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23, June, 2005Beauty2005, Assisi, Italy Electroweak Penguin decays at Belle Akimasa Ishikawa KEK.

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Presentation on theme: "23, June, 2005Beauty2005, Assisi, Italy Electroweak Penguin decays at Belle Akimasa Ishikawa KEK."— Presentation transcript:

1 23, June, 2005Beauty2005, Assisi, Italy Electroweak Penguin decays at Belle Akimasa Ishikawa KEK

2 Flavor Changing Neutral Current Decays Flavor Changing Neutral Current decays, b  s , b  sll  Forbidden at tree level  induced through Penguin or Box diagrams at lowest order  sensitive to heavy particles (SUSY, heavy Higgs) Observables  Decay Width (Branching Fraction) Inclusive decay, theoretically clean, experimentally hard. Exclusive decays, large uncertainty due to form factor   test of QCD in B decays  Ratio of Decay Width Some theoretical and experimental uncertainties cancel Good probe also for exclusive decays!  CP Asymmetry  Isospin Asymmetry  Up-Down Asymmetry  BF ratio of electron mode to muon mode  Forward-Backward Asymmetry Penguin diagram in the SM Beyond the SM diagram

3 OPE and Wilson Coefficient Effective Hamiltonian is expressed in term of Operator Product Expansion.  O 1,2 : current current operator  O 3-6 : QCD penguin operator  O 7,8 : electro- and chromo-magnetic operator  O 9,10 : semileptonic operator  C i : Wilson coefficient Wilson coefficient is a strength of corresponding short distance operator. Precise measurement of Wilson coefficients is one of the goals for B physics. For b  s  and b  ll case, only O 7, O 9 and O 10 appear in the Hamiltonian. New Physics changes the Wilson Coefficients

4 b  s  and b  sll decays can be extracted from B(b  s  ), B(b  sl  l  ) and A FB (b  sl  l  ) ! Decay widths for b  s  and b  sll can be described with Wilson coefficients.  Absolute value of can be measured. Interference terms (sometimes we do not use C i but A i which is leading coefficient)  Relative signs can be also determined from interference terms!! In the SM

5 Branching Fraction of B  K*  b  s  was observed at CLEO in K*  K* is reconstructed from 4 modes  K +  -, K s  0, K +  0, K s  +  |M K*  M K  | < 75MeV Better than 10% accurary! Theoretical preduction  QCD fact. (70  25)  10 -6  LEET (68  23)  10 -6  pQCD (35  10)  10 -6  Lattice (35  16)  10 -6 B(B 0  K *0  ) = (40.9  2.1  1.9)  10 -6 B(B +  K *+  ) = (44.0  3.3  2.4)  10 -6 Theoretical uncertainties are large 80/fb data K* K 2 *(1430)

6 Asymmetry in B  K*  Isospin Asymmetry  0+ is sensitive to sign of Wilson coefficients C 6 /C 7  0+ = +5~10% and C 6 /C 7 >0 in the SM If C 6 /C 7 <0,  0+ <0. Direct CPV is less than 1% in the SM 5% CPV is allowed in new physics A CP = (-0.1  4.4  0.8)%  0+ = (+3.4  4.4(stat)  2.6(syst)  2.5(f +- /f 00 ))% B0B0 B0B0 A.Kagan and M.Neubert, PLB 539, 227 (2002)

7 Time dependent CPV in B  K s  0  Not only the K* 0 , but any K s  0  can be used for TCPV measurement. In the SM, S<0.1, A<0.01. Right handed currents induce large value of S  S corresponds to fraction of C 7R to C 7L M Ks  < 1.8GeV 250/fb data K* K 2 *(1430) Atwood, Gershon, Hazumi, Soni PRD71 (2005) 076003 First Measurement

8 Observation of B  K  K s  can be used for time dep. CPV measurement to search for right handed currents. B  K + , K s    is reconstructed from  and  0  M K  < 2.4GeV First Observation 250/fb data B0B0 B0B0

9 Observation of B  K 1 (1270)  B  K    final state via K 1  can be used for up-down Asymmetry to search for right handed currents.  K 1 (1270) is reconstructed from K +  +  - and K s  +  -.  0.6< M  < 0.9GeV (  mass region) to enhance K 1 (1270)  Resonance components are extracted by fitting to the hadronic mass distribution. First Observation 140/fb data M.Gronau et al. PRL88 051802 (2002)

10 Observation of B   p  Baryon production via weak decay of meson Near threshold enhancement of di- baryon system is observed in B  p  (b  s process) Near threshold enhancement also observed  Fragmentation? First Observation 140/fb data Theoretical prediction ~10 -6

11 Inclusive B  X s  Full inclusive b   Photon with E>1.8GeV Veto photons from  0 and  Subtract continuum with off-resonance data Moment analysis to extract HQET parameter = 2.289 ± 0.026 ± 0.035 GeV - 2 = 0.0311 ± 0.0073 ± 0.0063 GeV 140/fb data  HQET parameter used to extract V cb and V ub

