 hep-ex/0405068 Nsig=15.14.8 Sig. = 3.5 Evidence BF=(5.11.60.9)·10-6 • BF higher than the theoretical predictions • central value higher than BaBar limit 82fb-1 BF < 2.9·10-6 Some contributions to the decay ampl. higher than expected => isospin analysis more complicated Liliana Teodorescu

  17. B-> h (h=K, ) r p BF (10-6) 82fb-1 140 / 78fb-1 9.1fb-1 Theory BF’s ratio Babar • R  6 tree level estimates Z. Phys. C34, 103 (1987) • R  2-3 penguin, off-shell B* Excited states, scalar +- resonan. PRL 86,216 (2001), PR D66,034019(2002) Acp no evidence of direct CP violation Liliana Teodorescu

  18. B-> (h,h,w,f)(h,h,w,f) ´ ´ Physics interest • test of theoretical models – many different approaches • search for New Physics signature • suppressed amplitudes => BF ~ 10-6 or even less (e.g. BF(B->)~10-9) • model independent bound on PRD 68, 015004 (2003) S: time–dependent CP asymmetry parameter calculated with BF’s of If the experimental S much higher than this bound => New Physics Liliana Teodorescu

  19. B-> (h,h,w,f)(h,h,w,f) ´ ´ Sign. Babar82fb-1 Cleo3.1fb-1 hep-ex/0403046 Submited to PRL With the new BF values: HFAG average Scharmonium= 0.7360.049 S’Ks = 0.270.21 B0 ->  Liliana Teodorescu

  20. * B->VV (V =K, ) F,r Physics interest • angular distribution reflects strong and weak interaction dynamics • aditional observables for detecting direct CP violation or NP fL=L/  - longitudinal polarization fraction •  modes provides an alternative method for  measurement Liliana Teodorescu

  21. * * rr, rK, FK B-> B->K*- pure b->s P (unambiguous signiture for P) B->K*- dominant b->s P + b->u tree B->- b->u Tree and CKM suppressed b->d P (potential  measurement) BF (10-6) 82fb-1 78fb-1 9fb-1 ACP 82fb-1 78fb-1 ACP expectations K* :1% in SM, <30% with NP contribution K *: possible large (T–P interf.) +0: isospin-breaking processes (e.g. EW P)=> high CP asym. Liliana Teodorescu

  22. * * B-> rr, rK, FK Polarization Theory predictions – longitudinal polarization dominates in all modes Measurements - helicity angular distribution analysis - full 3-dim. angular analysis ( K*0 - Babar, Belle) fL 82fb-1 78fb-1 Less than expected!! As expected As expected B->K*NP in b->s penguin transition?(hep-ph/0310229) Liliana Teodorescu

  23. Conclusions • observation of B->00 BF = (1.90.5) 10-6(HFAG) • observation of direct CP violation in B-> +-(Belle) • no other evidence of direct CP violation • time-integrated CP asymmetries (Babar) need more data to establish a conclusion • evidence for B->00 , Sig. 3.5(Belle) BF higher than theoretical predictions • (Babar) • B-> fL 1 expected (Babar and Belle) B->K* fL<<1 not expected (Babar and Belle) time-integrated B factories are living interesting times. More interesting ones will come! Liliana Teodorescu

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