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Rare and Radiative B Decays

This paper presents recent measurements and constraints on rare and radiative B decays, including B -> Xsγ, B -> B+pΛγ, B -> Xsl+l-, and b -> dγ. The results are consistent with theoretical predictions and provide valuable information on Wilson coefficients and the determination of |Vtd/Vts|. The paper also highlights the significance of these measurements and the potential for further exploration in this area.

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Rare and Radiative B Decays

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  1. Rare and Radiative B Decays • Outline • Introduction • B → Xsγ moments • B → B+pΛγ • B → Xsl+l- • B → K*l+l- FB Asym. • b → dγ • Summary M.-Z. Wang (王名儒) on behalf of the Belle Collaboration ICFP2005

  2. C7,C9,C10 C7 Motivation and Review ICFP2005

  3. 1.6 229M BB Integrated Luminosity ICFP2005

  4. hep-ex/0508004, 88.9 MBB Eγ>1.9 GeV B → Xsγ from a sum of 38 exclusive decay modes ICFP2005

  5. B → Xsγmoments from measured spectrum Consistent with theory ICFP2005

  6. Inclusive B → Xsγand Acp hep-ex/0507001, 88.5 MBB Use lepton tagging consistent with zero ICFP2005

  7. 140fb-1 Eγspectrum of B → Xsγ ICFP2005

  8. Retrieving true moments from measurements ICFP2005

  9. Comparing with theory hep-ex/0508005 ICFP2005

  10. bsγMC +7.1- 6.6 +0.58- 0.53 140fb-1 B+pΛγ • PRL 95, 061802, 2005Simultaneous fit on BpΛγ and BpΣ0γSignal Yield for BpΛγ with MpΛ<2.4GeV/c2: 34.1 • Statistical Significance: 8.6σ • BF(BpΛγ ): 2.16 ± 0.20x10-6BF(BpΣ0γ):<4.6 x 10-6 pΛγSignal ICFP2005

  11. γ Photon energy and Angular distribution θx p Fit results in bins of cosθX with MpΛ<4.0GeV/c2 (Assuming XpΛ, calculated in X rest frame.) Λ Lab frame X frame qq background bsγMC Signal Yield Signal Yield ICFP2005

  12. B → K(*)l+l- hep-ex/0507009, 229 M BB Assuming charged equals to neutral and ICFP2005

  13. Decay width for bsl+l- decay Decay width for bsll can be described with Wilson coefficients. Interference term Sign of C7 flipped case SM T.Goto et al. PRD 55 4273 (1997) sign of C7 relative to C9 as well as absolute values |Ci| can be determined !! ICFP2005

  14. Measurement of B(BXsl+l-) M. Iwasaki et al. submitted to PRD, hep-ex/0503044 • Semi-inclusive technique • Xs is reconstructed from K+ or Ks + 0-4p (at most one p0 is allowed) • MXs < 2.0 GeV • Electron or muon pair • Mll>0.2GeV • Charmonium veto 140/fb data Wrong flavor MXs q2 Theoretical preduction by Ali et al. ICFP2005

  15. Constraints on Ci from B(BXsl+l-) P.Gambino, U.Haisch and M.Misiak PRL 94 061803 (2005) • Clean prediction for B(BXsll) with 1<q2<6GeV2is available. • Combine Belle and Babar results • Sign of C7 flipped case with SM C9 and C10 values is unlikely. Donut : 90% CL allowed region C10NP C10NP C7 = -C7SM C7SM C9NP ICFP2005

  16. New Measurement of AFB(q2) in K*ll • Forward-backward asymmetry is induced by interference btw virtual photon and Z0 contributions. • Relative signs and magnitudes of C7 to C10 and C9 to C10 can be determined from AFB(BK*ll)!! We do not use Ci but Ai which is leading coefficients. ICFP2005

  17. Signals for BK*l+l- hep-ex/0508009 • 357/fb data •  386x106 BB pairs • Electron or muon pair • Charmonium veto • K*(K+p-, Ksp+, K+p0) • |MKp– MK* | < 75MeV • Signal yield • K*ll 114  14, purity 44% • Null test sample • K+ll 96  12, purity 57% • K+ll has no asymmetry. ICFP2005

  18. Null test with K+ll Projection to AFB Fit results for ratios of Wilson coefficients Best fit for negative A7 (SM like) J/Y Y’ Unbinned fit projection SM Best fit for positive A7 (non-SM like) (This solution is also allowed) ICFP2005

  19. A10/A7 ＳＭ A9/A7 Confidence contours for Wilson Coef. • For any allowed A7, we obtain 95% CL • Sign of A9A10 is negative!! • Sign of A9A10 flipped case is excluded • The first and third quadrants • Sign of A7A10 is not determined yet. • The second and fourth quadrants SM fit result A9A10 sign flipped A7A10 sign flipped (to SM) Both A7A10 and A9A10 signs flipped ICFP2005

  20. Motivation for b → dγ Complementary to the Tevatron Bs mixing program ICFP2005

  21. Observation of b → dγ ICFP2005

  22. Combined fit results ICFP2005

  23. Constraints on |Vtd/Vts| ICFP2005

  24. Summary of B → Xsdγ • HFAG releases new world average after major international conference • Web Site: http://www.slac.stanford.edu/xorg/hfag/ ICFP2005

  25. Summary of B → Xsl+l- ICFP2005

  26. Summary • Radiative B decays are well established, more tests can be done with various aspects. • First determination of the Wilson coef. from B → K*l+l- (Xsl+l-) decays. • First observation of b → dγ. • Thanks to HFAG, one can have easy access to up-to-date information. • Looking forward to unexpected new physics with a much larger data set – Super KEKB-factory talk by M. Hazumi. ICFP2005

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