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A.Drutskoy, University of Cincinnati

B decays to open and hidden charm at Belle. A.Drutskoy, University of Cincinnati. 32 nd International Conference on High Energy Physics. August 16-22, 2004, Beijing, China.

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A.Drutskoy, University of Cincinnati

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  1. B decays to open and hidden charm at Belle A.Drutskoy, University of Cincinnati 32nd International Conference on High Energy Physics August 16-22, 2004, Beijing, China A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  2. Outlook • Improved measurementofColor-suppresseddecays B ->D0p0 , D0 w , D0 h , Dh’. 0 (*) 0 - _ _ 0 2. Improved measurement of B -> D K and D p decays + + s s - _ _ + 0 3. Study of B -> D K and D p decays + sJ sJ 0 (*) 0 4. Study of B -> D p+p- decays 5. Study of B0-> J/Y p+p- decays A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  3. Full statistics at U(4S) ~250 fb-1 274 x106 BB pairs Partial statistics includes ~140 fb-1 or 152 x106 BB pairs A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  4. Procedures to extract B signal yield Two almost independent variables MB and DE can be used to select B meson signal: Shape of B signal, MC (example). * MB = (Ebeam)2 – (S Pi)2 DE = SEi - Ebeam * Methods to extract B signal yield: 1) Cut on MB and fit to DE 2) Cut on DE and fit to MB 3) Double dimensional fit to MB and DE distribution 4) If B->P1P2P3: cut DEand MB box and look at resonant structures in M(P1P2) mass distribution. A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  5. Color suppressed B-> D0p0, D0w,D0h decays Color suppressed diagram L=140 fb-1 D0->Kp Kppo Kppp BB and continuum backgrounds are studied and modeled in detail Branching fractions are larger than naïve factorization model predictions of ~0.5x10-4 A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  6. Color suppressed B-> D0h’, D*0h’ decays h’ghpp, h’grg L=140 fb-1 D*0h’ D0 h’ Color suppressed branching fractions measured by Belle collaboration are one-two sigma lower, than those obtained by BaBar. D*0 h’ D0 h’ Measured color suppressed branching fractions are larger than theoretically predicted within factorization model. u It indicates to significant contri- bution from final state interactions. Better understanding of that effect is important for some CPV measurements. A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  7. _ _ _ + 0 Study of B0 -> Ds K- and B -> Dsp+ W exchange diagram Final state interactions (FSI) b to u diagram with Ds DsK– final state has quark content completely different from initial B meson. Rather special diagrams (W exchange and Final state inter- actions) are used to describe this process. Within factorization approach Cabbibo-Kobayashi-Maskawa matrix element Vub can be obtained from ratio: Bf(B-> Dsp+) / Bf(B-> Ds D+) = (0.424+0.041) x |Vub/Vcb|2 - - Problem: factorization approach does not work well (FSI, next order corrections … ). Theoretical predictions vary in wide range from few units 10-6 to 10-4. A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  8. _ + - Improved measurement B0 -> DsK- and Dsp+ decays Full statistics 274x106 BB pairs Decay modes: Ds-> f p+, Ds-> K*0K+ and Ds-> KsK+ Double dimensional fit to DE and M(Ds) Measured branching fractions: Bf(B0-> Ds K-)= (2.93+0.55+0.79)x10-5 Bf(B0-> Dsp+)=(1.94+0.47+0.52)x10-5 _ + _ - Obtained results are consistent with previous Belle and BaBar measurements and have better accuracy. _ - B0->Dsp+ decay Bf agrees with expectation (if Vub is extracted from semileptonic decays) _ + B0->Ds K- decay Bf is larger than it was initially expected -> FSI contribution has been discussed. A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  9. _ _ + - B0-> DsJ K- and B0-> DsJp+ decays : retrospective Tree, 4-quark DsJ content W exchange diagram Final state interactions Narrow DsJ(2317) and DsJ(2460) resonances were recently observedate+e- collisions. Masses of these resonances are significantly smaller, than it is predicted in potential model, widths