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Electroweak Penguin decays at Belle

Electroweak Penguin decays at Belle. Akimasa Ishikawa KEK. Flavor Changing Neutral Current Decays. Flavor Changing Neutral Current decays, b s g , bsll Forbidden at tree level induced through Penguin or Box diagrams at lowest order sensitive to heavy particles ( SUSY , heavy Higgs )

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Electroweak Penguin decays at Belle

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  1. Electroweak Penguin decays at Belle Akimasa Ishikawa KEK Beauty2005, Assisi, Italy

  2. Flavor Changing Neutral Current Decays • Flavor Changing Neutral Current decays, bsg, 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 Penguindiagram in the SM Beyond the SM diagram

  3. OPE and Wilson Coefficient • Effective Hamiltonian is expressed in term of Operator Product Expansion. • O1,2: current current operator • O3-6 : QCD penguin operator • O7,8 : electro- and chromo-magnetic operator • O9,10 : semileptonic operator • Ci : 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sg and bll case, only O7, O9 and O10appear in the Hamiltonian. New Physics changes the Wilson Coefficients

  4. bsg and bsll decays Decay widths for bsg and bsll can be described with Wilson coefficients.  Absolute value of can be measured. Interference terms Relative signs can be also determined from interference terms!! can be extracted from B(bsg), B(bsl+l-) and AFB (bsl+l-) ! (sometimes we do not use Ci but Ai which is leading coefficient) In the SM

  5. Branching Fraction of BK*g • bsgwas observed at CLEO in K*g • K* is reconstructed from 4 modes • K+p-, Ksp0,K+p0 , Ksp+ • |MK*- MKp | < 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(B0  K*0g) = (40.9  2.1  1.9) 10-6 B(B+ K*+g) = (44.0  3.3  2.4) 10-6 K* K2*(1430) Theoretical uncertainties are large 80/fb data

  6. Asymmetry in BK*g • Isospin Asymmetry D0+ is sensitive to sign of Wilson coefficients C6/C7 • D0+ = +5~10% and C6/C7 >0 in the SM • If C6/C7<0, D0+ <0. • Direct CPV is less than 1% in the SM • 5% CPV is allowed in new physics A.Kagan and M.Neubert, PLB 539, 227 (2002) B0 B0 D0+ = (+3.4  4.4(stat)  2.6(syst)  2.5(f+-/f00))% ACP = (-0.1  4.4  0.8)%

  7. Time dependent CPV in BKsp0g • Not only the K*0g, but any Ksp0g 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 C7R to C7L • MKsp0 < 1.8GeV Atwood, Gershon, Hazumi, Soni PRD71 (2005) 076003 First Measurement 250/fb data K* K2*(1430)

  8. Observation of BKhg First Observation • Kshg can be used for time dep. CPV measurement to search for right handed currents. • BK+hg, Kshg • h is reconstructed from gg and ppp0 • MKh < 2.4GeV B0 B0 250/fb data

  9. Observation of BK1(1270)g M.Gronau et al. PRL88 051802 (2002) • BKpp0g final state via K1g can be used for up-down Asymmetry to search for right handed currents. • K1(1270) is reconstructed from K+p+p- and Ksp+p-. • 0.6< Mpp < 0.9GeV (r mass region) to enhance K1(1270) • Resonance components are extracted by fitting to the hadronic mass distribution. First Observation 140/fb data

  10. Observation of BpLg • Baryon production via weak decay of meson • Near threshold enhancement of di-baryon system is observed in BpLp (bs process) • Near threshold enhancement also observed • Fragmentation? First Observation Theoretical prediction ~10-6 140/fb data

  11. Inclusive BXsg • Full inclusive bg • Photon with E>1.8GeV • Veto photons from p0 and h • Subtract continuum with off-resonance data • Moment analysis to extract HQET parameter <Eg> = 2.289 ± 0.026 ± 0.035 GeV <Eg2> - <Eg>2= 0.0311 ± 0.0073 ± 0.0063 GeV • HQET parameter used to extract Vcb and Vub 140/fb data