12 BF of Inclusive B  X s  Subtract b  d  assuming B(b  d  )/B(b  s  ) = 3.8 ± 0.6% Measured BF is consistent with theoretical predictions.  M H+ >200GeV 95%CL (M.Neubert CKM2005) Limit on Wilson coefficient A 7  -0.36 < A 7 < -0.17 or 0.21< A 7 < 0.42  In the SM A 7 = -0.33 at  = 2.5GeV G.Hiller and F.Krueger PRD 69 (2004) 074020

13 Exclusive B  X s  / Inclusive b  s 40% of b  s  are measured exclusively. Next step : B 0  K 0 S 0  for TCPV analysis.  K  ’, Kf 0, Ka 0 ….. K* K 1 (1270) K 2 *(1420) K*  KK KK KK pp 59 ±6.0% missing Isospin symmetry for B and K* decay is assumed

14 Search for B   b  d  process has not been observed Simultaneous fit to B -   - , B 0   0  and B 0   From isospin relations: constrain |V td /V ts | B(B -   -  ) = 2 (  (B - )/  (B 0 ))  B(B 0   0  ) = 2 (  (B - )/  (B 0 )) B(B 0   ) B(B  ( ,  )  ) = B(B   -  ) < 1.4  10 -6 250/fb data SM predictions: B(B -   -  ) = (0.90 ± 0.34)  10 -6 (Ali-Parkhomenko) B(B -   -  ) = (1.50 ± 0.50)  10 -6 (Bosch-Buchalla)  R : form factor ratio  : SU(3) breaking effect Just above the SM prediction!!

15 Inclusive B  X s ll Semi-inclusive technique Electron or muon pair  M ll >0.2GeV  Charmonium veto Xs is reconstructed from K + or K s + 0-4  (at most one  0 is allowed)  M Xs < 2.0 GeV 140/fb data Theoretical preduction by Ali et al. Wrong flavor M Xs q2q2

16 Limit on Wilson Coefficients Clean prediction of BF of B(B  X s ll) for 1(2m  ) 2 4.11±1.15.6±2.04.5±1.04.4±0.78.8±0.7 1 { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/13/3599120/slides/slide_16.jpg", "name": "Limit on Wilson Coefficients Clean prediction of BF of B(B  X s ll) for 1(2m  ) 2 4.11±1.15.6±2.04.5±1.04.4±0.78.8±0.7 1

17 Branching Fraction of B  K ( * ) ll K +, K s or K*(K +  -, K s  +, K +  0 ) + e + e - or  +  -  M ll >0.14GeV A ratio of BF of K ( * )  to K ( * ) ee is sensitive to neutral heavy Higgs in 2HDM with large tan . In the SM, the ratio is 1.00 and ~0.75 for Kll and K*ll 250/fb data Prediction by Ali et al. Y. Wang and D. Atwood PRD68 (2003) 094016 G.Hiller and F.Krueger PRD 69 (2004) 074020

18 First look at A FB in K*ll Sign of C 7 C 10 can be determined from Forward- Backward Asymmetry in K*ll. Raw A FB in each q 2 region is extracted from M bc fit. Kll has no asymmetry, so it is a good control sample. Curves show theoretical distributions including experimental efficiency effect (not fitted lines! ). Both curves are in agreement with data, so far. A FB K* l  l  Ali et al. Phys.Rev. D61 (2000) 074024 SM q2q2

19 Summary Many results for BF are consistent with the SM  Precision of BF(b  s  ) is 15% level. Negative A 7 solution is consistent with the SM A 7 value  Upper limit on B(B  (  )  ) is just above the predictions Constrain |V td /V ts |  Improved measurement of inclusive B  Xsll decay Sign of C 7 flipped case with SM C 9 and C 10 values is unlikely stringent limits on C 9 and C 10 Many measurements of Ratio  Precisions of  0+ (B  K*  ) are 5% level Towards sign of (C 6 /C 7 ).  Time dep. CPV in B  K s  0  is measured for the first time Search for right handed component in C 7  First look at Forward-Backward Asymmetry in B  K*ll Will be used for measurement of A 9 and A 10 New results will be presented at Lepton Photon 05. Stay tuned

20 Backup Slides

21 A FB at Super Belle 1 year running at 5x10 35 /nb/sec  5/ab integrated luminosity, 10 billion B mesons!!  We have accumulated ~0.46/ab, about x10  A 9 /A 9 ~11%,  A 10 /A 10 ~13%  A 7 fixed to SM value  systematic error is not included Belle Toy MC with 5/ab C 10 NP C 9 NP Donut : B(B  Xsll) with140/fb A FB K*ll with 5/ab


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