are consistent with zero in contrast to expectations. DsJ(2317) and DsJ(2460) mesons are selected to search for B->DsJ K and B>DsJp decays. Recently Belle and BaBar seen these DsJ mesons in B -> DsJ D decays with branching fractions of order of magnitude smaller than in B-> DsD decays with pseudoscalar Ds. Theory: branching fractions for B-> Ds(J) D (and also Ds(J)K , Ds(J)p) decays are expected to be similar for Ds(1968), Ds(2112), DsJ(2317) and DsJ(2460). Studies of B->DsJD, B->DsJK and B-> DsJp decays are important to understand nature of DsJ mesons (2-quark or 4-quark DsJ content ?). A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  10. _ _ + - First study of B0->DsJ K- and B0-> DsJp+ decays + + DsJ(2317)+ -> Ds p0 , DsJ(2460)+ -> Dsg 152 x106 BB pairs, L= 140fb-1 + Ds-> fp+, K*0K+, KSK+ 6.8 s DsJ(2317) K- DsJ(2317) K- DsJ(2317) p+ DsJ(2317) p+ DsJ(2460) K- DsJ(2460) K- DsJ(2460) p+ DsJ(2460) p+ A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  11. _ - + Study of B0->DsJ K- and DsJp+ decays Fit to mass difference DM = M(DsJ)-M(Ds) (mass and width are allowed to float): Data: DM(DsJ(2317))=(351.2+1.6) MeV/c2 MC: DM(DsJ(2317))=(348.5+0.3) MeV/c2 (2317.5) Resolution s: Data: s=(6.0+1.2)MeV/c2MC: s=(6.1+0.2)MeV/c2 Flat -> Jp=0+ Obtained branching fraction and upper limits: Bf(B0->DsJ(2317)+ K-) x Bf(DsJ(2317)+->Ds+p0) = (5.3+1.5+0.7+1.4)x10-5 -1.3 Measured B0-> DsJ(2317)+ K- branching fraction is of the same order as B0->D+s K- branching fraction and at least 2 times larger than one for B0->DsJ(2460)+K- decay (Bf(DsJ(2460)->Dsg)~30%) -> unexpected !!! A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  12. Study of B0 -> D(*)0p+p- decays In heavy quark limit, total angular momentum of light quark Jq is good quantum number. Charm meson spectroscopy provides good opportunity to test predictions obtained within HQET and QCD sum rules. - Previous Belle measurement of B -> D(*)+p-p- decays (PRD 69,112002,2004) demonstrated good agreement with theoretical expectations. A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  13. Study of B0 ->D(*)0p+p- decays L=140fb-1 D*0p+p- D0p+p- D0 -> Kp,->Kppp B decays are used to constrain D** resonance production. D0p+p- Fit includes simultaneously all known resonances with phases. D*0p+p- Two narrow D** resonances are seen. Agreement with previous B- ->D+p-p- decay studies and theory (excluding J=1/2 resonances branching fractions (next slide)). A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  14. Study of B0 -> D(*)0p+p- decays A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  15. Study of B0->J/Yp+p- decays L=140fb-1 r J/Y -> e+e- m+m- f2 Cut DE and MB signal box (B meson) and look at p+p- mass distribution: p+p- can be resonant (r, f2) or nonresonant. Five components assumed in p+p- mass spectra fit: 1). r 2). f2 3). non-resonant p+p- 4) KS0 background 5). combinatorial background Bf(B0 -> J/Yr0) = (2.8 + 0.3 + 0.2) x 10-5 Bf(B0 -> J/Y f2) = (9.7 + 3.9 + 1.9) x 10-6 (2.9s) <1.5x10-5 (90% C.L.) Bf(B0 -> J/Yp+p- (non-res) = < 1.2 x 10-5 (90% C.L.) A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

  16. Conclusions 1) New B decays with open and hidden charm have been observed and many improved measurements of B decay branching fractions have been obtained by Belle collaboration. Achieved accuracy of such BF measurements is around 10-5. • 2) New measurements: • B0 -> DsJ(2317)+ K- -> first observation, large BF ! • Upper limits are set for DsJ(2460)+ K- and DsJp+ decays. • B0 -> D**- p+ -> agreement with previous measurement, • except small BF of wide J=1/2 resonances. • B0 -> J/Y f2 -> first evidence (weak). _ - • 3) BF measured with improved accuracy: • B0 -> D0(*)p0 (/w/h/h’) -> color-suppressed modes. • B0 -> DsK- and B0 -> Dsp+ -> rare decays. • B0 -> J/Yr -> improved accuracy (color suppressed). _ _ + - 4) Obtained results provide good opportunity to test theoretical models applied to describe B decays, it’s important for future CP studies. A. Drutskoy 32nd Int’l Conference on High Energy Physics August 16-22, 2004, Beijing

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