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Status of V ub from Belle

Status of V ub from Belle. Appetizer: W -annihilation modes with V ub vertex Entree: decay modes that we (can) use to measure V ub Dessert: to finish with something sweet. Youngjoon Kwon Yonsei University for the Belle collaboration. Course. * other triangles are difficult to measure.

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Status of V ub from Belle

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  1. Status of Vub from Belle • Appetizer: W-annihilation modes with Vub vertex • Entree: decay modes that we (can) use to measure Vub • Dessert: to finish with something sweet Youngjoon Kwon Yonsei University for the Belle collaboration Course ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  2. * other triangles are difficult to measure The Unitarity Trianlge ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  3. A W-annihilation decays with Vub vertex • The cleanest mode with Vub vertex is fully leptonic B decays • uncertainty in fB • BF is very small for (helicity suppression) • or experimentally very messy due to multiple neutrinos for • a good place to search for new physics ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  4. A Belle-CONF-0247 ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  5. A Belle-CONF-0247 Results Preliminary • Fitting pl distribution • no evidence of signals => 90% CL upper limits ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  6. u E0 Semileptonic B decays for Vub • Semileptonic B decays provide the best opportunity for measuring |Vub | - strong interaction effects are much simplified due to the two leptons in the final state ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  7. E1 Vub from • use detector hermeticity to “measure” undetected neutrino • the events should be consistent with • hermeticity assumption |Qtotal| < 2 ; only one ID’ed lepton ; • only one missing neutral particle = neutrino • attribute missing (E,p) to the neutrino ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  8. E1 ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  9. E1 Preliminary BF( ) & Vub (Khodjamirian et al.) PRD 62, 114002 (2000) ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  10. E1 q2 distribution of Bp l n preliminary Unfolding of true q2 distribution from observed distribution, by considering efficiency/smearing ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  11. E2 Belle-CONF-0242 ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  12. Excess in m(3p) after side-band subtraction = 59 15 events E2 Belle-CONF-0242 N(events) in the signal region with 0.76 < m(3p) < 0.81 MC est. ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  13. E2 Belle-CONF-0242 • Systematic uncertainties • background est. 18.0% • signal fitting 9.2% • MC statistics 5.1% • tracking 6.0% • photon-finding 4.0% • electron ID 3.0% • Total: 22.3% preliminary ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  14. E3 • Similar “neutrino reconstruction” using hermeticity • 2-dim. fit to DE vs. M(pp) ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  15. E3 • Tentatively, using ISGW2 for - efficiency, hence BF; and - Vub • Projections onto DE and M(pp) preliminary ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  16. D ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  17. D1 Belle-CONF-0248 preliminary We also have ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  18. D1 preliminary • Using PDG2002 for Vcb, ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  19. D2 Belle-CONF-0247 • back to W-annihilation decay with Vub vertex • same 3 Ds decay modes preliminary ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  20. preliminary Conclusion (1) ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  21. preliminary Conclusion (2) UKQCD Khodjamirian, et al. (LCSR) • From new measurement of and using factorization-based calculation ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  22. Backup slides

  23. The KEKB Collider • asymmetric energy e+ (3.5 GeV) e- (8 GeV) • design Luminosity = 1034 /cm2/s • E(cm) = 10.58 GeV on resonance of (4S) production ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

  24. The Belle detector ICHEP2002 Amsterdam 7/25/2002 Youngjoon Kwon (Yonsei Univ. /Belle)

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