  12. BF of Inclusive BXsg • Subtract bdg assuming B(bdg)/B(bsg) = 3.8 ± 0.6% • Measured BF is consistent with theoretical predictions. • MH+ >200GeV 95%CL (M.Neubert CKM2005) • Limit on Wilson coefficient A7 • -0.36 < A7 < -0.17 or 0.21< A7 < 0.42 • In the SM A7 = -0.33 at m = 2.5GeV G.Hiller and F.Krueger PRD 69 (2004) 074020

  13. Exclusive BXsg / Inclusive bs K* • 40% of bsg are measured exclusively. • Next step : B0K0S0g for TCPV analysis. • Kh’, Kf0, Ka0….. K1(1270) 59 ±6.0% missing K2*(1420) Isospin symmetry for B and K* decay is assumed K*p Kr Kh Kf Lp

  14. Search for Brg wg • bdg process has not been observed • Simultaneous fit to B-r-g, B0r0g and B0wg • From isospin relations: • constrain |Vtd/Vts| B(B-r-g) = 2 (t(B-)/t(B0))  B(B0r0g) = 2 (t(B-)/t(B0)) B(B0wg) B(B(r,w)g) = B(Br-g) < 1.4  10-6 SM predictions: B(B-r-g) = (0.90 ± 0.34)  10-6 (Ali-Parkhomenko) B(B-r-g) = (1.50 ± 0.50)  10-6 (Bosch-Buchalla) Just above the SM prediction!! DR : form factor ratio z : SU(3) breaking effect 250/fb data

  15. Inclusive BXsll • Semi-inclusive technique • Electron or muon pair • Mll>0.2GeV • Charmonium veto • Xs is reconstructed from K+ or Ks + 0-4p (at most one p0 is allowed) • MXs < 2.0 GeV Wrong flavor MXs q2 Theoretical preduction by Ali et al. 140/fb data

  16. Limit on Wilson Coefficients P.Gambino, U.Haisch and M.Misiak PRL 94 061803 (2005) • Clean prediction of BF of B(BXsll) for 1<q2<6GeV2is available. • Combine Belle and Babar results • Sign of C7 flipped case with SM C9 and C10 value is unlikely. C10NP C10NP C7 = -C7SM C7SM q2 MXs C9NP

  17. Branching Fraction of BK(*) ll • K+, Ks or K*(K+p-, Ksp+, K+p0) + e+e- or m+m- • Mll>0.14GeV • A ratio of BF of K(*)mm to K(*)ee is sensitive to neutral heavy Higgs in 2HDM with large tanb. In the SM, the ratio is 1.00 and ~0.75 for Kll and K*ll Prediction by Ali et al. G.Hiller and F.Krueger PRD 69 (2004) 074020 250/fb data Y. Wang and D. Atwood PRD68 (2003) 094016

  18. First look at AFB in K*ll SM • Sign of C7C10 can be determined from Forward-Backward Asymmetry in K*ll. • Raw AFB in each q2 region is extracted from Mbc 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. AFB K* l+ l- q2 Ali et al. Phys.Rev. D61 (2000) 074024

  19. Summary • Many results for BF are consistent with the SM • Precision of BF(bsg) is 15% level. • Negative A7 solution is consistent with the SM A7 value • Upper limit on B(B(r,w)g) is just above the predictions • Constrain |Vtd/Vts| • Improved measurement of inclusive BXsll decay • Sign of C7 flipped case with SM C9 and C10 values is unlikely • stringent limits on C9 and C10 • Many measurements of Ratio • Precisions of D0+ (BK*g ) are 5% level • Towards sign of (C6/C7). • Time dep. CPV in BKsp0g is measured for the first time • Search for right handed component in C7 • First look at Forward-Backward Asymmetry in BK*ll • Will be used for measurement of A9 and A10 • New results will be presented at Lepton Photon 05. • Stay tuned

  20. Backup Slides

  21. AFB at Super Belle • 1 year running at 5x1035/nb/sec •  5/ab integrated luminosity, 10 billion B mesons!! • We have accumulated ~0.46/ab, about x10 • DA9/A9~11%, DA10/A10~13% • A7 fixed to SM value • systematic error is not included AFB K*ll with 5/ab Donut : B(BXsll) with140/fb C10NP Belle Toy MC with 5/ab C9NP

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